ocean yachts hull construction

Attainable Adventure Cruising

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• Hull Materials, Which Is Best?

As Phyllis and I think about what our next boat might look like, one of the primary decisions is hull material.

We have several chapters in this Online Book about the characteristics of the four general available options, steel, aluminum, wood and fibreglass (see Further Reading below), but that still leaves the question: Which is best, not just for Phyllis and me, but for you, too?

As usual, the answer is the oh so annoying: it depends on what we plan to do with the boat.

But what I can say, is that there are two materials that are pretty easy for Phyllis and me to drop from the hull materials prospect list. So let’s start with that, and then move on to the two left standing to pick a winner.

Hull Material We Won’t Consider

We will not even be looking at boats made of steel or wood—not quite true, we might consider a good wood epoxy saturation build—and that’s also our advice to most of you.

Why neither of those two materials? Both are intrinsically unstable. Or, to put it another way, no matter how well the boat is built, if left to their own devices, wood will rot and steel will turn into a pile of iron oxide.

OK, before you take me to the woodshed in the comments, let me make clear that I understand that good boats can be built of both wood and steel.

One of my good friends has a wooden boat that has given great service (including a bunch of ocean crossings) for decades, and will continue to do so for many more. But he built her himself, has cared for her meticulously, and has incredible skills. But I’m not Wilson (that’s his name) and, in all likelihood, neither are you.

The same applies to steel. If you built the boat yourself, or supervised every step of the build, and then cared for her yourself, it can work. Just look at the amazing voyages made by AAC contributor Trevor Robertson in Iron Bark .

But we are talking about second-hand boats for most of us, so steel and wood are out because it’s difficult to be reasonably sure in a pre-purchase survey on either material that something horrible is not going on deep within the structure. Something that, when discovered, can turn our new-to-us boat into a worthless pile of junk—we are talking the risk of serious wealth destruction here.

Still not convinced? Let’s dig deeper.

There’s another big problem with wood. If we find say a rotten stern post, or any other structural member after purchase, the skills and time to replace it are prodigious. Heck, just replacing a single plank in a way that will actually be watertight takes great skill and perseverance. Way beyond practical DIY for most of us. And I have seen professional replacement of just a few rotten members in a wooden boat cost over US$100,000.

What about steel? Well, on the positive side, repairs require less skill than wood. But the problem is it is very difficult to build a boat of steel under about 45 to 50 feet that will sail or motor well. The reason is that steel plating must be of a certain minimum thickness to be workable and not deform, regardless of boat size, so small steel boats are pretty much always too heavy, at least for the performance that Phyllis and I want.

And, finally, the maintenance of a steel boat is simply no fun—unless you have some perverted love of chipping rust and working with toxic chemicals—and to make that worse, any breach of the coating must be dealt with promptly and properly.

The bottom line is that I know a lot of people who own a steel boat, or have done so in the past, but I have never met anyone who has owned a second steel boat.

All that said, I guess purchasing a steel or wood boat with a history like those I mention above, from someone you really trust, would be OK—particularly if you make clear that if they have lied to you, you will hunt them down and… And the advantage of this course is that you can often get a lot of boat for very little money.

Hull Materials We Will Consider

Where does that leave Phyllis and me, and probably you, too? Yup, with fibreglass and aluminum. Both are intrinsically stable—assuming we don’t do something stupid, and, when built right, a hull of either does not deteriorate just because of the passage of time.

And both can be surveyed prior to purchase to make fairly sure (there is no certainty) that there is not something horrible lurking. Yes, I know there are many horror stories (I have one of my own) about fibreglass boats with hidden faults, but that’s a survey failure, not a material one. (More on how to avoid survey failures coming soon.)

So which is best, aluminum or fibreglass? Brace yourself. I’m going to do it to you again. It depends on what you want to do. Let’s look at each.

As a 30 year aluminum boat owner, I love the material. And if Phyllis and I were planning to go to seriously hazardous places (as we have in the past), aluminum would be our only choice.

But on the other hand, aluminum is a bitch to keep paint on, an expensive bitch. And, by the way, don’t think for a moment that leaving the hull bare solves that. Prepping and painting the deck and cabin of an aluminum boat to the yacht standard that many owners want and want to maintain, will, if done right by professionals, cost as much or more than painting an entire fibreglass boat.

The point being that if you are considering aluminum, you need to do as I do: take your glasses off when you see the paint bubbling. Or, better yet, seriously embrace the industrial look and have no paint on deck or hull, other than non-skid.

Also, although there is no question that most of the horror stories you hear about aluminum are just that—stories—the material does require caring for, including closely supervising anyone who works on the boat. Most boatyard professionals are dangerously ignorant about aluminum and many will make that worse by not appreciating their own ignorance.

So that leaves fibreglass. And for Phyllis and me, who now want a boat that we can safely leave unattended far from home—we are now part-time cruisers—that’s the way to go.

Also, as we age further, we will be paying boatyards to do more and more for us, another plus for fibreglass, since it’s more resistant to unsupervised ignorance—boats with core in the hull, particularly balsa, not so much—than aluminum.

Bottom line, if you are not willing to learn the basics of aluminum boat care and won’t be constantly present to rigorously enforce that knowledge on others, choose fibreglass. On the other hand, the good news is that said aluminum boat care is not hard, and not magic. See Further Reading for our complete guide.

I’m guessing that many of you steel boat owners are now seething and reaching for your keyboards to tear me a new one. Feel free to disagree and tell me why steel is great, but be realistic.

And please keep in mind that we have a lot of readers who do not have a lot of boat ownership experience. So if you blow sunshine about the issues with steel boats, particularly old steel boats, you may make yourself feel better, but you may also tip someone into a life altering decision with substantial negative consequences. Not something any of us need on our conscience.

Further Reading

• How to care for an aluminum boat in 27 easy steps.
• Much more on buying a boat .
• How to care for a cruising boat, once you have bought her.
• The engineering characteristics of hull materials.
• Impact resistance and why it matters .
• More on boats from Boreal .
• More on Ovnis .

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More Articles From Online Book: How To Buy a Cruising Boat:

• The Right Way to Buy a Boat…And The Wrong Way
• Is It a Need or a Want?
• Buying a Boat—A Different Way To Think About Price
• Buying a Cruising Boat—Five Tips for The Half-Assed Option
• Are Refits Worth It?
• Buying a Boat—Never Say Never
• Selecting The Right Hull Form
• Five Ways That Bad Boats Happen
• How Weight Affects Boat Performance and Motion Comfort
• Easily Driven Boats Are Better
• 12 Tips To Avoid Ruining Our Easily Driven Sailboat
• Learn From The Designers
• You May Need a Bigger Boat Than You Think
• Sail Area: Overlap, Multihulls, And Racing Rules
• 8 Tips For a Great Cruising Boat Interior Arrangement
• Of Cockpits, Wheelhouses And Engine Rooms
• Offshore Sailboat Keel Types
• Cockpits—Part 1, Safe and Seamanlike
• Cockpits—Part 2, Visibility and Ergonomics
• Offshore Sailboat Winches, Selection and Positioning
• Choosing a Cruising Boat—Shelter
• Choosing A Cruising Boat—Shade and Ventilation
• Pitfalls to Avoid When Buying a New Voyaging Boat
• Cyclical Loading: Why Offshore Sailing Is So Hard On A Boat
• Cycle Loading—8 Tips for Boat and Gear Purchases
• Characteristics of Boat Building Materials
• Impact Resistance—How Hull Materials Respond to Impacts
• Impact Resistance—Two Collision Scenarios
• The Five Things We Need to Check When Buying a Boat
• Six Warnings About Buying Fibreglass Boats
• Buying a Fibreglass Boat—Hiring a Surveyor and Managing the Survey
• What We Need to Know About Moisture Meters and Wet Fibreglass Laminate
• US$30,000 Starter Cruiser—Part 2, The Boat We Bought
• Q&A, What’s the Maximum Sailboat Size For a Couple?
• At What Age should You Stop Sailing And Buy a Motorboat?
• A Motorsailer For Offshore Voyaging?
• The Two Biggest Lies Yacht Brokers Tell

What are the hull and deck panel thicknesses on MC?

As I remember, hull 1/4 to 3/8 in the keel. deck 3/16″. That said just looking at plate thickness does not tell you a lot. For example MC is built with very closely spaced frames and stringers which add a lot of strength but less weight than heavier plate and fewer frames and stringers.

John, I hear your warnings about steel, and I know this might be a complicated route to go. My main reservations about fiberglass boats is that the majority of them come with external keels which is fine for me for a one or two weeks charter but something I absolutely do not want for my own future boat. Encapsulated keel structure (or welded on as with steel hulls), a deep V forefoot, and a rugged skegged rudder, are characteristics that can more often be found with steel hulls as with “plastics”. When going for my survey I plan to come with a fiber optic to inspect all those remote places, and would certainly rule out a boat where I would not have access to most if not all hull places. That said, if I were to buy now, my current favourite on the market is a fiberglass ketch 😉

I would not recommend discarding all external keel boats from your list. Yes, the modern trend to bolting through light skins and then using a glued in web to stiffen things up is intrinsically dangerous, but there are plenty of external ballast boats that are built properly.

And internal ballast is not without problems. Like with most things it all depends on the execution.

And there are good hull forms in GRP too. In fact, in my experience, a lot of steel boats are designed very poorly.

Anyway, I would not take on the risk and maintenance burden of a second hand steel boat for those reasons.

Agree with everything you say about steel boats. When I got back from Vietnam in 1969, I took all of my savings and bought a steel 45 steel schooner and lived on her. I went to work at the Naval base in Pensacola, FL and left my wife to chip, sand and paint the rust spots that seemingly appeared almost every day inside and outside ( no wonder she divorced me! ) I finally sold the boat to a “know it all” and bought a Hinckley 50 fiberglass yawl — problem solved!

Hi Patrick,

Thanks for the report. Another person who has owned one steel boat!

I totally agree with your conclusions on this. No material is perfect but fiberglass has a lot to be said for it overall and aluminum is great when a bit extra is required. Aluminum is actually the only material you have listed that I really don’t have much experience with beyond little skiffs so it is the one I can’t properly comment on but I like the concept.

I have had a lot of interactions with wooden boats including having a good sized one in the family and working aboard several. While I love these boats and think they look great, our boat is fiberglass and that is intentional. For that matter, our boat doesn’t have any wood on deck at all. With wooden boats, like most things, it really comes down to who the owner is. An owner who gets it and stays ahead of maintenance puts in surprisingly little time (still a whole lot) dealing with rot and paint that won’t stick. An owner who is a little less vigilant and deals with a deck leak by hanging a diaper under it rather than getting out their irons to fix it will find the boat falls apart on them incredibly quickly. In my experience which is all salt water based, deck leaks are the biggest killer of these boats by far and they are actually comparably one of the easiest to track down and fix. Even for an owner who farms out the wood work, I would say that if you can’t fix a deck leak and don’t have oodles of money, then it is a disaster waiting to happen.

With steel boats, all I have to say is that I hate the sound of a needle scaler. If you have a ton of money, there are great examples like the Columbia replica but that is not attainable for most of us.

I realize that there are a lot of people who get very nervous with keel bolts (and bolts in general in anchors and other things) and while it is something to watch, I think that it is a good trade-off given the other options. I think that a lot of the issue is that the average person does not know how to evaluate whether a bolted connection is a good connection and there have been an awful lot of poor connections built over the years. An example of a good connection is most connecting rod bolts which have enormous numbers of cycles, vibration and other factors to contend with but yet basically never fail unless there is another underlying issue such as the caps being mixed up. By getting the bolt stretch length long enough, using appropriate materials, having appropriate mating threads and using enough torque/tension, you end up with bolts that don’t back out and do not fatigue. Keels are a bit tricky as very few materials won’t suffer from some sort of corrosion if there is any water and fiberglass creeps so it is difficult to maintain constant tension but I think that you would find an extremely low failure rate on well designed connections and that most of the failures were on connections where an analysis would have shown that the margins were low and best design practices were not followed.

On wooden boats, although I have little first hand experience, as you say, and I see demonstrated by Wilson, a skilled and diligent wooden boat owner can make the maintenance look easy, but let a wooden boat get away from you and there will be tears.

On keel bolts, a question for you? If contemplating buying an old boat with external ballast, would it make sense to insist that before purchase the keel bolts (assuming accessibility) were torqued to the proper value for their material and size?

My thinking is that, assuming the construction and bolts were right when built, the biggest risk, particularly with SS bolts, is that they have wasted at the keel to deck joint due to water ingress, so if they withstand the appropriate torque without breaking we can be pretty sure that that they are not appreciably weakened. Does that make sense?

I would make no such assumption about the keel bolts. They may be seized, in which case you’ll see the correct reading on the torque wrench but the pre-load tension in the bolt will be wrong. They may also be partially corroded, in which case they may withstand the torque but still be capable of failing in tension if the boat were to, for example, ground on a reef.

If it’s possible to get at them to check their torque, it shouldn’t take much longer to completely remove the nuts, one at a time, to check the studs or the cavities for signs of corrosion before re-torquing them to the proper specs. If it’s not possible to do this, then it’ll be difficult for *any* non-destructive examination to reveal what you want to see.

Thanks for coming up on that. How about just loosening a half turn and then torquing to spec? What I’m trying to come up with here is a way to at least check for a really bad keel boat situation in a way that will be acceptable before purchase, and I fear that if we try and actually remove the nuts and backer plates the seller will reject the idea—just torquing the bolts is going to be a hard enough sell.

So, I get that the bolts may still be a long way from original after this test, but at least it will catch the ones that have corroded really badly. Also, I’m not sure that removing the nuts would tell us much since the bad bolts I have seen were corroded where the keel meets the hull, but would have looked fine from above, even with the nuts off.

Bottom line, I get that this is not a great solution, but my thinking is that it’s practical and a lot better than nothing. Would you agree?

Pull a few and inspect is probably the only real way to to be sure. At least this is done on a woodenboat.

Ignoring whether a seller will or should allow retorquing keel bolts, the theory is good but the practice is somewhat more problematic. Proof testing is a well established industry practice that has proven to be pretty effective. Periodic hydrotesting of pressure vessels such as boilers, tanks, etc is just one example of something that has been successful at eliminating a lot of dangerous failures.

The first practical issue is what torque do you apply. I design capital equipment not sailboats so don’t know exactly what is done as there are multiple schools of thought but if I were designing one of these joints, I would figure out my worst case loads, choose a preload of ~2X and then upsize the bolts from there a bunch to give a corrosion allowance but not increase the preload any more. The question is, what was done on the boat you are looking at. The average person does not have the knowledge to calculate what the maximum per bolt load is and then we don’t know the factors from there. I suspect that there are some boats out there where the torque value from the factory is 75% of yield just like most bolts are but I also suspect there are a lot of boats out there where the preload will be more on the order of 30% (I have it written down at home but I believe this is approximately what I calculated for ours with the assumptions I made). In the case where the designer did not leave a corrosion allowance, then a torque to 75% of yield is entirely appropriate but on other boats, you could break a bolt which while corroded was actually still well within allowable parameters or you could crush the laminate if there is insufficient load distribution for the higher tension. All of this can be calculated with fairly simple calculations but having anybody without training apply it is problematic and even then, you are really doing a proof test not just a retorque as you likely won’t know the original torque. If anyone knows of a standard that all designers hold to so a way to avoid the guessing game of the factory torque, I would love to know it.

The other practical issue that comes to mind is the imperfect relationship between torque and tension. Engineers refer to this relationship as K factor which is basically friction between the threads and the faces. When tension is really critical, the standard thing to do is to actually use oil or grease which are more repeatable and represent a lower K factor. If there has been any galling at all which is a real problem with stainless, all bets are off and you could even break the bolts before bottoming out if it is really bad. This is really the long way of saying that it is really inexact if you do it dry, you would really want to clean everything well and then oil the threads. Of course, if you are NASA, then you can actually measure tension on the bolts but everyone else is left using torque as a proxy.

Given all of this, I am not sure that most sellers could be made to agree to a specific torque number unless original build documentation can be found with a number which I don’t think that I have ever seen (unfortunate and kind of scary). Retorquing is definitely not a bad idea and I have done it on our boat, I just don’t know how to implement it simply and quickly unless someone knows that all keel bolts were originally torqued to some % of yield or something equivalent.

Hi Eric (and Matt),

Thanks for going to all the trouble to explain that. As so often happens, I’m a lot wiser after reading your and Matts thoughts. And clearly my idea is not a good one.

The sad part about that is that I think those of us considering an older boat may have a real problem that’s not generally recognized: Having wandered around boat yards a lot lately, I’m seeing a lot of otherwise good looking boats with stains indicating that water has penetrated between the keel and hull. I’m also guessing that a lot of boats for sale have had those stains covered up with paint.

Add in that many of those boats will have stainless steel keel bolts and I’m starting to think that the only good answer with a boat like that is going to be to drop the keel to check the bolts before heading offshore.

Of course we will not be allowed to do that before purchase, so that leaves walking away from a lot of good boats, or assume the risk. And the risk is not trivial. If the bolts are bad, replacement can be a serious matter. One experienced person at a quality builder said that the best and least expensive solution is to recast the keel with new bolts! The point being that most keels have J bolts cast in, and he said that hacking them out is a disaster—he has seen it tried.

So the more I think about this, the more I think that a lot of people who think they have refitted their boat for sea may in fact be sitting on a pretty nasty problem that would be hugely expensive to fix. And that as the years go by, this is only going to get worse. (A lot like the problems with SS in old rudders.)

I would really appreciate any other ideas of how to deal with this, or alternatively reassurance that I’m overthinking this. Also, do you think bronze keel bolts relieve at least some of this worry? With SS all I can think about is those bolts sitting in a wet oxygen deprived environment for 30-40 years! How about industrial x-ray? Expensive, I imagine, but probably a hell of a lot less than a keel bolt replacement.

John, you just elaborated very wisely the reasons why I will certainly not be looking for a boat with an external keel. You just can’t look inside (and I doubt even industrial xray could reliably see cast-in bolts). It is just like playing lottery, and what I learnt is at least that I will never win 😉 You’re right that encapsulated ballasts have their own issues, but at least they cannot fall off during a passage.

Your call, but what I’m finding is that there are so few really good boats out there for sale that even come close to my critical needs that to settle on a single keel construction type would limit my choices. This is particularly true since I want a boat with good performance, which is harder to do with an encapsulated keel, particularly in GRP.

Also, a boat with a bad encapsulated keel can be really bad. Think steel punchings in concrete. If that lot gets cooking and splits the outer sheath (I have seen 3 of these in the last month while wandering around boat yards) the repair would be way harder than new keel bolts. Just think about jack hammering out all that stuff!

Point being there are good boats built both ways, ditto bad boats.

Just to clarify, I was not asking about X-raying the bolts inside the lead. The problems I have seen are wasting in the hull to keel joint and a bit above. Seems like X-rays would pass through the GRP and show the bolt, but then again I have no clue, which is why I asked the engineers. As I remember Matt has worked on medical imaging equipment, so we may easily get a good answer.

Hi John, Your question highlights for me that another valid comparison (apart from hull material) might be long run production boats vs short run / custom boats. Long run production yachts of course favour fibreglass of course and tend to have more than a few things worked out over time – one of which is to make them as “charter friendly” (aka idiot proof), as possible. But am I right in my supposition that for this reason, most long run production boats will have steel keels, secured with stainless bolts tapped down into the metal keel? And short run designs (not generally being for charter markets) take advantage of the performance gain with lead keels, but have studs penetrating up through the hull, with securing nuts? Reading between the lines of Matt and Erics’ responses, it seems you must remove the keel to really check the studs on a lead keel and even then there could be something lurking deeper inside. Conversely, to check the keel bolts in a steel keel yacht, you could simply specify removing say 25% of the bolts at pre-purchase survey time. For total peace-of-mind, replacing all the keel bolts on our Beneteau 473 with original OEM bolts costs about $200 US, available ex-stock from the Beneteau Spares web-site (as are most other parts by the way, even now 15 years since launch). Now I get there are pro’s and cons of lead vs steel keels. But the simplicity and integrity of a steel keel is really hard to beat. I know of a Beneteau 473 that hit a rock doing 8-9 knots under motor, coming to a crash stop. The only damage the surveyor could find on the Monday (up on the hard) was a fleck of anti-foul chipped off. No gap in the hull joint, no weeping at the keel / hull join, no cracking in the anti-foul. Internally, no damage to the lay up or the supporting girders either. No harm, no foul as they say in America. So how about a long run production boat, John? br. Rob ps – no, it wasn’t our B473!

That’s a good point although I do wonder about the actual practicality of unscrewing a keel bolt that’s been imbedded in steel for years without it shearing off. I guess it would depend on how well the original builder had treated the bolt threads with an anti-seize of some type. As usual, we are at the mercy of the builder’s QC since one small mistake in construction can lead to a world of hurt 20 years later.

And good to hear that a Beneteau withstood a grounding so well. However, I would not want the impression left that this is always the case with boats from Beneteau since at least some of their later boats are built with a keel construction technique that is fundamentally dangerous, particularly after a grounding: https://www.morganscloud.com/2014/06/05/cheeki-rafiki-tragedy-time-for-changes/

I also need to point out that if the boat in question was built using the same methods as “Cheeki Rafike” there is no practical way to know for sure that she was not damaged.

(Both are conclusions from the report on “Cheeki Rafike” and engineering done my the Wolfson Unit at Southampton University. https://www.morganscloud.com/2015/06/25/cheeki-rafiki-report-misses-an-opportunity-to-make-boats-safer/

All that said, I have no problem with the idea of a production boat and have thought about several. In fact, as you say, there are a lot of advantages to one, particularly later in the series when the bugs have been worked out.

I think you could get pretty good contrast and detail of a set of keel bolts in cross-section via X-ray, given sufficiently high quality X-ray equipment. And if the X-ray crew has access to a megavoltage source like Co-60, you’ll be able to see the bolts cast into the lead quite clearly.

This is not going to be cheap, however. And whether it tells you anything useful will really depend on the exact design of that particular boat.

You could try ultrasound, but that’s highly dependent on the technician’s skill and on the access situation for that hull.

If stainless steel, or galvanized mild steel, bolts are cast into the keel (forming studs that protrude into the boat), and there’s evidence of water intrusion, then I think dropping the keel a few inches is the only reliable way to tell the extent of damage.

With lead keels, bronze bolts are definitely the correct choice; the bronze/lead combination is basically indestructible for more than the life of the hull.

Galvanized mild steel bolts with a cast iron keel also seem to be OK as long as the bolts are accessible for periodic replacement, and I’d definitely undo one or two to check during pre-purchase survey. Stainless makes me nervous. Bronze bolts with a cast-iron keel make me nervous.

Don Casey has a good article on assessing keel joint issues here: https://www.sailmagazine.com/diy/how-secure-is-your-keel

Thanks for that great information. Sounds like there’s nothing for it but to plan to drop the keel unless it’s bronze bolts into lead. Good to know what the reality is.

Thanks for linking to that article. I’m way better informed after reading it. Casey is the real deal.

Thanks for posting link to Don Casey’s article.

I was worried what you would ask what to do about it. Unfortunately, I don’t have great ideas beyond actually taking a look. I work on the design side of things and so don’t know a lot about non-destructive testing other than where I need to make allowances for it to be done (this is something that is definitely not done in the design of these joints). My experience with X-ray is limited to inspection of welds and castings and I am not sure how it would work on keel bolts so I can’t really add anything beyond what Matt said. I believe that there are also design solutions to make this a much smaller concern that could involve changing materials, designing to be inspectable, designing to be repairable (iron keels that are tapped and bolted from the top being an example), etc but that doesn’t deal with the already built boats.

In my case, there are a few things that made me feel comfortable with our boat. Looking at the ISAF statistics compiled in 2013, of 72 recorded keel failures, only 3 could be attributed to the bolts (important to note that 40 were undefined so the actual number could well be higher). Weld failures, and internal structure failures both had a more than double incidence ratio. I actually find this failure rate pretty low given the number of poorly designed (or designed with low margin for racing), poorly maintained and poorly repaired joints out there. Our boat has a pretty conservative keel attachment, the lever arm is small and the attachment is wide in both directions and the bolts are large. Given that, I calculated the required bolt strength and then looked at the bolt size on our boat and concluded that the designer had been appropriately conservative in upsizing to allow for corrosion. Next, our boat did not show any of the problem signs such as large rust streaks, signs of grounding damage, etc. Finally, I did exactly the test that you were hoping to do which is a torque test on all of these bolts (note, this and all the calculations were done post purchase) to values I calculated and felt comfortable with. Obviously this is not perfect but has mitigated the risk to a level where I feel there are other more important places to put my efforts.

Actually pulling the keel in a properly equipped yard is not that big of a deal, often on the order of what people spend on electronics for the boat. What becomes really problematic is if the bolts are found to be compromised to the point where they must be replaced. Given our location, I would contact Mars Metals if I ever got to this point. For people who do not live near a facility like this, it gets more tricky. I have limited experience installing bolts from the bottom of a keel and I could see it working in some instances but not all.

Thanks very much for expanding on that. Obviously it’s disappointing not to have a generally applicable risk reduction strategy. But then again, when did that every happen around boats!

The good thing is that I now understand the issues and how to reduce the risk to acceptable levels. One thing I would say is that I would need to think long and hard before buying a boat that say had tankage or mast step structure over the keel bolts since that can make the job of dropping the keel from, as you say, comparatively simple, to a much bigger job.

Hi John, thought I should address the keel questions for anyone considering a Beneteau cruiser and reading this. Cheeki Rafiki, was a Beneteau First designed primarily as a racer / cruiser. They have light hulls and rely on a structural liner for much of their hull rigidity, with bulkheads and “furniture” glued in. In the main, the boats are fit for purpose and they don’t have a history of losing their keels, even though there seems to be a serious question over the keel to hull design. I personally wouldn’t sail one offshore but would have no hesitation in owning one around the NZ coast, if I raced more.

The Beneteau Oceanis 473 was designed by Beneteau as their offshore model and as I have heard it told, the model was built to help alter their “bendy Beneteau” reputation. The Clipper Oceanis range (of which the 473 is one), are the last of the all hand laid fibreglass models before European regs changed to enforce epoxy, vacuum bagging and sandwich construction. The hulls were built super-thick of solid glass fibre and more so around the keels and other high stress areas. 473s then have massive supporting girders glassed into the bottom of the hull. The bulkheads are also glassed in not glued. The flanges of these girders are wide to improve the hull bonding and spread the keel load. Around the front and back of the keel area, the girders are only about 250 mm apart. The keel bolts go through both the girder flanges and the hull. Unlike the First, the 473 in particular has a much wider keel base and a double row of bolts (single row on the First). Comparing the two boats for offshore use, is like comparing a Toyota MR2 with a Toyota Land Cruiser – built for two very different things. My experience with owning a Beneteau is the QA processes were (are?) excellent, but I must add inspecting one or two bolts a year to my maintenance list. I haven’t so far because we run a dry bilge and the bolts are like new. And John, therein lies an opportunity for an astute buyer – there are gems in most production yacht manufacturer’s ranges, just as there are bad’uns. It is finding those good’uns that can pay off – the 473 is an absolute diamond. best regards Rob

Good to hear that the 473 has the bolts through the flanges and the grid glassed in. The key to the Cheeki Rafiki disaster is that she and her sisters had neither. Also, the report stated that other boats of her class had keel problems.

I wonder what Beneteau is doing these days with their newer boats.

Also it’s important to realize that Beneteau sold the class that Cheeki Rafiki was a member of as ocean capable. They make the same assertion for most of their current offerings.

Summary: any buyer needs to check to make sure the keel support structures are glassed in (not just glued) and that the bolts pass though the flanges, not just the hull skin. If they find this is not the case, run a mile.

And anyone considering buying any modern boat with a fin keel should read the Cheeki Rafiki report so at to know what to look for.

One more thought. Sorry to be such a pain in the ass on this. But one thing I have learned over the years running this site is that people skim (particularly the comments) not read carefully. They also tend the hear what they want to hear.

The point being that while I fully understand that you are not saying all Beneteaus have safe keels, just yours, I still need to jump in with the realities from the report.

Hi John, Why do sailboat keels smile? Because they are thinking about how much fun it would be to swim freely in the ocean like the dolphins, free of the heavy burden on their backs!

Of course we all know that GRP is forever. Even after you scrap the damn thing it’ll still be recognizable land fill or artificial reef for the next thousand years. Still there is one other material that deserve a passing derisive remark: Concrete. It’s a material used exclusively by amateur builders that never seems to survive the first owner.

Insurance company do not underwrite concrete boats in Canada. Not sure of USA. Since they need civil responsibility, place are limited for an owner. Altough it was a most decent material, well insulated, cheap, partially insulated.

Yes, we have friends with a concrete boat that has served them well. That said, I decided to leave the material out since good concrete boats are pretty rare.

For what it’s worth Joe Adams (the designer of our boat) had his first big success with the original Helsal that was a ferrocement boat. It smashed up records for the Sydney Hobart classic and was forever known as the ‘Flying Footpath’.

http://rolexsydneyhobart.com/news/2012/pre-race/helsal-tribute-to-joe-adams-in-rolex-sydney-hobart/

What a great name!

Ask any physicist about the stability of Aluminum alloy and they will say ; the aluminum stability derive from its oxyde layer which is the strongest material on earth after diamond. Thus any object built of aluminum alloy should make sure that oxyde layer is preserved. A simple piece of wood on an aluminum plate staying outside in the rain will get holed in a few months and will prove you that it can be attacked easily once the Al2O3 layer is depleted in oxygen poor environment. And aluminum is born of electricity and can be destroyed by electricity.

The ebook should have started with the french joke: Circumnavigators knows that 50 % of the boat going around the world have a metal hull, the remaining are US boats.

Each aluminum boat is a unique closed loop battery and had to be kept under cathodic state under all conditions. Some boat well builts have it naturally, some others don’t and with maintenance mistakes, this is were horror stories come from.

I am not found of polyester boats because the environnmental cost of getting rid of those tons of plastic polluants at the end of life have never been taken into consideration is the first price. Polyesther fiberglass is not recyclable. We are just pushing the problem forward to the next generations. One day not to far someone will wake up and put environnemental cost on the new GRP production boat and people will realise its not cheap.

Wood as said before, is only up to the maintenance made. My marina neighbor has a magnificient wood boat that he built himself, on the plan of Joshua. He told me last weekend, 6000 to built and 6000 hours to maintain since 30 years. A tribute to those brave men.

Steel… if only the genius of the french architects who recommended to build hulls in steel and the deck and infrastructure in stainless would have been more commonly communicated, we would have less steel boats relics today. 95 % of the paint maintenance of a steel boat is on the deck. A steel hull/stainless deck has about 1 hour of touch up maintenance every year (for all those logs and obstacles hit on the water)

Thus for metallic boats ultimately the material is not the problem, its the way it has been put together and maintained. A production aluminum sailboat could be the perfect boat for circumnavigators. For some specific usage, only steel can survive. This special boat is quite an achievement, almost 20 years in the polar sea: https://vagabond.fr/en/vagabond/

(Of course i am biased i have a year of mechanical engineering classes in material resistance and my full welding certification for both Aluminum alloys, Steel and 304 and 316 stainless on conventional SMAW and also on GMAW and GTAW.)

My experience over nearly 30 years is that the aluminium alloys used in boat building are a lot more durable than you indicate. For example my boat had teak decks and toe rails for the first 12 years of her life. And, despite the fact that water had got under the teak in many places and been there for years, we found only a little surface corrosion of no consequence when we removed the wood.

Yes, as I said in the article, it’s important to follow the rules with aluminium, but that’s far from rocket science and occasional mistakes do not result in a wrecked boat in a few weeks, as many will tell you.

Also the horror stories of wrecked aluminium boats are in my experience pretty much all of the “my cousin has a friend who knew someone who…” variety rather than reality. In fact I have yet to see an aluminium boat trashed by corrosion of any type and I have seen a bunch that have been horribly neglected.

I think the key point in all of this is that marine grade aluminium is far more durable that the grades most people have experience with in other uses.

And it’s also worth keeping in mind that aluminium has a higher strength to weight ratio than steel, so in fact a stronger boat can be built in aluminium on a practical bases. That said, aluminium is not as abrasion resistant as steel.

As to the environmental issues with GRP, I hear you but I don’t think it’s that simple. For example steel boats use a lot of really nasty coatings and insulation. Also those coatings must be renewed at a regular basis. And the making of both steel and aluminium plate have a pretty big environmental impact. Point being, it would take an in-depth study taking all these factors into account to determine which, over the life of the boat, inflicted the most environmental harm.

Hi John at the marina were my boat is (Québec city) we had to get rid of an old 30 feet fiberglass sailboat unused and leftover. The city environmental personnel came in and said we could not use the city garbage service and it had to be destroyed on site and buried in a special area (city owned) for about 100$ per ton. It ended up costing us 2000$ to get rid of this boat. If it would have been alu or steel people would have paid to pick it up.

If course Quebec is very serious with garbage and landfill management and not all jurisdictions are equal. But the trend has started here…

As for alu alloy indeed 5083 is a magic material if properly maintain. I did own a 34 feet powerboat for 6 years in my auxiliary coast guard previous life and there was a corrosion meter on the dash of it (silver anode isolated under water connected to the hull) and the owner book went to great lengths explaining the potential issue. At sea no problems because electrolytic voltage are low. But I had a AC current leak from the battery charger once and I noticed a month later(boat in water) tiny droplets of water appearing at the inside of the hull in the engine room just over the propeller. I wiped it everyday and when I hauled the boat out it could be seen from outside that the aluminum was severely pitted at 3 places… almost 1/8 depth. I had to replace and reweld the plate… it was full of tiny holes. I had magnesium anodes on the boat ant they were untouched. So it was galvanic corrosion at its worst. One season…

I agree it’s a worst case scenario but I was a first line witness of it. In this case the corrosion meter didn’t showed any problem although a problem was occurring.

Do you have a corrosion meter on MC?

This being said I would not be nervous of having another aluminum boat built of marine grade alloy by professionals- it’s is certainly the best boat material if properly built and maintained.

The meter you you had would not have warned you about that particular problem. Also, my guess is that the boat was not fitted with an isolation transformer, which is absolutely required for any aluminium boat plugged into shore power.

For a complete guide to aluminium boat ownership, including a gauge that would have warned you immediately about the current leak, see the links under further reading.

Having a strong electronic/electrical background like John, I’d like to reinforce his point on isolation transformers. It’s my view they should be mandatory on all metal boats, and considered highly desirable on all others. They serve at least three safety critical purposes:

1. The obvious one is that they isolate the ground loop to the shore power ground. Essential to prevent electrolysis and ensuring swimmer safety.

2. They provide inherent shore power reverse polarity protection. This is often an overlooked and not very well understood benefit.

3. The secondary of the transformer effectively becomes a ‘local power source’ and the neutral bonded to the boat hull ground. This provides a rock solid ground path for the boat that is independent of the shore power ground. This is essential to ensure any Earth Leakage/Residual Current Balance protection devices will work reliably. Depending on a shore ground loop that may have multiple cables and connectors, all subject to corrosion and miswiring, is a hidden and underestimated danger.

While the first attribute is highly relevant to metal boats, the second and third are common to all. Probably most boats don’t have an isolation transformer, and if they all were beautifully wired to a high standard it’s a compromise I’d be more sanguine about. But isolation transformers aren’t expensive in the wider scheme of things, and from an electrical perspective I regard them as the single most valuable investment you can make.

I agree. I would never own a metal boat without an isolation transformer, and would even seriously consider one for a GRP boat.

Hi John indeed it didn’t had an insulation transformer, and i took care of installing a Victron one on my steel sailboat. The anodes barely work on my boat i have the same since 2011 🙂

Andre, GRP is recycled in Europe and on an industrial scale. Additionally GRP boats are deposited in land fill, cut up, as it is considered inert. In the UK land fill sites are now sealed for future reclamation as well as the avoidance of leaching. Regarding recycling, it is not commercial for smaller batches but tends to be the waste streams from large GRP users. Alastair

Thanks Alastair for the information, Europe is in advance on us ! Indeed fiberglass is most inert … but 10 000 years later we don’t know… probably it would still be there !

You have [predictably] left out Ferro Cement – order should be (I owned a Ferro Cement yacht for many years so speak from experience)

Fibreglass Ferro Cement Aluminium

Although I have friends with a very good ferro cement boat I did not put it in because there are so few good FC boats available. Also, to say FC is “better” than aluminium is to ignore each materials characteristics. For example aluminium has a much higher strength to weight ratio and is far more ductile.

As my wife reminds me every time I look at a “beautiful” steel boat: “Rust never sleeps”

Donald that is also true for everything apart gold, platinum,titanium and a few other incorruptible elements.

We human live in the bottom of an air ocean and the O2 is a powerful oxydant. By chance is it diluted in nitrogen because otherwise we would have all burned including everything around.

Oh and that brings a point. A steel and férocement boat would survive a fire but others not. GRP is like a gallon of gasoline waiting for its match…

One of the secrets to a good life: marry a wise spouse.

I’ve had three steel cruising boats, two of which I’ve cruised extensively with. Each were bought used, 20 or more years after they were built. If I was in the market for another boat, I’d definitely consider a steel one.

Everything depends on how the boat was built and maintained.

My current steel boat was built very well, with no longitudinals to trap water, and–more importantly–flame-sprayed with zinc inside and out (properly-prepped & applied epoxy coatings can be almost as good as this). Rust is not a problem with this boat.

Yes, there are poorly built and/or maintained steel boats that will require a lot of work to go sailing (and may not be worth restoring). I think that holds true for any hull material–a couple of years ago I was offered a once-beautiful boat, professionally-built of fibreglass, effectively for free. I turned the offer down. The boat had been neglected, and while the solid fibreglass hull was undamaged, the plywood bulkheads and most of the interior had rotted due to water sitting inside the boat (it was left unattended in a boatyard for a few years).

A steel boat with: * properly-applied coatings, * easy access to most areas (to all areas would be best, but realistically, you’re unlikely to remove tanks to inspect the plating under them unless you suspect a problem), * few or no areas where water can sit, shouldn’t be a maintenance problem.

Everyone I’ve met with a stainless steel deck, as Andre mentioned above, has had good things to say about them (none of my boats had stainless steel decks, so I don’t speak from personal experience, here).

It is true (and important) that damaging the coating on a steel boat requires fixing it promptly (how promptly depends on temperature–corrosion happens very slowly below freezing). Zinc coatings on the steel have some advantage here (if underwater), as the zinc migrates to the bared area electrolyticly, but this is only for small scratches. POR-15 (buy some small cans before leaving North America, as it isn’t all that widely available), a coating developed for the antique car restoration market (which deals with thinner steel plate), makes maintenance painting of damaged areas much easier, since it doesn’t require sandblasting before applying.

>This is the reason that by far the majority of experienced high latitude sailors have aluminum boats. Are you sure of that? When I went thru the NW Passage, there were more steel boats than aluminum boats. In Antarctica, I don’t recall aluminum boats outnumbering steel boats. In Patagonia, I saw more fibreglass boats, and roughly equal numbers of steel and aluminum ones.

Steel probably isn’t suitable for you, because you are looking at buying a considerably smaller boat than the one you have. But for someone looking to cruise long distances, high latitudes and remote places, a used steel boat could be a good choice. It all depends on the construction and maintenance that has been done, and that’s something that mostly can be determined before buying.

Best regards, Richard

Hi Richard,

Thanks for a great report from someone who clearly knows. Clearly you are the exception to the second steel boat crack I made!

As to my assertion about high latitude sailors. No, I don’t know for sure, although it has been my experience, but of course that’s not definitive. One thing I have noticed is that several high latitude sailors with substantial steel experience ended up with aluminium. Skip Novak and Hamish Laird are two that come to mind.

One thing I would say is that I would have no worries about you buying another steel boat, but I don’t think that alters my concern about buyers without your experience taking one on.

Yes, two professional, high-latitude sailors, Skip Novak & Hamish Laird have moved to aluminum charter boats after extensive experience with steel ones. I think most people who own steel boats would consider or have considered aluminum boats.

I don’t think there is any definitive list of boat types that are out doing high-latitude cruising. Records are kept of vessels that go through the NW Passage. I did a quick search of the sailboats that went through the NW Passage in 2017. I counted 4 of aluminum, 4 of steel, 3 of fibreglass, 2 of wood, and 8 that I was unable to determine the construction of. Of the two sailboats that went thru in 2018, one was ferrocement, and I don’t know about the other one. The NW Passage is very much a high-latitude trip, and anyone who has gone through it has at least that much high-latitude experience (and, I would greatly hope, a lot more experience than that before they attempt it!). Those NW Passage numbers are pretty recent, and are in accordance with what I have observed while cruising. So I respectfully disagree with the statement, which the article puts in bold print, ‘by far the majority of experienced high latitude sailors have aluminum boats’.

Some people considering a metal boat will find themselves in the situation of feeling they can afford to buy a steel one, but can’t afford to buy an aluminum one, and see their choice being to own a steel boat or not own a boat. I would encourage people considering a steel boat to read books about them (‘Steel Away’ and Tom Colvin’s ‘Steel Boatbuilding’ were both of much use to me when I was a beginner), talk to people who’ve owned steel boats, and talk to boatbuilders, yards and surveyors that work with them. I don’t know of any particular site on the internet to recommend for information on steel boats.

I agree that steel boats are not for everyone, but disagree that they are only suitable for those who have owned them before–steel boats can be learned about.

I agree, a hard to define stat. I should have written something like “most of the high latitude boats I have encountered are aluminium” or some such.

That said, I still think that steel is a tough material to own, particularly for those new to boat ownership.

I changed the line in the post. Thanks.

Thanks, now we’re in agreement.

Jut some musings.

There is an aluminium boat from 1936 still floating around and the oldest aluminium boat builder started building aluminium hulls in 1898, Savage Aluminium Boats. I think there are GRP hulls from the early ’50s still pottering about today.

I read that a typical, modern 40’ish GRP yacht has around £5000 worth of materials to make it. Today we see new and old GRP yachts sailing around the globe frequently, managing the stresses and strains of the Souther Ocean and plenty of arctic and antarctic voyages. A colleague ran his Contessa 34 onto a boulder lee shore, F5, big damage, the boat dragged off and significant repairs; owner of a Sigma 41 ran into a rock and snapped the steel toe of the hull flange from the keel all theta through, as well as significant hull damage, I too rammed a ledge at spring tides at speed and busted GRP stringers etc, none of these yachts sank. One thing that GRP has going for it, is that it flexes considerably on impact before it yields, although the area will have been significantly stressed and weakened. The same for aluminium, recently at Ardfern Marina, a modern aluminium yacht was on the hard, after the owner ran her over rocks and bashed the hull significantly at the turn of the bilge, I guess the aluminium though would have maintained a lot of it’s strength. The skills were not available to fix and she was being prepared for road transport back to the builders yard in France when I saw the boat; GRP on the other hand can be fixed easier, I suggest. The point I wish to make, is that GRP is a strong material, it has resilience and a history of surviving neglect and abuse. This is what makes it a superior material in my opinion. Sailing is a minority pastime, the vast majority of participants will have reasonable funding and GRP has proved to be very cost effective and allowed some fantastic low cost, extreme voyages to be made by amateurs. I don’t particularly value steel or aluminium for their strength in hull choice as avoiding the sort of impacts that damage hulls should be the name of the game for any serious voyager. If one is in a situation that impact damage is happening, then it is luck that is stopping the hull from foundering. I think hull design with collision bulkheads and water tight compartments is more relevant for security against foundering than GRP v aluminium v steel. It is this sort of design feature that buys time and allows options to be worked. There are always exceptions of course.

John, I think your reasons for going GRP are very valid. I am a lazy hull cleaner, preferring to let the waves do the washing. But about every 3 years I polish and wax the hull and it comes up beautifully.

Hi Alastair,

Lot’s of interesting points. One thing I differ a bit on is GRP repair. Yes, you can repair a GRP boat easily, but, and it’s a big but, it’s very difficult to be sure that said repair is properly bonded, at least without using epoxy, which has its own difficulties. Secondary bonding is a far bigger problem is generally recognized. More in a future post.

Also, metal boats have another advantage, other than just strength, and that is it’s much easier to make them stiff, and that in turn makes it much easier to make them watertight for the long haul.

And finally, strength is very important in the high latitudes where, no matter how careful, sooner or later we will hit something, either ice or an uncharted rock.

In summary, having owned both for long periods, I don’t think that GRP is “better” than aluminium, just better for my needs going forward.

We chose steel because we saw the boat we purchased had been prepared properly and we were aware of the need for prompt maintenance. Everything in “adventure cruising” being a compromise, the key to happiness is, we feel, this awareness. We are a few weeks from leaving on what we hope will be a five-year circ with an emphasis on independence from the shore and the ability to do our own repairs save for major refitting. Few people get to do this, irrespective of hull material. The wisdom of our choice will soon reveal itself, one way or another. Now, if you’ll excuse me, I have to wire up a fridge compressor…

Hi John, A few vignettes;

Steel: Bernard Moitesser’s Joshua; Washed ashore in a hurricane in Cabo San Lucas– filled with sand. Given away to two guys walking on the beach. Pumped out and motorsailed all the way up to the Pacific Northwest where she became a dock mate to my Cape George 36. Every fiberglass boat that washed ashore on the same beach was cut up and hauled away.

Brewer Atlantic 45: Built by a well know Canadian yard. Sailed around the world and arrived in Trinidad with several overlaid hull patches. Spent a year being “completely” re-plated and re-decked while sitting outside as is the practice there. (and rusting all over again) Repainted and looked “smooth as glass.” Sold to a naive young couple who panicked the first time they hoisted sail. I was offered it for $15,000 and turned it down.

Classic 110 ft. Feadship In our yard for a complete restoration. Hull built with overlapping strakes — every overlap rusted out. Re-plated the majority of the hull, re-powered and restored interior to new. Fixable, but at tremendous cost.

John Guzzwell was one of the earliest pioneers of cold molded wood boat construction. I met him when he hauled his Laurent Giles ketch out in our interior storage area. It was built in the days before epoxy— he used resorcinal glue just like the Spruce Goose. Planking was mahogany rather than the more rot resistant Alaskan cedar. And the hull sheathing was Dynel in polyester resin. John spent the winter removing the old sheathing and replacing it with glass cloth and epoxy out of concern over moisture penetration from the resin. I made it a point to chat frequently to pick John’s brain and learn everything possible about cold molding. When he finished bringing “Treasure” back to bare wood there was only a small area of discolored wood— the planking was as sound as new and she was ready to receive her new modern sheathing.

I built my Cape George 36 deck without fasteners, epoxy bonded over an epoxy/glass base over Port Orford Cedar. Lived for 36 years outside with no covering and little care by multiple owners, but was still watertight and serviceable.

So yes, properly built wood boats can be durable.

At the same era the PT Shipwrights Co-op worked on a caravel planked boat that was built in 1898. She required a new stem timber and about 40% of the bow planking replaced. The repairs probably cost little more than all the Beneteaus that were being peeled and glassed under warranty at the same time.

So yes,traditional wood boats that have been properly built can be repaired over and over again so they last forever.

Fiberglass:

A J130 that has a perfect black paint job, new carbon sails, the latest electronics, and a custom $30,000 factory upgrade interior just sold for $15,000! Underwater delamination and extensive wet core. My proposal was to completely re manufacturer the hull bottom with epoxy resin infusion and close spaced foam/carbon ribs and stringers and no core. The end result would be the best J 130 in the world.. Some extensive rebuilds actually make sense!

And not all fiberglass boats last forever! Especially if they have a balsa core underwater.

All good examples that can teach us a lot. As you say, many of these problems can be solved. But, at least to me, the key take away from all those stories is that the fixes take huge expertise and if done wrong the result can be huge wealth destruction. Bottom line, I would have no worries about you taking on any of the above situations, but for the average person my advice would be “not a good idea”.

Hi John My little stories weren’t chosen as examples of good projects for do-it-yourself dreamers! What I was trying to illustrate is that good (and bad) boats can be built of all materials. I could have included an aluminum Italian motor yacht with black AC current “peppercorns” in the hull that you could push a screwdriver through, or a 90′ fiberglass motor yacht where the underwater exhaust outlets had burned all the resin completely away from the adjoining area and was a single wave away from sinking.

The skill level required to undertake repairs runs the entire range:

John Guzzwell’s 24 year preventive maintenance project required a strong back and weeks of work with a heat gun and scraper, but technically anybody could learn how to do it with a couple of weeks of practice. The guys who nursed the battered Joshua up the Pacific coast were adventurers, not shipwrights. Hundreds of graduates of wooden boat schools know how to re-plank a traditional wood boat– that skill has not entirely disappeared. A teak deck originally built like my Cape George only takes a day with a grinder to be ready to be glassed over, unlike the can of worms in a screw fastened fiberglass, aluminum, or (heaven forbid) steel boat teak deck.

On the other hand, the hull rebuild I suggested for the J 130 is probably more technical than building an entirely new boat and requires engineering and solutions not found in the typical professional boat yard.

All in all, i am not sure the hull material is a strong discriminating factor in a purchase. If i my boat would be lost and have to shop for another one, the first criteria for me would be a metallic hull. Because it is a metallic hull it can have also a safe swing keel and a flat bottom to go on the beach or where there is tides. Shopping for a boat is a matter of luck for the availability of what we want. And age is important also. i have 58 and plan to use my boat for another 20 years if God helps. But suppose my boat would be lost and i would be 70 – knowing that in 6 to 8 years the boat will have to be sold back would mean a very important criterion would be to be able to sell the boat rapidly and profitably. For this reason i would opt for a good aluminium sailboat or if a catamaran then GRP. Not because technically they are better (in my humble opinion) but rather because its easy to sell. I thinks its also the thinking of many prospective buyers….

I submit that it is possible to find a world cruising sailboat for under $100K that is not a project boat: http://www.cruisersforum.com/forums/f152/aluminum-30-ted-brewer-cutter-for-sale-202692.html This is also a not too subtle plug for checking out Cruisers Forum when researching said topics. Full disclosure, this has been my beloved boat for nine years, and AAC is the first site I recommend to not only aluminum hull boaters, but every boater. Thanks John, Phyllis and crew

She certainly looks to fit the specification and supports the my thinking that when constrained by that budget the best alternative is to go a bit smaller than the 40′ that seems to be the new “standard”. Better a smaller good boat than a bigger crap boat.

And thanks very much for the kind words.

Also, if you feel like sharing, it would be interesting to know what comes next for you after she sells?

Hello John, I guess I’d like to also throw in my little “grain of salt”. I am one of those “idiots” who is on to his second steel boat…The first one, a 1975 van de Stadt ketch, I spent 10 years rebuilding, while living on board and working full time, in the heat and humidity of the Florida Gulf coast. I never finished! However, my second boat, a one-off Treworgy 38 built in 1995, is of a combination you haven’t mentioned, but which is used in a large proportion of the luxury mega-yachts, as well as military and work ships: Steel hull and aluminium deck and superstructure. They are built using a flatbar, called a Datacouple, that has one side of steel imploded onto the other side of aluminium. This is welded to the steel hull and the aluminium deck, and the junction being a very fine micro-line, presents absolutely no electrolytic corrosion problem whatsoever, is 100% watertight, maintenance free, and very strong. It allows the eternal problem of maintaining steel horizontal surfaces to disappear, and lowers the weight topsides. Isolation transformers: Obviously a must, although most GRP boats can get away with a galvanic isolator. One thing to be careful of: The Marinco deck receptacles for the AC connection, as they come out of the box, have a small chromed metallic jumper that connects the ground terminal with the casing. Pleas make sure this is removed! Last but not least, no one has mentioned lightning! With 20 years working professionally on boats in the Tampa Bay area, which is also know as the lightning capital of the US, I can assure you that when you are living aboard full time, and have these daily and very scary lightning storms pass right over you, such that you know is a lottery and at any moment one of those blasts will be right on top of you, having a metal boat is a big reassurance. It won’t keep equipment from being damaged, but it will certainly keep you from being damaged if inside the boat. Very cozy! Best regards and thanks for the great website. Jonathan

Hi Jonathan,

Yes, I have a friend with a boat with a steel hull and aluminium deck, who is, or was (we have lost touch) happy with the boat. That said, I personally would prefer to go all aluminium if considering another metal boat. And yes, I agree that metal is really nice when the flashing and banging starts.

I agree, a really good paints system goes a long way on steel. (On aluminium its just cosmetic.) That said, getting to that point on steel is seriously hard: https://www.morganscloud.com/2012/02/16/why-not-steel-part1/

And, judging from what I see out there on the water, a paint system that good is not that common.

Dear John your comment is not scientific… the sample of steel boats you might have seen doesn’t necessarily represent the reality. We should not compare amateur built steel boat versus commercial built aluminum boats.

When I built my boat I visited a professional alu boatbuilder who had learned in French yards his skills. Although I had welding skills I find out that I was not capable of building correctly without experience a first aluminum boat. I turned to steel with the compromise of a stainless steel deck and superstructure and using commercial Amercoat primers and finishing paints + a certified paint inspector. The sandblast + paint costed me 18000$ CAD in 2008 which account to approximately 3 % of the total cost of the boat.

And frankly unless the builder as in your example as strictly adhered to products and applications guides an as proof or it we should not even consider it in a fair comparison.

This being said, almost all semi professional and professional yards have turned to aluminum in the last 20 years.

In the commercial world, steel boats, freighters, petrol carriers, liners etc.. all got a paint system valid for their 50 years of life. We don’t have the number but I guess that if we count all the ships in the world the number of square feet built of aluminum would be less than 0.01% (probably even less) of the worldwide commercial fleet.

Demonstrated valid protection system exist for steel immersed in sea water with 50+years of useful life.

Conclusions: 1-We should compare apples to apples in our discussion otherwise we get lost in armchair stories.

2-Shopping for an amateur built steelboat should involve much more scrutiny than a professional made steel or aluminum boat.

I never claimed it was scientific, that why I said “judging from what I see”.

Yup, Colin did a great job on that piece. As you say, they did a great job on the boat. That said,I would not class it as “over and above” but rather the minimum required to be a happy steel boat owner, and that in turn is why I don’t recommend second had steel boats. Just easier for most of us to own GRP or aluminium.

Hi John Judging from what I’ve seen, a really good paint job on an aluminum boat is not that common either! The difference with steel construction is that the most important area for protection is on the inside where perfection is the hardest to achieve and recoating is difficult or impossible. Thats’ why steel boats rust out from the inside. And why there are so many home built rust buckets.

re aluminum boat structures: As you mentioned in an earlier comment, an aluminum design with multiple frames and stringers covered by relatively thin plate like MC and aluminum race boats is stiffer per pound than one with thick plate. However I’ve never seen that method of construction result in a surface with so little distortion that it doesn’t require fairing and paint to look decent. Isn’t that the reason you’ve never stripped MC back to bare aluminum?

I’ve worked on two heavily framed aluminum boats— a 12 meter designed to Lloyds scantlings and a 300,000# motor sailor where the owner insisted that the longitudinals be continuously welded on both sides “to make it stronger.” The 12 meter had 3/8″ of mud in some places, and the megayacht had so much accumulated welding stress that it crushed the decks and engine room overheads.

At the other extreme of aluminum construction, my friends Garcia Passoa was built with 12mm plate up to the waterline because they wanted to be able to set it down on rocky bottoms in Patagonia without damage. Back in those days Sr. Garcia used a massive roller to shape 50′ long curved aluminum panels that were so fair you could paint directly onto them and it would look like molded fiberglass. Or you could leave them bare and marvel at his craftsmanship. As I recall the ribs were over a meter apart, and served more to attach bulkheads to than to add stiffness. Different boats for different folks– and purposes.

Thanks, John, for featuring a lovely photo of us and our boat at the beginning of this post. However, and with great respect for all the contributors, I think that the discussion of the “best” hull material misses a couple of essential points.

Most of us build, own and sail boats simply for the pleasure they give. For me at least, a large source of pleasure lies in the boat’s look and feel. Does the boat look good from afar and up-close? Is it pleasing to your eye and comfortable under your bum as you sit in the cockpit with drink in hand? Is the cabin warm, dry, and cozy? Do passers-by offer compliments? Does it perform well under way and at rest?

Hull material strongly influences the look and feel of the boat. Metal boats tend to the industrial strength go-anywhere-any-time look that can be very impressive and pleasing if well executed. Wooden boats tend to fall into the fussy, look-but-don’t-touch category or, at the other extreme, the hairy old, gaff and baggy-wrinkled character boat group, irresistible to some, anathema to others. Fibreglass is the most adaptable of materials but seems to be dominated by a white desert of angular shapes and shiny metallic trim.

My suggestion is to consider “best” material in the context of the ways in which you expect to gain pleasure from your boat. Don’t buy/build something that is built of a material that can survive pounding on lee shore rocks or banging into ice floes unless the resulting look and feel and knowledge of its strength will please you every time you climb aboard.

Our boat is made of wood because that’s what I know and like. I have confidence in its strength and durability for the type of sailing we have done and dream of doing. Countless times we have had folks say to us something along the lines of “what a beautiful boat, but it must be a lot of work”. Well, it is a lot of work, but keep two things in mind. First, I enjoy the work and annual rhythm of varnishing and painting (at least most of the time). If I didn’t like that work, I would have a different boat. Second, structure and finishes that attract onlookers’ initial response are relatively small parts of the whole boat in terms of initial cost and ongoing effort. Our wooden boat has the same needs as any other boat in terms of underwater paint, rig, sails, electrical and mechanical systems, ground tackle, safety, and other gear.

So, my advice is to get a boat that will give you pleasure in the overall scheme of things and consider hull material within that context, not as a starting point.

Hi Wilson, Nicely put and a wise way to look at things. My best, Dick Stevenson, s/v Alchemy

As Dick said, well put. However, I still think that you are discounting the importance and the level of your own skills and how that affects your enjoyment of owning a wooden boat. Or to put it another way, I stick by my assertion that wooden boats can be heart breakers for those with less skill and dedication.

All I was doing in my comment was explaining that one can’t view plate thickness in isolation. I was not saying that the light plate many frame construction technique was a better idea, just different. As to paint on aluminium, I agree, in fact I made that point in the article above.

But the key point in all of this is that a good paint job on aluminium is cosmetic, on a steel it’s a matter of boat preservation.

No disagreement from me. I was just trying to point out that there are always connections: in this case the relationship between how an aluminum boat is engineered and whether it is a good candidate for bare aluminum finish.

You make a very good point. I have never enjoyed the boat part of cruising so much as when sailing on an extended family member’s beautiful wood S&S. As someone who has worked on several nice wooden boats, I always felt a bit awkward when I would answer the inevitable question of which yard takes care of the boat and I would explain that it was not yard kept and also that no, I couldn’t claim credit for most of it either, I was just lucky enough to get to enjoy it.

When getting our current boat, we really thought hard about whether we should take over stewardship of that boat. In the end, we went to the opposite end of the spectrum and decided to get as low a maintenance fiberglass boat as possible. We certainly have given up something that is hard to describe but the design is much more suited to the actual sailing we do and we can keep up with doing all the maintenance ourselves. I am someone who enjoys metalwork but does not enjoy the more artistic elements of woodwork which means that while I can spile a plank just fine, I have trouble motivating making elements that require an “eye” and as a result they don’t come out very well. Every time I see a picture of that boat, I wonder whether we made the right call as the feeling of being aboard was just so wonderful despite it lacking the creature comforts of newer boats.

Great way of describing the Real Purpose of owning a boat! If she doesn’t warm your heart every time you row out to her at anchor, perhaps it would be best to invest in a motor home with the obligatory wavy graphics on the side!

While talking to Larry Pardey years ago on the dock a passerby commented: “what a beautiful boat, but it must be a lot of work” LOL Larry didn’t say anything for a minute, having heard the same comment a thousand times in a hundred harbors. “Well, we don’t have anything else to do” he said. (having just crossed the North Pacific from Japan in a self-built wooden boat with a 24′ waterline)

Nobody has raised the difficulty of getting a good antifouling for an aluminum hull, when i was building i remember the ban on TBT taking place in Europe. Is there good protection available today ? (this article is old) for current owner of alu boats what is the current state of the art antifouling ?

https://www.practical-sailor.com/issues/37_17/features/10783-1.html

Steel hull is very easy to protect with a simple copper oxide suspension.

We have a good solution that we have been using since the end of tin: https://www.morganscloud.com/2009/06/18/zinc-based-antifouling/

E Paint also does consistently well on tests at Practical Sailor and has the other advantage that it’s less environmentally damaging that copper based paints.

Colin is also having very good results from a new copper free paint from Petit.

Hi Rob, I find your report of a Beneteau 473 hitting a rock at 8-9 kn and then a surveyor finding no damage extraordinary. I know you were discussing lead vs steel keels, but, less others think that sailboats can get away with that, I will share a couple of observations. For years I lived near a boatyard in a town with a very seductive rock a few miles away. Most every year, boats would limp in having hit that rock. Every one (or almost every one, I can’t remember) that hit that rock at hull speed with an external keel was considered a total write off by surveyors and the insurance companies. Usually the killer was structural damage of the fiberglass just aft of the keel, sometimes forward, as the keel tries to lever its way off the hull. Beyond that there always was near to the keel bulkheads pulling their tabbing from the hull and furniture etc. being dis-lodged. That was usually enough for the complete insurance write-off. Now, a steel keel would, I would think, transmit the forces more abruptly/directly into the hull as lead has a bit more “give” to it. I suspect the difference altogether may not be all that great. It is my understand that the average boat will not survive a keel to rock grounding at hull speed. I have been told, by those who know about these things, that it would be very hard (read expensive) to have a boat that could withstand an external keel to rock grounding at hull speed (I suspect full keels and some shoal draft could come closest). My best, Dick Stevenson, s/v Alchemy

We saw a Beneteau 50 (2004 ish) hit a rock at speed last year and damage the hull with water ingress. Damage was as described, fore and aft of keel, stringer damage. I think after removing the interior, reglassing and putting everything back, it was around 50-70k ish which the insurance company paid.

Hi William, Absolutely horrible thing to witness as a sailor I’m sure. I think I am right in saying the Beneteau 50 you refer to above is a completely design to the B473 I referenced above. I have never sailed one, but from the pieces I have read, it seems to share the hull liner design of the lighter First models, like Cheeki Rafiki. I am sure the hull would be thinner, too. That doesn’t in anyway detract from your corroboration of Dick’s point about many boats being massively damaged or written off by such impacts. It just doesn’t mean that well designed production boats and in particular the Beneteau 473s and their smaller sister-ships 423 and 393 have the same issue with their external steel keels. br. Rob

Would it really be that hard to engineer a keel joint to survive routine impacts at hull speed?

Today in 3 Minutes of Rough Physics Approximations:

Say it’s an 8 knot boat…. round that to 4 m/s. Displacement 10,000 kg. Draught 2.5 m (of which 0.5 m is hull and 2 m is keel). The keel tip hits a rock, the boat pitches forward, she comes to a dead stop in half a metre (measured at the waterline), average acceleration 16 m/s2. About 80 kJ of kinetic energy needs to be dissipated. Impact forces are on the order of 160 kN at the keel tip, for a pitching moment of 320 kN.m. Couple that through a keel root joint with a 2 m chord length that’s already supporting maybe 5 tonnes of keel, and simplify to pseudo-point loads at leading and trailing edges, assuming the middle part does nothing. That looks like about 190 kN of tension shared among the leading keel bolts and 140 kN of compression on the trailing edge of the keel root joint.

So the question “is it possible to make a 10,000 kg fin-keel boat with a 2m keel survive an 8-knot hard grounding on solid rock” is reduced to “is it possible to share 19 tonnes of tension among the first few keel bolts, and carry 14 tonnes of compression from the trailing edge of the keel joint into the hull, plus appropriate safety factors”. 19 tonnes is below the proof load of four M16x2.00 – Class 5.8 bolts, which seem considerably undersized for a boat of this class. 14 tonnes from a point load can easily be spread through a tapered U-shaped rib/frame about 20-30 cm in moulded depth, or a partial bulkhead, spanning most of the beam of the boat.

I think it’s not a matter of “that’s hard” or “that’s expensive”, but rather a matter of “we build to the scantlings in the class rules and they don’t consider this load case to be routine”. But it seems to me like, at build time while the hull is still in the mould, you’re talking maybe a three-digit dollar figure for this kind of reinforcement.

Hi Matt, how right you are! The boat in question (Beneteau 473) has internal “U” shaped tapered beams almost exactly as you describe, but with thick, wide flanges. The beams are probably slightly over 30cm at their deepest, in the centre, near the bilge and the keel bolts, tapering to not very much at the turn of the bilge (fairly flat bottom especially around the back of the keel). The beams are very close together at the front and back of the keel and about 20 cm wide. These beams are so tough that during our pre-purchase inspection, the surveyor’s hammer bounced off them like they were steel. He called me over to remark on their size and thickness and how many there were around the keel area. Being an ex-yacht designer, offshore sailor and boat builder he didn’t seem the sort to be easily impressed. We both thought they might have a steel core, but I later discovered they are 100% moulded fibreglass. Matt, I think these beams may have cost a little more than a three digit number more, but as you say – not a lot. But I have heard that due to EU heath regulations, such hand lay-up techniques can’t be used anymore, and that most large items like beams would be epoxy injected and vacuum bagged, then cured and simply glued in. I wonder if this is not as inherently impact resistant. Do you have a view on this? br. Rob

The Cheeki Rafiki report makes clear that a glued in grid is intrinsically dangerous and, if memory serves Matt has already agreed with that in our original discussion about said report.

Bottom line, your boat may be a battleship, and that’s great. But I need to make sure others understand that extrapolating that construction to any other Beneteaus, without carefully checking, might be a very big mistake, particularly in light of what you heard about EU regs.

This is my biggest problem with modern fiberglass boats. Boatbuilders that still exist are exceedingly good at value engineering. The ones who weren’t went bankrupt decades ago.

Value engineering requires warranty claims for its feedback mechanism: make something weaker, and if there aren’t any claims then it’s still too strong.

But most pleasure craft spend nearly all their time floating next to a dock, plus an occasional few hours underway in Force <5 conditions.

So value engineering is walking boats down to the point where they're good at floating next to a dock and occasionally sailing in benign conditions—plus Class.

But Class is controlled by manufacturers, and they'll continuously make the case that real world experience shows that Class is too conservative. So Class is value engineering with a delay, and that's how we end up with (for instance) brass thru-hulls and glued matrix liners.

Yes, sadly, I think you are right in every detail on that one. Definitely narrows things down. I’m starting to think the sweet spot is around the 90s when better techniques became available but value engineering had not kicked in quite as much as it has today. Also I totally agree that class is inadequate and in fact has just become a fig leaf to cover up poor boat building:

https://www.morganscloud.com/2015/06/25/cheeki-rafiki-report-misses-an-opportunity-to-make-boats-safer/

Dick, If you go to YouTube and search for “Crash Test – Dehler 31 yacht” you can see Dehler ramming their yacht against all sorts of objects at hull speed. It’s a GRP hull with a standard fin bolted to the hull, not a bonded in grid or encapsulated. The video is worth watching all the way for all the ramming scenarios this boat is going through, including a keel strike against a breakwater base. I am not doubting your observations. My position is that GRP hulls can be designed strong enough for extreme loads at sea, and that inherently makes them strong enough for many types of impact. As design changes over time we now see hull designs with very efficient keels that meet a performance criteria with some sacrifice in strength and are less resilient. I do agree that steel can be stronger but I think GRP can be relied on as safe and secure material, where the design demonstrates that. I won’t post the link here as I am not sure if that is allowed. Regards, Alastair

Hi Alistair, I fully agree that fg hulls can be built to withstand almost anything the sea may challenge it with. I also agree that fg hulls can be built strong enough so that the keel to hull joint is not compromised by anything the sea has to offer. In fact, it is my take that most are. It is a non-sea event that I was referring to: hitting a rock at speed low down on a conventional keel. It is a predictable event for a certain (hopefully small, like lightening) percentage of those who put significant miles on their boats. It is my take and observation that the average sailboat can’t tolerate hitting a rock down low on a keel (possibly excepting shoal draft and full keel where the lever arm is mitigated to a large extent) without substantial damage and often leading to total loss. As to the video, you cited: hitting floating wood objects and log booms should leave only a dent and did leave gauges as shown in the video. But that should be all the damage. I believe the video shows the boat hitting the rock wall with the underbody leading up to the keel high up on the keel, not low where the lever arm is most powerful. This is augmented by the video of a keel placed well aft and the boat rising at first and then largely stopping dead with very little tipping forward. A boat hitting the bottom of their keel at hull speed looks like it will pitchpole. It is incredibly dynamic and looks to eject the people in the cockpit into orbit. This hitting the breakwater was gentle by comparison and says they were sliding up the hull, absorbing the loads till they got to the keel. Very little was shown of keel dents or evidence on the forward underbody where I suspect there was contact. Also, the keel to hull footprint is one of the tiniest I have ever seen on a fin keel boat: harder still to believe it could survive unblemished a bottom of the keel rock grounding at hull speed. Your Dehler video was not, to my observation telling or compelling: it was an advertising stunt. (Reminded me of the old Hunter destruction tests done back in the day: I am not a fan of manufacturer testing.) Now, I am largely unfamiliar with Dehler boats and they may make great boats, but I am not impressed by the video as evidence that a conventional fin keel boat can survive a bottom of the keel rock grounding at hull speed. My best, Dick Stevenson, s/v Alchemy

Hi Dick, that was my understanding entirely, so I fully understand your note of surprise. This was also the owner’s expectation at the time – the boat was rushed back to the nearest haul out facility, with crew in life jackets, coastguard on standby and bilge pumps primed. Most people are reticent about admitting things like going aground, never mind crashing into a rock at full tilt. So I have no reason to doubt a first hand account of the incident, from the owner to me, on board their boat some months later. At the time of the impact the owner was down below, having handed over the helm to a friend to check something. The rock concerned is well marked by a beacon and for some inexplicable reason, the EXPERIENCED sailor and friend took the beacon on the wrong side – hey stuff happens. The crew were lucky to avoid injury. Please see my answer to John above, on the way Beneteau Oceanis 473s are built for the reason why I think they could withstand such force, without any visible damage. Not that I am looking to test it mind. Inside the hull the keel bolts, girders and hull are all completely visible by simply removing a few floor boards. All easily checked by an experienced surveyor. I have to say if it was me, I would have insisted the insurer pay for the keel to be removed, keel bolts changed and the whole thing re-seated at a minimum, and this may well have been done – I don’t have the detail of that. By the way, I do wonder that marine insurers don’t sponsor more marine buoyage. We have a notorious rock near us, that collects about four launches a season. br. Rob

Just to clarify, the Cheeki Rafiki report makes clear that after a grounding it is extremely difficult, perhaps impossible, to determine if dangerous damage has been done to this kind of construction.

So to say “Inside the hull the keel bolts, girders and hull are all completely visible by simply removing a few floor boards. All easily checked by an experienced surveyor.” is simply not correct.

The report also goes on to show that with this type of boat repair is not cost effective and so to be safe the boat will probably be written off.

I think it would be a really good idea if you would read said report, and the associated Wolfson unit report.

Sorry to be so harsh, but this is important stuff and further me constantly arguing with you and quoting the report is only going to get us crosswise, which would be sad.

Hi Rob, It sounds like you have a very solid boat and you must be re-assured to have it validated especially if you were not the one doing the testing. My interest in responding to your initial letter was primarily to point out that, in my experience and in talking with others, most of the regular sailboats out there could not survive unblemished what you described. And I concur with your thought of further examination of the keel. Internal furniture etc. are one thing, but I would also be concerned about the shock load’s effects on the rig, chainplates etc. My best, Dick Stevenson, s/v Alchemy

Hi John, I am not convinced that the average offshore boat buyer need be so pessimistic and precautionary about keel to joint integrity. For those boats being considered for offshore use (for ex., Malo, Hylas, Rival, Valiant, J Boats etc.), I would think that a good survey, boat history (no evidence of groundings), general consideration of the quality of boat construction (including details on the keel to hull joint, caulking, bedding etc.) and the history of sister ships would reveal a lot and make it likely that the keel would stay attached during her sailing life. I think for most boats nowadays (including those mentioned above), all bets are off for untoward events like groundings. That said, I think there is a good long way to go ensuring that new builds are better done in this area and in inspecting those that have been around awhile. My best, Dick Stevenson, s/v Alchemy

Hi Dick, I agree with your conclusions. However I have some interesting information, several fg yachts with fin keel in Scandinavia are built so strong that they can tolerate to hit a stone with the keel in good speed. The ones I have sailed are X Yachts of Denmark, Arcona Yachts of Sweden and Baltic Yachts of Finland. The keel construction of this three are all different, but looks very strong and stiff. You can find the drawings on the net. They all sail well. I like to sail in uncharted waters and then you must be prepared to meet this problem every year. Then it is not so difficult, but most fin keeled fg boats are not built to handle this difficulty.

Hi Svein, Thanks for the info. When sailing your part of the world, I saw those boats pretty regularly and thought they looked fast and well built, like J boats from the US, but had no other contact with them. I was unaware they were robust enough to tolerate hitting a rock at cruising speed unscathed. My best, Dick

I have just bought my *third* steel boat – so there you go, you do know of at least one person who has bought more than one!

One of these is coming up to 100 years old and has not had a spot of rust on the undersides in the last 15 years – though to be fair, she sits in freshwater.

The game changer for steel is proper grit blasting and professionally applied two part epoxy paints. Done properly, it lasts for decades.

Steel is a nightmare if not maintained and if poor quality preparations / coatings are used. A pure DIY life of grinding and painting rust is indeed a mugs game. With proper blasting and painting however, you have an extremely strong, durable and low maintenance system.

My latest steel boat is 30 years old and the paint failed about five years ago so there is some remedial work. With that done and a visit to a Dutch yard for an SAE3 blast and glass flake epoxy paint job (when I can afford it!) – I expect it to go another thirty years. How many fiberglass boats can confidently expect to last 60 years?

Hi Richard well said. Here in USA/Canada people are afraid of steel boat..European are not and they have made plenty still traveling the globe. We should not forget “attainable” in the adventure cruising. I’m talking of used boats of course as I made it clear that all professional yards have turned to aluminum and I’m fine with this.

People look after non metallic boat as a magic bullet for secure world traveling but there are all sort of dangers awaiting: rocks, corals, UFOs, containers, fire, and the most dreadful and invisible… the 1 million cycle of flexing in the ocean after a few years. Attainable cars still have their coil-springs and chassis made of steel. Every polyester boat owner have experienced the need tighten up the rig after a rough passage…

I would have no problem of buying another steelboat if mine one day would be lost. You are right that with proper preparation steel in marine conditions can go many decades – just look at the oil rigs they are built for 40 years up.

Thanks for the informated post!

Just to be pedantic, what I wrote was:

I know a lot of people who own a steel boat, or have done so in the past, but I have never met anyone who has owned a second steel boat.

As I suspected would happen, we have had a bunch of comments from steel boat owners defending the material and extolling steel’s virtues. These comments make many good points. The most important being that steel when properly coated can have a long and useful life.

That said, I do need to make clear that none of this alters the basic fact that steel is a fundamentally unstable materiel, or as one commentator said “rust never sleeps”.

As I said in the article steel can work for those with the knowledge, time and dedication to care for it properly.

“If you built the boat yourself, or supervised every step of the build, and then cared for her yourself, it can work. Just look at the amazing voyages made by AAC contributor Trevor Robertson in Iron Bark.”

And there is no question that a buyer can often get a lot of boat for a good price in steel. But for most of us steel boats, and particularly old steel boats, are not the best option. Nothing I have heard changes that.

As a steel boat owner I understand why people have their reservations. The way in which an old steel boat can crumble before your eyes is disheartening and if that kills your confidence in it then that is that. And as another person mentioned, the fear of old steel boats does seem more prevalent in North America than elsewhere; there may be good reasons for this.

Personally I’d love a good aluminium hull, but all the ones I could access in Australia were well out of my budget. And many of the fibreglass ones came with other problems, osmosis, cracks, delamination, water logged cores and so on. Or they were really heavy old designs that sailed like slugs.

Plus I really wanted rigidity, as an engineer this attribute seemed fundamental to me, so in the end I went with steel despite knowing full well that rust never sleeps. And truly modern coating systems really are remarkable and quite surface tolerant. They’re designed for aggressive industrial applications where ideal surface preparation isn’t possible or economic.

If I could build new it would be a steel hull with no horizontal stringers, stainless deck, integral tanks, total bilge access and a full noise Jotun or International paint system. Thirty year life easy.

Still I don’t feel any pressing need to defend steel; it’s not as good as aluminium and it will never be as popular as fibreglass. Besides there aren’t that many really good steel hulls out there and those of us who like them wouldn’t want to see them become too much in demand 🙂

A good analysis, thank you. I agree particularly about the stiffness advantage of steel.

And, even though I’m an aluminium fan, I would not say it’s simply better than steel, just better for most usage profiles. That said, steel is easier to weld and more abrasion resistant than aluminium.

Hi I would love to meet and talk hulls, but that would ruin your “I never met” a second steel boat owner. I am on my second steel boat. I have owned steel, fiberglass and wood boats in my sailing life. My first steel boat was an Ebbtide 36, built like a brick shithouse as they say, in the UK. As a newbie to cruising, I read Jimmy Cornell’s “Ocean Cruising Survey” where most long term cruising boat owners preferred metal. I sailed it hard across the Atlantic and Pacific and points in between (over 35k passage miles in 5 years). I even had the opportunity of living through an experience of driving it ashore in a strong wind. My (now ex) wife fell asleep on her watch and let us drive it directly into a rocky shore of an island in the Caribbean at about 7 knots. The boat was eventually hauled off and the dents in the hull needed to be repainted. No leaks, no lost keel, and after, no rust. My current steel boat is a Folkes 42. I had the electrical system completely rebuilt after my purchase. On a trip from WA state mainland to the San Juan islands, we had a voltage regulator (brand new, just installed Balmar regulator) fail, start on fire and allow two batteries to explode before the fire suppression system blew the fire out. We had to abandon ship into our dinghy. The boat did not sink, but was totaled per our insurance company. After many months negotiating with Balmar they finally admitted fault and paid for a complete rebuild of our boat. As we gutted the interior to bare steel we got a chance to check for interior rust and found none. Now (three years later) we are back on the water sailing again. With modern coatings and a minimum of maintenance chasing after any scratches a properly built steel boat offers an inexpensive (relative to the other metal choice-aluminum) safe and strong boat. I think the boat has to be properly built originally (professionally) and then properly coated inside and out. One other advantage of steel is that it can be repaired anywhere in the world. Charley s/v Hongvi

As I am still considering buying some (used) steel boat in a couple of years time this tells me one important lesson – access to the inside of the hull must be able _everywhere_, at least good enough for proper inspection using some fiberoptic or the like. Even (and especially) below tanks, or similar built-in structures. It is quite easily possible to blast and recoat the outside, and doubtful areas on the outside can be easily spotted. But it must absolutely be possible to routinely inspect the complete hull area from the inside as well, without too much ado. If (heaven forbid) there would be some blasting and recoating necessary it is still a chore removing parts of the internal structures, but you need to be able to detect it first.

And the story about your exploding batteries makes me shiver. What had you done if your boat was from plastics?

There would be a different ending to the story.

Yes, I think that’s the key: inspect every square inch of the inside of the boat. The trouble is I’m pretty sure that’s a lot harder than many people will have you believe. But it must be done since I understand from people that know that steel boats die from the inside out, so re-coating outside does not solve much.

Very good advice John, all boat need total inspection capability. Unprotected steel can rust, aluminum should be kept free of any standing water (wood is terrible in contact with bare alu) that can attack the oxyde and start up a crevice corrosion.

On any metal boat the bilges should be dry all the time.

Aluminum corrosion protection is not a simple science…if only aluminum could be alone but the problem start when attached to another metal or with itself sometime.

On the periodic table of element Aluminum is a much more active element (less stable) than iron. But neither are used on a boat, it is rather in alloy: Alu 5083 is an alloy, Steel is an alloy and the same for 304 and 316 stainless. All have their corrosion issues and can be attacked with the proper conditions/oxidant.

I have read on Collin post that his Alubat seacocks are in plastic…what are yours John on MC ? Mine are stainless steel and for the plastic speed and depth transducer i have built a safety chamber over it. I would NEVER leave a plastic seacock alone (without side impact protection or safety chamber) on a metal hull.

I think we are starting to go in circles here since I have coved all of this on aluminium and sea cocks in other articles and comments.

As I have written before, I have never had problems with aluminium from standing water or contact with wood, and I have owned an aluminium boat for nearly 30 years.

As to dry bilges, simply not practical once the water temp gets below about 8C, due to condensation. The result is that our boat’s bilges have been wet for most of her sailing life and still we have no significant corrosion problems.

As for plastic seacocks, the good ones are very good, and I would choose them over any other material if building a boat from scratch. Nor would I worry about a safety chamber, as long as they were properly installed. And, as a general rule I don’t like stainless steel below the waterline.

Hi Charles,

Wow, if I had been through the same two experiences I would be living on a farm…in Saskatchewan!

One thing I do need to clarify. Generally a Steel boat is only less expensive that aluminium is both boats are painted. Leave the aluminium boat bare, except for the underwater surfaces, and I’m pretty sure the equation reverses.

Hi John, I also have had 2 steel yachts. The first had no corrosion issues as it had only paint on a rather bare internal fitout. Surprisingly, in Sydney Australia it had almost no condensation due to adequate ventilation. It was 6 t, and 20 years old. The second yacht had a full internal fitout but the hull was done in corten steel which only ever showed minor surface rust. However the mild steel frames in the anchor locker were rusted out to half their original size. It was 20 t , and 28 years old. It should be noted that Lloyds would not let me build in Corten due to its brittleness in subzero temperatures. If I were looking to buy another yacht I would look for another steel one with these provisos. 1/ a good design. Backyard builders don`t pay for a high quality design 2/ The price has to allow for a total strip out, sandblast and paint ,and refit, rewire etc. 3 If the insulation is sprayed on foam then walk away. According to the US Navy their paint systems are good for 25 years. My third yacht was an alloy 55 ft 1969 racer. At 14 t it always felt fragile and it`s motion too lively. In asking what alloy they used I could not say, but probably not the modern 5083 and not the old duralium.

Hi William,

That’s interesting about corten, thank you. Just spent an interesting 10 minutes reading about corten. I had heard of it, but really did not know much about it. Always more to learn.

And a good point about design. I never understand why anyone would cut corners on that vital step.

Lloyds is out to lunch. Old Corten A was brittle (which is why USS sold Corten B) but modern A588/A606 has excellent cold notch toughness for an HSLA and is significantly better than A36.

A588 is sold primarily for bridgemaking and is an excellent structural material in most conditions.

To be fair to your mild steel frames: they almost certainly sacrificed themselves to the corten, which is more noble than mild steel.

Hi, what about plywood builds? Would you consider them an option? What would your conditions be, what would you survey? My first reaction when I read your specifications for your next boat was “that’s a RM1200!”. I’m not stating that they are perfect: they definetly have some drawbacks, and I wouldn’t be able to assess if one is a safe buy. But their twin keels are well-designed (just as the twin rudders of the Boréals, maybe!), and make for boats that are quite good upwind, despite being roomy, light, and of moderate draft.

Depends what you mean by “plywood”. If we are talking about cold molded with epoxy, then yes, certainly an option. And yes, I agree RM1200 is a really interesting boat. Thank for pointing her out.

Just to clarify, the Boréals have single rudders, and two dagger boards aft.

Ouch, plywood without epoxy? I don’t even want to know about this!

Sorry for the mistake regarding Boreal: I meant “aft daggerboards” and not “rudders”, of course. The point being that, as far as I know, the RM were the first twinkeel boats on which the keels are properly angled, so as to reduce leeway when sailing upwind.

I was pretty sure you knew that, but just had to clarify.

Fun facts, back in the day some quite good boats were made with “tortured plywood” in much the same way as metal boats with chines are made. I think this was one: https://www.sail-world.com/Australia/Ragtime-Revisited/-28564?source=google

Also, I have a very faint memory that there were some early IOR race boats with toed in boards to help with pointing. We also experimented with auto jibing centreboards in the 505 class, with the same idea. As I remember, it was a trade off because drag goes up as we angle the board—you point higher but go slower.

Thanks for the information! I didn’t know about tortured plywood.

I see on the internet that the best trade-off for an auto-jibing 505 centerboard is around 2.5-2.8°. And something I didn’t suspect: if the daggerboard is well-made, slightly lifting it brings it back to the centreline! Which would be ideal downwind. The keel angle on RMs and similar designs is less than that (around 2.0°?), but keels have to be kept in place when not sailing upwind! In my experience, the advantage of this is not that you could point higher, but that, for the same angle between the wind and your route, the hull can point a little further from the wind, yielding 1) a better hull shape through the sea (there is another saying about sharp edges: when the sharp edge opens the way, it works better!) and 2) a little more distance between the two sails, which seems to help, too. I know it may sound like I’m overmaking this, and 2 degrees may not seem that important, but the difference is quite visible, especially with 15kts of wind and a flat sea (it becomes all the more visible if you heel too much, but that’s not advisable anyway).

Yup, the 505 boards in my time were made so they only jibed when all the way down.

As to the exact mechanism of how jibing boards works, way beyond my pay grade, but if the 505 fleet are still using them clearly they do work since the boat has always attracted some of the best minds in sailing.

Tortured Plywood? A Kamanu catamaran built with the Hughes Cylinder Mold process has been in daily commercial service in the rough Hawaiian waters for THIRTY YEARS. That is perhaps equivalent to 100 years use for the average full time cruising yacht.

Fairly recently an entire half hull of a 70′ CM catamaran was built in the Philippines in a single day using the process. It is a full curvature hull shape, not a chine boat like Rags.

A few years ago I met the skipper of a 55′ CM cat built 20 years ago for Lake Tahoe. It sits outside in the snow every winter and carries passengers every summer. The best story over beers was about the time a jet ski hit it at full throttle and ended up inside of the hull. Sailed it to the dock, pulled the jet ski out, scarfed in a new hull section, and went back to work carrying tourists.

Tortured plywood, a phrase you won’t hear anywhere but AAC!

Thought all you metal heads would like to know that a new process for refining wood has been developed in the lab. All the lignin is chemically removed, and then the remaining fiber massively compressed. The resulting material is stronger than steel on a weight basis. May never be a boat building material, but who knows!

Hi John, As a metal head, my perfect hull material is SAF 2205 ( DUPLEX ) stainless steel. It has a yield strength 3 times that of mild steel and excellent corrosion resistance, as well as great fatigue resistance. See sv tanielle Thanks Jordan Bettis for the update on Corten

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In Cored Hull Construction, Does High-Tech Mean High-Quality?

Despite the numerous advances in modern boatbuilding technology, sailboat construction is far from being a perfect science..

There is nothing inherently wrong with core construction when it is done right. Over the years, however, Practical Sailor has seen a variety of core failures resulting in costly repair. There are five common types of failure: poor workmanship, excess flex (poor engineering), point loading, bad chemistry, and water intrusion. Even with a generous safety factor, things can still go wrong at the factory. High-tech materials and construction methods do not necessarily solve quality control problems.

Think you have boat problems? Consider this one: A high-end ocean racer, barely a year old, shows up in a boat yard with sauce-pan-sized blisters bulging up from the slick, blue skin. A prominent surveyor is hired to define the problem. After some testing, he announces that the solution is fairly straightforward.

All that this new, nearly $1 million boat needs is a complete face lift. The entire outer laminate will have to be removed. Any core that is damaged when the outer skin is peeled away will have to be faired again. Next, a new Kevlar and S-glass skin will have to be vacuum-bagged in place, and the hull will need to be post-cured in an oven. Finally, the finished surface will have to be faired (requiring hundreds of man hours), before the hull can be primed with epoxy and the topsides can be painted with linear polyurethane.

One can almost imagine dollar signs registering in the boatyard managers eyes when this news is announced.

In this actual case, the resin manufacturer blamed the maker of the core material. The core producer blamed the resin chemistry. No one was happy with the boatbuilder. It is just this type of astronomical repair job that has led to many new insurance policies limiting the amount of coverage on this sort of hull “deterioration.”

The engineering philosophy behind any composite construction is that the strength of the finished product is greater than the sum of its individually tested components (see “Core Concept,” page 34). Initially, the garboard of a fiberglass boat was laid up as thick as the plank it replaced. Performance-oriented boaters soon saw that lighter was faster, and some&emdash;but, unfortunately, not all&emdash;boatbuilders recognized that better engineering had to go hand-in-hand with any plans to strip out structure. The shift toward cored hull and deck construction brought great potential for weight savings, but also introduced new challenges. In core construction, a low-density material is sandwiched between high-modulus, fiber-reinforced-plastic (FRP) skins, resulting in a strong, but light panel. So long as the bond between the outer skins and core remains intact, this light component will exhibit extraordinary structural properties. Cored panels are now the norm for most sailboat decks. Hulls, on the other hand, can be completely cored, partially cored, or solid FRP laminate.

There is nothing inherently wrong with core construction when it is done right. Over the years, however, Practical Sailor has seen a variety of core failures resulting in costly repair. There are five common types of failure: poor workmanship, excess flex (poor engineering), point loading, bad chemistry, and water intrusion. Each of these results in the loss of connectivity between the inner and outer skins, much like losing the span connecting the top and bottom of an I-beam. The result is a massive drop in stiffness and increased flex, and if left unattended, this can result in the critical failure of the component. If the region in question happens to be the garboard area of a cored hull, the failure may include the ballast tearing free from the hull. Such failures are rare among cruising boats, but not unheard of among racing vessels. The reasons for this drive home a good lesson about stress and scan’tlings&emdash;the specified measurements for structural components.

As explained in our recent special report on fiberglass hull failure (“ Lessons from the Boneyard ,” August 2007), a stress riser is a focal point of energy. On sailboats, the areas near keelbolts, chainplates, rudder bearings, and the mast step are good examples of such high-energy hot spots. The best builders use well-reinforced solid laminate in these areas, creating a tapered junction between solid and cored laminate that better distributes the forces focused on such hot spots.

By using computer software that carry out finite element analyses, naval architects can get a clear picture of where hot spots might lie in a new design. These programs yield graphic images of the hull that is “painted” with color-coded hot zones associated with high loads. Using this data, designers and engineers can change hull and deck laminate schedules to better respond to changing load dynamics. Although these computer models can be confirmed by actual data collected by onboard sensors (as well as post-failure forensics), computer modeling of sailing loads is not an exact science. The frequency and degree of failures in the most recent Volvo Ocean Race (“ Life at the Extreme ,” August 2006) bears this out.

Over the years, Practical Sailor’s contributing editors have seen boats – both with solid laminate hulls and cored hulls – that, either by defect or design, are clearly under-built for their job. In one extreme case, a current editor and a friend were able to place their feet on the keel of an early model Pearson 365 that was hanging in the Travel Lift slings. With shockingly little pressure, the two were able to make the keel swing side-to-side like a pendulum. The hull skin in the garboard area dimpled in and out with each oscillation. Each time the vessel tacked, the flexing garboard destroyed more and more of the FRP-resin bond, a process that would have eventually caused a catastrophic failure.

The good news is that most builders have gotten better at composite boatbuilding and their efforts to beef up high-load areas have improved. In the case of keel attachment points on cruising boats, theres usually a long, wide junction point where lead meets fiber-reinforced plastic, and the weight of additional reinforcement from extra laminate is of little concern.

However, the modern bulb keel on a racing boat or racer-cruiser is usually heavier and deeper, yielding a greater righting moment and more pressure on the keel-to-hull attachment point. The upper portion of the keel is usually narrow and thin, meaning that heeling forces are focused on a small area of the hull. An interior structural grid and well-engineered keel junctions are essential, but even the best built hulls of this design can be vulnerable in a severe grounding. A smack on a hard bottom can result in hidden damage well beyond any obvious failures in the garboard area.

QUALITY CONTROL

Aside from the reality that cruising sailors run aground, strike submerged objects, and sail into storms, another strong argument for a generous safety factor when designing a voyaging boat is the relative lack of quality control in the boatbuilding industry. In some ways, the aerospace industry has gotten boatbuilders into trouble by being too good at producing composite structures. Skilled workers in near-laboratory conditions are able to consistently create fiber-reinforced structures that meet the highest standards. Product inspection includes the careful analysis of test samples and X-ray inspection.

This meticulous approach yields composite panels that reliably resist the loads that they are designed to handle. These include ordinary tensile and compressive stress, which run perpendicular to the panel, as well as the more complex shear and “twisting” loads that run tangentially to the material face (see “Core Concept”).

Unfortunately, the data collected from the aviation industry often gets directly transferred to boat designers and builders, where the manufacturing process is far less controlled. In many instances, laminators are the lowest paid workers with the highest turnover rate of any employee in the company. Ultimately, manufacturing lapses result in a hull that falls far short of the engineers ideal.

Solid hulls are not immune to problems of quality control. Prior to the mid-1980s there was little climate control, so temperature and humidity at the plant often followed Mother Natures seasonal profile. The result was, and continues to be, less stringent control of manufacturing variables and more chance of panel inconsistency. In those early days, overbuilding tended to cancel the downside of inexact methodology. Early fiberglass boatbuilders were skeptical of the new material and tended to add extra layers to solid FRP hulls. The simple, wet, hand lay-up process may have been resin rich, but if the crew used their serrated rollers diligently and made sure that edges of mat and roving overlapped, all turned out pretty well&emdash;if the chemistry was right.

Polyester and vinylester resin cures or thermo-fixes when a catalyst and a promoter react, producing oxidation and subsequently generating the heat that causes the resin to harden. If theres too much of one ingredient and too little of the other, an impartial cure results, and un-reacted chemicals are left in the material. The resin never reaches the prescribed hardness.

Some manufacturers purchase resin that has already had promoter added while others prefer to mix in their own promoter according to ambient temperature and humidity. In quite a few unfortunate situations, applicators either added extra promoter or, worse, left it out completely, resulting in an uncured or under-cured laminate. All too often, the solution was to apply the following layer with a “hot” batch of resin that would, hopefully, completely cure the layer below. Often it didnt and the boat left the factory with uncured or under-cured laminate trapped between hardened layers&emdash;in essence, a polyester time bomb that would eventually erupt into mega-blisters, causing a colossal headache for some future owner.

Core construction introduces a whole new set of challenges. This I-beam-like structure greatly reduces the amount of FRP material required to achieve the desired hull rigidity. To reduce flex, early, solid FRP hulls required two to three times more resin and fiber than a modern cored hull needs today. Unfortunately, the core materials and techniques used by boatbuilders generally make these boats more vulnerable to water intrusion, a major drawback.

The water doesn’t have to come from rain or seawater. One common boatbuilder shortcut that can lead to eventual problems is encapsulated tanks (those that use the inner skin of the hull as one side of the tank). In one particular case, a marine surveyor found holding tank residue leaking from the forward portion of the hull after a grounding had damaged the laminate. The point of impact was 20 feet away from the encapsulated holding tank, and an internal leak had filled all the void slots (described below) in the hull skin with effluent. That pungent surprise is actually not as big a disaster as when the same problem occurs with a diesel fuel tank and spreads oily residue throughout the core.

KERF ISSUES

One persistent challenge when constructing a cored hull or deck is how to minimize voids in the kerfs, the channels that are scored into a cored panel so that it can be shaped into complex curves (see photos, page 32). To better ensure the integrity of the composite structure, these channels should be filled. Typically this is done using either resin-rich chop-strand mat or a core bonding adhesive, which also bonds the core to the outer skin. When laying up a hull inside a female mold, these kerfs face down (toward the outer skin), resulting in a “blind bond” that cannot be visually inspected during construction unless a clear gelcoat is used and the outer skin LPU painted.

Not only do unfilled kerfs and other voids compromise the integrity of the panel, they offer an effective channel system for water to travel and weaken larger areas of core. One marine industry expert has been recently making the pitch that wet core is nothing to worry about. To the contrary, wet core is a precursor to balsa rot and structural failure.

In cold climates, the expansion that occurs when water freezes splits the bonds in FRP. Even in its liquid state, water does interesting things to residual promoter and/or catalyst trapped in the laminate. It also can attack the water-soluble compound that coats each glass filament and allow it to bond with resin. Finally, contact with wet core material can cause capillary action to wick water deep into the laminate, weakening the mechanical properties that help hold it together.

Today, vacuum-assisted lay-up techniques like vacuum-bagging (in which vacuum pressure is used to squeeze resin-impregnated laminates together during the cure phase) and resin-infusion (in which vacuum pressure vacuum is used to draw resin through dry laminate as well as squeeze the laminates together) can help fill kerfs. These processes can markedly reduce voids, creating a better quality composite. However, these new building techniques require more skilled technicians. And if things go awry, the consequences can be severe.

In one case at Pearson Yachts, the resin flow in a resin-infused hull had ceased before it had reached all of the shear line. A 30-foot length of deck flange and hull remained as dry as when the laminate came off the roll. The repair required a secondary bond&emdash;an inferior bond between a new layer of FRP and laminate that is already cured&emdash;eliminating a key advantage of resin infusion.

In another instance, Ted Hood complained that when fiber/resin ratios get too high and fibers are not being sufficiently saturated, it can actually increase the likelihood of delamination. Clearly, when the resin-fiber ratio is intentionally held to a minimum, careful quality control is essential.

Point loads such as the tension of a sheet block on under-structured portions of the deck are another notorious cause of core problems. The repeated on-and-off bending caused by point loads can crush core material and result in delamination. Water intrusion exacerbates the problem and telltale cracks usually appear (see, “Curing Core Problems,” at right). If left unattended, catastrophic failures can occur, such as a genoa track actually being torn from the deck.

Repairs can be complicated because the failure was actually more a symptom than the cause of the problem, but its not always seen that way. The real villain is often a poorly engineered structure and returning the damaged area to “good as new” condition isn’t good enough in these cases. The correct fix must include additional reinforcement to the area in order to prevent the same problem from reoccurring.

With metal boats, extra strength is generated by using thicker plates or welding in more longitudinal and transverse supports. The same principal applies to FRP construction, and naval architects have reference tables that relate the size of a span or unsupported panel and what its core and skins must be composed of in order to handle the anticipated loads. Equally important is the fatigue cycle or rate of flex that the structure will endure and the time frame in which the object is to remain viable. These same designers also build in a safety margin that increases the strength of the structure by a factor of two, three, or more depending upon how rugged the vessels use will be or how dangerous its working environment might become. Naturally, the average production boat made for the inshore weekend sailor or powerboater will be less ruggedly built than a Southern Ocean expeditionary vessel.

Automakers have reverse-engineered product viability and attempted to come up with a pattern of uniform systems decay. Ideally, the life span of all ancillary components, from exhaust system to upholstery, match the longevity of the engine and drive train.

Fortunately, most boat designers and boat builders havent fully embraced the concept of intentional product obsolescence. However, cost-cutting and the age-old art of putting lipstick on a pig are a very real part of the industry. Hence, savvy boat buyers know that they need to look through the bilge and crawl into tight spots with a bright flashlight to see the hidden parts of the hull and deck laminates, and hunt for good and bad indications of the builders best kept secrets (See “Core Check” ).

So whats the bottom line? Even with a generous safety factor, things can still go wrong at the factory. High-tech materials and construction methods do not necessarily solve quality control problems. Ultimately, hiring a marine surveyor who is skilled in FRP construction can be as wise a choice for new boat buyers as it is for those hunting for a 20-year-old bargain boat.

• Boatbuilding
• Hull Core Comparison
• Core Concept
• Curing Core Problems

RELATED ARTICLES MORE FROM AUTHOR

A common failure in foam sandwich laminates is due to air entrapment. Balsa sandwich does not have this problem as it uses individual blocks which allows the air to escape (but balsa suffers from rot if it gets wet). I used to build Tornadoes and the air entrapment problem was easily solved by drilling the foam sheets 3/16″ diameter on 4″ centres. A pair of Tornado hulls were built with clear gelcoat, one hull had drilled foam the other had undrilled. After vacuuming large areas of air entrapment were visible on the undrilled foam hull and not a single bubble in the drilled foam hull. This test was done in 1971 and still is not being employed by most builders. Also, at all points of high stress the foam was tapered to zero and extra glass layers added. The Tornado is one of the most demanding hull structures having to take high stresses but keeping to class minimum weight. The fact that this was achieved shows that with good detail design and techniques a good structure can be achieved.

Balsa Core is a useful lowest cost core material BUT SHOULD NEVER NEVER EVER be used if the structure could be accidentally punctured or cracked to allow FRESH (not salt) water to reach the core in room temperature conditions. WHY? you say Because Balsa (The Tree) was created by whoever to be self disposing. It grows self including spores of the fungus that we know as “Dry Rot” which grows fastest in the presence of luke warm (body temperature) fresh water and balsa. It then becomes a mush much like over watered Breakfast Porridge. —— An outer skin or inner skin can and does then flex and bend sufficiently to cause total failure and death of crews. I have seen so many cases and worried that other friends lost at sea were the other cases. BIG MONEY SUPPORTS THE USE OF BALSA and it is the cheapest. I am not popular but I am retired and can say USE OF BALSA CORE IN YACHTS/ PLEASURE VESSELS Should be made CRIMINAL And Suppliers who sell into that industry should be Persecuted Michael Anthony Pope aged 87 a shipwright and sailor, not so smart, but honest!

Mr. Pope, with all due respect to your age, you should be aware that there’s no such thing as dry rot. Fungal organisms which degrade cellulose fiber, such as wood, depend on moisture and not just a little bit of it, but above 20%. Dry rot is a myth that has been perpetuated in the housing industry because many times there is wood that rotted because of staying wet, which then subsequently dried because of removal of a moisture source. A lay person looks at this rotted wood which is dry and says, oh this must be dry rot. On boats, if the balsa core can be kept dry, there is no better core material considering all aspects of construction, performance and ownership.

What is “&emdash”?

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how fortunate my CSY 44 was built of solid glass. Some blisters when I purchased when I purchased it, where the price of blister repair was negotiated, a great repair yard; Yacht Maintenance in Cambridge MD and I am blister free all these years. Ernest M Kraus sv Magic Kingdom CSY WO #123

My 1978 Mainship MK1 is a solid glass hull with a balsa cored deck. The only issues I have are in the cabin top do to the screws that held the flybridge down. I have some cutting and removing to do. I recently installed a windlass, as the boat never had one. I had to drill a new hole for the windlass. The 1 inch of Balsa was as good as the day it was installed, 52 years ago.

Mr. Pope was right and Wayne Richard used an attack on a term to substitute for logic, experience, and science. “Dry rot” is simply rot. Don’t argue about terms, argue about facts. In point of scientific fact, balsa rots very easily and quickly becomes structurally unsound post water penetration. Building a balsa-cored boat is cheaper but the repairs to a wet core, almost inevitable over time, are an expensive nightmare. No boat should ever be built with a core that rots. Cores in general are a bad idea for any boat exposed to the open ocean or a large lake environment. The inferior performance in high flex areas, to sharp blows, in propensity to allow water penetration post damage, etc. keep me from even considering ownership of such a vessel. Weight in a displacement vessel is not a huge consideration and racing with sails is sort of an oxymoron.

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Category A “Ocean” Certification – What Does It Mean?

MJM made it a primary objective that all MJMs would be certified at the highest level of safety possible… which meant those models under 40 feet are ISO CE Certified Category B Offshore, while the 40z and 50z are Certified ISO CE Certified Category A Ocean. There are no other boats of their type, of any size, achieving this high level of offshore safety. In fact, in the worldwide database of the International Marine Certification Institute (IMCI), we have only identified two other models under 40-feet with this certification, both being heavy displacement trawlers. The former achieves this with a low vertical center of gravity and the latter with massive tonnage. What does ISO Certification mean and how should it affect one’s peace of mind on the water? Let’s take a look at the subject.

When the European Union started in 1998, a Recreational Craft Directive was developed to set design/building standards for recreational boats up to 24 meters (79 feet). New and used boats sold in Europe, including boats built in the U.S. or anywhere else being exported to Europe, had to be certified as complying with one of four design categories for seaworthiness. These categories are based on factors such as the wave height and wind speed a given design is capable of handling, plus hull scantlings/strength and stability.

In essence, the further offshore a vessel is expected to venture, the greater the requirements for the vessel’s construction strength, stability, reserve buoyancy, resistance to flooding, deck drainage, crew safety, and other seaworthiness criteria have to be. Let’s take a look at the four categories.

Category A — Ocean  – This is the category with the toughest standards and covers vessels 40’ and over designed to be self-sufficient for extended voyages. It is defined as the “category of boats considered suitable for seas of up to 23 feet (7 meters) significant wave height and winds of Beaufort Force 9 (41-47 knots) or less, but excluding abnormal conditions such as hurricanes.”

Category B — Offshore  – These boats are designed to go offshore with the ability to handle winds up to gale force 8 of 40 knots, and seas up to 13 feet (3.96 meters).

The difference between Category A & B is shown in the above graphic,  where Mass is tons and AVS is the Angle of Vanishing Stability when the boat goes upside down. Category A boats need to be to the right of and above the blue line and a Category B boats to the right and above the red line.

Category C — Inshore  – These boats may venture away from the protected harbors, but within striking distance of home… operating in coastal waters or large bays and lakes with winds up to 27 knots with and significant seas 8 feet (2.44 meters) high.

Category D — Inland or sheltered coastal waters  – These are your typical day boats, operating in protected harbors, small lakes and rivers with winds to Force 4 (up to 16 knots) and significant wave heights to 4 feet (1.22 meters).

Now This Is Important

While a builder may claim that a boat is designed to a certain standard, it doesn’t necessarily mean that it ends up being built to it, unless inspected and certified by an IMCI (International Marine Certification Institute) surveyor, AND the builder can show you this plaque affixed to a bulkhead.

Because the number of people in the boat can reduce stability, the plaque shows the max number of people for Category A conditions, which on the 40z is 16. That’s not a USCG limit for liability purposes at all times. That’s just for Category A conditions.

Good story here. When Bob Johnstone was told that the 50z could carry only 2 more people under Category A than the 40z (18 versus 16), he was concerned about losing a 50z sale to a 40z owner who was moving up, because he wanted to be able to take 20 or so friends on the ICW to eat at Coconuts Restaurant near Bahia Mar… and might be concerned about the liability. “No worries,” said the IMCI surveyor, “We can provide the 50z with a ‘B’ rating as well as an ‘A’ rating, showing he can carry 30 people…and if he’s just going down the ICW or close to shore, you can post a ‘C’ rating, too, showing a capacity for 50 people.” Bob thought was going a bit too far and was happy to settle with the following plaque for the 50z.

Impact on Design and Manufacturing?

MJM Yachts is dedicated to producing the safest, strongest and most durable yachts possible. For this reason, while those under 40 feet can only be rated “B,” each of our powerboats is designed and built to exceed small craft structural requirements for ISO Category A Ocean. ISO requirements for strength are based on a design’s top speed and the expected impact to be absorbed by hull bottom and sides, as well as decks, bulkheads, structural grid, and any part of the vessel’s structure. The laminate schedule and materials are then specified to meet such stringent requirements.

ISO standards for polyester or vinylester resin and the 50:50 glass-to-resin ratio are lower than those achieved on MJMs, built by Boston Boatworks. An MJM is built using a wet prepreg epoxy, Kevlar, Eglass and Corecell with a glass-to-resin ratio of 62:38. Epoxy is significantly more expensive, but 25% stronger, unlikely to crack with use, and is water-resistant… which is why epoxy is used to coat the bottom of boats suffering from osmotic blistering. The MJM is built right from the start!

That’s Not All…

ISO CE certification also takes into account engine emissions. In a world where greenhouse emissions are taking their toll on our environment, this is an important point. Meeting strict ISO CE emissions standards is comparable to meeting similar U.S. CARB requirements.

Additionally, sound levels will come into play. Boats are limited to 75 decibels for a single engine and 78 decibels for twin, triple or quad installations from a distance of 25 meters.

Highest Standards for MJM Yachts

MJM meets and exceeds all applicable standards, because ISO CE standards are more stringent than those of the United States Coast Guard (USCG), American Boat and Yacht Council (ABYC), or National Marine Manufacturers Association (NMMA) which mirror ABYC.

Boats sold in the U.S. do not have to be ISO CE certified… which costs upwards of $20,000 per model. USCG regulations require safety items such as PFDs and flares, carrying capacity for boats under 26 feet (7.93 meters), and level flotation if swamped for boats 20 feet (6.1 meters) and under. ABYC has distributed American versions of ISO CE Standards and Recommendations…but, they are strictly voluntary. Most critically, there are no ABYC design categories to differentiate between boats of different capabilities suitable to differing sea and wind conditions.

NMMA certification in the U.S. requires only about 70% of the ABYC recommended standards. While most U.S. builders follow the ABYC standards, and indeed many exceed those required by the NMMA, they are not mandatory as is the case in Europe with ISO CE mark standards and don’t involve the cost and post-build survey inspection of ISO.

The MJM Category A Ocean certification ensures MJM owners are boating on a stronger, more stable yacht, designed and built to exceed the highest standards in the world. It means having the peace of mind that comes with knowing that should you find yourself in weather and sea conditions outside your prior boating experience, you will be in one of the safest powerboats in the world. At sea, that comfort is the most important form of comfort a yacht can have.

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Catamaran Construction – Hulls, Laminates, and Composites

• Post author By BJ Porter
• Post date October 15, 2020
• 4 Comments on Catamaran Construction – Hulls, Laminates, and Composites

It’s a given that catamarans are more sensitive to weight and loading than monohulls. Catamaran builders strive to build the lightest boats they can without sacrificing strength and stiffness, and have adapted new building techniques and materials to meet this target. Cutting weight allows more passengers and gear without sacrificing performance.

And the marketing materials reflect it–they load every review and website with polysyllabic technical jargon describing the design and production choices each builder made to deliver the best boat they can.

But when you’re reading a brochure and you come across phrases like “ hand laid bidirectional GRP ” or “ vacuumed bagged e-glass with vinylester resin over a Divinycell core ” do you know what that really means?

All modern production catamarans are made with “FRP” construction (for Fiber Reinforced Polymer). Composites aren’t new–it’s just using materials together to strengthen the whole assembly. Straw was added to bricks centuries ago, and steel reinforced concrete is a staple of construction over the last century. For boats, it’s the use of stranded fibers and cured resins which make FRP different.

The term “FRP” doesn’t get into the technical detail of which fibers and which plastics, and how they’re put together to build your hull. There’s a wide variety of fiber types which can be stranded, woven, chopped or sprayed in a varied of patterns then combined with several types of resins to make hulls with different characteristics.

Some FRP techniques produce lighter, stronger shapes, while others are quicker to build and less expensive to produce. The choice of technique is a function of many factors, from the number of hulls and parts to be built, the type of parts, the budget for the project, and many design specific requirements for weight and strength.

1. FRP Basics

The principle behind all FRP construction is the same – you lay our fibers in the shape you need, then saturate them with resin, removing all the air and voids you can. Resin is left to cure, then the piece is ready to finish and use.

The reality is more complex, since building a boat isn’t like making a flat board or a simple door. You’ve got a complex shape with a designed set of curves to build. “Tooling” is the set of shapes to make the boat parts; molds to cover with fiberglass to get the right shapes.

That’s what makes FRP so effective – you can make almost anything out of it. But to do so requires a lot of choices about what you need for the project at hand.

There isn’t a “best” all around material or technique choice for all jobs, and sometimes a lower cost technique or easier to work with material may be the better solution to the problem.

A. Fiber types

Fiber choices in the last few decades have expanded past the glass fibers used in the first mass produced boats in the 1960s. FRP construction wasn’t new even then, they built the first composite boats using modern fiberglass in the 1940s.

The major fibers used in marine construction fall into three categories – glass, aramids, and carbon. The primary differences are in the strength to weight ratios of the fibers, durability, elasticity, and cost. Some construction may use blends of fiber types to combine performance characteristics.

Glass – the most common material still, because of its low cost and versatility. The most common variety used in GRP (Glass Reinforced Polymer) is “E-glass” which refers to its strand size and mineral content. Other grades have different and sometimes better mechanical properties, but may be more expensive and less appropriate for boat building use. Fiber sizes run 10 to 25 microns for E-glass, though other grades may be smaller.

Brands like Leopard, Lagoon, and most higher production volume builders use E-glass.

Aramids – this includes brand names like Kevlar, Technora and Twaron. They have higher tensile strength than E-glass, and resistant abrasion and punctures. Kevlar is a common choice for bullet proof body armor, and can built a tough, lightweight hull. The materials can be difficult to work with, as it is very tough to cut the cloth. It is often blended with carbon fiber or other materials – Catana is known for using Twaron blends in hull construction.

Carbon – the ultimate in lightweight, strong construction material. Carbon fiber is the most expensive fiber, and is available in a variety of weights, grades and strengths. Fibers are smaller than glass – down to 5 Micron.

The lightest, most expensive hulls are made from carbon, but a catamaran builder may use carbon in places other than the hull to add strength and stiffness. Carbon boards, rudders, and reinforcing structures can enhance performance without driving the price of the boat beyond reach. Carbon is the fiber of choice for many custom builds, racing cats, and Gunboat.

B. Mats, Strands, Roving, Direction, and Weights

Fibers are woven into matting and cloth for construction. Depending on the application, different weights of cloth and cloth patterns and weaves may be more appropriate for the job.

Cloth weight refers to the weight per square yard (or meter) of the cloth. A square yard of nine ounce cloth weighs nine ounces. The heavier the cloth, the stronger it is in a laminate.

Fibers carry loads along their length, so cloth weaves have directionality to their strength. Most builders use several layers of cloth with different orientations to give good universal strength to hulls. Specific FRP applications with strict load-path requirements may have more unidirectional fiber layering – for example, a chainplate manufactured from carbon fiber may use unidirectional fiber.

Cloth – fiberglass cloth is commonly used on outer layers of composites. Cloth may have unidirectional or bidirectional strength. Bidirectional cloths have maximum load strengths in two perpendicular directions. Variations on weaves like a modified twill allow a more flexible cloth for better shaping around complex molds.

Mat – is omnidirectional strands of fiber compressed into a cloth. This is often held together with a resin soluble glue, which makes mat great at conforming to mold shapes without folding and bunching as it collapses when wetted. Because the strands do not align, fiber strength is the same in all directions.

Woven Roving – a heavier cloth made from larger bundles of strands. Woven roving allows for quicker buildup of material and strand weight.

Most FRP layups include multiple layers of different cloth and mat. Finished layers may be finer cloth over courser cloth, over woven roving and mat.

Three primary resins are in common use in marine construction – polyester , vinylester , and epoxy . All resins have materials safety concerns and require care in their use and handling.

Polyester is the least expensive and requires breathing protection because of the VOC emission (Volatile Organic Compounds…nasty, smelly fumes). It doesn’t have good bonding/gluing capability, and should only be used with glass fibers for structural building. Some polyester resins are referred to as “isophthalic” resins.

Vinylester is chemically similar to a hybrid of polyester and epoxy, and performs best with fiberglass. It shouldn’t be used in high strength applications with carbon or aramid fibers. It has some adhesive qualities which polyester lacks, it shrinks less during curing, and has better impact resistance.

The added strength of vinylester coupled with increased water resistance makes it an attractive option for many catamaran builders. It costs less than epoxy, but still has better performance than polyester.

Epoxy is the most expensive, but is three times the strength of the others. It offers the best adhesion and the only resin for building structural elements with carbon and aramid. It resists water intrusion better than the other resins, resists blisters, emits no VOCs, and shrinks less. The major drawback is it is more brittle if it takes an impact.

While epoxy is “the best” in terms of strength and ease of building, there are many applications where other resins are appropriate. Budget is a big driver – a boat made from E-Glass doesn’t need epoxy resin, and considerable cost savings to meet a construction price target may drive the choice.

They can build quality boats from all material combinations, but price and performance will drive materials choices to keep some boats more affordable.

2. Cored Construction

What’s the best way to make fiberglass strong? To a point, you can make it thicker. As it gets thicker, it gets heavier. A hollow shape can take more compressive load than a solid one of the same weight, and the same principle applies to fiberglass construction.

Consider an I-Beam used in building construction. It has the same strength (or more) as a solid rectangular beam of similar mass. The compressive load on the beam is supported by the outside edges of the material, the metal in the middle doesn’t contribute much to the strength. So we can remove metal to get the “I” shape while still keeping those sides rigid, making a lighter girder with less material.

The same principle applies to cored construction with fiberglass. Making a sandwich of two layers of fiberglass with a light core between them allows for the greater strength with weight savings.

There are drawbacks – the biggest risk is damage which breaks the skin, which can let water into the core. Earlier cored construction used materials prone to saturation and rot if they got wet. Some builders opt to do cored construction above the waterline and solid below to minimize some of these risks.

But the advantages in weight savings and increased stiffness offset the drawbacks, and there may be a few other side effects like sound and temperature insulation. Like resins and fibers, core materials offer distinct advantages, disadvantages and price points.

Most builders have adopted a hybrid approach, building solid hulls below the waterline, and cored hulls and decks above. This gives a balance of weight and safety.

A. Balsa Core

Balsa is light and inexpensive. The first cored construction used balsa, but it has the disadvantage of being wood. As a natural material, if it gets wet it can rot and break down. Builders use “end grain” balsa – shorter cross cut sections – to prevent wicking of water if there is an intrusion.

B. Foam Core

Closed cell foam cores give good strength to weight savings while minimizing water intrusion. If you get water in the core, it won’t spread very far. Divinycell is a popular PVC foam core, though there are several choices with different densities and compressive strengths.

Some foam cores are not suitable for heat treatment, but infused or vacuum bagged boats like the Outremer and PDQ do well with it.

C. Honeycomb

Honeycomb cores are often the most expensive, but also give some of the best strength to weight ratios. Honeycombed cells made from resin cured aramid papers are some of the best, but also among the most costly. They offer good stiffness, but can be hard to shape. Aluminum and other resin-infused papers are other core materials builders can choose from.

3. Construction and Resin

When building a hull, there are optimal ratios of fiber to resin saturation for target strength and weight. Too little resin and you may not have enough strength (or worse, voids and gaps), and too much, and you’re just adding weight without adding strength. Resins are also a significant material cost in building the boat, so over application not only increases weight but adds cost.

There are many ways to assemble the cores, fibers and resins to build a finished laminate hull – we’re addressing the most common in boat building. Each approach has strengths and limitations, and an impact on the bottom-line cost to build the boat. Any voids or air pockets in the laminate can be disastrous; these techniques have been developed to increase saturation and reduce the risk of voids.

A. Hand Layup / Open Molding

As the name implies, this is the application of resin by hand to cloth as it’s laid into a mold. Wetting is done with a brush, and the laminate is rolled out to remove any air pockets and voids. This is the simplest way to lay up fiberglass, but also the least precise and consistent and will use the most resin.

Skilled craftsmen have built some of the finest vessels in the world this way. Though it’s more popular with monohulls, which are less sensitive to weight, many catamarans built with hand layups on open molds are still out cruising and performing well.

B. Spraying

Using chopped-strand fiber mixed with resin, a “chopper gun” can spray the mixture into a mold to lay down the composite. A consistent thickness can be difficult, but this is a low cost construction technique which makes a very resin-rich laminate. Using sprayed fibers gives lower strength in all directions compared to meticulously laid down mat and bi-directional cloth. But it is a quick technique popular with mass produced, smaller boats.

It is an excellent technique for parts with complex geometry where weight is not an issue, but you will not see it often in catamaran construction. It’s heavy with resin without any resultant increase in strength.

C. Vacuum Bagging (Wet layup)

When an open molded component has been laid up and wetted with resin, vacuum bagging takes the process a step further. After the wetting is complete, air tight plastic bagging is secured around the wetted area, and the air is pumped out of the bag. The vacuum pulls excess resin out and collapses air pockets.

The goal is to get thorough wetting and produce as strong a laminate as possible without excess resin. Knysa and Leopard are two builders that use vacuum bagging on their hulls to reduce weight.

D. Resin Infusion

For resin infusion the cloth, matting and core is laid in place dry, then sealed in an air-tight bag. A vacuum pump attaches to one side of the bag, and on the other a feed for resin. The vacuum sucks the air out of the dry cloth stack, then pulls the resin through the stack, infusing and wetting it.

Resin infusion, when done right, gives the lightest, strongest laminates with no voids and the minimum resin weight for maximum strength. SCRIMP is a variant of the resin infusion process used by some builders, including TPI which build many early Lagoon cats.

E. Pre-preg

Using pre-preg (for “Pre Impregnated”) cloth for your laminating gets rid of the resin bucket. They manufacture cloth with a partially catalyzed resin pressed into it, then it’s chilled or frozen to stop the curing process. There is no need for seperately mixed resins, and there’s no worry your resin might “go off” and harden before you’re done wetting the cloth. Instead, the cloth is assembled, vacuumed, then heated to kick off the curing process.

There are both advantages and disadvantages to using pre-preg for your laminate work. The big disadvantage is the cost; it is most expensive material to use. You also need to chill and store the cloth until you need it, though some can be at room temperature for a couple of weeks without kicking off. And you need an oven which requires some clever tricks if you’re building a forty or fifty foot boat.

But the strength to weight ratio will always be perfect. High tech honeycomb cores are best suited to pre-preg lamination, and without racing against resin cure times, you can ensure perfect cloth placement and precise layout in the build process.

The primary use for pre-preg in boating is high performance race boats. With catamarans, pre-preg may be used high load parts, like Gunboat does for foils and rudders.

4. Industry Examples

Across the catamaran building industry you’ll find almost all the above techniques and materials used, though some are less common. You aren’t likely to find chopped strand sprayed layups in ocean going cats, and hand layups can lead to heavier hulls than weight sensitive catamaran designers prefer. Most manufacturers have moved to vacuum bagging or resin infusion, with a few of the highest end boats using pre-preg for key components.

Built by Robertson & Caine in South Africa, the hull material is vacuum bagged, end-grain balsa-cored E-glass with polyester.

Hand laid, bagged vinylester over an Airex foam core in the hulls.

Earlier Prout catamarans like the Snowgoose 34 featured hand laid solid FRP hulls and decks. Over time they switched to foam or balsa cores for decks and above the waterline.

Older PDQ boats were made from vacuum bagged vinylester – solid below the waterline and cored with CoreCell foam above the waterline and in decks. Newer PDQ models switched to epoxy resin.

All glass is vacuum bagged. Below the waterline is solid E-glass and vinylester. The rest is unidirectional, bidirectional, and triaxial cloths over a Nida-Core polypropylene honeycomb core with isophthalic and vinylester resins.

The Gemini cats are built with a solid hand layup of woven roving and fiberglass mat and polyester resin. Decks are cored with end grain balsa. The Gemini 3200 introduced vinylester resin into the layup to prevent blistering.

Older Lagoons were SCRIMP infused vinylester with and end grain balsa core above the waterline and in the decks.

Newer Lagoon catamarans use polyester and vinylester resins, also infused with balsa cores above the waterline and solid below.

With a carbon fiber inner skin, Catana also uses Twaron aramid fibers in the sandwiched hull over a foam core.

Fontaine Pajot

Primary hull construction is resin-infused vinylester with a balsa cored hull and deck.

Beneath the waterline, Outremer uses a single layer, solid vinylester laminate for safety. The hulls and deck are vinylester with a Divinycell foam core. They stiffen certain components with carbon for rigidity and durability.

Gunboat hulls are epoxy infused carbon fiber with a Nomex honeycomb core. They build dagger boards and other high load components with pre-preg carbon.

• Tags Buying Advice

By BJ Porter

Owner of Hallberg Rassy 53; world explorer.

4 replies on “Catamaran Construction – Hulls, Laminates, and Composites”

Excelent. Thank you for this I learned allot. Johan

Very straight forward information. Thankyou for doing this.

Damn…What an Amazingly Informative Article. *Cheers*

Outremer publish on their website that they use polyester. Not vinyl ester as you have stated.

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Choosing a Blue Water Yacht – Hull Construction

Posted Monday 27th July 2015

Over the last few weeks,  Grabau International has taken you through a variety of subjects which encompass choosing the right yacht for blue water adventures. This guide is not written to dictate what to choose, or to supply a comprehensive encyclopedia of every option and variable, but simply a basic explanation of the main options and some guidance on what to look out for. Finding a yacht will always be a battle of your head over your heart, so the purpose of this guide is to give your head some questions to ask in the hope that an amicable compromise can be made with your heart.  Part 5 of this guide looks at the question of hull construction .

Hull Construction

With the vast majority of production yachts constructed from GRP laminates, choosing a hull construction type is not usually something a buyer has to consider. However, for those looking to venture into high latitudes, those who have differing requirements in terms of maintenance or even for those lucky enough to be in a position where they can embark upon a project from the drawing board upwards, there are plenty of tried & tested alternatives to the ubiquitous glass fibre.

Italia Yachts 13.98 in construction

Universally adopted by production manufacturers and very much the ‘easy option’ thanks to simple re-use of a female mould allowing multiple identical hulls to be quickly and efficiently produced. Traditionally overbuilt, but with often with questionable material quality, GRP production is now seriously advanced with advanced vinylester or epoxy resins and lamination techniques such as vacuum infusion almost completely removing the risk of osmosis (which in itself is never as bad as tradition made out), dry spots or hull voids. Usually allied with some form of core material such as balsa or closed-cell foam, the structure is both strong in tension, but also stiff and well insulated against heat and noise. Solid laminate hulls are still quite common and are popular amongst those with the ‘keep it simple’ attitude, but even here, core materials are usually added in the deck and superstructure areas.

Traditional GRP hand laminate construction

Carbon/Composite

Very similar to GRP construction but using more advanced fibres such as Carbon or Kevlar to create extremely light, stiff and strong hull shapes. Carbon and Kevlar are usually combined as Carbon on its own has very little impact resistance, whereas Kevlar has plenty. Many GRP yachts are also reinforced with Kevlar in the bow section for this very reason (Kevlar is often referred to as Aramid or Twaron after its manufacturer’s name).

A composite weave of glass and Aramid (Kevlar) fibres

Extremely strong but quite heavy. Steel hulls are liable to rust unless well protected from water. Whilst it is relatively easy to monitor the paint system on the outside of the hull, it can be very difficult to see what is happening in the deepest, darkest recesses of the bilge, so most problems with steel hulls manifest themselves from the inside out. Steel is however cheap and very easy and low tech to work with, so for a rugged solution that can be maintained anywhere on the planet, steel certainly has a place.

Steel hull construction

One of the lightest materials for building large yachts, aluminium construction also enjoys a healthy market in smaller craft. For those wanting the security of a metal hull, aluminium will allow the closest match to a GRP hull in terms of weight, stiffness and feel. Traditionally the preserve of specialist manufacturing skills, aluminium welding and construction skills can now be found in most parts of the world, so it is fairly safe to assume that repairs can be made almost anywhere. The downsides are corrosion, both below the waterline and above where imperfections in the paint system can lead to rather unsightly blistering. Many manufacturers side-step this problem by simply not painting their hulls. Electrolysis is also an issue so it is important that the yacht is correctly wired and most well constructed yachts have a double poled system.  When exposed to oxygen in the air, aluminium will develop a very thin layer of oxidization which will then protect the material from further corrosion.

Allures 51 in construction with an alloy hull and a GRP superstructure (photo courtesy of Allures)

Traditional Wood

The original boat building material and in some eyes, still the best. Naturally buoyant, easy to work with and excellent at cutting out vibration and noise, wooden hulls can be an absolute delight. Rot is always a concern, but this can be mitigated by using woods containing natural preventative chemicals (such as teak, magohany and cedar).  Construction methods vary from traditional clinker construction found in smaller dinghies to the more common carvel construction found on larger yachts.

Traditional wooden boat building

Worthy of a separate section of conventional wooden construction, wood epoxy or cold-moulded construction allies wood (usually cedar or mahogany) to epoxy resins and fiberglass resulting in a hull with very few downsides yet with all the benefits of GRP and wood rolled into one. As each hull is in effect a one-off rather than simply laminated in a female mould, wood epoxy contraction is more unusual in the production market (although the French builder RM Yachts and English build Spirit Yachts are two notable exceptions).

A classic Dargon one design in cold moulded (wood epoxy) construction (photo courtesy of Petticrows)

Further considerations.

Hull Colour

Not a construction material, but a process which can have a profound effect on both the aesthetic of your yacht and in some cases the construction material beneath. Very simply put, dark coloured hulls can get hot. A stunning flag blue hull will heat up more in the Caribbean sun than a white hull. This could potentially cause a number of problems for a GRP hull such as post-cure shrinkage of the gelcoat or even delamination, but fortunately these problems are extremely rare and not a reason to avoid dark coloured hulls if you have a hankering for them. The biggest issue with a coloured hull is keeping it looking good. Colours will fade over time and whilst polishing them will bring them back, ultimately, there is only so much polishing you can do before it is time to repaint the hull. If you are happy with this limitation, then there are few things in life as pretty as dark blue yacht, and the manufacturers love dark colours as they create the useful visual illusion of slimming the topsides. Another more modern option is to apply a vinyl wrap to the original topsides. This allows total fleixbility over colour and design and can be removed at any time. The vinyl wrap can also do a good job of preserving the gelcoat or paint finish beneath.

The faded blue topsides of a motor yacht receiving a new lease of life via a blue vinyl wrap (photo courtesy of MBY)

In many instances there will be little choice as to whether the yacht has teak laid decks or not. High-end Scandinavian or British built yachts will almost always have circa 12mm of teak glued and/or screwed to the sub-deck. Teak has its advantages in terms of aesthetic, grip when wet, and insulation against heat and noise. On the downside, teak is expensive to source sustainably and very labour intensive to restore properly. An 8-12mm teak deck should have decades of serviceable life if looked after and not aggressively scrubbed. Even when the caulking is failing and screw fastenings are showing through, there should generally be enough teak left to re-caulk and refasten the deck. This is in effect, a mid-life refit for the deck. The key with a teak deck is to keep it watertight. Missing caulking or exposed screw fastenings can allow water to penetrate through to the sub-deck which can then cause problems within the deck core. Keeping a small tool kit with caulking and fastening materials aboard the yacht will allow continual maintenance to be carried out and the hopeful avoidance of a big bill – or at least will enable you to put off the evil day.

Teak decking on a modern Italia Yacht

Synthetic decks

Increasingly common on cruising yachts where an alternative to teak is desired, a synthetic ‘fake’ teak deck can provide the much of the look and insulation properties of teak without the cost, maintenance and wear implications.  Manufacturers such as Amel and Allures, have made such deck finishes a trademark and there are many products in the market which can be fitted in place of teak very easily.  The finishes available are improving all the time.

Modern synthetic teak decking

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Understanding the True Definition of Full Displacement Hull Design Reveals the Kadey-Krogen Difference

Naval architect James S. Krogen once said, “To produce a successful design, you must make an honest determination of how the vessel really will be used and then prioritize every design decision to favor that outcome.” In the case of Kadey-Krogen full displacement trawler yachts, that outcome is a seakindly, live-aboard ocean crossing yacht. Achieving this objective might appear simple enough but it has long been our view that there is often confusion over what “full displacement” really means.

Unfortunately many people tend to think that all full displacement vessels are the same. Nothing could be further from the truth .

Describing a full displacement hull is very similar. We can differentiate between full displacement hulls based upon two form fundamentals: longitudinal symmetry, and displacement-to-length ratio (D/L)

“To produce a successful design, you must make an honest determination of how the vessel really will be used and then prioritize every design decision to favor that outcome.”

Longitudinal symmetry refers to the degree to which the stern shape matches the bow shape. A simple way to describe what is desired is that a hull with good symmetry will have V-shaped sections and sharp waterlines at both ends.

So why do you want a vessel with a symmetrical hull form? There are four compelling reasons.

First, the fine entry has superior wave-cutting ability making it more efficient compared to blunt, stout-looking forms. The fine entry also yields a softer ride, which means less pounding in head seas. Second, symmetrical forms track better in a following sea. The V-shaped sections aft slice following seas rather than surfing them, making for a safer and more comfortable ride. Third, the aft V-shaped sections also offer less resistance and drag than the broad waterlines of asymmetrical hulls. This results in better fuel economy, a key component of any long-distance trawler.

And fourth, symmetrical forms roll less. Yes, contrary to popular belief, an asymmetrical hull with an immersed transom and/or relatively flat aft sections will actually tend to roll more than a symmetrical hull in a following or beam sea. Why? Simple physics. The leverage (upward force) that wave action has on those flatter sections is greater than on a hull that is more rounded and/or tapered. The upward force on one side creates a downward force on the other side and voilà, you have roll. It is this roll (the downward pressure on the opposite side) that will then cause the vessel to veer off course (yaw). The appropriately symmetrical hull form is much more seakindly than one that is not. Vessels roll and heave as though they are on springs, with less symmetrical forms having stiffer springs (lots of force per immersion) whereas the Kadey-Krogen transom effectively rides on softer springs.

Contrary to popular belief, an asymmetrical hull with an immersed transom and/or relatively flat aft sections will actually tend to roll more than a symmetrical hull in a following or beam sea.

Displacement-to-length ratio

The displacement-to-length ratio (D/L) indicates whether a given displacement is carried over a long waterline length or a short one. It reflects the load the vessel has to carry on a per-foot of waterline basis. Lower ratios tend towards lean and slippery forms with fine ends, and higher ratios tend towards full-bodied and less efficient forms with blunter ends. The lighter the load per foot of waterline length the better the economy and hence the better the range will be. Low D/Ls result from either long waterlines or streamlined underbodies, or a mix of each. Both characteristics serve to improve hull efficiency and therefore fuel economy. Longer waterlines permit higher displacement speeds and streamlined sections result in a hull more easily driven through the speed range. For example, if a given displacement is stretched over a longer waterline, two things happen: The LWL increases (higher hull speed) and the ends get finer and sectional areas less full, i.e. streamlined (less hull drag). Of course, reducing a vessel’s fully loaded weight (displacement) will lower D/L and improve economy but the fully loaded displacement requirement is usually already more or less locked in by the voyaging requirements (living quarters, fuel supply, provisions, etc.).

Reducing D/L yields a more easily driven hull form thereby improving fuel economy and allowing for the use of smaller engines

This long waterline low D/L approach (those in the 260-310 range) can be compared to a bank account earning compounded interest. Reducing D/L yields a more easily driven hull form thereby improving fuel economy and allowing for the use of smaller engines. The improved economy reduces the weight of fuel that must be carried for the desired range and the use of lower horsepower engines will reduce the weight of propulsion machinery. All this weight reduction now results in even greater fuel economy resulting in more weight savings resulting in even better economy, and so the benefits compound.

Interestingly, D/L is often applied incorrectly in the evaluation of long-range trawlers.

Many inaccurate conclusions are made using this ratio. It is important to understand that low D/L does not mean lightweight, or a less substantial structure, or a long and narrow form. How did these misconceptions come to be? Back in the “early days” the market consisted predominantly of shallow flat-bottom coastal craft with insufficient internal volume for the fuel and supplies needed for long-range voyaging. These craft had very low D/Ls. To help bring some clarity to the topic, more than 50 years ago venerable designer and world-voyager Captain Robert Beebe published very useful minimum values of D/L, below which the vessel was said to have insufficient “heft” or carrying capacity for long-range voyaging. Therefore, D/L was used to verify that a vessel had sufficient heft instead of being used to rate hull efficiency. Heft was rightfully considered to be a good thing in that context. And back then, since most boats’ D/L ratios were way under the minimum for long range, the higher the D/L the better. Beebe and other experts agreed that the minimum D/L should be around 260. With many modern passagemakers in the 350+ range, that makes those in the 260-310 range seem “light” and some builders have tried to capitalize on this incorrect assessment.

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The 20 biggest superyachts under construction

Take a peek inside the sheds as we shine a light on the largest superyachts currently under construction, starting with a unique explorer project and followed by a quartet of Lürssens...

REV Ocean | 194.4m

With a new length of 194.4 metres, REV Ocean remains the largest yacht in build anywhere in the world. Construction on the goliath vessel was briefly halted, but happily, in 2023, we got the news that the build had picked back up at Vard's facility in Norway. The mission-based REV Ocean will be a research vessel-superyacht hybrid designed to traverse the globe undertaking crucial studies and visiting the furthest corners of our planet.

Luminance | 145m

Project Luminance is a powerful-looking Lürssen with a classic raked bow and a high, brooding superstructure. Her two-tone exterior in navy blue and silver features two helipads and a large infinity pool and is the work of Espen Øino , marking the 30th collaboration between the designer and the shipyard. Interior design is the work of Francois Zuretti but details remain a closely guarded secret. She was last seen on sea trials in April.

Project Ali Baba | 142m

Another enormous Lürssen project is Project Ali Baba . After leaving the construction shed in two halves in May 2022, she was officially launched in December 2023. The launch comes after the yacht was prematurely revealed when a technical failure of the dock gate at the yard's Bremen facilities forced the yacht's nose into the dock curtain. Aside from the first image showing a grey profile with an elongated bow and bold exterior lines, including two helipads, the remaining details have been kept under wraps.

Project Deep Blue | 130m

While no official specifications have been released by Lürssen, Project Deep Blue is estimated to measure around 130 metres. The semi-complete hull was seen to be preparing to leave the shipbuilder's Lemwerder site in July, where she will move to Lürssen's Bremen facility for the next stage of construction. Here the bow segment will be attached ahead of her expected delivery date in 2025.

Project JAG | 122m

Commissioned by a repeat client as a replacement for his 96-metre superyacht, Project JAG is the owner's third Lürssen. Nuvolari Lenard has given this big vessel a futuristic, winged mast structure and a long pointed bow with what looks like a kind of bowsprit walkway. She can accommodate 20 guests in 11 cabins, with berths for 40 crew (that's two crew to each guest). She was seen for the first time in her full form in August 2023. Since splashing, she was last seen in October 2023, heading out to sea trails sailing down the Kiel Canal in Schleswig-Holstein, Germany.

Amels 120 Full Custom | 120m

Announced as a new evolution of the Amels Limited Editions line, the 120-metre in-build Amels superyacht is designed by   Espen Øino and marks the second custom collaboration between the studio and the Dutch shipyard. Described as a “unique and powerful” vessel, the project is set to be a "green, ecological superyacht" with diesel-electric engines and Azipod propulsion with superlative noise and vibration management.  The yacht is currently the largest project in build in the Netherlands and was last seen arriving at the Damen Yachting facility in Vlissingen, the Netherlands, to begin outfitting. Delivery is slated for 2025 when it is expected to be the largest Dutch-built motor yacht in the world.

Abeking 6514 | 120m

In October 2021, German shipyard Abeking & Rasmussen announced it had signed a contract to build a 120m+ superyacht . The Abeking 6514 will be the largest project undertaken by the shipyard since the commissioning of 118-metre Project 6507, now better known as Liva O .

Feadship 821 | 118.8m

Feadship's future flagship was spotted for the first time as she was floated out of her construction shed in April 2022 . The project, known as Feadship 821 , is said to be the largest yacht built by the Dutch shipyard to date, usurping the 110-metre Anna and, to our understanding, topping the recently launched Project 1010 . Project 821 is due for completion in 2024.

Project 1010 | 118.8m

The 4,999GT Project 1010 marks a significant milestone for Feadship. The design comes from the pen of the redoubtable Espen Øino, whose fluid lines are interrupted by an unusual pair of “eyebrows” amidships. Otherwise, Project 1010 displays a dark blue hull, a heavily raked white superstructure and a unique observation lounge “bubble” deck with curved floor-to-ceiling glass, tucked just under the mast.

Project Cosmos | 114m

Project Cosmos is yet another mega-build by German shipyard Lürssen and was glimpsed for the first time in March 2023.  The fuel cell-powered vessel was commissioned by a Japanese owner in 2020 and features an explorer-style profile with a glass observation lounge, swimming pool and an unusually large tender bay. Her exterior is the work of Australian designer Marc Newson, whose portfolio includes the 139.7-metre Solaris . She was last seen in transit from the yard’s facility in Rendsburg en route to begin outfitting in August 2023, with delivery expected in 2025.

Dorries 156 | 113.5m

In August 2022, it was reported that Dörries Yachts had signed a contract for the construction of a 100-metre-plus superyacht for an American tech mogul.

Oceanco Y722 | 111m

The 111-metre Oceanco Project Y722 was first glimpsed in June 2022 as she left the construction shed and was shipped to Alblasserdam site to begin outfitting. The project is expected to sit around the 5,000GT mark, which would put her as the largest yacht by volume to be built by Oceanco. 

Oceanco Y726 | 111m

Joining Project Y722 is another 111-metre Oceanco, Project Y726. The project moved to outfitting in December 2023, arriving at the Alblasserdam facility in an unconventional graffiti-style wrap designed by Rotterdam-based graffiti artist I AM EELCO. Interior details helmed by   Mark Berryman are understood to be "refined",  with little else being known.

Project Icecap | 107m

When she was revealed last summer at Lürssen’s Peene-Werft naval yard, it was clear that Project Icecap was shaping up to be a very capable explorer yacht. With an axe-style bow and the superstructure well forward, the yacht should punch safely through big seas, while offering big cargo-carrying capacity on the open aft deck. Owner’s rep Moran Yacht & Ship described the boat as diesel-electric powered. An ice-classed hull, heli-hangar and forward observation lounge are also on the spec sheet. 

Freire NB729 | 105m

Little is known about the 105-metre explorer under construction at the Freire Shipyard . It is understood that the yacht has been penned by Bannenberg & Rowell Design i nside and out. The contract was signed in July 2021 with the Spanish yard but no further details have been released. She is expected to be delivered in 2024.

Project JASSJ | 103m

Lürssen revealed the first details of the 103-metre Project JASSJ at the Monaco Yacht Show in 2021. Designed inside and out by RWD , Project JASSJ features accommodation for a total of 22 guests in 11 cabins, with an “industry-leading” beach club aft. Moran Yacht & Ship negotiated the contract and will supervise the build. She was last spotted emerging from the shed of the Rendsburg facility while being technically launched, in the same week that Project Ali Baba also emerged. The yacht shrouded in secrecy is scheduled for delivery in 2025.

Ulysses | 103m

The third Feadship to make this line-up of the biggest yachts under construction is the 103-metre project, christened Ulysses , with expected delivery in 2024. The yacht, last spotted on sea trials in November 2023, has been penned inside and out by Sinot Yacht Architecture & Design , making this the 10th collaboration between the designer and yard. Feadship has said that the yacht’s modern profile used 1,100 square metres of exterior glass and will feature a single-deck engine room. Ulysses will follow in the footsteps of famous yachts under the same name, including two Kleven-built explorers. Once delivered, Damen Yachting’s U-81 will serve as her support vessel. 

Project Jash | 100m+

Turkish shipyard AKYACHT has signed a contract for the build of a 100-metre-plus superyacht, with delivery scheduled for 2027. It is set to be the largest superyacht built on Turkish soil and the biggest undertaking by the shipyard, succeeding the shipyard's flagship project – the award-winning 85-metre Victorious. 

Feadship 824 | 98m

The latest significant milestone in Feadship’s Project 824 is the joining of the hull and superstructure in September 2023. The yacht is now at the yard’s Kaag base, after moving out of the NMC facility, and will undergo outfitting. The yacht’s plumb bow, low profile and contemporary curves draw similiaries to Feadships Pi and Najiba . So far, little has been revealed about this project, but according to BOATPro data she is expected to splash in 2025.

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Best Ocean Boats: Types and Brands to Buy

15th nov 2023 by samantha wilson.

What makes a good ocean boat ? It’s a valid question, commonly asked, but as with many boating questions, there is no one answer. In fact, there is no best ocean boat either. Only the best ocean-going boat for you and what you want it to do. Whether it’s offshore fishing, sailing around the world, coastal cruising, or extended voyages, there will be good boats for the task—and others, not so good. 

Of course there are many characteristics that ocean-going boats will need to have that are different from those designed to ply gentler inland waters where breaking seas, long distances, and inclement weather rarely if ever are a factor. Here we’ll take a look at the types of boats that are designed for the ocean and also look at some of the best ocean boat brands on the market today. 

What Characteristics Do the Best Ocean Boats Have?

Seaworthy in open water and stormy weather: A boat tackling ocean waters needs to be sturdy enough, large enough, and/or nimble enough to navigate the bigger seas and stronger winds that can arise. If you’re tackling oceans, you’ll typically want a boat that is 20 feet long or larger and built with strength. It’s important to know your boat’s limitations, to check the weather carefully before venturing out, and prepare accordingly. Knowing your boat’s range—is it a long-distance, bluewater voyager or a day-sailing coastal boat?—is also key to staying safe. 

Deep-V hulls and deep draft: Most ocean-going boats have deep-V hulls and adequate draft to provide extra stability in turbulent waters, high waves, and bad weather. An exception to that are multihulls, which can offer excellent stability thanks to their multiple hulls and wide shape. In addition to a deep V hull, ocean-going boats are often designed with strakes—molded lines running down the hull of motorboats that help them reach planing speed and reduce the slap from large waves. If you don’t plan to venture offshore or undertake long voyages, a shallow or modified V hull is often ideal for more coastal ocean cruising in shallower waters. 

Corrosion resistance : In contrast to fresh water, salt water is highly corrosive and damaging to boats, and they need to be designed for and maintained to cope with those damaging effects (see our guide to the differences between saltwater and freshwater boats for more advice). Boats designed for salt water will have marine-grade metals such as stainless steel, and must be built with corrosion-resistant hardware.  

Power and fuel capacity : If you’re going to cruise farther, it makes sense that your boat will need a fuel-efficient engine as well as a larger fuel tank to allow you to carry on longer without refueling. Fast boats such as those used for offshore fishing commonly have large powerful engines, allowing you to get to the offshore fishing grounds in less time. For those crossing oceans, sailboats have long been the boat of choice since wind-power is free, if occasionally finicky. 

Sleeping and storage capacity: If you’re cruising long distances, you’ll need to ensure that you have enough cabin space, living space, and storage space for supplies to accommodate all those on board. Bunks will typically be fitted with lee cloths to securely hold sleeping crew members in their berths. Ventilation is also critical, allowing fresh air below decks without bringing sea water along at the same time.

The Best Types and Brands of Ocean Boats

Ocean sailboats.

Sailboats bring the romance to cruising the oceans, and are able to sail motor-less for thousands of miles, making them the top choice when it comes to long range ocean cruising. The choice of sailboat is endless, but it depends how far you want to travel as to how big a sailboat you’ll need. Coastal sailing can be done in most sizes and styles of sailboat, while you’ll ideally be looking for a strong and sturdy sailboat over 35 feet to travel long distances (see our guide to bluewater sailboats under 40 feet for some exciting small sailboat options and what to look for in an ocean sailboat). 

The best ocean sailboat brands

• Hallberg-Rassy has been producing quality ocean-going cruising boats in Sweden for more than half a century. The company’s current lineup of comfortable, seaworthy, premium-priced yachts from 34 to 69 feet LOA.  Hallberg-Rassy boats for sale
• Beneteau ’s impressive range of Oceanis cruisers ranges from 31 to 60 feet and offers spacious, versatile layouts and sound performance at a moderate price.  Beneteau boats for sale
• Jeanneau has produced ocean-capable sailboats for more than 60 years and has a good reputation for building innovative boats that perform well. The company’s current range includes large yachts, small ocean racers, and 35- to 49-foot cruising models.  Jeanneau boats for sale

Hallberg Rassy 400. Hallberg Rassy photo.

Trawler Yachts

Known for their long-range capabilities and excellent fuel efficiency, trawlers are becoming increasingly popular as ocean-going liveaboards. Unlike the fishing vessels from which they draw their name, this new breed of power-cruising yacht typically offers extensive living space, home comforts, and even luxury living, which is highly regarded among many cruising great distances or spending extended periods of time living aboard.  

The best trawler yacht brands

• Nordhavn is a long-standing, all-American brand producing some of the best trawler yachts on the market today. Ranging from 41 feet all the way into superyacht classification sizes, Nordhavn trawlers balance robustness with comfort.  Nordhavn yachts for sale
• Selene is a Dutch brand, building up to 100 world class boats every year. Their impressive inventory includes boats from 40 feet to 128 feet, with their mid-sized models in particular offering excellent use of space and a classic styling.  Selene boats for sale
• American Tugs is one of the best smaller shipyards, with 20 years’ experience producing high quality coastal cruisers under 45 feet.  American Tugs boats for sale

Nordhavn 475. Nordhavn photo.

Center Console Boats

  Center consoles boats are high-powered vessels, commonly used for offshore fishing due to their open deck layout allowing for 360 fishability. Fast, stable, roomy, and well-equipped, they are wonderfully versatile and are available from trailerable 17-foot models up to 45 feet and longer, with cabins and heads. They are typically able to handle big seas and weather, but don’t have the sleeping, living, and storage space of longer-range types of ocean boats. 

The best center console boat brands

• Boston Whaler have been around since 1958 and have one of the best reputations in the center console industry for both their fishing and recreational boats.  Boston Whaler boats for sale
• Everglades is a brand offering 23- to 45-foot center consoles with a clear focus on fishing offshore. It is known equally for premium quality finishings and strong hull construction using high-density foam core to offer a smooth ride in waves. https://www.rightboat.com/boats-for-sale/everglades Everglades boats for sale
• For more check out our article on the best center console boat brands and the best center consoles over 40 feet . 

Boston Whaler 250 Dauntless. Boston Whaler photo. 

Sport Fishing Yachts

Powerful, robust, and equipped to take anglers on deep sea fishing adventures, sport fishing boats are more than capable when it comes to big ocean conditions. They’re capable of cruising up to 100 miles offshore where the big pelagic creatures such as bluefin tuna and marlin live, allowing anglers to fish for several days at a time in comfort. With all the equipment needed for fishing, storing, and living, sport fishing yachts aren’t inexpensive, but you can buy a seriously high-performance yacht for the money. 

The best sport fishing yacht brands

• Viking Yachts has a huge range of world-class sport fishing yachts ranging from towable 38 footers all the way up to 90 feet, although the majority fall within the 45 to 70 feet range. Impeccable finish and extremely high performance is the norm throughout the fleet.  Viking Yachts for sale
• Hatteras Yachts bring elegance and innovation to sportfishing with their four convertible sport fishing yachts from 45 to 70 feet. For more than 60 years, the firm has been creating high-performance sport fishing boats that ooze luxury.  Hatteras Yachts for sale
• Bertram has a long history of building fishing yachts focused on seaworthiness, stability, and safety. The company offers serious blue water fishing machines, as well as smaller, capable boats ranging from 28 to 61 feet.  Bertram boats for sale

For more top fishing boat brands, see Best Offshore Fishing Boat Brands .

Viking 68C. Viking Yachts photo.

Cabin Cruisers

Cabin cruisers make up one of the most versatile and popular of ocean boats as they are multifunctional, seaworthy, and well-designed for coastal cruising. While not normally suited to prolonged periods at sea or long-range cruising, this style of boat features home comforts, modest galley areas, and cabins that can be used for extended trips.

The best ocean cabin cruisers

• Sea Ray are masters in producing small, luxurious cabin cruisers that offer weekends at sea, plenty of home comforts, and reassuring seaworthiness. Their Sundancer range is from 26 feet to 37 feet, and the SLX series goes up to 40 feet.  Sea Ray boats for sale
• Chris-Craft has been producing elegant, traditionally styled cabin cruisers (as well as center consoles) for decades, and their range of boats certainly turn heads. Offering pocket-sized luxury and packed with amenities, they remain one of the best brands in the industry.  Chris-Craft boats for sale
• Grand Banks Yachts is a brand that has shifted over the years from producing what was the iconic ocean-going trawler yacht to a higher-performance luxury motoryacht that fits better in the cabin cruiser category. Design and construction attend to hull shapes, weights, and materials to produce a capable, quiet boat in rough conditions.  Grand Banks Yachts

Grand Banks 54. Grand Banks photo.

Cruising Catamarans

Cruising catamarans are fast gaining popularity for their long-range capabilities as well as their stability and huge amounts of extra living and storage space compared to monohulls of the same size. With salons and cockpits that stand well above the water line you get wrap around sea views, as well as huge cabin and galley space. They’re extremely capable blue water cruisers, but also perfect for coastal adventures with larger groups than you could comfortably get on a monohull. They don’t keel over in the same way as sailboats, offering impressive stability and speed, and are fast becoming a popular choice for around the world cruisers and charter companies. 

The best cruising catamarans

• Fountaine Pajot is one of the biggest names in the cruising catamaran world and are instrumental in shaping this new industry of long range, high performance blue water multihulls.  Fountaine Pajot Catamarans for sale
• Lagoon Catamarans have a huge inventory of cruising catamaran models throughout the size ranges, and are one of the top choices for charter companies.  Lagoon Catamarans for sale
• Leopard Catamarans offer a huge range of top-of-the-range sailing and motor cruising catamarans through boat builders Robertson and Caine. In their 50 years of business they’ve delivered an impressive 2,500 vessels, making them one of the most popular cruising catamaran brands out there.  Leopard Catamarans for sale

Leopard 40 Powercat. Leopard Catamarans photo.

Written By: Samantha Wilson

Samantha Wilson has spent her entire life on and around boats, from tiny sailing dinghies all the way up to superyachts. She writes for many boating and yachting publications, top charter agencies, and some of the largest travel businesses in the industry, combining her knowledge and passion of boating, travel and writing to create topical, useful and engaging content.

More from: Samantha Wilson

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TWO CLASSES

The next edition of The Ocean Race will be open to two classes of high-performance ocean-going racing yachts

The Ocean Race 2022-23 features two fleets of highperformance ocean-going racing yachts – both are capable of high speeds and in the right conditions can cover 600 nautical miles or more in 24-hours. The 60-foot IMOCA Class is racing around the world for The Ocean Race Trophy, while the 65-foot VO65 Class is racing for The Ocean Race VO65 Sprint Cup over three legs: Leg 1 from Alicante, Spain to Cabo Verde, Leg 6 from Aarhus, Denmark to The Hague in the Netherlands, and Leg 7 from The Hague to Genova, Italy.

Perhaps best known for single-handed or doublehanded racing, the IMOCAs will race with a full crew for their first participation in The Ocean Race.

The IMOCA Class uses a development design rule which allows the designers to experiment with hull and sail shapes within set parameters. However, masts, booms and standing rigging are one-design.

Like the VO65, IMOCAs also have a powerful sail plan and a canting keel, but the class rules also allow the use of retractable underwater foils which further boost performance by lifting the boat partially out of the water.

• 60-foot (18.3 metres) carbon construction single hull yachts
• Built to a development rule, so designers can experiment within hull and sail shapes within set parameters
• Raced by mixed sex crews of four or five sailors
• A weighted swinging keel and a pair of retractable underwater foils dramatically boost performance
• Capable of travelling over 600 nautical miles in 24 hours

Having previously raced around the world in the last two editions of The Ocean Race, in the 2022-23 race the VO65s are racing over three legs for The Ocean Race VO65 Sprint Cup.

Built to a strict one-design rule, the boats are identical in every way, and therefore extremely evenly matched.

 A towering sail plan along with a weighted keel that can be canted horizontally underneath the boat make the VO65s powerful and fast in open ocean conditions. 

• 65-foot (20-metre) single hull carbon construction yachts
• built to a one-design rule, so identical hull and sail design
• raced by mixed sex crews of minimum seven sailors
• a weighted swinging keel gives the boat huge leverage and power
• capable of travelling over 600 nautical miles in 24 hours

We are a yacht production company that delivers sturdy well built yachts with premium quality interiors and luxurious furniture.We know what our customers want and we offer them yachts with great performance that are safe, reliable and comfortable.Our primary focus is to keep offering beautifully made yachts that are practical and modern with the latest technology and an aesthetically pleasing design.We believe to be different than our competitors looking to add more value per money so that our clients can enjoy extraordinary experiences on extraordinary yachts.We always keep up with the market changes and aim to build more modern designs that have never been offered by other brands before.From renovating our older models to offering brand new ones our yachts are our pride and joy, proof of excellent thoughtful craftsmanship.

Ocean Yachts are designed to go around the world! Our boats are manufactured to sail into challenging seas with confidence and supreme seaworthiness and with the added value of enjoying blue water cruising with as few as two people.

In all our yachts, primary controls are within easy reach of the helmsman. Each boat's layout is designed to make extended periods at sea truly comfortable. Maximum stowage and comfortable areas for relaxation are of paramount importance when developing the interiors.

The build quality of Ocean Yachts and the standard of finish are truly world class. The entire Ocean Star range is designed and built for all round blue water capability and at the same time provides standards of luxury, comfort and accommodation that have previously only been available on fully commissioned yachts.

Ocean Yachts Manufacturer is one of the few Greek yacht manufacturers in the world. The seagoing tradition of Ocean Yachts and the wealth of talented professionals combine their skills and high quality craftsmanship to produce the Ocean Star range of sailing yachts in Greece.

The Ocean Yachts boatyard and its 40 person, strong workforce are located in Kalivia, 50 km from the center of Athens. The boatyard is built to allow the combination of traditional craftsmanship and semi custom production and has the capacity to manufacture up to 15 yachts a year.

Ocean Star Yachts

Ocean Star yachts are recognized for their strength and sailing capabilities world wide. Safety on board is a fundamental consideration, which is illustrated by the traditional methods of hull lamination, where the bulkheads are structurally reinforced and the GRP girder grid system is bonded underneath the entire surface and hull’s full perimeter to ensure extra strength and solidity. All of the hulls are laminated by hand and molded internally, while special attention is given to detail during production.

Ocean Yachts are very popular as yacht charters in Greece, due to their quality and great value for money.

Ocean Yachts consistently strives to retain the traditions of hand craftsmanship, while keeping its customers’ ever changing requirements in mind. Each new Ocean Star sailboat is launched as a result of personal involvement and professional skill. An Ocean Star is always well-built, enduring and offers first class sailing performance. The well proven construction materials, construction process, and finishings ensure the longevity of these yachts and make them sound investments.

Founded in 2003

Timmerman Yachts is a Russian builder of quality luxury motor yachts. Based in Moscow, it is owned by a group of Dutch and Russian investors and operates out of Moscow Shipyard. Several noted naval architecture and yacht design firms are involved with Timmerman, including Vripack, Guido de Groot Design, Ginton Naval Architects, Jon Bannenberg Ltd., and Francis Design Ltd.

Founded in 2003, the company was named for 17th century Dutch boat builder Franz Timmerman who brought Dutch boat manufacturing techniques to Russia and co-founded the Russian navy. Timmerman Yachts has more than 1,000 employees working at the Moscow Shipyard.

Timmerman has delivered a number of semi-custom luxury yachts between 26-47 metres in length, including TM26 and Timmerman FD-51, designed by Francis Design Ltd. Other notable Timmerman yachts include Victoria M, Alexandra (now Latitude) and Olsten 125′.

One of the 10 largest yacht builders in the world, Timmerman is focused on building high-quality luxury yachts at more competitive prices. Its Russian-Dutch partnership provides great yacht-building capabilities. Timmerman builds yacht to the highest standards and holds DNV, MCA and Russian River Register certification. The company reportedly has more than a dozen yachts in some phase of construction.

Yachts built by Timmerman

Yacht brokerage

Construction of a perfect vessel is a special, incomparable pleasure. ARCON YACHTS gives you a unique opportunity for individual and practically unlimited choice of shipyard, size, design, layout, style, and all the materials. We build each boat in accordance with individual requirements and desires of the customer, taking into full consideration the smallest details and features.

However, at the same time this is a very time-consuming and important process that requires careful and professional monitoring. At this stage, the main objective of the managing company is to find and optimize the complex chain of contractors (shipyards, designers, engineers, audio/video distributors, narrowly focused technical specialists), to minimize risks and expenses of the client, create absolutely new and unique vessel. Set of tasks claims certain algorithm and special schemes of interaction at all stages of construction. The most important criterion of high quality and successful work becomes all Owner’s wishes in conjunction with technical safety requirements and international standards.

ARCON YACHTS undertakes the following tasks:

• Preparation of construction plan with the shipyard;
• Liasons with subcontractors;
• Coordination of design works;
• Execution of customer requirements throughout the working process;
• Monitoring of compliance with all the rules and regulations of technical plan and GA;
• Financial Management;
• Providing reviews and reports;
• The certification, examination for compliance with the class and safety standards;
• Recommendations for vessel registration and ownership structures;
• Representing the interests of the owner;
• The owner has the opportunity to observe the construction progress and milestones;
• Performance testing, commissioning and delivery of the yacht ;
• Warranty support .

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OLSTEN Timmerman Yachts

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If you have any questions about the OLSTEN information page below please contact us .

A General Description of Motor Yacht OLSTEN

Timmerman Yachts completed the building motor yacht OLSTEN in 2004. Accordingly, she has the distinction of being built country of Russia. OLSTEN is a yacht which had design completed by Moscow Shipyard and Moscow Shipyard. This superyacht OLSTEN is able to accommodate a maximum of 12 passengers all told aboard together with around 6 professional crew. Finished and launched in 2004 the comparatively recent interior design and decor demonstrates the proficiency which are originating from Moscow Shipyard and the owner who commissioned the yacht.

Building & Designing relating to Luxury Yacht OLSTEN

Moscow Shipyard was the naval architect firm involved in the professional vessel composition for OLSTEN. Also the company Moscow Shipyard successfully worked on this undertaking. Interior designer Moscow Shipyard was commissioned for the internal interior styling. Russia is the country that Timmerman Yachts built their new build motor yacht in. After her formal launch in 2004 in Moscow the boat was then handed over to the owner after final finishing. Her hull was constructed with steel. The motor yacht main superstructure is made predominantly from aluminium. With a width of 6.8 m or 22.31 feet OLSTEN has moderate internal space. A fairly shallow draught of 1.7m (5.56ft) affects the number of harbours she can berth in, taking into account their particular depth.

Engineering And The Speed The M/Y OLSTEN Can Reach:

The 3406E engine installed in the motor yacht is produced by CATERPILLAR. Connected to her Caterpillar engine(s) are twin screw propellers. The engine of the yacht creates 600 horse power (or 442 kilowatts). She is fitted with 2 engines. The total thrust for the yacht is accordingly 1200 HP or 884 KW.

On board Superyacht OLSTEN There is Passenger Accommodation Capacity For:

Providing room for a limit of 12 visiting passengers spending the night, the OLSTEN accommodates them in luxury. She also has room for circa 6 expert crew members to operate.

A List of the Specifications of the OLSTEN:

OLSTEN Disclaimer:

The luxury yacht OLSTEN displayed on this page is merely informational and she is not necessarily available for yacht charter or for sale, nor is she represented or marketed in anyway by CharterWorld. This web page and the superyacht information contained herein is not contractual. All yacht specifications and informations are displayed in good faith but CharterWorld does not warrant or assume any legal liability or responsibility for the current accuracy, completeness, validity, or usefulness of any superyacht information and/or images displayed. All boat information is subject to change without prior notice and may not be current.

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Capt Fred Senior Member

Has anybody heard or know anything regarding a class action lawsuit against Ocean Yachts deal with teak getting into the hull during construction. This issue from what I'm told deals with Ocean Super Sport boats in the 40' range. The thought was there was a loss of hull integrity due to the oil in the teak. I'm trying to help a friend who has an offer on a 40 Ocean SS.

olderboater Senior Member

Haven't heard of such but with Ocean Yachts out of business, wouldn't expect such to be very beneficial. Would seem like something very difficult to win even if they were in business and would have to be proof of actual damages and proof of cause. Plus, as if that's not enough, would have to be special circumstances to overcome the statute of limitations, although there are situations in which that is possible.

There was no interest in joining the suit but more about how this suit would effect the value and integrity of the boat. More along the line of how hull blistering effected Uniflite.

Well, I don't know that there is a suit and, if there is one, it's not widely known, but now that you're publicizing the problem that could lower value if enough people jumped on the bandwagon with you. I have no idea where you're getting your information. The concept of a class action suit against a company that isn't in business any longer just doesn't sound credible.

PacBlue Senior Member

We fixed the b Capt Fred said: ↑ There was no interest in joining the suit but more about how this suit would effect the value and integrity of the boat. More along the line of how hull blistering effected Uniflite. Click to expand...

Just Cruisin Member

"I'm trying to help a friend(possibly Capt Fred) who has an offer on a 40 Ocean SS." Have to admit his statement sounds fishy. No details on age of boat, current condition, location, hours, etc. A google search on lawsuit turned up nothing. As well, anyone would know that their are no assets for Ocean. The Name only and molds were sold, nothing else. A lawsuit would have no merit and most likely be thrown out. A class action suit would have been published. Know some owners of 40 foot something oceans, not a peep on a class action suit. My guess someone is trying to drive down price of boat. Not a good way to do it and other owners will not be happy with it if it effects resale on their boat.

Beau Senior Member

I'm always curious when someone writes " I'm helping a friend", also. Why doesn't the "friend" make the inquiry?

Well, when someone posts unsubstantiated rumors under the guise "has anybody heard" and "from what I'm told" it just can be damaging to a brand with no substantiation at all. I could post about any brand, "Have you heard anything about a class action suit against them?" If you have information please just say it, but don't put out innuendos and hearsay. If you know of a specific incident then share it. But oil in the teak damaging the hull integrity? When I know of actual litigation against a builder or issues that I have 100% confirmed to be the case, then I'm the first one to want to inform others. I go read the court documents and post based on them. If such a suit as he suggests has been made then it would have been filed in a court somewhere. If so, then let's discuss based on what has been filed and alleged.

Now, to Capt Fred. On April 7, you said, "I recently got a Ocean 44". On June 18, you said you'd just gotten your Ocean insignia and couldn't wait to install it. On June 21 you said you'd sold your boat. On June 23, you said, "I have a cockpit freezer in my ocean". On July 10, you said "On my Ocean 44, it is located" referring to the water tank location and you said "My fill is in the cockpit at the sink" still in the same thread as you also said "my holding tank is under the sole." So, do you have an Ocean or did you sell it? And as an Ocean owner or one who just sold one, what is this really about? Or did you have multiple Oceans? I'm very confused in trying to follow your posts.

JEG New Member

To Olderboater, Fred was just trying to help us a "Friend" like he said. We have put in a offer on a 1978 40 Ocean but was told by a boat broker about this Class Action Lawsuit, but also haven't found anything on it. Fred was just reaching out to the boating community to see if anyone else has heard of this lawsuit. It also could be this boat broker is butt hurt that we didn't buy a boat from her and making up things. I know Fred and he not trying to start any rumors and work the price down. Wouldn't you want to make sure you done all you research before purchasing something this big? Thanks, Chuck, Janece, and Justin

Also to Olderboater, If you think Fred made a new account to back his story he didn't. I have no problem giving you my number and talking to you. Anyways up for a nice conversation. I'm looking forward to joining the ocean community. Thanks Justin

JEG said: ↑ To Olderboater, Fred was just trying to help us a "Friend" like he said. We have put in a offer on a 1978 40 Ocean but was told by a boat broker about this Class Action Lawsuit, but also haven't found anything on it. Fred was just reaching out to the boating community to see if anyone else has heard of this lawsuit. It also could be this boat broker is butt hurt that we didn't buy a boat from her and making up things. I know Fred and he not trying to start any rumors and work the price down. Wouldn't you want to make sure you done all you research before purchasing something this big? Thanks, Chuck, Janece, and Justin Click to expand...

JEG said: ↑ Also to Olderboater, If you think Fred made a new account to back his story he didn't. I have no problem giving you my number and talking to you. Anyways up for a nice conversation. I'm looking forward to joining the ocean community. Thanks Justin Click to expand...

olderboater said: ↑ So does Fred have an Ocean now or did he sell it? Click to expand...

This is for Fred then, did you not sell your boat on June 21 or was that a different boat or what?

Yes I sold a Tollycraft 37 (read my earlier post), I was a two boat owner for a short time. I'm currently a proud owner of a 44 Ocean SS. Two different boat brokers said they knew of the lawsuit and it was concerning 1978 and 1979 40' Ocean SS and the suit goes back to the 1980 time frame, way before Google. Nothing malicious meant by my post, truly trying to help a friend. I'm satisfied that nobody on this forum has heard of such a suit.

Fred, I am also the owner of a 94 53 Ocean Super Sport and very pleased with her. A little advice, next time why don't you try starting with Boat US and asking them if they are aware of any pending litigation or problems with a certain boat. They have very good resources. I am sure most other Ocean owners do not appreciate a thread that starts with Class Action Lawsuit Against Ocean. Much better to ask of info on a certain boat and hear the pro's and con's.

Capt Fred said: ↑ Yes I sold a Tollycraft 37 (read my earlier post), I was a two boat owner for a short time. I'm currently a proud owner of a 44 Ocean SS. Two different boat brokers said they knew of the lawsuit and it was concerning 1978 and 1979 40' Ocean SS and the suit goes back to the 1980 time frame, way before Google. Nothing malicious meant by my post, truly trying to help a friend. I'm satisfied that nobody on this forum has heard of such a suit. Click to expand...

Donzi 54 Member

I do remember that there was a lawsuit that was brought against Ocean yachts. But it was a very long time ago and it went know where. Nothing ever came of it and from what I remember it was dropped.

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Ukraine war latest: Poland to ramp up ammunition production amid fears Putin will attack NATO

Poland wants to ramp up its production of 155mm artillery rounds in the hope of ensuring sufficient supplies if Russia attacked NATO, a senior official has told Reuters.

Wednesday 4 September 2024 17:39, UK

• Poland to ramp up ammunition production amid fears Putin will attack NATO
• Russia continues heavy bombardment of Ukrainian cities
• Seven killed in Lviv - including three children
• Dominic Waghorn: Putin rubbing salt in wounds as Kyiv pleads for long-range attacks
• Ukraine planning to hold seized Russian territory indefinitely
• Watch: Zelenskyy discusses Kursk invasion in TV interview
• Live reporting by Niamh Lynch

That brings an end to our live coverage of the Ukraine war for this evening.

We'll be back with any major developments overnight and our rolling updates will continue soon.

Before we go, here's a reminder of the day's key events:

• Seven people were killed in an overnight strike in the western city of Lviv. One injured man lost his wife and three daughters - aged 21, 18 and seven - in the strike;
• Another strike in President Volodymyr Zelenskyy's hometown left five people injured ;
• Poland said it aims to ramp up ammunition production in anticipation of a Russian attack on NATO;
• Ukraine's parliament approved the dismissal of four ministers in a mass Cabinet reshuffle to bring "new energy" to the war effort but the highest profile dismissal so far, of foreign minister Dmytro Kuleba, has not yet been voted on;
• Ireland and Ukraine signed a co-operation deal after Irish premier Simon Harris said it would provide a €43m (£36m) funding package.

Military analyst Michael Clarke says the campaign, which started early last month, "is not hurting Russia as much as hoped".

Watch his full analysis here...

Three civilians were killed and two wounded by Ukrainian shelling in a village in Russia's Belgorod border region, governor Vyacheslav Gladkov has said. 

The Belgorod region has come under frequent cross-border shelling and drone attacks in the course of the war. 

It is adjacent to the Kursk region where Ukrainian forces pierced Russia's western border last month in an incursion that Moscow's forces are still fighting to repel. 

The US is set to accuse Russia of a campaign to influence the 2024 elections using online platforms to target American voters with disinformation

CNN reported that Russian state media network RT will be a focus of the announcement. 

The news comes just hours before attorney general Merrick Garland is due to make public remarks at a meeting of the Justice Department's election threats task force. 

The department had previously warned that Russia remains a threat to November's presidential election. 

In a speech last month, deputy attorney general Lisa Monaco warned that President Vladimir Putin "and his proxies are using increasingly sophisticated techniques in their interference operations".

She said: "They're targeting specific voter demographics and swing-state voters in an effort to manipulate presidential and congressional election outcomes. 

"They're intent on co-opting unwitting Americans on social media to push narratives advancing Russian interests. They’re working to diminish American support for Ukraine. And they’re always adapting."

Parts of the Republican Party has been hugely critical of billions worth of funding packages provided to Ukraine - with previous House of Representatives' bills caught up by divisions in the GOP.

Donald Trump has said he can resolve the Ukraine war with possible peace talks that might require Kyiv to cede territory.

The Democratic Party has been broadly supportive of maintaining Ukrainian funding.

Russia's foreign minister Sergei Lavrov has warned the US not to joke about Moscow's "red lines".

The US was losing sight of the sense of mutual deterrence that had underpinned the balance of security between Moscow and Washington since the Cold War, he said.

He was commenting on a report that the US is close to an agreement to supply Ukraine with long-range JASSM cruise missiles that could reach deep inside Russia, which President Volodymyr Zelenskyy has been lobbying for.

"I won't be surprised by anything - the Americans have already crossed the threshold they set for themselves. They are being egged on, and Zelenskyy of course sees this and takes advantage of it," Mr Lavrov told a Russian TV interviewer.

"But they should understand - they are joking about our red lines here. They shouldn't joke about our red lines."

Vladimir Putin has repeatedly warned the West since launching what he called his "special military operation" in Ukraine not to try to thwart Russia, which has the world's biggest arsenal of nuclear weapons.

But Washington and its allies have increased military aid to Ukraine, including by providing tanks, advanced missiles and F-16 fighter jets.

That has prompted some Western politicians to suggest Putin's nuclear rhetoric is a bluff and that the US and NATO should go all-out to help Ukraine win the war. 

Mr Zelenskyy has said that Ukraine's incursion into Russia in recent weeks makes a mockery of Putin's red lines.

Some NATO officials say the Kremlin might be ready militarily to attack countries that are members of the alliance in five to eight years' time, once it has rebuilt its forces after the war in Ukraine.

Moscow has regularly dismissed Western suggestions that it might consider an attack on NATO.

"Our ambition... is to have the ability to fill up Polish warehouses in parallel to achieving a full, independent capacity to produce ammunition in Poland, within five to eight years," Maciej Idzik, board member of the state-owned Polish Armaments Group, said.

Demand for 155mm artillery rounds has soared in the wake of the invasion of Ukraine. Allies' supplies for their own defence have been run down as they have rushed shells to Kyiv.

The European Union is seeking to expand the bloc's ammunition production capacity to two million shells annually by the end of 2025 by allocating €500m (£421m) in funding to increase shell supplies to Ukraine and replenish EU stockpiles.

We brought you news earlier about a father who lost his family in the overnight strike in Lviv. 

New footage shows Evgeny Bazylevych being comforted by emergency workers after losing his wife and three daughters, who were aged seven, 18 and 21. 

The eldest daughter, Yaryna, was a programme manager at the European Youth Forum, a platform of the continent's youth organisations, her colleagues wrote on Facebook. 

"We will neither forget nor forgive" the attack, they said in the post.

Lviv's mayor said Evgeny was in a critical condition after the strike.

Ukrainian authorities have since updated the number of people injured in the attack to 53.

The Swiss government has said it will not lift its protection status for Ukrainian refugees fleeing Russia's invasion before 4 March 2026, as the situation in their country is not expected to change in the foreseeable future. 

Switzerland granted Ukrainian refugees protection status "S," which grants temporary protection to those in need as long as they are exposed to serious general danger, in March 2022. 

Russian airstrikes hit energy facilities and critical infrastructure in nine Ukrainian regions over the past 24 hours, Ukrainian officials have said.

Energy facilities in the western region of Lviv, Sumy and Kharkiv in the northeast, Donetsk in the east, east-central Dnipropetrovsk, and Mykolaiv in the south were attacked, the energy ministry said on Telegram.

The ministry did not provide additional details on the scale of recent damage to the energy grid.

Meanwhile, Ukraine has cut nuclear power output after Russian attacks damaged the country's electricity transmission system, nuclear firm Energoatom said today.

It said output was reduced after "hostile shelling of infrastructure" and "significant fluctuations in the parameters of the grid".

President Volodymyr Zelenskyy has said he wanted to "express his gratitude to Ireland" after signing a co-operation deal with the Irish prime minister Simon Harris in Kyiv.

Mr Harris announced earlier that Ireland would provide a €43m (£36m) funding package for Ukraine (see 8.56am post). 

The deal includes work on demining Ukraine, which Mr Zelenskyy said would save Ukrainians and improve the resilience of Europe.

The deal also includes work on cyber security.

The taoiseach also expressed Ireland's full support for the Ukrainian bid for EU membership while also discussing continued humanitarian assistance. 

Following the bilateral meeting, Mr Zelenskyy told a press conference that he thanked Ireland for its support of work on returning abducted Ukrainian children to the country.

"Ireland's participation in the reconstruction of Ukraine will be a substantial support for our people and our countries and our European way of life."

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