Boat Size and Price are About Displacement and Righting Moment

Tons=$ € £


  • Q1: What do the Adventure 40 and a Westsail 32 have in common?
  • Q2: What’s the biggest difference between the Adventure 40 and a Valiant 40?
  • Q3: What parameter governs the size and expense of the mast and rigging of a sailboat?
  • Q4: Of the common metrics used to describe a boat (LOA, LWL, Beam, Displacement, Draft), which one tells you the least about the boat and how much she will cost to build and maintain?


  • A1: They are both about the same size.
  • A2: The Valiant 40 is a bigger boat, almost 30% bigger.
  • A3: Maximum righting moment.
  • A4: LOA (Length overall).

The point of this little quiz is to show that boat design can be really counter-intuitive. And while we voyaging sailors certainly don’t need to become naval architects to select the right boat for our needs, the way that boats are generally described and talked about these days does set us up to fail if we don’t take the trouble to understand the fundamentals of how our boats work.

Size is About Displacement

For some reason the first metric that we always use when describing a boat and comparing it to others is length overall. But that is simply wrong. The right number to use is displacement, being the weight of the water that a boat displaces. Or to simplify further, the size of the hole in the water that the boat makes.

If we think for a moment, this truth becomes obvious. If two boats weigh about the same, like the Adventure 40 and Westsail 32, the volume of the hole in the water they make will be about the same too, and therefore they will be capable of holding about the same amount of gear and people.

Further, it will take about the same amount of material to line that hole in the water (the hull) and about the same amount of furniture and gear to fill it. And theretofore these two boats are about the same size, and will, assuming the same construction techniques, cost about the same to build.

Using the same logic, we can see that the Valiant 40 is a bigger boat than the Adventure 40, and will be much more expensive to build, even though they are about the same length, because the former weighs much more than the latter.

Rig Size is About Stability

Now let’s turn to the size and cost of rigging a sailboat, what determines that? The answer is a single number that has nothing to do with overall length: the maximum righting moment.

Imagine you attach a line to the top of the mast of a sailboat and use it to winch the boat over on her side. The strain on the rope will start off quite small, but as the boat is heeled and the keel is pulled away from the vertical, the pull needed to keep heeling the boat will increase until a maximum load is reached. That is the maximum righting moment. And, as we perform this experiment, the loads on the rigging will go up in exactly the same way.

The same thing happens when the heeling is a result of wind pressure on the sails. The loads on the sails and winches will again max out when the boat’s keel weight exerts the maximum force against them in trying to right the boat. And if we make the boat more beamy, or increase the weight of the keel, she will be more stable and the rig will cost more too because everything will need to be stronger and bigger.

By the way, don’t confuse maximum righting moment with safety from capsize or knockdown. It is perfectly possible, in fact likely, that a long thin boat (like the Adventure 40) of a given displacement will have a lower maximum righting moment and therefore a less expensive rig package than a short beamy boat, and still be safer in the ocean from capsize risk.

Don’t believe me? Think about a catamaran, which has a huge maximum righting moment due to her extreme beam—this is called form stability—but a quite low ultimate stability angle and almost no ability to return to upright from a capsize.

(I’m not beating up on cats here. I do know that they have advantages too. I’m simply using them to illustrate a basic point.)

Also, don’t make the mistake of assuming that a longer narrower boat with a lower maximum righting moment must heel more (be more tender) than a shorter fatter boat of the same weight. In fact, because the former hull form tends to be easily driven through the water, if designed properly, she can be sailed fast with less sail area and little or no more heel angle than her beamy competitors.

Why 40 Feet?

So we can now see that you could build the Adventure 40 at a lot of different lengths and still spend the same amount.

So why 40 feet? Well, first off, she may get a bit longer, or a bit shorter, as the designer optimizes the hull form. Displacement may go up a bit too, as we make sure that she is sea kindly. But a few initial sketches have confirmed that she will be between 39 and 41 feet overall, and comparatively narrow, but not excessively so. This combination will yield the best combination of speed and sea-kindliness.

Adventure 40 Price

[The paragraphs below are based on 2012 prices and so we must adjust them for inflation.]

The point of all this is that the Adventure 40’s target price of less than US$250,000 is a lot more credible when you understand that she is a smaller boat than many 40 footers and also, because she is narrower with a lower maximum righting moment, she will have a cheaper rig, sail, and winch package than many of her heavier and/or beamier competitors of the same length.

To see what this means in the real world of hard cold cash let’s compare the Adventure 40 to the Beneteau Oceanis 45, a 23,000 lb boat that sold for about US$225,000 in 2012. The Adventure 40 will be:

  • Substantially smaller.
  • Have a much smaller rig and lower maximum righting moment.
  • Have no dealer network.
  • Be tiller steered instead of having twin wheels. The savings here alone should pay for the massive strength that we plan to build into the Adventure 40.

It’s all starting to make sense, wouldn’t you say?


OK, I know I simplified in this post, maybe even oversimplified. For example I left much about form stability and everything about wetted surface, prismatic coefficient and water plane area out of the discussion.

Please don’t waste a lot of your time and mine nitpicking at those items, or any others that you can think of, that are not material to the overall point of this post. Keep in mind that I’m trying to explain, in the simplest and shortest way possible, the factors that effect boat size and cost to build.

On the other hand, if you have a question, or if I have missed something that is material to the core point of the post, I’m all ears. Please leave a comment.

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C. Dan

Rather than try to form coherent sentences of my own, I will just steal one of yours:

For some reason the first metric that we always use when describing a boat and comparing it to others is [price paid]. But that is simply wrong. The right number to use is [total 10 year cost of ownership].

I think if we could re-frame the discussion around this point, the cost/benefit of the A-40 would be even more manifest.

Dick Stevenson

Dear John,
At some point, it might be wise to take your ideas, with the combined resources of this group, and generate some more broadly based publicity with the goal to educating the general sailing audience about what a good sea worthy sailboat looks like and is built like. This has been sorely missing in recent decades to my mind and I see a generation of sailors who do not have much notion of what attributes a good ocean going sailing vessel should have nor do they have many examples ready at hand. I suspect that there could be interest and an audience. I am reminded of the book “Desirable and Undesirable Characteristics of Offshore Yachts” (collaboratively authored and put together by the Cruising Club of America) that was one of my bibles (among others) in the early days. Your writings and the responses of the site’s participants could easily generate a few articles or be put together into a book format. This recent blog alone could be an article in itself. This in turn could generate some momentum at the right time for the public and/or a manufacturer to get excited and on board. It is an exciting endeavor very likely to appeal to some minority of sailors, but also to many armchair types who could root for the project all leading to momentum, interest and a wider base for generating sales.
My best, Dick Stevenson, s/v Alchemy


Very interesting! And some really good and simple explanations. I think I refer to this text later on when I sell my own boat. Some of it makes sense for my old 38´as well. Eager to read more later on.

/Nemo in Puerto Williams, Chile

richard s.

dear phyllis and john, what am i doing wrong with the donation site as it won’t register my fl address…wants only canadian data even though i indicate u.s. as the country ? this is your christmas gift so please advise and thanks

richard in tampa bay
s/v lakota



Change the country in the drop down to a non-us country, the change it to the US again. Make sure you click on the country with your mouse and not just use the arrow keys and return. This will populate the states after you select the US again.

I had the same issue and got around it this way.


Hi John,

Great post and good easy understable synthesis of the main points of what should become a great design,
i would add the title of a recent post of the french forums :
“Esthétique d’un voilier et rapport confort/performances”,
easily translated by : esthetics of a sailboat vs comfort and performances,
S&S used to say that a nice boat would sail fine, a fast shortcut to say what we all think,
sleek and nice lines make it all tru in the end,
(even if mine is a short and bulky old hull, but sleek one in my heart …)

Matt Marsh

Great post, John.

To elaborate on one common point of confusion: There are at least four different ways of stating a yacht’s displacement.

When we talk about the Adventure 40’s performance, we are usually talking about “m_LDC”, the displacement at design load- including crew, fuel and gear so that she’s sitting at her designed waterline. This is approximately what she’ll weigh in actual service.

Some marketing materials for other boats state “m_LCC” (the dry weight, fresh from the factory) or “m_MOC” (the displacement in minimum operating condition, including minimal crew, minimal gear and 1/2 tankage). This makes the boat appear lighter, and her performance ratios more favourable, than would be the case in normal service.

There are no set-in-stone numbers yet, but the very rough ballpark for the Adventure 40 is m_LCC ~8300kg and m_LDC ~10250kg, making her about 20% smaller than the Beneteau mentioned in the post.

(PS- John, there’s an extra http/ in that Beneteau link.)

Matt Marsh

One other thought.

Rigging costs are indeed dictated by rig size, and therefore righting moment. But the relationship is not linear. The winches, blocks, tracks and such to handle an 800 sq.ft sail cost far more than double what you’d pay for gear to handle a 400 sq.ft sail. There are also sudden jumps in price as you go larger- at some point, you hit a threshold where you need electric help (or beefcake crew on coffee grinders) to turn the winches, and the hardware cost skyrockets.

Keeping the Adventure 40 slim, efficient and not too portly will keep her rig size (and therefore cost) in a regime where a crew of two average adults can handle her without having to rely on electric assistance.

Will Taylor

Very educational post. Many thanks.

Jus wondering if there might be pilot berths in the A40?

Will Taylor

Dave Benjamin


The older Amel’s like our have a nice arrangement for the sea berth. The back rest swings around and becomes a padded leeboard. I could easily document the design with some photos. We find it’s brilliantly simple and the settee makes for a great berth in any conditions. We don’t have the berth in the pass-thru like some of the larger and newer models.

Will Taylor

John —

Thanks for the reply. Pilot berths are a fetish of mine. Perhaps the worst experience I have ever had on a boat was aboard a J42 in the 1999 Halifax race, nine in crew. The J42 has two settees, OK as sea berths with lee cloths, and one quarter berth, so in the best conditions there will be one or two people sleepingon the cabin sole. We had a 30 to 40 knot Nor’easter with the most uncomfortable sea conditions I have ever experienced, all nine crew seasick and the off watch and two or three others all below trying to find a place to lie down. Chaos. Drives me crazy that no production boat that I am aware of offers pilot berths these days.


Horatio Marteleira

Very clear and helpful explanation, as usual. But there’s one aspect that doesn’t make sense “to me”.
You said “the volume of the hole in the water they [boats] make will be about the same too, and therefore they will be capable of holding about the same amount of gear and people”.
Won’t an overbuilt (heavy) boat have a lower load-bearing capacity than a larger lighter boat of the same weight, insofar as the heavily built boat’s extra weight is, in essence, cargo?
Not nitpicking, just wondering if I’m missing something here.
Horatio Marteleira

Horatio Marteleira

Thanks John,

You know, for years I’ve been reading that heavy displacement boats have a better load-bearing capacity…the logic seemed to elude me but I never gave it much thought until now (maybe I didn’t want to hurt my brain either). As the owner of a Corbin 39, it also made me feel better; don’t we all like to feel good about our boat choices?
Anyway, maybe that’s why your blog is so popular and interesting – you push the right buttons to get us boat owners thinking.

Matt Marsh

Sounds about right, John.

Horatio, it’s worth noting that the bare structure of a cruising monohull accounts for only about 30% of the boat’s dry weight. 40% is keel, and the remaining 30% is interior joinery, hardware, engine and rig.

The net difference between a “built strong like bear” Adventure 40 and a “built light and fragile like bird” Adventure 40 would be about one-third of the structural weight, or less than one-tenth of the boat’s dry weight. There is no stability penalty for beefing up the structure, and the performance penalty for the extra structural weight is on the order of 2%- a good sacrifice, in my opinion, for a boat that will have a far longer service life and be much less prone to damage.

Horatio Marteleira

I agree with you.

However, I was basically saying the following (another perspective of what I originally stated): A heavy displacement boat of the same length and beam as a lighter displacement boat will not be able to carry as big a load. This is because the heavy displacement boat is inherently already carrying an extra load (its heavier weight).

Paul Tetreault

Hi John,
I have been enjoying your postings for months; usually I’m in full agreement with your conservative approach and philosophy to off-shore sailing …and I find myself in full agreement again.

As the owner of a Bill Tripp Jr. 1961 Block Island 40 (Series I) yawl, you are in many ways describing Tripp’s design approach …albeit without the CCA rule-beating overhangs, the 800 lb. bronze swing keel or the rule-beating mizzen stay sail. (Items that I love …for their simple beauty and for island-hopping through skinny water). Other than those (okay …big) differences, you might be describing the same boat!

The BI40 was the first “big glass boat”, the forerunner to the Bermuda 40 and is literally a floating rock, solid glass throughout. That’s one reason (for good or bad) we decided to restore her. I am sure she weighs a lot more than today’s typical 40s. At 22,000 lb, she’s a big, relatively narrow hole in the water.

My question is; when comparing the A40 to the heavier displaced Valient, how might construction and hull lay-up differences effect the calculations? …or might the differences be only minor?

Thanks again for managing this incredibly worthwhile site! Best, Paul

Dave Benjamin

In comparing these boats, it can be noted that cost of ownership for the A40 will be far less than for that 30 year old Valiant. Here in the US, a boat mortgage can be had for 4% or less at 15-20 year terms. And if someone were to buy and refit an older Valiant, they would have a substantial percentage of what they would pay for an A40 invested.

Dave Benjamin

Refits are exceedingly expensive and very little of that investment can be regained. When we bought our Amel Maramu, the previous owner had invested about $130K and a few years into the refit before health issues forced the sale. Needless to say he lost almost all that investment. I would expect the A40 to do a good job of maintaining value. So if someone buys one, uses it for an extended cruise, they would likely be able to re-sell and recapture a far greater percentage of their purchase price than they could ever hope to refitting an older boat. And while there’s certainly challenges commissioning a new boat, if they keep things simple and quality control is good, it will be a win for sure.

capt richie

A minor point perhaps but why not aim for an LOA a few milllimeters shy of the 12-meter cutoff in the COLREGS so as to reduce the future costs of compliance? I expect more and more regulation and fees on private yachts as governments expand their efforts to discourage free, noncommercial navigation, with the 12-meter parameter being the point under which such regs may be a bit more lenient in their requirements.


11.99m is indeed a cut-off, my irish reand Terry just sold his 4 years old ovni395 for that reason, and will buy or an older 385 or a new 445 …

Matt Marsh

She’s known as the Adventure 1195 in my preliminary notes, for this exact reason….

Dave Benjamin

Here in the US, there’s a variety of small rule changes that cumulatively add up to additional expense. For instance lighting requirements would require deck lights with more visibility range. Most of us just use a masthead tri-color at sea. If the design goal is a 40 footer, making it an inch or two less than 40′ and saving some money on equipment is laudable.


Well I’v got 2nm navigation lights (those for boats over 12m) on my 31ft boat because I want to be seen at night. This is imho the wrong part to save money – not to speak of liniting the design of the whole boat.
The limit for the use of a tricolor masthead light is 20m as far as I know. (at least in Europe)
Are there other rules that I’m not aware of?


Please google “Adams 13” or We built one in the early 80’s and did over 25000 miles in her. Great boats and nearly fit your design parameters perfectly. Brett

John Armitage

What a great posting, John!

RDE (Richard Elder)

Hi Brett,
Gorgeous boat— (Adams 13) I spent a couple of weeks in the Bahamas aboard a Tom Wylie 44 with similar dimensions, although it had an 8′ /5′ ballasted lifting keel. We saw 12.8 knots under plain sail, and regularly sailed at tens. Although we did interisland day passages they were by no means an adequate test of an ocean cruising boat. My take away was that as much fun as sailing the Wylie was, it wouldn’t be my choice for crossing oceans.

The Adams design is a perfect example for discussing the trade offs that any design choice represents:

Cost: Given the same level of interior and equipment fit out, this 14,460# 43+ boat would cost less than the 18,000# Adventure 40 with a masthead rig, and skeg mounted rudder.

At first glance the Adams looks to be 50-55′— its sleek lines become more understandable once you realize that at 5’11” with no headliner it doesn’t have standing headroom for most Yanks. A real world production design would have to have 4″ more hull freeboard and would suddenly look more ordinary.

Beam: Having once built a boat with a 10’5″ beam and struggled to find 1/4 inches here and there to fit what I wanted into the center of the boat, I’d emphatically argue that with a 10′ beam you get two parallel berths and a removable or double drop leaf table, with 11′ you can have a fixed table and semi-U shaped dinette, and at 12′ you can have a pilot berth or bigger bookshelves. “You pays your money and gets what you pay for.” The choice of beam completely determines your interior layout options. Play artsy interior designer with curved settees and the like and you simply make it non-functional.

Fractional rig: With this type of boat that needs to be reefed early and often, a frac makes economic and sail handling sense, although I’d want a 7/8th with a stiff mast instead of a 3/4. Smaller, cheaper winches. Easier, faster reefing with a full batten mainsail. Cheaper roller furler. Less overall sail cost. Downside is a less balanced downwind sail plan.

Transom hung rudder:
With a tiller boat hanging the rudder on the transom makes a lot of sense. Cheaper, easier to repair at sea, can even be made to kick up if you catch a drift log at just the wrong angle. Major downside is that it makes a wind vane installation awkward.

Weight carrying ability:
The Adams has a length/beam ratio similar to a Santa Cruz 5o, and is only slightly heavier relative to its overall size. Actually all the difference is in the amount of extra ballast necessary to keep such a narrow boat on its feet as a shallow draft centerboarder. As such it will not like to be loaded down with luxuries like extra toothbrushes. Although the interior volume is larger than the Adventure 40, the available space is in the ends of the boat. I guarantee she will not be happy with a 60# Ronca and 300′ of chain in the bow or a watermaker and genset in the lazerette—.

Everything is a trade-off. Personally I’d love to have a Adams 13 m or 14m built using my catamaran designer friend Kurt Hughes’ ultra-rapid cylinder molding technique and clear epoxy finished 3mm Sapele plywood as the hull interior. Different strokes for different blokes.

RDE (Richard Elder)

Anyone else intrigued by the Adams 13 design? Particularly intriguing is the aluminum one with retractable bulb keel for about 60k ask. Looks to have hull insulation and just waiting for somebody to weld on a proper hard dodger. Under different circumstances I’d be on a plane to look at it!
ps— want it delivered back to the US?

RDE (Richard Elder)

Spent two weeks on a boat with these dimensions. About the same interior volume as a conventional 36 footer, and adequate for long distance cruising for a couple who have a non-consumerist life style if it is thoughtfully designed. What is neat about the lifting keel is that you can put enough lead in the bulb and put it deep enough to end up with a relatively stiff boat even though it is narrow. And with aluminum construction the chances that the keel box design is ultra-strong are greater. Keep in mind that this boat is “only” 8″ narrower than the first proposal for the A 40. You don’t really open up more interior options until you expand the beam to about 12′.

I’d be the last to suggest that a painted aluminum round bilge hydraulic lifting dagger keel Adams 13m design is cost feasible within the A40 proposal budget! And given the budget to build this design in painted aluminum today, I’d allocate my money toward different priorities and design direction.

Dick Stevenson

Dear John,
You asked and I concur with your comments about the load carrying attributes of the Valiant 40/42. I have been extremely pleased over the years at how much weight Alchemy has absorbed while generally maintaining her fine sailing characteristics. Scott and Kitty did their second circumnavigation on a V40 with their 2 sons so I am sure Tamure was in no way svelte during those years.
And, like a good host, you understate a tad how much weight Alchemy has gained. More specifically from the 24,500 that is reportedly our base weight we exceed 32,000 on a couple of travellifts of m_LDC weight or full fuel/water, provisions, and stores. And for those that envision a full attic/garage rather than an aft cabin and with bikes, kayaks and jerry cans all over the deck: that is not the case. While quite comfortable and in no way deprived, we do not have a lot of weighty toys: most weight is in spare parts, tools, guide books etc. Many would assume, with those kinds of numbers, that our sailing capabilities would be compromised, but, and I am reminded of Dodge Morgan on his weighty American Promise, I continue to be pleased with a Valiant’s capacity to deliver good days runs in light air as well as heavy.
I am not sure whether the following distinction between good offshore boats is actually valid, but it may be helpful at some juncture. I hear some discussants making points and I think to myself that he/she is referring to what I think of as expedition boats: boats where time aboard may be measured in months, but where a return to a land base is built into the head set. The plans for these boats have delineated goals and parameters, are more likely to have crews of more than a couple, and emphasis is more on Adventure. Then there are the offshore vessels where the vessel is their full time home, (no land base), and most often crewed by a couple, where there are cruising plans, often quite ambitious, but rarely expeditions. I have called that group, in past posts, as the Sustainable Adventurers.
Clearly there are broad overlaps, but I think the distinction might prove valuable in the design stage of an A40. I also suspect that some of the differences expressed between participants on the AA site may tracked to the differences viewing the offshore world from these 2 perspectives.
My best, Dick Stevenson, s/v Alchemy

Capt Phillip Carr

Off topic but as an interested purchaser of the 40 a plea!
Every sailboat I have used for ocean cruising as opposed to my J-Boat racing, I have fitted a high quality spray hood on day one and sold the boat with it still in place. This is a plea for an integral fixed dodger or open wheel house. It will just add so much to the enjoyment of open ocean sailing. Thanks

Dave Benjamin

Quite frankly, it’s beyond my comprehension how any builder marketing a “real cruising boat” doesn’t include a hard dodger in the design. About the only argument against a hard dodger would be the inability to reduce windage while riding out a hurricane or cyclone in a marina.

Hard dodgers are far more economical than canvas dodgers. Here on the west coast it’s not usual for customers to spend $3000-5000 and up on a conventional frame and canvas dodger. The hard dodger on our Amel requires a fraction of the maintenance of a hard dodger. It’s limited to the usual painting like any boat structure. We made an inexpensive cover for the dodger windows so those will last many years with nothing other than periodic cleaning. It’s safe to stand on and the grab rail is a secure to hold on to.

Colin Speedie

Hi Phillip, John and Dave

I’m in total agreement with all that’s been said – after our latest passage, I’m utterly sold on the idea of a hard dodger as standard on any passage making boat, for all the reasons outlined in your comments, but also because I believe that with some form of screen/door between the cockpit and the saloon, both on and off watch crew can benefit. On watch you’re in better shelter and can read and relax more and off watch your sleep is not disturbed by the inevitable comings and goings (and lights going on/off) of the watch keeper.

When our sprayhood dies, we won’t be replacing it, but will fabricate a hard dodger in light weight alloy, or composite materials.

Best wishes


Dave Benjamin


On our Amel we have a boltrope track for a curtain that divides the area between the galley and salon. So with the curtain in place, lights in the galley don’t disturb the off-watch person in the best sea berth we have. In practice, since it’s usually just the two of us, we can get by using our headlamps in the galley for snack or beverage prep.

John DeLong

I’m intrigued – you plan to build a boat that is $25k less expensive than the Beneteau, but is smaller, no dealer support and no wheel – the offset appears to be greater strength. Presumably the B is not strong enough – but for what… We have just crossed the Pacific and seen many Bs doing the same thing. In 7 yrs of full time cruising we have never heard of a B that has sunk or failed in respect of “strength”. And the size and comfort at anchor is a substantial appeal to many (witness how successful they are at selling them).

Another point that has been brought up is load carrying capacity – full time voyaging requires substantial spares, provisions, and “gear” (books, kayaks, legos etc.) This “base load” is much more difficult to stow safely into a smaller, light displacement boat – most importantly as the loads on the rig and rudder increase substantially above the design parameters of the lighter boat. The rig etc must be designed to the projected final displacement of the boat in cruising set-up, i.e. fully loaded.

Finally, our experience is that “faster” is not really a benefit in most real world situations. We transited Galapagos to Marquesas in 19 days – our 43′ 16ton displ cruiser was 12 hrs slower than a 55′ catamaran – largely due to our better seahandling capability in large following seas and higher winds. We are not capable of outrunning weather systems (e.g. Dashew) and so the theoretical benefit of an additional 0.5-1kt is substantially immaterial. What is important is durability of equipment (sails and rig and rudder foremost) and comfort/seakindliness. There is an acceleration coefficient that some people use to compare boats that intuitively strikes me as one of the most important criteria. I don’t think a light, narrow hull will provide this comfort/kindliness. On this metric the Westsail is one of the most comfortable boats out there – and when momma’s happy, everyone is happy!

Thanks for your site – I just started perusing it and have found it interesting. Cheers, John DeLong SB43 ALOUETTE

Dave Benjamin


There are certainly many Beneteau’s successfully cruising. I am personally a big fan of the 80’s vintage First Series having sailed a First 38 quite a bit. The similar aged Idylle’s, while never well recognized, are great boats. What would hold me back from doing much cruising in a newer model is that I’d be one moderate to hard grounding away from needing repairs that can only be done in a first rate boatyard. The liners pop loose after groundings. This has happened countless times, particularly in the charter fleets. Since the hull integrity is derived in large part from the liner, you can’t go too far if it’s dislodged. Repairing is a fairly extensive job. One customer of mine spent $40 or 50K USD when it happened to him. His repairs went above and beyond the Beneteau recommendations.


Is there merit to the idea of starting multiple design category topics at the same time? A moderator with some expertise could be recruited to assist on that topic. Then we could set a target date to complete this most interesting dialogue and move it to the next step towards reality.


John, thls, great own pragmatic moderation as usual,
fun and the intellectual challenge, great goals indeed within the ebbs and flows of personal creativity

Ray Verlage

Your process is AOK, and your timelines are fine too. I was concerned that this boat would become mired in musing beyond my baby boomer window of opportunity.
Currently have a PSC Dana 24, and your ideas are one of the few boats that would have me thinking about a switch. All that being said, the Dana is a fine option.
Keep the posts coming, and look after that leg!

Jacques Landry

John, and all the followers of this great boat,

Up front, I am all for it, and think this is a great idea and we are in much need for a design of that kind. But the Beneteau’s fan did strike a flag here. No, I don’t particularly like Benetaus, as I don’t like most production boats. But they are not all flaws and wrong doing. They serve a purpose, or should I say a market. I also think that slim, narrow long boats have been done in the past ( I have one that would fit right in with your philosophy, not a production boar evidently, but will keep it for a later post) and maybe you want to look at them, not to copy, but to dissect and see what was good/wrong with them.

I also think that in the discussion there is a need for some room for the fixer upper peoples. We don’t all have the money to buy an Adventure 40, or anything else by the way, but are willing to spend tremendous time fixing an older boat. Agreed, not a good return on investment on the long run in most cases, but nevertheless, all we can afford in the short term. Should we stay on land, because we can’t buy the right thing up front? I know I wont! I also know that being new or old …er all we do is spend too much time fixing the beast! But we love it.

Hope you are doing better John and will recover fully !

Jacques Landry


I was evidently talking about the older Beneteaus, Wauquiez or the likes kind of boat, as I fully agree that the newer stuff is for the show in the marina. This might be true for most production boats (with probably some rare exceptions) and that is why, being poor (and not yet Bob, but who knows what the future reserves) I have little choice but to go the older boat route and try to fix it the best I can. However, charter oriented older boat (or any cheap production boat) is not what I would recommend! I sailed some of these in not even rough weather and did not like the feeling. I bought a custom made steel boat (by a reputable french boatyard, Metanav) based on the Sylvestre Langevin Flot 38 (or Triade 38) which does fit pretty well with your description of the Adventure 40. Long and narrow, solidly built, with a simple tiller, traditional layout (maybe Collin his the one who likes that) 2 good and well located sea births, and an interior designed for moving safely in rough seas. The boat was designed and equipped for long term voyages for 2 persons (500 l. water, 400 l. fuel, wind vane, windmill, solar panels, short wave radio, and more. I think it has most of what you suggest, beside being for the 80’s (1989) and not being exactly light (18,000 lbs empty)! It sails fairly well, the equipment is simple but sound, and the essentials (sails, standing and running rigging, most hardware) have been all replaced by new, the engine rebuilt, the winches rebuilt on a CNC machine, some new electronics added, a new ocean life raft, and still at less than 20% of the cost of a similarly sized Beneteau or an Adventure 40. So I had the choice of being “intelligent Bob” and wait to save enough money to live my dream, or be “just Bob” and go for it within my budget.

I have to add that I have the skills to do most of the work myself, and the knowledge to understand when I should let the pro do the job. So evidently in my cost analysis my time is worth next to nothing! But I love it. I do see a lot of people attempting the same thing but being burnt (or broke) because they have to delegate too much of it.

Between you and I (and the readers;-), does stupid Bob really think it was all a mistake ? Didn’t he learn a fair bit through it, and maybe live some of his dream many years earlier that he would have been able to afford ?

Having said that (yes, stole this from you), I don’t think you can have such a great site and acquire such extended knowledge simply by buying a new boat (even an Adventure 40) and just sail around ! But I thank you for trying to make our life easier!

All the best to you on your recovery. Still waiting for the post about “Ten reasons for not leaving the boat while at anchor”!


Dave Benjamin


The older Wauquiez are terrific boats also. I’m pretty fascinated with your boat. I did not recognize the model so I did some web research. Looks like an excellent passage maker. I noted they are built in aluminum as well. We rarely see boats like that on the US west coast. If you have a blog or website with some photos, please post a link.


jacques, good post, good remarks !
i think there is a place for all at aac or in those discussions, … for the reasons you mentionned, i’m most probably in the category of the ones who will buy a second hand A40 in 10 years … so much interested in her today design choices !

i’m now also in the renovation process of good old 1979 “Moscatel”, you describe it so well, unreasonable and maybe uneconomical, but passionate,
and preparing a party with our architect’s (Harlé) wife in 8-2013 in south Bretagne for the 40 iest birthday of the Romanée’s serie,
PS : i loved the “B” First serie of the eighties …

RDE (Richard Elder)

re the discussion regarding transom mounted kick-up rudders for an Adventure 40 type boat, here are some great shots of the ones from Banco Popular, current Globe leader:

And talk about different boats for different blokes! How about this family of 4 (soon to be 5) screaming around the world on an Open 40!


Thanks, John, for a very informative site, and to all the contributors, especially on this thread, for really interesting comments.

Let me say first of all that my sailing experience is extremely limited, but I have dreams … At the moment I am thinking of a small sailing voyager, but my wife, a firm believer in the future of the internal combustion engine, inclines me to designs like Karstenmarine for long distance motor cruisers.

I have a question about the discussed need for speed. Contributors seem to feel fin keels and skeg rudders are justified if they add a little speed. Is that realistic? On our Overland Africa trip last year our old Cruiser was slower than the other vehicles, but our average speed over the whole 25 000 km was 45 km per hour. The faster vehicles did the same … They had bigger sleeping space, and we did get tired of pitching a tent every night and packing it up again the next morning, but then our vehicle was lighetr, and had less things to go wrong. (Oh the electrical problems one guy had!)

Would the seasons and best sailing winds not constrain your voyaging so that an extra knot or so would not make much difference?

What about the Wharrram saying, that sailing is like mountaineering: the luxury is in being there, in the scenery, not in the boat or the technology you have with you?

Thanks for your comments!

Dave Benjamin

There is no justification in my mind for traditional full keels. Boats were built that way for a long time due to limitations of the materials used. They have a lot more wetted surface area and require a larger rig to power. The width of the keel prevents the boat from pointing well. In my experience from spending months at various anchorages, the full keel boats tend to be a lot more rolly at anchor. In a marina environment, they are challenging to maneuver unless a bow thruster is fitted. While there are certainly a lot of successful full keel cruising boats out there, I wouldn’t design one from scratch with anything other than a low aspect fin keel.

RDE (Richard Elder)

Hi Dave (and John)

While I certainly agree with the general thrust of your comments, particularly if the boat used as comparison to the Adventure 40 is a “Tubby 32”, you should be aware that all full keel boats are not created equal. I speak from experience of having built one and lived aboard and sailed her for seven years.

The boat I’m referring to is a modified Atkins design that had its origin in the 1940’s. In its Cape George 36 form it has a wood house and deck and solid fiberglass hull. I’ve demonstrated on a number of occasions that in moderate 15 knot conditions it was slightly faster than a MK I Valiant 40 and the similar fin/skeg Bill Garden Fast Passage 39 that represented the next generation of cruising boats. And, much to their chagrin, I once won a 4 hr. windward tacking duel against a race prepped Express 34 ULDB. And two sistership circumnavigators of my acquaintance swear to have achieved the magic 200 mile days. So not all full keel boats are “slow.”

When you look at the design characteristics it is not hard to see why it has a decent turn of speed.
1- Easily driven hull form. The Cape George is all waterline, and the beam is only 10’5″. No bumps, humps, bustles, or canoe sterns. Nice entry angle, looks to be finer than a V 40.
I’d wager that if you did a tank towing test at 5 knots you’d find lower overall resistance than the V 40 of the same displacement because of additional beam and turbulence around the trailing edges of the appendages of the Valiant.
2- Much higher ballast ratio with full tanks. This antique full keel design when rendered in fiberglass carries 70 gallons of fuel and 140 gallons of water sitting directly on top of the lead ballast. And that lead already was 50% of the total displacement.
3- Resulting in larger sail area and the ability to carry it, especially in moderate conditions.

Bottom line is: there is as much difference in full keel designs as the difference between a Moorings charter boat and a new J-boat.

ps.—Perhaps ignorance is bliss, but I did manage to dock single handed without assistance literally hundreds of times, and thought nothing of taking her through the Lake Union locks by myself without a bow thruster.

ps2. I agree there is no justification for a full keel boat in the modern world. “Nobody” is going to buy a boat only 10’5″ wide with no aft stateroom and 3/4 the interior room of an (also outmoded) Valiant 40 for $450,000 when they can buy a 47′ Beneteau with multiple bathrooms and genuine finger touch sidewise drive for less money.

ps3. Dave, there is one real advantage of a full keel design like the Cape George. Put the helm down and you are hove to behind a slick that looks like you could launch a bath toy in it. Your mid-passage lunch breaks will be much more comfortable than on any modern boat if the seas are up!

ps4. And yes, when she comes to fruition the Adventure 40 should be a better set of compromises than a Cape George or any other full keel boat for that matter!

Dave Benjamin

Anecdotes aside, waterline length is your friend upwind in moderate conditions as described. I’ve raced on boats that routinely achieved speeds in the teens that were inevitably slower upwind than boats with more waterline. We just completed a set of sails for a Mini 6.5. That boat will hit incredible speeds off the wind but upwind, it’s just another 21 foot boat.

An Express 34 is 28.33′ LWL. The Cape George is 31.5. In 15 knots, both boats should be hitting hull speed. You have to travel a bit further due to the fact you can’t point as high. However if there are some seas up, the Express has to foot off a bit like any light boat, to avoid getting slowed down punching through waves.

Lighter boats and boats with less wetted surface area may be sailing when you’re motoring. You mention “more sail area and the ability to carry it.” As a sailmaker, that’s music to my ears, but having to carry a larger and heavier rig has drawbacks. So for me personally, the low aspect fin and skeg rudder wins out. I love the looks of that Cape George though.

RDE (Richard Elder)

I’ve suggested previously that the idea of a transom mounted kick up rudder should be considered in the design of the Adventure 40.

Two obvious benefits:
—–Reduced damage potential for the steering system.
—–Potentially less expensive, especially with tiller steering.

Here is a quote from Alex Thompson on the result of hitting something at 20 knots in the southern ocean—.

” As I enter night down here it is now dark and it’s still a pretty rough southern ocean sea. Saying that conditions have definitely improved from what they have been and I have been able to maintain good speed. Last night I had a bit of a shock, I was sat in the cockpit reasonably relaxed and then Bang! My first instant reaction was the mast I looked up and everything was fine. I then looked back and could see the windward rudder was up. I checked the rudder system and could see the fuse had broken. Something must of hit the windward rudder. Luckily on our rudders we have a fuse system in place which is a weak link, breaking to allow the rudder to kick up so it doesn’t break. I replaced the fuse and put the rudder back down. There doesn’t seem to be any damage to the rudder blade so most likely it was a soft impact maybe with a fish. I am glad that we have got the fuse and it did its job well in preserving the rudder.”

And a photo showing a rudder in the lifted position on a competitors boat. Note the end plate seal and the compatibility with a swim step transom.

C Dan

That sounds sensible. Some questions:

1. how much incremental expense is associated with such a system (I am guessing not much)

2. is this really a safer system than a robust skeg-mounted system (obviously better than a regular spade, but don’t think that’s under discussion for the A-40)?

3. would such a system interfere with a typical wind vane self-steering set-up?

RDE (Richard Elder)

Hi John,
Both the Cape Horn and Hydrovane wind vanes claim offset mounting capabilities of up to 30″. With a kick up rudder there remains a perhaps 25% probability that a rudder kick up would damage the servo rudder or break its fuse link, but there would still be a high probability that it could be repaired underweigh. Still far better than loosing the rudder, all steering capability, and perhaps putting a hole in the boat when you hit something solid.

One of the most common failure modes on rudder systems comes from crevice corrosion of the rudder shaft that develops when the seal between the fiberglass rudder overlay and the stainless shaft breaks down.

Actually if I were building a transom hung rudder without kick up capability I would avoid building it “very strong.” I’d rather have a sacrificial lower half and even a spare tucked under a berth.

With most partial skeg designs there is some question as to whether the skeg is supporting the rudder or the rudder is supporting the skeg. That has been my observation, but far more experienced people than I— Steve Dashew for example— have raised the same point. And yes, a transom hung rudder, even with a simple cassette kick up system, will be less expensive to build and to maintain than a hull mounted rudder.

Paul Squire

Does the performance of modern beamy yachts change anything. I’m thinking of cruisers like the Pogo 12,50, that routinely exceed their “hull speed.” A traditional displacement yacht runs before the trade winds at hull speed rolling 30 degrees either side of upright tossing everything unsecured below (including people) from side to side relentlessly. The light, beamy alternative broad reaches fast enough to sit on the wave fronts and/or pass them, more or less upright & steady.


I’m sure you’re right. Great fun round the cans and round the coast but perhaps not offshore. I wondered myself what would happen when sailing to windward in big seas and a wave got itself under that massively wide flat hull. I suppose the boat would just slide sideways but it could get messy.

Erik de Jong

Hi Paul,

I think there is a misunderstanding here. The Adventure 40 is not considered beamy at all, that is the problem with modern boats, and one of the reasons that this project was started in the first place.


I wonder whether boats like the Pogo might make sense for cruisers if they were viewed as very large small boats.

In other words, travel very light, with minimal gadgetry and stores, and accept hard limitations on capability.

People have crossed oceans on tiny craft, so a voyage can be done without loading the entire contents of a supermarket, if the crew are prepared to be very frugal.

A small boat has to abandon hope of making ground upwind at much lower wind speeds than a craft like the A40 … but people like Webb Chiles, Frank &Margaret Dyer, Nick & Julie Grainger, have managed ocean crossings in boats with much less upwind ability.

Pogos are unusually well-engineered, so in the hands of someone who understands and accepts their limitations, I don’t see why they couldn’t be used. It would be a very different style of sailing to an A40 … but nobody should put to sea without a understanding and accepting the limitations of their vessel, and an A40 will have its own limits. They happen to be more balanced, and will work better for most people, but an A40 crew who fail to “know your boat” will be in trouble too.

Dave Benjamin

Maybe Paul Squire was referring to a leaky-teaky with a full keel when he made mention of rolling 30 degrees to each side. I’ve sailed in company with some boats like that and practically got seasick watching them. I always found it interesting to watch boats in a rolly anchorage. We had a leaky teaky anchored near us for some weeks in a rolly anchorage on the Pacific side of Mexico. In spite of some stabilizing device hung from a spin pole, that boat rolled 3 or 4 times as much as our old Amel ketch.

As for boats like the Pogo 12.5, I don’t think of it so much as a one trick pony, but simply not a practical boat for the way most people cruise. It requires a more advanced skill set than most of the US market has. And it certainly lacks load carrying capacity that most people seem to require these days for the abundance of crap that gets carried.


Displacement has 2 components, weight of the boat and the payload. What payload are you aiming for?


It’s Ok, I found my answer elsewhere. You’re aiming for 4400lb. Cheers,