Yacht design – beauty versus efficiency
Most people’s idea of the classic yacht might be the one above or below:
… or even here:
… but sadly, there are two reality checks. One is money and so, when we try to get on the water in one of the above, the result is more likely that below:
Physics and mathematics are tyrants in boat design and pesky things like enough buoyancy, enough distance between sea and gunwhale [freeboard] and headroom impinge on the dream something awful. In fact, it’s not too farfetched to say that physics and mathematics oppress the designer, forcing him into things he simply doesn’t want … but must have.
The second militator against beauty is the modern surrendering of classic lines and sheer beauty for out-and-out efficiency. There are those – and I suspect dear Ivan is one – who are so technical that cutting edge technology has a certain beauty to it. For him, perhaps the modern superfast maxis, computer designed and with only that on board which goes fast, are the ultimate beauties:
for me, they’re flat, straight, bland, great for winning but not for something like cruising. There have been attempts to make the boxy, shorter boat more classic:
… but one is still tyrannized by the necessity for a certain amount of headroom inside and the concave nature of normal sheer [the lines of the boat] in a small boat means the gunwhale will be under water more, plus by reducing freeboard, one must add a boxy cabin – there’s no way out of this.
Where this tyranny against beauty really comes out is with multihulls and in particular – cats:
Cats, by the very nature of their fine hulls [longitudinally], must have sufficient buoyancy up front to prevent burying but not enough to create a bathtub. The best which can be done for classic lines is the straight sheer you see above and though not beautiful, it tends to efficient.
In fact, if efficiency and accommodation is the goal in a cruising multihull, then reverse sheer is the order of the day:
… but cabin considerations, struts and the like all militate against beauty. Some designers compromise and run classic lines up front but then the necessary reverse sheer further aft:
… and have different shapes for different hulls, something I really don’t like in design, excellent though the Quorning Dragonflies are. No one questions the efficiency of the design and the sumptuous appointments below with Quorning.
And if you don’t do that, in an attempt to go classic, you end up with a Wharram:
People swear by them and they’re some of the most seaworthy boats but in the smaller versions, low freeboard amidships means a boxy cabin is needed for headroom. To throw off beauty altogether and go for a rectangular, boxy shape which gives you the buoyancy and space you need, this is the result:
Sorry but I find that depressing. This is as bad:
… and the more extreme it gets towards creature comforts inside, the less freeboard, the more wallowing in the sea and the slower it gets, before even looking at the aesthetic side:
Why can’t cats do as classic designs do:
… with classic overhang bow and stern and fine, curvacious lines? The answer is partly waterline length equalling speed, the need for stability in having all your hull in the water, given the hulls are thin and just all-up buoyancy.
Some designs do try and this one has a fine entry at the bow, before broadening out but each broadening out slows the boat down and makes it more tubby:
And look at that boxy cabin! Plus the slick metallic look is a bit depressing to me. Multihulls can have beauty:
… but not efficiency and/or accommodation. This is why, under 40′, one is forced into either a monohull or trimaran. My current designs go more for a “triple-pontoon”, conceding weight and drag and reducing spaciness inside for overall accommodation and retained classic lines.
So they take a classic design:
… and make an ama either side in the same lines, construction, colours – the resultant trimaran having one design advantage in terms of lines/efficiency – that the centre hull can then be a bit higher and boxier and slopes down towards the outer hulls, which are lower and prettier.
Avoiding netting and having a bridgeway amidships, the compromise is not grotesque. Why even bother with the tri? It allows the boat to go in shallow and even be beached, which a keelboat can’t.
Current project is to assume it will bottle [flip right over in a storm] and to design systems into the amas which, with the assistance of the ship’s boat with outboard, will allow the hulls to be released and turned over where they are in situ – a process taking a couple of hours but that’s better than not at all.
Filed under: Leisure, travel & sport, Technology & ideas






























Thought beauty like that might attract interest.
It does! But we’re rendered speechless. ,-o