water, so maintaining its height and pitch with respect to the water surface is critical. And this is where having a very powerful and also very accurate control system becomes so important.
‘By comparison the last America’s Cup boats were very big so, relative to their size, the waves are very small. Basically they sail along and don’t take much notice of the water surface at all – they just carry on – whereas a Moth in large waves has to track the surface. Now, if you haven’t got adequate amounts of feedback, it will fly out of the water or crash down into the water, or both in turn, which is just the end result of it not being stable in terms of pitch-stability and height-stability. And pitch-stability is hugely important if pitch- poling is to be avoided.’
In late 2013 Ellway and Smith were given an opportunity to see if their theories could be proven on the water. Soon after the dramatic conclusion of the America’s Cup in San Francisco, the C-Class cat community gathered in Falmouth in the southwest of England for the 2013 Little America’s Cup.
According to Ellway, the C-Class cats have similar problems to the AC72s, in large part due to the restrictions of the class rules. ‘The C-Class is similar in that there are many things about it that just aren’t really suitable for making a properly fast foiling boat. The rules governing what you can put under the boat are restrictive and the boat also isn’t wide enough for the amount of rig height it’s got. It’s just not got enough righting moment. So, anyway, they pretty much copied – or perhaps were even a testbed for – the America’s Cup
38 SEAHORSE
boats. I’m thinking of Groupama C and the other sort of boats that are around. And, well, these things, most of the time, didn’t foil. When they did foil they were hazardous to the occupants, and there was an awful lot of breakage.’
Longtime long-distance multihull race campaigner Will Sunnucks joined Ellway and Smith in Falmouth… Sunnucks was less than impressed with what he saw. ‘Will came down and looked at the regatta, and saw how the foiling C-Class cats were all over the place. Similarly, he’d looked at Moths and they just seemed to work. Without any particular, proper scientific understanding, he came to the conclusion that what you needed was some form of wand-to-flap control system, or at least some kind of control system… And that also you really needed canted foils. So, without understanding quite
why, he kind of got the right answer.’ Impressed by the speed and more pre- dictable ride of the Moth, Sunnucks approached Ellway with the idea of devel- oping a foiling mechanism for his Marström 20 catamaran that incorporated the wand-to-flap dynamic stability system of the Moth. ‘The key things were that he wanted a boat that would foil control- lably, both upwind and down in open water,’ says Ellway. ‘He also wanted a boat that he could drive up onto the beach, so the foils had to come out either up through the hull or be able to take them up over the top of the hull.’
Ellway accepted the commission, though with some reluctance. ‘The prob- lem with Will was that he didn’t really appreciate the complexity of the task. When I originally contacted Alan on this we both thought the project would require
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