Alinghi 41 with S-foils: trial horse for Alinghi 5/Seahorse

Alinghi 41 cat had S-foils not C-foils: quotes from Seahorse mag.

Nigel Irens: Cavitation is always a problem. Where any hydrofoil, by which I mean a rudder, or centreboard, or foil itself, passes through the water there is drag associated with it.
Q: Seahorse: We’re told that Alinghi will now start to be developed once they start getting feedback. Do you think we’ll end up seeing a completely different boat?

Nigel Irens: Oh yes, development is inevitable, but I don’t think we’ll see a really different boat. When you go out sailing on any race boat, you come back with a list of things you’ve got to change, but I think it will be obvious right away if something major has to be done. Obviously, the S-foils are very experimental; in a way you could say they’re the most radical part of the boat. There are limitations with a C-shaped board in that when it’s fully down you get the maximum lift upwards and when it’s fully up the last bit in the water is not much use for anything. In the case of Oracle, if the conditions were such that the foil wasn’t needed, the boat would primarily be using its centre hull centreboard to resist leeway. Alinghi doesn’t have that and, when the conditions are not suitable for looking for upward lift, you still need lateral resistance. A simple way to look at it is that, on Oracle, there’s a centreboard to resist lateral forces and a C-foil to create upward forces, but Alinghi have been obliged to combine the two into one. It doesn’t work to have two boards in the same hull, because they mess each other up.

Ernesto's people on cats/tris: >Philippe Cardis was steering Happycalopse at that time. Nicolas Grange owned and steered Bedat, a trimaran, and Ernesto was also involved as the owner-driver of 41 ft Le Black.
SH: And the broader future for multihulls? to PYJ, Ernesto B's multihull sailor.
Pierre-Yves Jorand: My view is that perhaps a couple of years from now most of the fast racing boats out there will fly. We saw an enormous step forward in small dinghies like the Moth and this is now extending to the 18-footer class. We have started to see some multihulls flying as well – there will be a 32-footer on the lake this summer, for example. I really think the next three to five years will be amazing in terms of progress; the biggest jump being boats flying up and downwind looking for the best VMG.
SH: And your own multihull background?
PYJ: I started in the mid-1980s on a boat called ASL, which was probably the first lake foiler. It was not supposed to fly but the lift coefficient was nearly 40 per cent of the total displacement!