sailing fag here. These the most recent photos of the British America's Cup yacht Britannia 2 in testing for the Challenger finals.

Much has been said in the sailing world about their foils and how they are 'flawed' or at least sub-optimal for the job at hand. These boats have a speed range of 25-50kts. (12.8 m.s^-1 to 25.7 m.s^-1 roughly). The hydrofoils are operating very close to the water and cavitation is a real issue considering how fast these boats go and how close the foils are to the surface.

I'm not a hydrodynamicist/aerodynamicist but does anyone here on /sci/ be able to make a reasonable and informed analysis of the foils in their present state?

I have a feeling they're trying to maximise foil area for expected light winds and therefore slower speeds while still maximising length within the limit of the rule by sweeping them back. With wingtips to limit wingtip vortices and maybe ventilation as they frequently pierce the water. They mass 800kg. What's the advantage of having the small bulb in the middle?

Thanks anons!