Hey Gibbon -- I'm not sure what catamaran you were looking at, but the America's Cup boats are actually even LARGER than that ...
The AC45 (the boat being used in current cup events while the larger AC72's are being designed and built) uses a 21.5m (71ft) wing ... and the boats that will be used in the actual Cup (the AC72) are even larger beasts -- a wing 40m (131ft) tall [1].
The design of and technology going into these AC class boats is fascinating. It's been a lot of fun watching the AC45's race and the AC72's will be quite a sight out on the water once they begin pushing 'em to their limits.
We went down to the wharf to see it the day it was launched.
Staggering size...
It's a catamaran with a 13m (42.7 ft.) tall solid wing and is expected to be able to hit 50 knots (90+ km/h).
They have to anchor it to a tonne and a half of ballast just to keep it from taking off on it's own.