I don’t know if the Hydroptère even qualifies as a sailboat inasmuch as it is almost a sailplane.  The key to it’s speed is that it literally flies above the water with a precious few control surfaces actually in the water.  The Hydroptère now holds the speed record at 51 knots = 59 mph = 95 kph generated in a 28 knot (32mph, 51kph) wind. 

Here is some footage:

And here is an illustration of the basic engineering behind the carbon fibre and composite material based craft3:

For further information:

http://www.popularmechanics.com/technology/engineering/extreme-machines/how-to-make-a-sailboat-fly-15890011?click=pp