Thanks Joseph,
James from Nude is no longer making speed and slalom boards. The 46 you have is the first version I did last year. I have one of these, and it was the fastest board in 2010 (actually proven rather than just stated in marketing noise

).
The 47 is my latest design that extends the lighter wind performance. The 47 is in production with Mistral for 2012.
This year the 42 is the fastest board (1st and 3rd in GP3s. 2nd is my old design from 5 years ago

). It likes lots of wind and a small sail to get the most out of. It can still be used with big sails, but the 47 is better unless its 5.0m weather or you are <80kg.
The 55 is the big speed board (95 litres). It is the longest board with the flattest rocker, and is designed to mow down nasty steep following chop. I designed it for bigger guys wanting to go really fast in crappy conditions. Its very easy to keep on the plane, considering its top end capability. A big guy will easily hit 45kts+ on this board in 30-35kts gusts and squalls, but will still be cruising around on it in the lulls.
The slalom boards are based on a similar concept, but have a different set of design criteria, to account for the different speed range, wind angles and gybing.
- V to double concave centre with panel V on the sides, back to panel V in the tail. I wrote a CAD program to design and balance the boards so that the more complex bottom shape does not cause problems with stability or drag. This was quite tricky. I designed the bottom shape to be as simple as possible for the desired performance. A plain V or simple double concave arrangement works some of the time, but there are always conditions where it will suffer. So I had to design something a little more elaborate.
I'm enjoying my slalom sailing more than ever. I dont fall off as much. I dont get tired as easily, and I'm going faster than I used to, more of the time. I really enjoy sailing in chop now because I can still go fast on these new boards without it being too hard or too dangerous.