I think it is time for the speed kiters amongst us to get back to the drawing board and think about a new way of getting the speed record back. Obviously we need to think about efficiency. 65 knots is super fast!
I think we need to consider board efficiency first. I think this is our biggest obstacle, since edging is simply not efficient. But big fins are only efficient/useful at low speeds. Does anyone know what the top speeds are for guys on race boards with big fins? It must be around 35 knots before the fins cavitate or vibrate or pull in air or whatever it is called (i.e. simply become useless at going faster). So what can we use to create lift that counters the kite downwind force? Sail Rocket proves that a foil/fin/keel can be useful up to 65 knots, but we will need to come up with a new idea to beat that (if we still want to of course. 65 knots is fast and dangerous).
Maybe we could use more than one edge? I've read that speed kite skiers go much faster than speed kite snowboarders, because two edges are more efficient than one. (effectively lengthening the edge). But will that give significant more efficiency to go to 65knots. Unlikely. Control up to 40 knots on one edge is difficult enough.
I think we need to look at a new technique. Cars have sideways resistance, yet little forward resistance because it has wheels. Why not make water wheels? (sounds silly?) What I think we should do is make a fin/wheel that allows the foil to see 20 knots of water speed when we are in fact travelling 60 knots. Just like the bottom part of a tyre of a car sees 0 km/h when the car is going 120km/h. The man who's idea it is has a interesting book (but for a different application) at http://www.amazon.com/dp/B0053NYVMM
with a chapter on what is called a wheel keel. In its simplest form you can think of the fin being a wheel, and the wheel rotates like the wheel of a car so that the water flowing over the foil of the fin travels over the foil slower than what the craft speed over the water actually is.
So could we apply this to a kiteboard? I think so. I think if we take a race board, and replace the fins with large air-foiled wheels (with most of the wheel above the board and only about the bottom 1/4 under water) and allow the wheels to turn than we might have a race board with unlimited top speed? The wheels could have small brakes, that allow you to set the tension, so that it allows the wheels to turn like a wheel, but not so fast that the foil part of the wheel goes at the same speed as the water. We do need some water flow over the foil/wheel to get lift to counter the kite, but we just don't want this flow to become too fast that the foil becomes useless.
Obviously a wheel will not allow us to have the best asymmetric high L/D foil under the water, but at low water speeds this should not be too much of a problem. With the wheel we can basically adjust the foil to see at optimum water speed, regardless of the speed we are travelling over the water.
Does it kind of make sense to anyone?