Lets see pictures and talk about T foils ...

Maybe they just know who you are?

Originally posted by G.R.F. Strikes me that canoe might work with this device if it were permitted.

This is where scale problems start kicking in. We learned this a few years ago. The immersed/unimmersed foil section is interesting but boy its wetted area...
We learned some years ago that on twelve footers you can give wetted area a v low priority, on 14 footers you have to start to take it seriously and on 17footers it gets really critical.
On boards where you tend to have lower wind limits and unlimited pumping then the tradeoffs and the points where things change are going to be very different.
Its always good to transfer ideas between different types of craft, but you need to be aware that the challenges of scaling are always there to bite you..

Originally posted by G.R.F. Well in a way sailboard design is also stuck a bit in the past, they make them with rounded pintails to assist the turns,

It does more than that... I was recently told by people I listen very carefully too that pointed sterns have an intrinsic tendency to squat at speed, which means that fore and aft trim issues are reduced. I suppose it explains how Canoes got away with sliding seats that didn't move fore and aft for about 40 years...

Edited by JimC - 26 Feb 13 at 9:09am

Originally posted by G.R.F. Well as I said at the beginning, it's got to do with a race board, my thinking. They, the only company still innovating race boards came up with this a year or so back and they nearly understand why it works. In a way it acts a bit like a surface running T foil, in fact what happens on a board is more about supporting the tail and preventing it squatting, we don't have the tremendous forces on the nose that dinghies have. Quite the contrary, what happens with a long board, the nose lifts, then the tail drags, and in lots of cases they run with fins that are too big and the leverage of that keeps the nose down so getting over the planing hump is problematic for the lardier boys. Strikes me that canoe might work with this device if it were permitted. Anyway, I digress, there's so much I hadn't realised that folk were doing, notably that trim device on the N12, I guess the moths must do that as well. Like the idea of a reversible system as well, but something that could be switched on the fly would probably be more useful.

as I understand it, ICs have to have a pointy stern- basically they still have to be "canoe" shaped. You might see it as pointless restriction; they see it as a quirk that makes their class what it is. 

T foil rudder on my IC - at the bottom of the blade for launching ( also the rules require it to be retractable above the bottom of the transom ).  The IC at 17 feet doesn't pitch too much, nor does it nosedive like a moth, so it wasn't that useful.
The first few moth T-foils were reversible - plain one end, T-foil the other, so in light winds the idea was to have the low-drag plain end. Surprisingly, the T foil end was faster except in a real flat drift due to reduced pitching.