For iGRF: New tunnel hull dinghy concept

Help me, I don't get it - the immersed part of the hull is not fore and aft but at an angle to the direction of travel (given the hull is sort-of triangular). Hence, energy from the rig is needed to push water sideways. How can that be efficient?

Edited by fab100 - 10 Feb 17 at 1:20pm

Who was it on here that came up with almost exactly that design when I was postulating about the V2, the guy on the IOW makes Canoes, Foils and things, my memory is just f**ked, blue something or other, anyway he had a CAD drawing for a similar triangular approach, it ovbiously relies on being heeled and the lee side gives it forward direction it wouldn't necessarily go sideways, well no more than a conventional hull makes leeway.
It's basically the same idea I was trying, to ditch half the wetted surface on the upwind leg and the tunnel affords a wide stern for stability with less wetted area, I was perhaps trying to be a bit too clever with a three stage rocker and wanting it to plane, which it did on flat water, but didn't so well in waves, I under estimated the downforce at the nose that dinghies suffer with, never something we're really aware of with free rigs that we windsurferssail with since they get canted over. Knowing what I'm now aware of I would probably have done that V2 differently with a more rounded underside than a flat planing hull, it would probably have worked just the same but not have been as sticky in the light nor as difficult to transition from displacement through gliding into planing although I'm not convinced any dingy actually planes at all in the same sense we windsurfers know as planing, actually skipping over the water surface, probably why foiling offers such efficiency and in truth is probably a better future direction.

Originally posted by iGRF Who was it on here that came up with almost exactly that design when I was postulating about the V2, the guy on the IOW makes Canoes, Foils and things, my memory is just f**ked, blue something or other, anyway he had a CAD drawing for a similar triangular approach, it ovbiously relies on being heeled and the lee side gives it forward direction it wouldn't necessarily go sideways, well no more than a conventional hull makes leeway. It's basically the same idea I was trying, to ditch half the wetted surface on the upwind leg and the tunnel affords a wide stern for stability with less wetted area, I was perhaps trying to be a bit too clever with a three stage rocker and wanting it to plane, which it did on flat water, but didn't so well in waves, I under estimated the downforce at the nose that dinghies suffer with, never something we're really aware of with free rigs that we windsurferssail with since they get canted over. Knowing what I'm now aware of I would probably have done that V2 differently with a more rounded underside than a flat planing hull, it would probably have worked just the same but not have been as sticky in the light nor as difficult to transition from displacement through gliding into planing although I'm not convinced any dingy actually planes at all in the same sense we windsurfers know as planing, actually skipping over the water surface, probably why foiling offers such efficiency and in truth is probably a better future direction.

Bloodaxe Boats?

Upwind the leeward 'keel line' would be lifting the boat to windward. The DB on the drawing on the media page seems to be at a slight angle to that 'keel line' but taking the boat to leeward. You'd really want the DB's toed in by slightly more than the angle between the 'keel lines' and the centreline, a bit like a gybing board but fixed. And, yes you would need to lift the windward on or suffer considerable drag. The whole thing's been done before anyway, they called it The Vortex......

yeah I did a design concept for V2+ ...  triangular, asymmetric boards - i just have to find it!