The big difference between sail boat and aeroplane wings is air turbulence caused by surface roughness that does not exist for planes flying above 600 to 1100 feet above the surface and the 800 plus times vicosity of water over air dragging on hulls rudders and foils. A sailplane can sink at 40:1 even 70:1ratios where the fastests sail boats ofcany design and size are below 3:1 with most racers below 1:1. Kites of a very high aspect ratio or foward swept semitar Prandel wing reverse curved tips can poduce three to four times the thrust to area ratio on average of any deck mounted sail and operate in twice the wind speed compared to at the surface with lift to drag ratios less line down pull vector of at least 30:1.
This leaves the hull drag problem. A ultra slender air bearing hull might have a 100:1 to 400:1 lift drag ratio if it was between about 50 to 200 feet in length. The best high aspect ratio hydrofoil possible is about 25:1 ti 30:1
This low drag air bearing sail boar hull has to be either a center flap plenum catamaran with inverted highly back raked bow and stern flaps instead of the cross wise flaps seen on SES ships today or it has to be a center divided or quadrant plenum SES hull for roll and pitch motion resistance without requireing displacement of center of pressure loss planing drag used to create balancing lift. All visible wake or spray is a sign of hull drag design failure. The low pressurized air can be introduced under this hull by spreading flap injector bow rudder. The sails forward power becomes an air pump for the first mile of increasing speed as full air separation is reached. Long hull. Is us drag is usually less than 5% or frontal drag but is in ersely parabolic curve reduced with length even without air separation. A ideal air supported hull consists only of thin low displacement side hull webs to hold the air in. A 10 ton boat could have as little as half a square foot of water penetrating displacement drag so slender you would not see any wake or spray from it at 100MPH even if the water was glass smooth. The side thrust resisting center board needs to be very high in aspect ratio and forward sweept to eleminate losses with a trailing flap to become a bidirectional air foil shape. If you want to use a wing sail a 360 degree self triming sail might best be height flexible to take on the differing directions of the apparent wind speeds and turbulence directions. This should also be high in aspect ratio, forward swept with a Prandle tip unloading triming system. Put all of this together and a sufi ie tly long bost should be able to go five to six times the speed of the surface wind and upwards of eight or more times wind speed with an ideal kite. Not one of these features has ever been tried, even separately, on any boat in history because we are all wanting to improve on ideas we socially see others doing. This is human nature. All together this is water sailing almost as fast as iceboats and iceboats as fast as propeller aircraft.
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