From George Jackson
Referring to the matter of wind power for ships, I tried this out in a 29-foot (9 metre) yacht some years ago. It was clear to me that the major advantage would be that the line of traction could be made to pass much closer to the line of resistance through the keel. In principle therefore much larger traction forces could be applied than was possible with a conventional sail. There were other advantages already aired, that the wind speed is higher at higher altitude and that its direction could also be different to that at the surface.
The kite I used was a small one in aerofoil section, controlled by two lines. The great difficulty was to get the kite launched, and when it dropped into the water the drag was naturally enormous. The solution seemed to me that the kite should be attached to a helium-filled balloon or balloons, which would prevent it from dropping into the sea. A two-control-line kite also has the problem that when going directly downwind the kite is almost overhead, when the horizontal pull becomes small. A four-control-line kite would get round this, but would of course require more control. I am sure however with a bit of development along these lines it would be possible to make small craft skim over the surface at considerable speed.
Higham Ferrers, Northamptonshire, UK
