[Abathar]

Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats.

[dead]

Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats.

It's not supposed to replace the engine, just supplement it when the wind direction coincides with the ship's direction.

[USFRIENDINVICTORIA]

"Yeah, tell that freighter captain to start tacking to the wind and zigzagging instead of taking a strait route and see how far this idea floats."

The kites are airfoils -- you can go upwind almost as easily as downwind (downwind is somewhat faster though). If the shipping version works anything like the sport version, you can control the direction of the kite much like any aerobatic kite. The ship would just have to steam ahead as usual -- the autopilot would take care of the kite flying.

[USFRIENDINVICTORIA]

After TChad posted his picture, I went to the Sky Sails site, and found this picture, which does a better job than I could of explaining the upwind thing, and establishing the limitations. It seems that the minimal heading is 50 degrees from the wind.