A while back, I visited San Francisco, and for the first time in my life, I witnessed people using huge kits as sails to lift themselves up out of the water. I was suitably impressed, I must say, and thought that the sport looked like fun. Personal anecdote aside, it seems that these large kite sails may be good for more than human sport. According to this article, a company called Kite For Sale
is testing these kite sails to add extra power to boats for use in shipping. The tests have worked well, it seems, as their test-bed is a trimaran which only uses the on-board engine for low speed travel and maneuvering. So, what we have here is a hybrid
... a wind/petroleum hybrid boat. Cool, old technology is made new again.