http://sailinganarchy.com/2013/10/28/drone-strike/
Video:
http://vimeo.com/77253491
Interesting stuff. Especially if you consider the implications of applying the propulsion to that DARPA project we did a few years ago, the sub hunting drone? Imagine one of them, under wing sail, just patrolling the assigned area, and then powering up the diesels to maintain contact on a target.