Sailboats with electric motors instead of diesel engines can use the motors to regenerate power; when under sail the motors are dragged backwards through the wa

Sailboats with electric motors instead of diesel engines can use the motors to regenerate power; when under sail the motors are dragged backwards through the water forcing them to turn. (I don't know if that's useful enough for 'braking' as boats have fairly high mass and lots of inertia and travel slowly as it is, so gradually slowing down over a very long distance would just be annoying compared to a burst of reverse thrust to slow them down sharply)