Most of the current technologies for extracting WavePower are onshore. However, a large ship in turbulent water moves around a lot. It should be possible to generate power from this, in an OffShoreWaveGenerator. I don't think that it is practical to generate enough energy to drive the ship from this—also, it's only going to work when there are lots of waves—but, I think that they could be a great addition to the TankerGenerator.
My current favourite idea is the AirSeeSaw.