This has just appeared on the OCC forum:

"Removing the barnacles with a paint scraper is an arduous task, so this time we tried using the WaveBlade tool.

We had looked at these tools with some suspicion over the past few boat shows. Its like a hand held electric chisel, waterproof, and powered by 12 volts DC. Faced with several acres of nasties, it seemed worth a try.

I can say this is a wondrous tool ! In use, the best description I can give is that its like shaving the hull. With a light pressure and low angle, the blade glides across the surface of the hull and simply explodes everything in its path. The small barnacles don't even slow it down, they just fall off, and the few large critters we found disappeared in seconds. The wave blade isn't specially fast, but it does make removing the critters an easier task."

Easy removal of well-stuck-on barnacles, underwater? Sounds good to me.