Oh it has got to be ramming attack only. At those speeds it would be such a fast moving target to do multiple passes, and take out rudders, propellers and putting sizable holes in a target would be quite easy. Leaving a slowly sinking and doomed vessel.
I just realized, such an attack is probably the most Humane way of taking out a ship. It ravages the target, and scares the hell out of the crew. But most if not all crew members would be able to abandon ship before it sunk. No explosions, just mighty wallops.
Too bad such a boat could not actually be made. Tonnage, with minimal loss of life and limb and looking like a creature from hell while doing it
