I have spent a little time a hundred miles out in a fishing boat. It would probably have felt like a speed bump at high speed. There was an account of some divers who encountered the tsunami while down below. They said they were rolled pretty good and debris from the bottom clouded the water up but they were OK as was their awaiting boat.
3 feet high....500mph....even in a big boat, being sideways to something like that....it would have to knock you pretty hard, off your feet, probably at least!
Plus, no real warning...."Hey Skipper, what's
that?....then, PHOOM!
Glad everyone was ok. This will keep me praying never to get 'sideways'!