I wanted to record the giant "thud" of ocean waves hitting a hole in
the rock, it's a sound that eats any known bass drum for lunch. (The
ground shakes from it.) Not having a portable audio recorder, I tried
to record the sound with my portable DV camera, setting sound quality
to "16 bit" for the best available resolution.

Well...

I got an hour of all sorts of ocean noise all right (and a few good
showers from head to toe... can't always predict which way the wave
will break), but the small camera mike sounds exactly like that:
small. The wave break sizzle is all there, but the bass is just gone,
vanished, kaputt.

What should i do? Sticking a bass drum mike near the water level would
probably capture the thud, but it would also drench the mike at the
first bigger wave break. I ran a search for "waterproof microphone" on
the Web, but all I got was blurbs about waterproof headsets to record
speech. Does anyone have some creative ideas? (Especially for a
solution not costing major $$$ ? :-)

Thank you in advance