Sounds like 'you dont know where to start'....
That being the case, a fully waterproof diving camera is going to be WAAYYY out of your price and ability range, too big to fit in a boat etc...
You need to get a nice compact 1 to 3 CCD digital camcorder, and then get a housing or Pelican Case for it.
Peli Case's ($15-$30) are way cheaper than housings (usually $300-$600) and in my opinion more reliable. Granted, with a housing you could shoot from you boat with wet hands while getting splashed......with a case you gotta get out, dry your hands, open your box and shoot.....but this is basically what everyone in the industry does, so....it works.
You can get a decent 1 CCD digital for @ $400 these days? (havent been in the market for while) These are totally fine if you are just starting, want some quality but dont need anything beyond good home entertainment.... I like Sony and Canon. Canon's ZR series is a good boating camera (small and takes good shots, pretty easy features etc etc... @400 i think). Alot of industry professionals I know from videoboaters to film makers say that Sony's are more durable and last longer.....
Try abesofmaine.com for good deals on digicams and to see whats out there and search for other sites like that as well as 'digital camera reviews'
There are tons of consumer review sites out there.