and don't be an elitist and shoot in only manual. instead of fumbling around with your settings while whales are jumping around you, just shoot in aperture priority if you don't want to worry about it. inb4 camera meter being fooled by looking at water, obviously, be smarter than the meter and use exposure compensation and take a test shot or too. if the light isn't gonna change then shoot manual if you want.
and i'm sure you're shooting digital so take some test shots, shoot in raw and nearly anything that goes wrong regarding exposure could be an easy fix if you can edit raws.
and to answer the basic question, a faster one. don't go overboard and do like f/2.8 iso800 and 1/4000 or something, you can do iso 400 or 200 and do like 5.6 or so and probably go with whatever shutter that corresponds with. 1/1000 is probably ultra safe with a whale jumping and you panning and the boat moving and water flying.