Who would win a chess match, Bigfoot (with scuba tank) or the Loch Ness Monster in Loch Ness?
I think that Bigfoot would win, even with the problem of the scuba tank, because he (or she) could manipulate the pieces better. It would not matter how good Nessie was. Those flippers would get in the way. Well, that would change if Nessie, a carnivorous dinosaur, ate Bigfoot. She would win by default.