Especially in a marine environment, I'd suggest that you focus on doing
it right (including safely) rather than on saving a few $. Not meaning
to be cute, but one ER trip or casket purchase can really tip the
accounting against you.

One possible alternative is a battery-powered saw. True, less powerful
than 120v, and more expensive, but much less likely to zap you when
wet. With gen at the head of the pier, you could take the batteries
there for charging.

HTH,
J