fishmonkey said..
i guess you would also need some kind of system for keeping the grinder dry enough to not short out when working in rain or with seawater washing over the deck...
A plastic bag would work a treat. A friend dropped his mast in the 2 handed Pitwater to COFFS race and only had a hacksaw and took over 2 hours to remove the mast plus a lot of damage to the boat from the mast flogging round. His mast did not snap at the deck, but bent which meant he had to cut the mast off with a hacksaw which was no easy task.
Prior to the race I had told him that I always carry a battery grinder. Guess what he bought the day he got home to Brisbane. Most new battery grinders are now brushless and it would take a lot of water to stop them.
Buy the way I always carry two fully charged batteries.