Re: cutting floor
How about determining the best place first, try locating any bracing or bulkheads by using a very small drill bit and wire to see if its clear underneath. After that get a deck plate and make the hole that size. that way when your done with the pump, you can use the deck plate to cover the hole. I prefer the screw type covers as they are nearly water proof, the pop out type can pop out and leak.
To cut the hole if the deck plate idea is used, the best way to cut is a thin blade jig saw. if its wood or fiberglass that would cut the easiest.
