personally i think it would be a bad thing......
1) metal in the pumps
2) heat from the motor
3) if it's a marine bilge pump...... isn't it dc????
4) most of those pumps (ac) aren't setup right, they need to be in a deep hole
5) continuous use will burn them out fairly rapidly if they aren't fully submerged, and even then they won't last very long
6) unless you buy big and/or expensive, they really aren't that strong.
there are other reasons i also can't think of right at the moment. we used these kinds of pumps extensively in an industrial environment where i used to work when the air-powered ones failed. it wasn't the right situation for the pumps i will give you, but they still weren't very impressive.
sorry