What is THIS!?!?

[Speedster SeaDoer]

The attached picture shows a loose part in the bottom of the engine compartment of my 1997 Speedster boat with twin 717cc. What is it? What does it do? What is if for? Where is it supposed to go? Thanks for any help!

 

[rusty nail]

It is the switch for the bilge pump. The water provides the electrical connection across those two terminals to create the circuit