They just lets water (saltwater in my case) under the aft cockpit area where my steering cables and steering quadrant are. The "intake" grid slots are huge, yet the drain hole is very small (1/2" maybe?). Green stuff accumulates there, it's a pain to keep clean. I can't think of any good reason. I'm thinking of maybe finding a way to seal it up. Does anyone know what these grid slots are about? (I have searched the forums)