As far as I know on our 240SD's the only water that drains out those pretty holes on the sides of the boat is from the sinks and the bilge pumps. All the deck water and locker drains all go to the engine bilge (I know cause I filled mine up washing the boat while it was in the water and the bilge pumps take a while to pump out water. Sure yo ucould take the first one over the bow but the second and third would probably sink ya.
Morpheus,
Actually we have two cockpit drains one on each side. Now if you are cleaning the anchor and ski locker area yes they do drain to the bilge. All other areas should be draining overboard. You need to check and make sure your storage and lower engine cowling are sealing correctly. If you where to say lay a running hose in the bow, no/very little water should end up in your bilge area. You should have an overboard drain on the port side just in front of the engine cowling and a starboard side drain just in front of the step if I remember correctly.