back of boat

Just purchased a used Cajun Maverick bass boat before putting it in for the first time I'm checking things out one questions which has me baffeled is in the back of the boat right next to the drainplug is another hole with no plug in it. If I lift the cover in front of the motor where the batteries are I can see a hose maybe 1 1/2" running forward, but with out removing the seats I can't seem to see where it goes, so when putting the boat in the water why it won't take on water through this hole, got any ideas what it's for. It looks like it has a white upraised lip on it as it goes into the boat. All the other hoses from the live wells drain right into the bilges.