I have an 1988 XTB. On the rear above the pad are 3 drain holes. I know the lowest one in the center is the bilge drain. What are the other 2? The one to the right of center is high enough that the cav plate cuts through the center of it. I have a leak in the boat and I have traced it to something in the livewell system. I will like;y replace all hoses and pumps this winter. Just trying to pin it down