I'm working on a 1958 Dorsett 14' ski boat. There is a small hole, a 1/8" at the base of the transom between the drain plugs. The hole seems to be there by intention. It is finished off with a metal grommet. No one can tell me what this :%hole is for. It drains water when I take the boat out of the lake. I'm concerned that it is letting water into the boat. Should I plug the hole?