In that model and year Aquasport the floor drains were very close to the outside water level with no one in the boat. The apparent intention was to allow the boat to self bail when left at a dock, and there's nothing wrong with that approach. By doing so the interior depth is maximized and generally that is considered a good thing. In later years the floor level was raised a few inches in an attempt to let it bail with people on board, but several inches of interior depth were lost. It's an un-avoidable trade off. With the floor of the boat under water level while it is in use a scupper must seal perfectly to keep all the water out of the boat. When the flapper gets old and stiff, distorted, or simply has a bit of trash in it, water flows in. The best solution is to put the drain plugs in those floor drains while you're in the boat. The boat was supplied with drain plugs when it was new for that purpose, but today so many people think it's a design flaw if they need a drain plug.
