I just picked up this little guy (below) and noticed it had a regular drain plug in the transom pan area, and another - what looks like a drain plug at the bottom rear of the boat, right at the bottom center. Thing is, a normal drain plug doesn't fit in there (the hole is smaller), it has plastic threads in it, almost like a plastic bolt or something should go in it. Any idea what it is, and where I'd score something to put in there? Just go to a hardware store and find a plastic bolt or cap of some kind?
