I haven't posted in like a year, but I've got a Pond Prowler as well... I sealed off the bottom with 3m 5200 quick dry, and it didn't attack the plastic or anything, it's actually held up quite well. I've got some major cracks on the floor of the boat that I've been wanting to seal, but can't seem to find a good way since they're all in the corners and what-not. So, I've been storing it upside-down now so it doesn't fill with rain water, that worked well until it got infested with ants... >
So now I've got two problems, but oh well, I can still get off shore!
If you're gonna use the 5200, test it on a small area first just in case, because it's not recommended for plastic style boats.