I have a new to me pond prowler type boat (no name anywhere), and am trying to figure out the two holes in the bottom. One is rubber (presumably for a plug) and one appears to be steel pipe with outside threads.

Can someone give me insight as to how/why these are there? They appear to be in a location higher than the "pontoons" on the side.

I don't know for sure, my version doesn't have them...but I'd make a guess that they might be used to plumb a supply and discharge for a livewell.