my pontoon has drain plugs in the rear of the toons .if it has water in it you should see s wet spot on the outside . that is if there is enough to git to the leak .i had a fiberglass boat the leaked when on the traylor no wet spot . the leak was under the bunk

acted like a plug when on the traylor . my pontoo has rollers that the toons sit on . there is 2 crack close to the back .i had them welded and still leaked . i tried jb weld on one side amnd 2 part expoxey on the other sode . haven`t run it enough to tell if it is holding . yesterday i found a LOCTITE marine epoxey i plann on using it if it is still leaking .this sets in 50 minutes .