[Skools Out]

there should be a pipe under the tank to let it drain. they get stopped up but you can clean it out by using a long 12 to 15 ft piece of ground wire about a #8 solid push it through the drain plug hole into the pipe under the tank to the front area it should clean all the trash out of the tube and let the water flow.

now it's not uncommon to use bondo in a boat actually Parker boats use's it to fill the hull strikes and then the glass the back side in the molds. bondo is fine as long as you seal it with resin. just sand that area and get the complete area of bondo exposed then let it dry. then once it's dry work that area till the boat looks straight then resin it with several thin coats once it cures sand it smooth without sanding into the bondo and paint it and you should be good to go.