Been There
This was the hardest task I have ever done on my boat, sorry to say. I decided to cut a an access hole in the rear bulkhead near the battery shelf on the port side. This allowed me to remove the leaking tank. I installed the new poly tank and secured it down with bondo, and a rachet strap. Then I covered the whole with a painted sheet of plywood. The hardest part was reconnecting the hoses. They connect on the starboard side and I cannot reach the connectors from above very well. I actually got stuck upside down at one point trying to reach them. If you try it and are not 6' 4" with long arms be prepared to have a friend pull you by your belt loop. After many tries and some help from a taller younger friend we got the old hose reconnected and then they leaked! After all this I decided to scrap the project for now and try a high capacity porti-potty. This option has worked very well. I bought the kind you can have pumped out or just empty by yourself. The new tank is still there ready to be connected if I choose, but so far the porti-potty has met all our needs. We do not stay on the boat more than just a few nights at a time so the 6 gal. capacity is plenty. In retrospect I think I should have planned new hoses as well as a new tank, then I think the connection would have held up, but I am pleased with the porti-potty. If you think about the capacity in a 12-15 gal holding tank and if you flush with enough water every time, the porti-potty matches up quite well because one does not have to flush so much water with each use. Anyway, good luck on the project!
