[jmk]

Have you considered inserting a bladder instead? I have looked into removing the water tank from mine just to repaint it and get to the bilge area underneath, and my racors and hatch supports would definitely need to come out, and even then it could be a tight squeeze between the motors and above the generator. Getting a plastic tank inside that aluminum one would require a considerably smaller tank and a reduced water holding capacity. Someone should be able to make a bladder that fits the interior dimension of the tank.