Ronco molds 20 gallons in more than one marine shape, and the B461 is the heavy one: an 80 lb blank, which tells you the wall thickness before you ever put a hand on it. This is the shell to choose when the tank will live somewhere hostile - against a hull that works in a seaway, in a bilge that sees impact loads, under floors that get walked on. Capacity is ordinary; construction is not.
Like the rest of the B-series it is dual-role. With fresh-water fittings it serves as an FDA-compliant potable tank; ordered for holding duty the same molding takes gray or black waste. Full of water the contents add about 167 lb to that already substantial shell, so build the bed to carry both.
Fittings are installed per order - spin-welded or threaded at the locations you mark - at Ronco's Tustin, California plant, in business since 1974. Print the drawing below, mark your penetrations, then set the order up in the on-page fitting planner. For the opposite philosophy at the same capacity, the light-duty 20-gallon RV57W shows how light 20 gallons can go.
More marine shapes under boat tanks; the complete catalog is on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
