The Ronco Plastics B309 is a 40-gallon marine molding in balanced proportions - 39" x 18" x 14" - that fits where neither a cube nor a pancake will: alongside an engine bay, under a quarter berth, against a lazarette wall. It is a true dual-purpose tank, finished either as a fresh water tank or as a gray or black waste holding tank depending on the fittings you order; the FDA-grade polyethylene is potable-rated when fresh service is specified. Ship weight is 86 lb, and a full water load runs about 334 lb.
Ronco installs every fitting per order - spin-welded or threaded at the exact locations you mark - which is what lets one molding close out either side of a plumbing diagram. Decide the role, then place the ports for it: suction low and vent high for fresh service, a generous discharge and rinse fitting for holding duty. Print the drawing below, mark your runs, and confirm the whole layout with the on-page fitting planner before ordering.
Molded in Tustin, California, where Ronco Plastics has specialized since 1974, the B309 is one of the most adaptable mid-size formats on our boat tanks shelf. Its coach-side cousins are gathered under RV holding tanks when the project has wheels. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B309 dimensional drawing - print it to plan your install and mark exactly where you want fittings located; Ronco installs spin-weld or threaded fittings to your marked spec.
