A 36 gallon tank that weighs 34 lb empty: the Ronco Plastics B478 holds more than a pound of capacity for every pound of tank you carry aboard. That efficiency comes from rotational molding done well, a single continuous polyethylene wall with material only where the engineering wants it.
The B478 is a dual-role molding from Ronco's marine B-series. Choose fresh water fittings and it stores potable water in food-contact PE; choose waste fittings and it serves as a gray or black holding tank. The shell never changes, only the plumbing, and Ronco installs that plumbing per order, spin-weld or threaded, exactly where your marked drawing says.
Loaded, expect about 300 lb of water at 8.34 lb per gallon. Print the dimensioned drawing below, confirm the fit against your compartment, and use the on-page fitting planner to position every port before ordering.
Ronco Plastics has molded in Tustin, California since 1974. A committed 36 gallon holding tank is available if the role is already decided, the marine range brackets this size in both directions, and the freight cost estimator gives a delivered lane cost in seconds. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B478 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.
