The B339 gives you 40 gallons in a blank that ships at just 36 lb - less than a pound of tank per gallon of water, the most weight-efficient way into this capacity class that Ronco molds. That efficiency matters in two places: getting the tank aboard (one person, no drama) and the boat's own displacement budget, where every pound of tank is a pound not available for water, fuel, or gear. For protected compartments where the tank is cradled and strapped, the standard wall is all you need.
It arrives without fittings and leaves Tustin, California configured to your drawing - fill, vent, outlet, and sender ports spin-welded or thread-installed exactly where you mark them. Print the drawing below, work through the fitting planner on this page, and the tank you receive is plumbed-for-your-boat rather than plumbed-for-average. Ronco has built tanks this way since 1974. On fresh water duty the molding is FDA-compliant and potable-safe; as a dual-role B-series shell it can instead be fitted out as a 40-gallon gray or black waste holding tank.
The load story flips once it is full: about 334 lb of water, so the lightness of the blank is no excuse for light bearers. Size against the rest of the boat tank range, or if this is bound for a trailer or coach, compare footprints in RV water tanks. The full catalog lives on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B339 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.
