Thirty-six gallons is the sweet spot for a mid-size cruiser's water supply - enough for a long weekend aboard with normal use, small enough that the filled tank stays manageable. The B330 delivers it as a bare marine molding: no pre-drilled ports, no assumptions about your plumbing, just the blank shell waiting for your fitting map. That is the point of buying a tank this way. Production boats get tanks with fittings wherever the factory put them; a refit gets fittings where the hoses actually run.
Mark your locations on the printable drawing below - the fitting planner on this page makes it a five-minute job - and Ronco spin-welds or thread-installs each port before the tank ships. They have been doing exactly this in Tustin, California since 1974, one customer drawing at a time. Ordered for fresh water, the molding is FDA-compliant polyethylene rated for potable supply; as a dual-role B-series shell, it can just as readily be fitted out as a gray or black waste holding tank if that is the gap in your boat.
The blank ships at 36 lb, easy parcel freight; full, it holds about 300 lb of water, so land it on structure and strap it down. If 36 gallons is not the right size, the boat tank category runs from day-tank small to passage-making large, and RV builders will find the road-going equivalents under RV water tanks. The whole Ronco line is on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B330 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.
