There are lighter 30 gallon tanks in Ronco's catalog than the B418 - this blank ships at 109 lb, and that surplus is all wall. Choose it when the tank will live somewhere unkind: against frames in a workboat bilge, under a sole that flexes, anywhere a thin-walled shell would oil-can and fatigue at the fitting bosses.
Fresh or waste is your call, not the mold's. As a B-series dual-role shell it becomes a potable water tank with drinking-water-appropriate fittings or a gray/black holding tank with sanitation fittings, and Ronco installs whichever set you specify - spin-welded or threaded - at the positions you mark. Print the drawing below, draw your fitting locations on it, and use the on-page fitting planner to settle sizes.
Filled, 30 gallons of water runs about 250 lb, so the mounting shelf matters as much as the tank. Ronco has rotomolded in Tustin, California since 1974, and the B418 comes out of that same shop. If the shape is close but not right, the boat tank lineup has other 30 gallon proportions, all indexed from the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B418 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.
