The Ronco Plastics B156 is 50 gallons in a 40 x 20 x 16 inch block, and it is deliberately two tanks in one tooling. As part of Ronco's marine water / waste series, the molding is finished to whichever duty you order: with potable fittings it is a fresh water tank in FDA-compliant polyethylene; with waste fittings it is a 50 gallon gray or black holding tank for a boat or coach that finally wants real tankage instead of weekend-limit tankage. One drawing, one footprint, your call.
Either way the fittings are installed per order - spin-welded or threaded, located to your marks. For water duty, that means a pickup placed to drain the tank dry under way. For waste duty, it means the dump outlet at the true bottom, the vent sized and placed for airflow, and the rinse or level ports where your system wants them. Print the drawing below, mark the layout, and set it in the fitting planner on this page.
The shell ships at 92 lb and holds about 417 lb of water when full - at 16 inches tall it keeps that mass usefully low, but the platform still needs to be framed for it, with restraint that assumes rough water. Ronco has molded in Tustin, California since 1974.
Fresh-side context is at boat tanks, waste-side at RV holding tanks; the Ronco Plastics hub holds the whole line and the freight estimator quotes your ZIP. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B156 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.
