The Ronco Plastics B391 is nearly eight feet of tank: 95 x 33 x 9 inches, 110 gallons, molded as a single low-profile slab for the long underfloor voids of large boats and coaches. Ronco names it a water and waste tank because the B-series shell is genuinely dual-role; potable fittings make it a food-grade fresh water tank, waste fittings make it one of the largest low-profile holding tanks in the line.
A full B391 carries about 917 lb of water at 8.34 lb per gallon distributed along its length, with the molding itself at 153 lb. Continuous support under the entire footprint is not optional at this scale.
On a tank this long, fitting placement determines whether it ever fully drains. Print the drawing below, mark your low points and pickups, and the factory installs each fitting per order, spin-welded or threaded to those marks; the fitting planner on this page structures the request. Ronco has molded to order in Tustin, California since 1974.
Browse boat tanks and RV holding tanks, and price the haul with the freight estimator. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B391 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.
