The B350 is what a compromise looks like when it is done well: 30 gallons in a 33 x 20.5 x 11 inch molding, low enough at 11 inches to slide under berths and floors, compact enough in plan to fit compartments that reject the truly wide pancake tanks. At 30 lb empty - a pound of tank per gallon - it is also one of the easiest tanks of this capacity to physically install. Most refits do not need an extreme shape; they need this one.
Its role is set by the fittings you order, because the B-series molds one blank for two jobs. Fresh water fittings make it an FDA-compliant potable tank sized for a weekender's full supply; waste fittings make the identical shell a low-profile gray or black holding tank. Either way, Ronco spin-welds or thread-installs the ports to your marks in Tustin, California, where they have molded to customer drawings since 1974. Print the drawing below, work the on-page fitting planner, and the tank arrives matched to your hose runs.
Full, it holds about 250 lb of water spread across that 33 x 20.5 inch bottom, so give it continuous bearing rather than corner blocks. Shape alternatives at this capacity live in boat tanks and RV water tanks, the dedicated waste moldings in RV holding tanks, and the whole family on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B350 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.
