The B347 holds 40 gallons in a 34.75 x 26 x 11 inch molding that ships at just 38 lb - a low, light, wide blank that installs like a much smaller tank and stores like a much bigger one. Eleven inches of height clears most underfloor bays and under-berth voids, and the sub-40-pound empty weight means one person can trial-fit it repeatedly while dialing in the compartment, which is how good installations actually happen.
Dual-role, per the B-series rule: order fresh water fittings and it is an FDA-compliant potable molding - 40 gallons is a legitimate primary supply for a coastal cruiser or travel trailer. Order waste fittings and the same shell becomes a low-profile gray or black holding tank. Ronco installs either set to your marks, spin-welded or thread-threaded into the blank at the Tustin, California plant that has done this work since 1974. Print the drawing below, place your ports with the on-page fitting planner, and what arrives is ready to plumb.
Do the full-weight math before you pick the spot: about 334 lb of water in an 11-inch-tall layer wants continuous support across that whole 34.75 x 26 inch bottom, not a pair of rails. Similar shallow footprints live in boat tanks and RV water tanks, the waste-side counterparts in RV holding tanks, and the full range on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B347 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.
