The number that tells you what the B329 is: 96 lb of polyethylene wrapped around 26 gallons. Most tanks this size ship at a third of that weight. All that extra material is wall - a heavy, thick-section molding built for installations where the tank gets leaned on, stepped near, or worked hard for decades. If you have replaced a cracked thin-wall tank once, you already understand why this blank exists.
It sells as a marine water tank without fittings, which is exactly what arrives: the bare molding, ready for Ronco to install ports where you want them rather than where a production line guessed. Fittings are spin-welded or thread-installed to your marks per order - print the drawing below, place your fill, vent, and pickup with the fitting planner on this page, and the tank comes back configured for your boat, not a generic one. On the fresh side it is FDA-compliant polyethylene, safe for potable water; as a B-series dual-role blank, the same shell can instead be fitted as a gray or black waste holding tank.
Full, it carries about 217 lb of water on top of its own 96, so plan bearers accordingly. Ronco has rotomolded in Tustin, California since 1974, and heavy-section blanks like this are a big part of why their tanks stay in boats so long. Compare wall weights across the boat tank category, check shipping on the freight cost estimator, or browse the maker's full line on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B329 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.
