The B421 is the light-shell 29 gallon tank in Ronco's marine series - the blank weighs just 42 lb, which means one person can pass it down a companionway and dry-fit it alone before committing to plumbing. For a weekender or coastal cruiser where the tank rides in a protected locker, that lighter wall is weight you do not have to carry.
Dual-role, like the rest of the B-series: fitted for potable service it is your fresh water tank, fitted for sanitation it is your gray or black holding tank. Ronco ships it with the fittings you specify already installed - spin-welded or threaded, at your marked positions, done in the Tustin, California shop that has molded tanks since 1974. Print the drawing below, mark it up, and lean on the on-page fitting planner for sizing.
Full, 29 gallons of water is about 242 lb, so even a light tank needs a proper platform. The boat tank category has the neighboring capacities if this one is close; the Ronco Plastics hub has the whole family. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B421 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.
