Small boats punish their gear hardest - more motion, more slamming, less structure to hide behind - which is why the B476 exists: 13 gallons in a 25 lb marine molding, a deliberately overbuilt shell for a modest capacity. If the tank is going into a center console, a small workboat, or anywhere it will be hammered, this is the 13 gallon shell to specify.
It follows the B-series dual-role pattern: ordered with fresh-water fittings it is FDA-compliant potable polyethylene; ordered for holding duty the same molding carries gray or black waste. Full, the water inside comes to about 108 lb, so even at this size the mounting deserves real fastening, not friction and hope.
Fittings are installed per order at the Tustin, California plant - spin-welded or threaded to the exact marks you supply, the Ronco way since 1974. Print the drawing below, mark it up, and place your penetrations in the on-page fitting planner. The featherweight counterpart is the light-duty 13-gallon RV35W from the RV line.
The rest of the marine range is under boat tanks; start broad at the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
