When an original-equipment water tank cracks, the replacement search usually starts with disappointment: the OEM shape is discontinued, the importer wants months, and nothing off the shelf matches the cavity. The RVB543 is the kind of molding that ends those searches. It is a 60 gallon light-duty fresh water tank from Ronco's deep B-series catalog, and because Ronco installs fittings per order, you can reproduce your old tank's port layout on it rather than re-plumbing the coach around a generic one.
Match the geometry first: print the technical drawing below and compare it against your existing tank and the bay it came out of. Then match the plumbing: mark the fill, vent, and outlet positions your lines already expect, and confirm them in the fitting planner on this page. Ronco spin-welds or threads each fitting at those marks in Tustin, California, where the company has molded tanks since 1974 - decades of exactly this kind of odd-cavity problem-solving.
The spec is right for the job: FDA-compliant polyethylene rated for drinking water, translucent natural walls that show the level at a glance, 102 pounds as molded, light-duty wall schedule for supported in-bay service. Remember that a full 60 gallons at 8.34 pounds per gallon needs the same solid floor the original had.
If this shape is not the match, keep hunting through the RV water tanks and the complete Ronco Plastics line - with this many moldings, the right cavity is usually in there. OneSource Plastics is an authorized Ronco Plastics dealer.