Seventy gallons puts the Ronco Plastics B153 at the top of Ronco's marine fresh water range - liveaboard and long-passage territory, where water capacity is measured in days of autonomy rather than weekends. A tank this size is usually the single largest liquid mass a mid-size cruiser carries besides fuel, and it is worth getting right the first time, because it is going in behind joinery that nobody wants to open twice.
Which is exactly why Ronco's per-order fitting installation matters most at this scale. Spin-welded or threaded ports are placed to your marks: the pickup at the true low point under sailing trim, the vent high enough to handle heel, the fill matched to your deck plate. Print the dimensioned drawing below, plan the ports against the compartment, and finalize with the fitting planner on this page. Ronco has molded this way in Tustin, California since 1974.
The FDA-compliant polyethylene shell ships at 115 lb; filled, it carries about 584 lb of water. That is serious structure - frame a full-bottom platform, glass in or through-bolt the restraints, and place the tank low and central where all that stored water becomes useful ballast instead of a trim problem. Smaller stablemates are under boat tanks; the entire family lives at the Ronco Plastics hub; the freight estimator quotes your ZIP. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B153 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.
