Forespar Ball Valves
Why Forespar Ball Valves Stand Apart on the Water
When it comes to marine plumbing, few components are more critical — or more vulnerable to the harsh saltwater environment — than the ball valves controlling water flow through your hull. Forespar has built its reputation in this space on a single proprietary material innovation: Marelon®. This glass-reinforced polymer composite is at the heart of every ball valve Forespar produces, and it fundamentally changes what boaters should expect from their plumbing hardware.
Marelon®: The Material That Makes the Difference
Traditional bronze ball valves, while long considered the marine standard, are susceptible to corrosion, dezincification, and electrolysis — a constant risk in both fresh and salt water. Forespar's Marelon® addresses all of these vulnerabilities head-on. Its non-corrosive proprietary formulation of polymer composite compounds uses resins and additives to produce an extremely strong marine-grade product that will not deteriorate like traditional bronze marine plumbing parts. Beyond corrosion resistance, Marelon composite resists electrolysis, UV damage, and temperature extremes while providing smooth, leak-free operation.
The operating temperature range of Marelon® is -40°F to +176°F (-40°C to +80°C), making the valves reliable in every climate and season. That kind of range matters for bluewater cruisers and weekend sailors alike.
Key Product Lines: MF850 and 93 Series
Forespar offers two primary ball valve lines, each engineered for specific installation and plumbing system requirements.
- MF850 Series: The Forespar® MF 850 series of ball valves are precision molded in high-strength glass-reinforced Marelon®. Great strength, light weight, easy installation and maintenance, as well as freedom from corrosion and electrolysis create the ideal valve for controlling inlet and outlet water flow above and below the waterline — and stringent testing makes MF850 valves meet or exceed industry standards. In a standout durability test, after 11,000 duty cycles, these valves still hold 80 psi of air leak-free.
- 93 Series: The Marelon® "93 Series" plumbing system comes standard with buttress-threaded thru-hulls that mate to buttress-threaded valves. These Forespar Marelon Integrated System valves were specifically designed for production boat builders and offer more configurations and options than any other brand or style of valve made for the marine industry.
Certifications and Thread Standards
Boaters and builders who specify to code will appreciate that Forespar ball valves are serious about compliance. Complete system valves meet or exceed ABYC, UL, and ISO marine standards. All valves sold throughout the U.S.A. have standard NPSM type threads — ensuring compatibility with standard marine plumbing systems — while BSP threads are available for international applications. Any marine-grade sealant or bedding compound can be used as you would with bronze fittings, and Marelon and bronze fittings can be fitted together as long as you are careful not to cross-thread.
Above and Below the Waterline
One of the key design mandates for Forespar ball valves is dual-service capability. These ABYC-compliant seacocks and valves can be used above and below the waterline, making them ideal for controlling inlet and outlet water requirements. Whether you're fitting out a raw water intake, a cockpit drain, or a livewell system, the MF850 and 93 Series cover the full range of onboard plumbing applications with a single trusted material platform.