4.2 GPM Watermaker Cat Pump 15.9 LPM 1200 PSI 316 Stainless Steel 1725 RPM Direct Drive 3/8" NPT(F) Inlet & Discharge Port Size

Cat Pumps 316 Stainless Steel Direct-Drive Watermaker Pump (4.2 GPM, 1200 PSI)

Engineered specifically for demanding marine applications, this commercial-grade, direct-drive triplex plunger pump is the premier choice for onboard seawater reverse osmosis (SWRO) systems. Designed as a highly reliable watermaker pump for sailboats, luxury yachts, and long-range cruisers, it features a specialized "wet end" constructed entirely of 316 stainless steel, encompassing both the manifold and valve assemblies. Unlike standard forged brass pumps, this high-grade stainless steel construction provides the essential structural integrity, longevity, and extreme corrosion resistance required when continuously pumping harsh, high-salinity seawater for offshore desalination.

To help vessel owners seamlessly match this pump to their existing watermaker system, it is built to mount directly to a standard NEMA 56C face electric motor via a 5/8-inch hollow shaft. Operating at a standard 1725 RPM, this compact positive displacement pump delivers a highly consistent flow rate of 4.2 gallons per minute (GPM) at a robust test pressure of 1200 PSI. It integrates a lightweight aluminum crankcase to effectively dissipate heat in tight engine rooms, along with solid ceramic plungers that minimize friction to significantly extend the lifespan of the standard NBR (Buna-N) seals. Furthermore, this specific model features a specialized internal design that reduces operating sound levels by up to 6 decibels, making it an exceptionally quiet solution for indoor or noise-sensitive marine installations.