Nylon Composite is Best Choice for Marine Plumbing
by Art Bandy

Marine plumbing components made of glass-reinforced nylon, like the sea cock above, offer many advantages over those made of bronze or plastic.

Boaters and builders need to make the right choice when selecting a material for the valves and fittings in their marine plumbing system. An incorrect choice can cause component failure and even sink the boat.

For these reasons, boaters and builders have searched for an alternative material. Recently, they have tried plastics, such as PVC, ABS and unreinforced nylon. These substances will not corrode, and are lightweight and inexpensive.

Since they act as insulators, plastic valves help minimize galvanic corrosion by inhibiting electrical flow to onboard metal items. Galvanic corrosion can be a serious problem with bronze valves and fittings.

Although they donít corrode, plastic valves, like all valves, can lock up after long periods without use. A valve stuck in the open position can be dangerous if a hose fails and allows water into the boat. For this reason, boaters should operate all valves at regular intervals to help prevent sticking.

Most plastic plumbing components, however, were not originally designed for the harsh marine environment. They donít handle heavy loads well and can freeze and crack in cold temperatures. They are not UV stabilized, and their slippery surfaces can allow clamped hoses to slide off.

Because of these disadvantages, an increasing number of boaters and builders have turned to a composite materialóglass-reinforced nylon. Like plastic, it resists corrosion and affords smooth, easy operation.
But, unlike plastic, this advanced composite resists UV rays and is extremely strong. In fact, glass-reinforced valves are the only ones made of synthetic material that pass the UL load-bearing test. In addition, hoses tend to remain securely clamped to the lightly textured, non-slippery surface of this material.

To summarize, while bronze may be suitable in high load situations, and plastic may be used when low cost is paramount, glass-reinforced nylon is the most reliable overall choice for marine plumbing components. In fact, dozens of builders have begun using this material over the past 18 years, including Catalina Yachts, Boston Whaler, Sea Ray, Donzi, Wellcraft, MasterCraft and Wally Yachts.

Art Brady is sales manager for Forespar, which offers a line of Marelon glass-reinforced nylon fittings and valves. Phone: 949-858-8820, website: www.forespar.com.