Washdown systems may not be on anyone's list of critical equipment to have on a boat, but they sure can come in handy. Whether hosing the anchor rode as it comes aboard, cleaning fish gore out of the cockpit or spraying off the latest osprey deposit on the cabin top, a washdown system makes life easier and a lot more pleasant – and it is something most boaters can install themselves.
Washdowns, for the uninitiated, are pump-driven plumbing systems that supply sea water from a thru-hull to a hose on deck that can be used for–you guessed it–washing things off. They are commonly found near anchor lockers, bait wells and swim platforms, but can actually be located almost anywhere.
If you have a simple system on a small boat, it can usually be installed in a day, provided you have scoped out the system, know where the components will be located and have all the needed parts on hand.
CHOOSING A PUMP
The heart of any washdown system is, of course, the pump. A variety of pumps are available but some are better than others. Many pumps sold as washdown pumps are basic marine water system pumps re-branded as washdowns. These models are differentiated by the volume of water they deliver, which varies from two to five gallons per minute.
PAUL ESTERLE
Most are three-chambered diaphragm pumps, producing the normal water system pressure of 40 to 45 PSI. Less common are impeller or vane pumps, which can move a considerable amount of water but usually at a lower pressure (they also cost more too).
Be sure to check the pump's duty rating. Most water system pumps are not rated for continuous duty, or running for long period of time. They turn on, supply the needed water to a faucet or shower, and then turn off. A washdown pump cleaning a long, dirty anchor rode may run for a considerable length of time, and you don't want to overheat the pump motor.
Just about every pump sold as a washdown is equipped with a pressure switch to turn the pump on and off. When the system is turned on, by a switch or breaker on the electrical panel, the pump pressurizes the system. If the nozzle is closed, the pump shuts off at its specified pressure. When you press the nozzle trigger, the water flows and the pressure drops until the pump kicks on. This usually results in a slow pulsation in the flow as the pump turns on and off. Adding an accumulator tank, which inflates pressure, downstream of the pump will smooth out the flow, but that's one more component and an additional complexity in an otherwise simple system. Most folks live without it.
Recently, manufacturers have started supplying pumps specifically manufactured for washdown systems. These pumps are rated for continuous use and produce higher water pressures, and many have built in strainers to weed out debris. One example is the West Marine 3.4 GPM Washdown Pump (model #7865678). This pump has five valves and five pump chambers for a smoother, less pulsating water flow and comes equipped with a strainer mounted on the pump. The best thing about this pump is that it is rated at 70 PSI, making it one of the highest-rated pumps around. It carries a three-year warranty and costs about $120.
