Salt Water Wash

Install a salt water wash-down system

by Conrad & Judy Kreuter

Q: Dear Boat Talk: I have a fishing style boat and have often wished I could clean the deck while underway. Last month you outlined a saltwater wash-down system which would be a welcome addition to my rig. Could you describe how to install such a system? HK, Deer Park NY.

A: Dear HK: A saltwater or raw water wash-down system pumps water from the ocean or the bay through a hole in the boat called a thru-hull fitting. A pump attached to the hose coming from the thru-hull fitting brings the water thru a hose and nozzle assembly to wash down the deck. It’s great for washing off sandy feet or fish guts.

Planning and installation of a salt water wash-down is more complex than other do-it-yourself projects, but with proper planning this project is within the skills of most boaters.

You will need to assemble the following parts.

A wash-down pump with an integral pressure cutoff switch and an output volume of at least 3 gallons per minute. The cutoff switch stops the pump from operating unless the pressure falls below a pre-set level.

An on-off toggle switch or push-pull switch for turning on or off the pump power.

Various lengths of 14 gauge wire, fuse holder, the proper sized fuse as specified by the instructions from the wash-down pump, miscellaneous electrical connectors such as butt splices, ring terminals, and heat shrink tubing.

A brass thru-hull fitting for use below the water line, and a brass ball valve to shut off water when the wash-down is not in use. This valve should be of the proper size to match the thru-hull fitting.

Various lengths of reinforced water hose to connect from the gate valve to the pump, and another length of hose to connect from the pump to the deck outlet, and various stainless steel band clamps to secure the hoses.

A deck outlet fitting for connecting the pump to a coiled wash-down hose, and a hose nozzle.

The boat must be out of the water to install the system. Locate a suitable position to install the thru-hull fitting as a water inlet. If you wish to use this system while the boat is underway, it will be necessary to locate the thru-hull on the bottom of the hull. You can mount the water inlet on the transom of the boat if you will only use the system when the boat is stationary. Remember that the transom is out of the water when the boat is underway. Drill the correct size hole to mount the thru-hull and bed with underwater silicone. Tighten the thru-hull nut. Thread the ball valve to the thru-hull fitting. Attach a length of water hose from the gate valve to the pump input and secure with stainless band clamps. The pump should be mounted high enough in the bilge to avoid being submerged in normal levels of bilge water. Mount the pump to a bulkhead wall using the four mounting holes provided. Find a convenient location for the deck outlet fitting and drill the mounting hole. Attach another length of water hose from the pump outlet to the deck outlet fitting and secure with stainless steel band clamps. Screw the coiled water hose assembly to the deck outlet fitting. If you find it convenient to locate the pump power switch at the rear of the boat, find a suitable location for the switch. Connect a black wire to one of the pump wires and route to the battery negative terminal of your battery system. Connect a red wire to the other pump wire and connect to one side of the power switch. Attach another red wire to the remaining terminal of the power switch and route towards your battery system. Connect the fuse assembly between the power switch and the positive terminal of your battery system or connect to the common terminal of your dual battery switch.