Bilge Pumps, Installation
and Operation Guidelines

Bilge pumps, which are standard equipment on many boats today, provide a measure of safety, and peace of mind. Numerous sizes and types of pumps are available to accommodate various size boats, and to fulfill the varying demands of each intended application.

While there are several hand pumps available that work well for smaller boats, most of today's pumps are powered by the boat's 12-volt electrical system. A typical installation consists of the pump, a length of hose running from the pump to a thru-hull outlet fitting, wiring, and an on/off switch. Many pumps can also be operated by an automatic switch, which turns the pump on only when water is present.

When installing a bilge pump, it is usually best to mount the pump at or near the lowest point, usually in the bilge, when the boat is sitting in the water. Some pumps use a remote pickup in which case the pickup should then be mounted at that location. When mounting the pump on the bottom of the boat, it is not usually possible to use screws or mounting hardware of sufficient length to hold the pump securely. A strong marine adhesive will work to attach most lightweight pumps to the hull, while heavier pumps may require a larger mounting plate bonded to the hull, with the pump attached to the plate by screws or small bolts.

The outlet or discharge for the pump is typically located near the gunwale, or top side of the boat, to reduce the risk of water coming back in through the outlet. A length of plastic or vinyl hose is connected between the pump and the outlet with clamps, thus allowing the pump to discharge water out if the boat. Always use a silicone or polysulfide sealer when installing any components that require drilling through, or into the hull. When connecting the 12-volt wiring, follow the instructions that are included with the pump, and be sure that any wire splices or connections are located as high as possible to avoid submersion.

When selecting a bilge pump for your boat, be sure it will fit in the area you have selected for mounting. You will also need to allow room for hoses, and it should be accessible for cleaning and maintenance. While any pump is better than none at all, be sure the pump you select is big enough to handle the job for your size of boat, and follow the installation instructions carefully.