Boat & Bilge Pump Maintenance

By Captain Matt

Maintenance of your bilge pump, its functionality, and its surrounding components is a crucial part of practicing good boat maintenance as a whole. As the wettest place inside your boat, the bilge is prone to all host of problems that come along with water: rusting and grime buildup on components and unwanted visitors in the form of bacteria can create serious problems for boat maintenance & upkeep.

Take out the trash:

Sailors used to refer to rubbish talk as “bilge”. Personal opinions on cursing aside, it’s important to keep the “rubbish” water on board as clean as possible. This helps you to prevent:

  • the growth of bacteria
  • the foul odors that come with them
  • and the rust and corrosion of equipment that lies in the bilge

You can get bilge cleaner in most marine hardware stores, however, it can be expensive. Liquid Tide is less expensive and does as good a job. Containing no phosphorus, being biodegradable, cutting grease and dirt and having a clean smell make it a good choice. However, if you are going to be using a large amount of cleanser, or if you will be discharging the cleanser into the water, choose an alternative from this list of Natural Cleaning Product Alternatives. If your boat usually has some water in the bilge just add the liquid Tide to the bilge and let the rocking of the boat do the cleaning for you.

Most grease and dirt can be removed with Tide and perhaps a little elbow grease. However, steam cleaning can be an alternative. Steam cleaning is a harsh method that can cause paint to peel, especially on a wooden boat. As they say on the stunt shows, don’t try this at home. Seek out a boat maintenance professional and check their references.

Swash Plates and Limber Holes:

Limber holes are found in the swash plates (ribs or partitions in the bilge which allow water to pass through them). The swash plates help water to flow to the lowest bilge points, usually where the bilge pump is located. This allows the water to be pumped out either automatically or manually.

You should keep these holes clear of residue to prevent blocking the water flow. Most boats will have a light chain running through the limber holes which allows you to pull it back and forth to dislodge any foreign matter.

Oil and Environmental Concerns:

Most newer model boats have drip pans installed under the engines to prevent oil from dripping directly into the bilge. Whether you have drip pans or not it is a good idea to put absorbent pads under the engines. They not only absorb the oil that could drip but provide a quick way to find leaks. Each time you do an engine check, which should be each time prior to starting, check the pad to see if any new oil spots have appeared. If so, try to track down the source immediately.

Remember that it is illegal to pump oily discharge overboard. If you find oil in your bilge water turn off the bilge pump and find an alternative way of disposing of the oily water. Don’t think just because there is only a little bit of oil it is okay. The test for illegal pollution is simply a “visible sheen” on the water.

What to watch for:

You should inspect the bilge and its surroundings with a flashlight at least once a month. Look for the following:

  • Lift up the float switch on your electric bilge pump to make sure it turns on the pump automatically.
  • If you find unusual amounts of water, be sure to track down the source.
  • Check all through-hull openings and fittings.
  • Make sure that all fittings below the waterline have double hose clamps.
  • Check the seacocks to make sure that you can turn them off. You could sink your boat if a hose comes loose from a seacock and you can’t stop the flow of water because the valve is corroded.
  • Look for corrosion and rust.
  • Check for unusual growth or mildew.
  • Check all pipes, hoses and clamps.
  • Check limber holes.

Find this and more of Capt. Matt’s boat maintenance articles online at