ArticleBoatingService Repair

Ever Have That Sinking Feeling?

The topic of bilge pumps is definitely not an exciting issue, but it’s without a doubt an extremely important subject matter that shouldn’t and can’t be overlooked. Bilge pumps are an essential element to any vessel, and if not properly installed and maintained, your relaxing day on the water with family and friends may be cut short and quickly replaced by an impromptu swim in the drink!


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Photo: FSF Mag

The term “bilge” dates back to the early 1500s and refers to the lowest compartment(s) in a vessel. Bilge pumps remove water that collects in the bilge(s) from various sources, such as a failed seacock, thru-hull fitting, clogged scupper or leaky exhaust hose. The original bilge pump was a rather primitive device, which nowadays we refer to as “buckets.” Over the years, technological advancements resulted in manual bilge pumps, and in today’s day and age all modern vessels are equipped with electronic bilge pumps that feature advanced automatic functions.

...your relaxing day on the water with family and friends may be cut short and quickly replaced by an impromptu swim in the drink!

When it comes to safety on the water boaters are meticulous about their lifejackets, flares, and signaling devices, yet they often overlook a crucial element that may require the use of these important safety features. If your vessel is not equipped with the right type and number of bilge pumps (with the proper pumping capacity) you may soon be in for an unpleasant surprise.

According to BoatU.S. insurance claims, for every boat that sinks while making way, four boats sink at the dock. Another stomach-turning statistic is that approximately 50-percent of dockside incidents are a result of water intrusion from failed underwater fittings.

Recommendations for Bilge Pump Installation and Maintenance

  • Always refer to American Boat and Yacht Standards (ABYC) prior to installing a bilge pump.
  • When choosing the appropriate pump, it’s always best to select the largest size pump that’s practical for your vessel. Some considerations to consider include existing electrical setup, existing thru-hull fitting and discharge hose. In an ideal situation, a two-pump setup is best – one smaller capacity pump as a primary pump for incidental water intrusion and a second, larger pump and switch mounted slightly higher in the bilge for emergency purposes. Ideally, each pump should be wired independently. Other considerations include a pump for each sealed compartment of your vessel.
  • It’s critically important to properly fuse all bilge pumps. A correctly fused pump will prevent thermal overloads, which could lead to a fire hazard resulting in property damage or personal injury.
  • It’s important that you routinely inspect the pump for proper operation, and it’s also a good idea to remove the pump from the strainer base and inspect for debris on a regular basis.
  • Always match the appropriate discharge hose with the pump nozzle. Ensure the use of a smooth bore hose for maximum pumping output and route the hose continuously upward. To prevent air locking, ensure that the discharge line does not have any dips in the line (refer to illustration).
  • Always mount your bilge pump and float switch in the lowest point in the bilge with the shortest run to the thru-hull fitting.
  • All wires should be connected above the highest water level in the bilge and sealed with waterproof connectors. Refer to the specific pump wiring specifications for more details. It’s wise to wire the pump directly to the battery to prevent losing power to the pump when shutting down the distribution or master power switch.
  • ABYC standards do not recommend the use of check valves except in situations where the water run-back from the hose continuously cycles the pump on and off.
  • It’s good practice to install a high water alarm with a visual and audible signal to alert you that your bilge pump is operating and/or is not keeping up with the amount of water accumulating in the bilge.

Inspect and Test

It can’t be stressed enough how crucial it is that you periodically inspect and test your bilge pump(s) by flipping the bilge switch from automatic to manual. While this is a suitable precautionary measure, you should also inspect the automatic float switch by making sure the pump(s) turn on by manually raising the float.