Boating Basics: What is a Bilge Pump?

Boating Basics: What is a Bilge Pump?

Fresh and corrosive seawater can find its way to the bilge wells due to leakage in pipelines, leaky pumps, valve glands, machinery, propulsion systems, overflowing of tanks, and even accidental spills. The resulting mixture formed is known as bilge water and you do not want it onboard. That’s where bilge pumps come in. Bilge pumps are that last line of defense against your boat sinking. Unfortunately, most boaters believe that one pump is sufficient. That is actually the bare minimum required, and three or four pumps per craft is recommended.

A bilge pump is easily overlooked as it is usually installed under the boat’s engine on an inboard. Also the U.S. Coast Guard does not require recreational boats to have them. But this is no optional piece of equipment. Here’s what you should know about boat bilge pumps:

• Most boats have either a submersible or centrifugal bilge pump
• Boat bilge pumps may be supplemented with an additional manual pump in case of power loss
• Centrifugal pumps can have a large footprint and can clog easily. We recommend an auxiliary diaphragm pump with in-line strainer to supplement
• A fourth kind of bilge pump, a high capacity pump powered by an engine or electricity is another great option
• It is also recommended to carry a five gallon bucket on board should your boat be caught in a gale and its bilge system fail

Automatic vs Manual Bilge Pumps

When it comes to electrical bilge pumps, there are two options: automatic bilge pumps, and manual bilge pumps. Automatic bilge pumps come equipped with a built-in float switch which detects water levels and will automatically turn the bilge pump on when necessary. Vessels over 20 feet long with sleeping accommodations are required to have automatic pumps installed, however any sized boat can utilize these convenient pumps.

Manual bilge pumps are an affordable option that works for most fishing boats and smaller recreational vessels. They’re easy to install, and typically easy to maintenance. Cartridge bilge pumps, for example, have a cartridge motor that can easily be removed and replaced. Additionally, you can add a float switch to your manual bilge pump, making it function similarly to an automatic pump.

Keep Your Pumps in Working Order

Get in the habit of routinely testing and inspecting your bilge pumps, especially if your boat will be sitting in water unattended. One of the main reasons bilge pumps fail is due to foreign objects jamming the pump. Sand, leaves, grass, and branches can breach the filtration system and cause damage to the pump itself.

If your pump isn't working, be sure to check the strainer and housing for damage. Some manufacturers offer drop-in motor replacements, which can be an economic option if the housing is still in good condition. Consider upgrading to a higher GPH if your current system isn’t working as well as you need it to. 

Remember to always keep a bucket or hand pump onboard as a backup in the event that your bilge system fails. If you have any questions regarding bilge pumps and bilge systems, give the boating experts at Wholesale Marine a call: 1-877-388-2628. Our team of boaters is available Monday through Friday, 9AM to 6PM EST.