Bilge Pumps

Bilge Pumps 101: How to Keep Your Boat Nice and Dry

A bilge pump is your last line of defense if your boat is taking on water. But in less dire circumstances, it can also help prevent corrosive water from finding its way into your bilge wells. Read on to learn more about why a boat bilge pump is so important to keeping your boat afloat, the true difference between automatic and manual bilge pumps, and why you may want to consider adding more than one to your prized watercraft.

What Is a Bilge Pump?

Fresh and corrosive seawater, a mixture better known as bilge or nuisance water, can wind up in the bilge wells of your boat for any number of reasons, including accidental spills, pipeline leaks, leaky pumps, rusty hose clamps, air conditioning condensation, old thru-hull fittings and overflowing tanks. This can lead to a destabilized boat, lifted fuel distribution throughout the bilge and osmotic blisters on fiberglass hulls.

Long story short: you do not want bilge water on your boat, and that's where bilge pumps come into play. They get rid of this nuisance water and act as the last line of defense if your boat begins to take on water or sink. While many boaters think one pump is sufficient, experts actually recommend three to four pumps per watercraft, depending on your boat's size.

What Does a Bilge Pump Do?

So, how does a bilge pump work if a watercraft is taking on water? The primary job of a bilge pump or sump pump is to flush out unwanted water from the bilge. If your boat is taking on water, it may allow you the crucial minutes you need to locate the source of the leak and fix it. If the boat has taken on too much water and is actually sinking, a bilge pump can also give you the time you need to put on your lifejacket and vacate the watercraft safely.

Where Is the Bilge Pump Located on a Boat?

The bilge pump will usually be installed under a boat's engine on an inboard or at the lowest point of the bilge, but this can differ based on your type of watercraft. In general, you'll usually want an automatic bilge pump in each compartment that can hold water, as well as a large manual pump for backup in the case of power loss.

What Is the Difference Between Automatic and Manual Bilge Pumps?

In terms of electric bilge pumps, there are two types: automatic and manual.

An automatic sump pump is equipped with a float switch. This allows the pump to detect water levels and automatically turn on if the boat is taking on water. It's important to note that all watercraft that are over 20 feet long with sleeping accommodations are required to have automatic bilge pumps installed.

A manual marine bilge pump is a more affordable option that is easy to install and maintain. Plus, you can typically add a float switch to your manual sump pump and make it function much like an automatic bilge pump. Manual bilge pumps are ideal for most fishing bop ats and smaller recreational watercraft.

While the U.S. Coast Guard does not require recreational boats to have bilge pumps, they should not be considered optional. They can save you on costly repairs and can mean the difference between life and death in an emergency.

When installing your new marine bilge pump, there are some key installation tips to keep in mind. Remember, these are just suggestions. You should always follow your bilge pump manufacturer's installation and instruction manual above all else.

How Does a Thermoelectric Cooler Work?

  • Clean out your new marine bilge pump prior to installing it. This includes disposing of any wood shavings, fiberglass, epoxy or oil that may have been left behind during the manufacturing process.
  • Use a smooth-walled marine-grade hose and marine-grade stainless steel hose clamps. Keep in mind that the sump pump hoses should be routed as directly as possible. You'll also want to properly support the hose every 18 inches in order to prevent chafing and excessive movement.
  • Discharge thru-hulls should be located well above the waterline to prevent water from siphoning back into the bilge. Use siphon breaks and riser loops when possible.
  • If your new bilge pump uses a flapper-style automatic float switch, note that you'll need to securely mount and install it so that the floating arm is clear of any obstructions that may get in the way of operation.
  • Ensure your sump pumps have intake strainers installed within easy reach and clear of debris.
  • Consider installing a dedicated bilge pump breaker panel to keep all your fuses and breakers together and easily accessible.
  • Verify that all bilge pump electrical wiring is located above the normal bilge water levels to reduce the potential for corrosion.
  • Don't opt for oversized wire and always follow the manufacturer's recommendations to a tee.

Do I Have to Regularly Maintain My Marine Sump Pump?

The short answer? Yes. You should get in the habit of regularly testing and inspecting your marine sump pump. This is especially true if your boat will be sitting in the water unattended for lengths of time. Be sure to consult your bilge pump manual for product-specific maintenance instructions and requirements.

Current system not working as well as it could? Consider upgrading to a unit with a higher GPH (gallon per hour) rate. While your boat most likely came with a sump pump preinstalled, most people upgrade to a larger marine bilge pump or add backup bilge pumps to give them more time in case of an emergency.

Upgrade Your System With Marine Bilge Pumps From Boat & RV Accessories

At Boat & RV, we take great pride in providing our customers with the best bilge pump products and accessories at the best prices. Because when you have a leak, you need a marine sump pump you can rely on to give you the most time possible to fix it. Have a question about our selection of bilge pumps or which product is right for your needs?

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