How To Install A Bilge Pump Counter On Your Boat


Think of the proverbial sailor in trouble, trying to use a bucket to take out water that is getting into the hull as fast as possible to prevent his boat from sinking. Of course, the story inevitably comes to a tragic end.

In comes the bilge pump. It is designed to remove water that gets into the boat either from the rough seas, spills, the rain, and of course leaks. It can be the difference between sinking fast or staying afloat long enough to get to the shore and make repairs to your boat. A high-quality boat propeller can help you reach the shore fast.

For fishermen who sail offshore or if you plan to use the canyons, coupled with a good marine GPS for locating fish, a good bilge pump that is powerful enough to dispense water faster than it is coming in is an indispensable part of your boat. When you buy your boat, it will often come with its own bilge pump.

Sometimes the pump is not powerful enough and you might feel the need to upgrade. In this case, ensure that you get a powerful and durable bilge pump. And always have good boat shoes to keep you from slipping due to water entering the hull.

Installing a bilge pump

To install a bilge pump, you must first fasten it on the bilge. Never perform a bilge pump installation without securing it. This is because it can fall over as the boat moves up and down on the waves causing it to suck air and burn out.

Fasten the bilge pump to a vertical structure or the stringer using brackets. Also, ensure that you fasten the float switches.

Picking the right hose

When doing a bilge pump installation, the type of hose you use to dispense the water from the boat can have a huge impact on the rate of output. A corrugated pump for example can reduce the pump’s output by 30%. Not exactly what you would consider ideal.

The right hose should have a smooth interior to maximize efficiency. Yet another thing that reduces the rate of output is a long pipe. A lot of energy is absorbed as the water flows from the pump to the end of a long pipe so ensure that it is as short as possible.

Thirdly minimize the bends on the pipe as these will reduce the rate of water flow. Coupled with making the pipe as short as possible, also make it as straight as possible. This often means fixing the pump to the side of the hull.

Where to place the discharge

The location of the discharge will be the difference between getting rid of the water and the water getting back into the hull.

As a rule of thumb, the discharge should be placed above the waterline. If it was at the same level or below the waterline, the water would get back into the hull when the pump is off. In this case, when water reaches the float switch, the bilge pump will run and eject the water. Only for the water to get back in. This cycle would go on until the battery run-outs.

Something to take note of is that for a discharge that goes through the transom, always make sure that it is just high enough not to go below the waterline when the stern squats. Also, if the discharge is through the hull, it should not go below the waterline when the boat heels.

The wall fitting

The capacity of the bilge pump can go down as a result of fitting it through the hull. To make sure it operates at maximum capacity, find a fitting with a large opening.

The bilge pump wiring

Special care needs to be taken on how to wire a bilge pump during the bilge pump installation. It should be away from the bilge to prevent them from sagging onto the water. We all know that an electric current and water are a combination to stay away from. Secure the wires so that they will not hang and come into contact with water in the hull.

Choose the right wire size

Many people may not pick the right wire size, especially when upgrading their bilge pump. The larger and more powerful the pump, the thicker the wires. For a 3500 gph pump, for example, a 10- or 8-gauge wire is needed.

If you are not conversant with pump wiring, a professional can help you determine the right wire size and thickness as well as provide valuable information on how to wire a bilge pump based on the capacity of the bilge pump.

Heat shrink and butt connectors

Butt connectors are necessary for making proper connections between the pump leads and the wires supplying the current.  To ensure the butt connectors do not come into contact with water, enclose them with a heat shrink.

When making the connections, take the heat shrinks and slide them over the wire before connecting the wires. Next, take the heat shrink tubing and center it over the connector and use a heat gun to shrink it. As you do this, ensure there is no explosive gas on the boat.

Connecting the battery

An important point to always remember is that just because you turned off the boat doesn’t mean the bilge pump should also be turned off. The bilge pump should be connected directly to the battery instead of through the distribution panel.

When connecting the pump to the battery, the positive wire should be connected to a fuse. This fuse should also be located close to the battery. There are switch panels that come with a fuse. If, however, yours doesn’t have one, you can connect a fuse holder to the end of the battery with a crimp butt connector.

Installing a three-way switch

Some bilge pumps feature a separate float switch. In such a case you may need to use a three-way float switch. It makes it possible to automatically select on and off. Ensure that you use cable clamps to hold all running wires and to prevent them from sagging. You can install the cable clamps every 15 to 18 inches.

The terminal fittings

Always use the right methods on how to wire a bilge pump especially when it comes to the terminal fittings. Never take the wires, strip them then loop them onto the battery terminals. Instead, get the correct size terminal fittings that are going to fit the battery. It is advisable to use a copper wire and not a steel wire to put between the ring terminal and the wing nut.

Using two pumps

While a big bilge pump will help remove the water from the hull faster, it does require a big hose which means that water that remains on the pump will flow back into the hull when the pump turns off.

That is why you might need to use more than one bilge pump on your boat. The preferred arrangement is using a 400 gph pump to get rid of the rain and a more powerful 3500 gph pump that is installed higher to deal with greater volumes of water on the hull.

To reduce the backflow of water, you can reduce the size of the hose, especially on the smaller bilge pump. This will ensure a dry bilge. If you prefer, you can connect the larger pump to a float switch, but some people may find the manual switch to be more effective.

One other benefit of making this type of configuration is that the larger and more powerful pump is held high and will likely not come into contact with water. This increases its durability ensuring that you can use it for a long time to come.

Globo Surf Overview

Installing a bilge pump doesn’t have to be the most difficult task. You simply need to observe certain measures such as making sure the bilge pump is fitted well and close to the hull and the butt connectors are covered with a heat shrink to prevent them from coming into contact with the water.

Also, you will find that using a two-pump configuration we talked about above will be greatly beneficial at keeping the hull of your boat dry.

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Globo Surf
My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!