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Avid boaters know that a bilge pump is essential to stay afloat, but do you know how to mount one?

Boat repairs can be expensive, and it’s a big hassle to find a qualified aquatic mechanic if you’re far from home.

Plus, sometimes you just want to be able to work on your boat yourself.

Today we’re going to discuss how to mount a bilge pump on your vessel.

Why is it important to mount the bilge pump?

While you may know why it’s so important to have a bilge pump, why is it so important to mount it

Why can’t the bilge pump simply run while unattached?

If the bilge pump is heavy enough to stand on its own, why do you need to fasten it to the hull?

Firstly, while the bilge pump may remain upright while you’re not moving, you don’t know what type of conditions you’ll experience when you leave the marina.

Waves, wind, and storms can easily knock over a bilge pump, and it may not remain upright for long.

In case you get in a sticky situation, you do not want to have to worry about your bilge pump falling over. 

You will have much more pressing things to think about, and an unsecured bilge pump adds unnecessary stress to your trip.

Also, if the bilge pump falls over, it will begin to pump air. 

If this happens, the bilge pump will quickly burn out, ruining the motor. You’ll be left with a useless bilge pump and an expensive bill.

So, for your safety and the longevity of your bilge pump, you need to fasten it down. 

Installing a bilge pump isn’t a difficult task, but it’s important to do the job well. This video provides a great introduction.

How to mount a bilge pump

Step 1: Clean the area.

Bilge pumps are great at moving water, but the other materials that come in with the water wear them down over time.

So, to make the most of your bilge pump, remove as much sand, dirt, grime, and debris as possible.

If you’re simply replacing an existing bilge pump, thoroughly clean the area where the previous pump sat. 

Make sure to remove all grime left over and give the new bilge pump a clean space.

If you’re installing a totally new bilge pump, clean the outside of the area. 

Keep a clean workspace to minimize the amount of debris that hits your new pump.

If possible, try to work when your boat is on land. 

This will make the cleaning process easier and will help you keep a cleaner workplace, free of debris and mist from the water.

For today’s purpose, we’ll assume that you’re installing a new pump and starting from scratch.

Step 2: Choose the location for the bilge pump.

First things first – where to mount the strainer basket? The strainer basket serves as the basis for the mount of the entire pump.

Select a location as close to the bottom of the V of the hull as you can get, and place the basket as far aft as you can.

If you’re lucky, your boat might even have a mounting location pre-installed. Look for a shelf or block built into the hull.

Step 3: Separate the strainer basket from the bilge pump.

Once you’ve found this location and thoroughly cleaned the area, remove the strainer basket from the bottom of the pump.

Take care to avoid bending or damaging the basket in the process.

Step 4: Pre-drill the holes.

Line it up against the hull and mark the screw holes using a pen or marker.

When you’re happy with your marks, put down the basket and pre-drill the holes in the exact locations marked.

Step 5: Apply adhesive.

Clean each hole well, removing any bits of debris or resin from drilling. Now, it’s time to apply the adhesive.

Fill each hole with a generous supply of 3M 5200 gel adhesive and make sure the holes are coated well. 

This will prevent water from invading and ruining the screws during use. 

The more protection you can give your bilge pump, the longer it will last.

Step 6: Attach the basket.

Reposition the strainer basket over the holes, and drill in the stainless steel screws. (These often come with the bilge pump.)

Most new bilge pumps come with built in automatic switches. 

But, if your bilge pump requires a separate float switch, be sure to orient the basket athwart ship. 

If you do not orient the bilge pump in this way, rushing water may hit the switch, locking it into an “on” position. 

This is a good way to wind up with a locked switch.

Step 7: Allow the adhesive to set.

Once you’ve mounted the basket, it’s time to wait. 

The basket will need at least a full day to set in place. It’s best to let it rest for several days if possible. 

The adhesive needs plenty of time to harden in place.

If you disrupt it too early, you’ll break the seal, leading to a difficult situation in the future.

How to finish installing a bilge pump

The rest of the installation is important, but you’ve prepared yourself well by this point.

After you mount the bilge pump and allow the adhesive to set, you can complete your bilge pump installation.

Now, you’re ready to run the wires. 

Prior to running wires, place the rest of the bilge pump into the basket so that you can accurately gauge the lengths.

After the wires are in place, it’s time to install the thru-hull discharge and the discharge hose. 

For more detailed information on completing your bilge pump installation, check out this helpful tutorial.

Featured image credit: Image ID: 1281600472