Bilge Pumps: Protecting Your Investment

A Basic Guide To Bilge Pumps

Unfortunately, bilge pumps are something that a lot of boaters don’t think about until they need them, simply because they’re such a basic element that most people don’t understand the seriousness of these pumps or how critical they can be to keeping your vessel on the water, rather than under it. These pumps are often your only line of defense against going under, and yet so many boaters aren’t even familiar with how they work or what they do, or how to maintain and repair them when issues do arise.

Take the time to read through this guide to learn the basics of bilge pumps, including how to maintain and care for them, as well as where you can find them and the pros and cons of electric versus mechanical pumps. You’ll also find some necessary insight on DIY bilge pumps and what they have to offer. Keep reading to learn everything that you need to know.

SeaFlo 1100 Bilge Pump
SeaFlo 1100 Bilge Pump. Photo by SeaFlo.

What is a Bilge Pump?

A bilge pump is a small pump designed to clear excess water from the bilges of your vessel and keep it afloat. Under normal circumstances, you’ll usually only have to deal with spray from the water, drips, and other runoff situations. This is water that a lot of boaters don’t even think about, and since it’s taken care of by the pumps right away, they don’t have to.

The bilge pump is not the same as the emergency pump, which is designed for high-volume water removal when there is an urgent situation. Bilge pumps are smaller and aren’t designed for when you’ve taken on a dangerous amount of water. However, if it’s the only pump you have, it’s better than nothing.

Where is the bilge pump located on a boat?

Generally there should ideally be two bilge pumps, since one may fail. The primary bilge pump should be located at the lowest point of the bilge, while the secondary pump should be located somewhere slightly higher.

Where Can I Find Mine?

As mentioned above, the primary bilge pump should usually be installed in the lowest part of the bilge and near the hull or frame for easy installation and access. You’ll generally find the pump in the the stern as that is usually the lowest point of in the bilge, in runabouts and ski boats. Those with inboard drives will typically have a pump under the oil pan.

Sailboats, on the other hand, will usually see the pump mounted right in the cockpit. If you aren’t sure of the location of your pump or whether your vessel even has one, you can consult your owner’s manual or ask your local boat shop if they can assist you.

Which Bilge Pump is Best?

Honestly, bilge pumps are as unique as the boaters who need them. There are many different models available and you can even make your pump if you want to save a little money or create a different setup. To determine what is right for your vessel, you’ll want to think about how much water you need to be able to pump out of the boat at any given time. Consider the suggested pumps for your type of boat, as well as where you need to install the pumps. If you aren’t sure how to proceed, feel free to contact your local boat shop and get advice on the best way to set your boat up for success with bilge pumps.

Electric vs. Mechanical Pumps

There are two types of bilge pumps that you can choose from: automatic, or electric, and manual pumps. On smaller vessels, mechanical pumps are often sufficient enough, but they may not be helpful in larger craft. Electric pumps are nice because they do come on automatically as the boat takes on water. However, this also doesn’t guarantee that they will always come on when they should. If you choose an automatic bilge pump or pumps for your vessel, make sure that it also offers a manual operation option so that you can override it and turn it on as needed.

Do bilge pumps come on automatically?

In a word, yes. They should anyways. They are built with either an automatic mechanical float switch, or an electric moisture sensor, either of which will trip the pump and start pumping water when the leves in the bilge start to rise above a normal level.

Speaking of pumps, there is a good chance that you might choose to install more than one bilge pump. If this is the case, you might find that a combination of automatic and manual pumps is going to be most effective. Your vessel might also fare better with all-electric or all-manual pumps. Take the time to review the pros and cons of each, think about the size of your craft, and use that information to decide how many bilge pumps you need and which style you’ll use.

DIY Bilge Pumps: What You Need to Know

Some people choose to build their bilge pumps, rather than buying prefabricated pumps. Using basic supplies from a hardware store and a little mechanical know-how, you can build your own bilge pump system that can get more water out of your boat than you might expect from this type of simple solution.

Bilge Pump Maintenance

The maintenance required of bilge pumps, including DIY models, is relatively simple. Making sure the motor is operating correctly, as well as clearing out debris from the filter and hoses, will ensure that you get the most life out of your pump system. Make sure that you check the pump regularly for debris buildup or other clogs that might be impacting how well the system works. You don’t want to wait until you’re in an emergency to find out that your pump needs to be cleaned out.

Cheap Bilge Pump Setups

DIY pumps do the same thing as manufactured bilge pumps, but with a different setup and installation process. Plus, you will have the option to attach an electric pump motor to your DIY model or choose a manual-style operation that is even more affordable. Popular Science offers a great diagram and installation guide for building and installing bilge pumps.

The Bottom Line

If you want to make the most of your boating experience, you have to know about ALL of the parts of your boat, including seemingly-insignificant things like the bilge pump. Even the most experienced boaters have reported forgetting about this valuable resource, but it’s one that you can’t afford to ignore or neglect if you want to make sure that you are truly safe on the water.

Written by: Valerie Mellema

Valerie Mellema is a writer, published author and avid bass angler who lives on the shores of Lake Fork in East Texas — the top bass lake in Texas and the fifth in the nation. For the past 10 years, she and her husband have enjoyed the pontoon boat lifestyle while fishing a lake that not only has bass but beautiful wildlife as well. She holds a BS in Agribusiness/Equine Business and regularly contributes articles to, YachtWorld and Boat Trader.


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