Bilge pumps: the essential safety equipment on board your boat

When sailing, keeping the bilge dry is a matter of safety. A bilge pump removes water that accumulates in the bilge, whether it comes from rain, waves, or a small leak. It is essential equipment to maintain the boat’s stability, protect the engine, and prevent damage caused by humidity. This guide will help you choose the right pump for your boat, with the expertise of dam-marine.com, specialist in bilge equipment for boats. On this page, you will find all the useful details to make the right choice, as well as practical accessories and installation advice.

Bilge pumps: an essential piece of safety equipment on board

The bilge pump plays a fundamental role on board: it removes water that collects in the lowest part of the boat. This accumulation can be caused by leaks, bad weather, waves, or even condensation. Water that is not removed can cause stability problems, accelerate corrosion of mechanical components, damage interior fittings, and, in the worst cases, lead to sinking. A reliable pump is therefore indispensable, even outside emergency situations. It offers real peace of mind, especially in cases of prolonged absence or difficult weather conditions. A good evacuation pump also ensures controlled watertightness and continuous management of the water level in the bilge.

The different types of bilge pumps for boats

There are three main types of bilge pumps: manual models, electric pumps, and automatic electric pumps.

The manual bilge pump

This model works mechanically, using a handle, lever, or pedal that must be operated manually. It is commonly used as a backup solution and is very suitable for small boats such as dinghies, tenders, or kayaks. It is also used to remove stagnant or dirty water. Some are designed to pump water continuously even without electricity. Its advantages are simplicity, reliability, affordability, and complete independence from the boat’s electrical system. On the other hand, its flow rate is limited (between 25 and 100 L/min), which makes it less effective for dealing with sudden flooding.

The electric bilge pump

It operates with an electric motor, in 12V or 24V. These pumps are faster and more powerful than manual models, with flow rates of up to 250 liters per minute. They are easy to install, simple to use, and can be activated from the dashboard.

There are two main variants: submersible pumps and non-submersible (inline) pumps.

• The submersible pump is installed at the lowest point of the bilge, directly in the water. It evacuates water through a through-hull fitting. It is compact, discreet, and easy to fit in the available space. It uses a centrifugal impeller to create suction. Some can handle small debris, especially if equipped with a strainer or filter. Brands such as Rule, Johnson, TMC, Attwood, or Osculati are well known in this category. Submersible pumps are specifically designed to remain in the water for extended periods without the risk of short circuits.
• The non-submersible (inline) pump is installed above the waterline, outside the bilge. It draws water through a strainer placed at the lowest point of the bilge. It is more resistant to ambient humidity, less sensitive to vibrations, and better protected against shocks. It is ideal for larger boats and works with a flexible impeller or diaphragm system. Brands such as Marco, Whale, Johnson Pump, and Matromarine offer robust and reliable models. These pumps also provide excellent performance when dealing with dirty or slightly oily water.

The automatic electric bilge pump

This is an electric pump equipped with a sensor, either mechanical (float switch) or electronic. The sensor detects the presence of water and automatically activates the pump once a certain level is reached, usually between 1 and 7 cm. This autonomous operation ensures continuous water evacuation, even in the owner’s absence. It is an ideal solution for hard-to-reach compartments or during long voyages. These pumps are often equipped with a three-position switch (ON/OFF/AUTO), and some models include an alarm or warning light. It is also possible to convert a standard electric pump into an automatic version by simply adding a float switch or water level sensor. Don’t forget to install a check valve on the discharge line to prevent water from flowing back into the bilge.

Criteria for choosing your bilge pump

The importance of flow rate for effective water evacuation

Flow rate refers to the amount of water a pump can remove per hour, expressed in liters (L/h) or gallons (GPH). A pump with too low a flow rate may be ineffective, especially in the event of sudden water ingress.

Here are some useful benchmarks:

• Less than 5 meters: 1900 L/h
• From 5 to 7 meters: 3000 L/h
• From 7 to 9 meters: 4000 L/h
• From 9 to 13 meters: 6000 L/h
• Over 13 meters: 7500 L/h or more

When in doubt, it is recommended to slightly oversize your pump, especially if the discharge is located above deck level.

Practical considerations for pump performance

The ability to handle debris is important. A diaphragm pump or one with a good filter helps prevent blockages. If the water contains oil or fuel, choose a model resistant to contaminated fluids. Head capacity (or discharge height) must also be considered if the water has to be pumped far or upward. Some pumps can also run dry for a few seconds without damage, which can prevent breakdowns. Finally, for noise-sensitive users, some models are equipped with soundproofing. To maximize pumping efficiency, make sure to size each fitting correctly and use appropriate hoses.

Integration with your boat’s electrical system

Check whether your electrical system is 12V or 24V. Small boats generally use 12V, larger ones 24V. Your system must be able to supply the current required by the pump. Some models come with a wiring kit including fuse, cables, and switch. Others can be connected to a booster or centralized control panel.

Ease of access and installation process

The pump should be easily accessible for maintenance or replacement. Installation is usually done at the bottom of the bilge, using stainless steel screws. Hoses should be securely connected with clamps and routed above the waterline. If necessary, consult a professional.

Our personalized advice for choosing your pump according to your boat type

• For leisure boats or small sailboats, a submersible electric pump with medium flow rate is usually sufficient.
• For fishing boats or larger vessels, install multiple pumps, combining an automatic electric pump with a manual backup pump.
• For liveaboards or long voyages, redundancy is essential. It is recommended to install several pumps (manual and automatic), with robust equipment capable of handling large volumes of water even in critical situations. Some boats even have separate compartments or deck hatches for quick access. In some cases, the pump is installed directly under a deck hatch for rapid external intervention.

Installing and maintaining your bilge pump

General installation steps

Start by choosing a location where water naturally accumulates, while remaining accessible. The pump must be securely fastened with stainless steel screws, and its float switch (if present) must be able to move freely. Connect a resistant hose, with minimal bends, leading to a through-hull fitting above the waterline. Ensure the pump body is correctly oriented to facilitate discharge. Install a check valve to prevent water backflow into the system. Connect the pump to the power source following safety guidelines: adequately sized cable (e.g., 1.5 mm²), protective fuse, automatic switch, and heat-shrink tubing on connections. Finally, test the pump by filling the bilge with water.

Our tips for safe and efficient installation

Use high-quality marine-grade materials resistant to corrosion. Secure all connections with hose clamps and ensure good ventilation in the installation area to avoid condensation. To achieve this, adding bilge blowers can be useful, especially on closed boats or in high-humidity environments.

Maintenance and cleaning

Regularly clean the strainer, filters, and hoses. Check that the electrical system shows no signs of corrosion or wear. Before winter storage or long trips, test your pump. Most automatic models have a test button or manual activation mode.

Regulations governing bilge pumps

In France: the requirements of Division 240

Division 240 regulates safety equipment on pleasure craft. It requires that a bilge system be present on board, fixed or portable.

• For boats under 6 meters: a bailer or manual pump is sufficient.
• For boats over 6 meters: a fixed pump is mandatory, in addition to a manual system.

Automatic pumps must have an audible alarm. Discharge must be made overboard, never into cockpits. Every intake must be fitted with a removable stainless-steel strainer.

International regulations: similar requirements

The United States (USCG), the United Kingdom (MCA), and Australia (AMSA) also require bilge systems depending on the vessel’s length and navigation area. Automatic pumps are often mandatory on boats with cabins or enclosed decks.

The bilge pump is an essential piece of safety equipment for safe navigation. It allows quick water evacuation, engine protection, and prevention of accidents. Choosing the right pump depends on many factors: boat type, size, navigation conditions, water type to be evacuated, build quality, and brand reliability. Proper installation and regular maintenance are essential to ensure correct operation. Compliance with regulations completes this set of best practices. On dam-marine.com, you will find a wide range of bilge pumps (manual, electric, and automatic) in stock and suitable for all types of boats. Each product is clearly listed with all technical details. We offer you the most recognized brands for performance and reliability: Jabsco, Whale, Rule, Attwood, Johnson, Flojet, Marco, Matromarine, Osculati, and Seaflo. Our team ships your orders quickly and helps you choose the right equipment. Take advantage of all dam-marine.com benefits: expert advice, best price guarantee, fast delivery, and 100% secure payment.