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Tel: 01492 338505
Mob: 07486 024405

Winter Opening Hours

Monday - Friday 9:00am - 5pm

Saturday - 9:30am - 5pm

Sunday - Closed

Electric & Manual Bilge Pumps

Leaving large amounts of water in the bilge can have several undesirable effects on your boat, including destabilizing it, lifting spilled fuel and distributing it throughout the bilge (where it can attack, among other things, the insulation on electrical wiring) and promoting the development of osmotic blisters in fiberglass hulls. And did we mention having the boat sink? Getting this water (we call it nuisance water) out of your boat is the primary function of a bilge pump.

In some cases the leak may be of a catastrophic nature caused by a hole in the hull from a collision or a wave taken on board in a storm. These situations call for very large pumping capacity. In many cases the largest pumps will only buy you a little time to effect repairs to the leak, limp back to shore or prepare to abandon ship. For emergency situations like this, it is advisable to have multiple electric pumps and at least one high-capacity manual diaphragm pump.

Therefore, we'd like to reinforce the following words of wisdom regarding bilge pumps so you're not disappointed in the future.



What is your Bilge Pump for?

Virtually no boat has a bilge pump system which is large enough to keep up with a leak caused by hull damage. Bilge pumps are designed for small quantities of water and are not damage control pumps like the ones Coast Guard helicopters drop. The American Boat and Yacht Council standards for electric bilge pumps state that they are "intended for control of spray, rain water and normal accumulation of water due to seepage and spillage.

Never leave a boat with a known leak alone with an automatic bilge pump in the hope that it will keep your boat afloat.

Selecting your pump will depend a lot on what type of boat you have.
Daysailers and open outboard powered skiffs generally use a portable piston pump, bucket or hand bailer.

Runabouts and ski boats!use a single submersible electric pump in the stern or in the lowest point in the bilge. Boats with stern drives may have the pump under the oil pan of the engine.

Small cruising and racing sailboats can use one large manual diaphragm bilge pump mounted in the cockpit.

Offshore racing sailboats are required by the ISAF Special Regulations to have two permanently installed manual pumps; one operable from the cockpit and one operable from down below.

Coastal and offshore boats! will generally want automatic electric bilge pumps located in each compartment (bilge area) that can hold water, and a large manual pump for backup.

Our Range - Electric

To see our selection of electric bilge pumps

Our Range of Manual Pumps

To see our selection of manual bilge pumps

Electric or Manual?

High-capacity centrifugal pumps are relatively inexpensive and the easiest pumps to install, but they are rendered ineffective if your boat's electrical system fails, and this is a likely occurrence if your boat takes on a lot of water. For this reason we recommend that, in addition to any electric pumps, you have at least one high-capacity manual diaphragm pump.

These can move substantial amounts of water (up to 30 gallons per minute or so). With the exception of the higher-end pumps, most are very tiring to use, so be careful in your selection. Each gallon of water weighs over 8lb. and pumping it 15' or so is a challenging task for both the pump and the pumper. This is especially true if the pump's location requires you to be on "all fours" or in some awkward position while pumping. An appropriate installation location and an effective pump is critical. When selecting a manual pump, it is most important to consider the gallons per stroke and the ergonomics of the pump.

Do you want automatic operation?

Do you want automatic operation?
Automatic operation requires either an automatic pump or a separate water-sensing switch. One disadvantage of using an automatic pump is that you may not be aware of your pump's operation if you develop a steadily increasing leak.

For example, your boat may have a brass gate valve that has become damaged through corrosion (electrolysis).

If an automatic pump cycles on and off without your knowledge, you could be unaware of the leak before it becomes catastrophic and beyond the pump's capacity. There are two solutions to this problem: Use a cycle counter to record how often your pump turns on and off. Log it. Alternatively, have a light or buzzer that turns on when your pump is energized to show you when it's in operation.

Pump switches

Pump switches
Many pumps are available with a float switch pre-wired to the side of the pump. This makes it simpler to install, especially in tight vertical bilges.

How Do They Work?

Electronic switches use a pair of Mirus detector cells that sense the presence of water through the plastic housing using a low-impedance electrical field. Switches like the Rule Electonric Submercible Pump have a design prevents rapid on/off cycling.

Centrifugal vs. diaphragm pumps

Centrifugal pumps are submersible and non-self-priming, so they must be sitting in the water in order to pump it, and can usually remove all but the last inch of water.

They work the best when the bilge has a small sump where water collects. Centrifugal pumps use whirling vanes to draw fluid into the centre of the pump and then push it outward from the centre through an outlet port.

They have a built-in strainer in their base that can be removed quickly for cleaning, which is important because the small impeller can get clogged with debris.

Diaphragm pumps are self-priming, which means they can lift water up an intake hose and expel it outside the hull. They use a membrane to increase and decrease the volume of a pumping chamber, drawing fluid in and pushing fluid out through a set of one-way check valves require an external strainer at the end of the intake hose, since a small amount of hair or bilge debris can cause the valves to clog.

Waste and water pumps

Waste and water pumps
When it comes to the size and shape of your vessel or vehicle. The number of water outlets you require, will determine the size of the pump and the other system components, and how much pipe work you will need. This schematic diagram depicts a typical system, and shows how the components are linked.

Accumulator Tanks

Is an important part of any pressure-controlled water system. Fitted close to the pump discharge, it acts as a pressure buffer, absorbing flow from the pump when demand is low, and smoothing the outlet pressure. By removing the need for the pump to run immediately an outlet is opened, it extends pump life and reduces battery drain.

The larger tanks have an appreciable water storage capacity - approximately half the nominal tank volume. The larger your pressurised system, or the higher the demand for water, the larger the accumulator tank should be. For minimum wear and tear on your pump, fit the largest you can

Accumulator tanks are also used as expansion vessels in conjunction with water storage heaters.
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