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Insufficient Bilge Pump Capacity!

Far too many Yachts I survey have both too few bilge pumps and inadequate battery power to run them. And for some strange reason, sail boat builders and owners tend to think that only one bilge pump is necessary, no matter how large the yacht is. In fact, the vast majority of 40' sailboats have only one bilge pump. If you think that's enough, consider the next point.

When bilge pumps fail, most people blame the pump. On the contrary, analysis of hundreds of insurance claims shows that when boats sink, the pump usually failed because of a faulty system before the boat sank. Here's why:

  • Due to dirty bilges, float switch sticks in up or ON position, burns up pump or wears down battery.

  • Bilge pump switch is not adequately secured, comes loose and lays on it's side, causing pump to run continuously, depleting batteries or burning up the pump.

  • Debris in bilge prevented float switch from operating. Even oil sludge can do this.

  • Wire splices to pump and float switch too low in bilge, or get wet from other water sources such as leaking deck hatches, causing corrosion to the wire connections and resultant failure of the pump. Bear in mind that corroded connections can cause high resistance in the wire that can cause the pump to fail.

Make sure that you have adequate battery power and pumping capacity. For every two pumps, there should be one back up because pumps are notoriously unreliable. That's why in no way could one pump ever be considered acceptable. More and more builders are recognizing that the primary pump (the one at the deepest point of the bilge) needs to have a backup in the even of failure. Indeed, that is just common sense.

Be sure that wire splices are as high up as possible and that they don't get wet from other sources. Remember that bilge water bounces around while underway. Coating connections with silicone sealer won't help. If the area routinely gets wet, install a gasketed plastic junction box.

Make sure that the pump discharges have adequate risers. But remember, especially sail boat owners, that too much riser greatly affects the pump's capacity. A pump located three feet below the waterline, with a 24" riser (sailboats need this much), for a combined rise of 5 feet, will have its pumping ability reduced by more than 50%. For that reason, sailing yachts need higher capacity pumps. The average Rule 1500 usually just won't do. Go to a 3500. And remember that pushing water uphill takes more battery power, too!

Keep bilges clean, especially free of things like rags, paper, string or crumbling foam insulation. This stuff is deadly around float switches. Make sure the wires aren't tangling up in the switch.

Far too many boats are wired so that shutting off the main power, either the main breaker, or the battery switches, shuts off the bilge pumps. Its truly amazing how many builders of expensive yachts make this amateur mistake. That means that if you shut off the power when you leave the boat (even though you're left pump switches on) you inadvertently turned off your pumps. Testing for this is simple: just shut off the main DC breaker and turn the battery switches to OFF, then lift the float switch and see if the pump works. If not then its wired wrong.

The vast majority of sailboats have one small bilge pump located in the keel sump, often under an engine and usually where it cannot be reached for servicing or testing. Battery power is usually not a problem, but pump failure is. The small pump for normal dewatering is fine, but I recommend that every boat should have a large back up pump , at least a Rule 3500 or similar. This pump should be located near the top of the keel sump so that it activates in the event the primary pump failures. In this case it would be an emergency and the larger pump would be better able to handle it.

Check your sink drains and make sure that the sink is well above the water line. Will the sink go under water when the boat is heeled over? Also watch out for die cast zinc alloy fittings on the underside of the galley sink that can corrode and fall apart. This can allow the hose to detach and fall below the waterline.

For heads, open the water valve and start pumping vigorously to get the water flowing. Then stop and leave the pump handle in the UP position. Does water continue to flow into the bowl without stopping? If so, you've got a head installation that can sink your boat.

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