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Automatic bilge pump

Hi - I'm now the owner of NB "Jamdrew of Larkfield" and wish to ask two questions about the stern gland bilge pump. Can you recommend the best small auto level control pump 12V and the best non return valve to fit the overboard discharge pipe

Asked by: bill goad  | 3.04pm, Thursday 13 November

WW says:

There are many small bilge pumps around, with the auto control being either a float switch or solid-state circuitry.
In my experience, float switches tend to be the cheapest, but least reliable. Float switches also tend to be separate to the main pump body.
Although there are many makes around, I have had good success with the Whale Supersub range of pumps. They are small, low profile and the auto versions (such as the Subersub Smart 650) appear to be very reliable, drawing a low quiescent current (negligible on measurement). The one I currently have fitted in a tight recess on my narrowboat also manages to drain the bilge water level far lower than any other pump, and the degree of rotation in the pick-up strainer are very useful. The pump is effectively horizontal rather than vertical, so easier to fit in a tight space, such as between the engine bearer and the stern gland.
I have found the pump more reliable than previous ordinary pumps with floatswitch, although the flow rate is lower than more conventional pumps,it easily copes with normal water accumulation in the bilge.
Whale also make matching non-return valves, which should be fitted as close to the pump as possible for best effect- something regularly left out of bilge pump installations on narrowboats!
You will need three-core cable (or three wires) to connect the blige pump to an on/off/auto switch, as the cables carry +ve auto, +ve manual and -ve common connections.
Other bilge pump systems are available with solid state electronics, but I have not personally evaluated them. Waterways World will be testing a range of bilge pump systems shortly.

Mark Langley  | 3.48PM, Thursday 13 November

It is best if you have a three-way switch. Also, it is ideal if the supply to the bilge pump is routed directed from the battery- by passing the master switch-but a seperate fus must be fitted as close to the battery as possible. This enables the pump to work if the power supply is interrupted.
Most switch panels for bilge pumps incorporate a fuse, but this should be seen as a secondary fuse- a primary one still needs to be incorporated.
An alternative would be to fit the +ve manual to your current switch (and assuming that the -ve is to a general non-switch return) and the +ve auto directly to the battery (via a fuse close to the battery). This would enable you to have manual control over the pump, but it would remain on "auto" at all times. However, I would suggest that use an auto-off-on switch instead, as this gives indication that the supply is live to the pump in auto mode (if indicator lights are fitted).

Mark Langley  | 4.03PM, Thursday 13 November

I have had good service from a RULE electronic level sensing automatic bilge pump.

Rupert Smedley  | 11.47AM, Friday 14 November

Hi Mike,
Draining the calorifier is usually a good idea- especially if the calorifier is in the engine room- those inside the cabin may be fine unless extended periods of below zero conditions are forecast.
You can still use the engine with the calorifier drained, but I would suggest leaving a hot tap open. This will help prevent any issues with pressure increasing in the cylinder as the air heats and expands.

Mark Langley  | 1.27AM, Saturday 15 November

Mike- I should also add if you run the engine to charge the batteries, ideally take the boat for a short cruise so the engine is under load- and also that the whole engine reaches working temperature. Short running can lead to condensation in the engine, which doesn't help with corrosion and oil state. Ensuring the engine is fully warmed up (under load) will drive off condensation.

Mark Langley  | 1.30AM, Saturday 15 November

Readers say:

Mark - thank you. I had looked at the Whale Smart 650 but couldn't find a review. I've only got a manual on/off rocker switch on the control panel so I'll have to modify that I guess

bill goad  | 3.58PM, Thursday 13 November

Should I drain the califier by taking the plastic blanking caps off for winter,if so can I still run the engine to top up the batteries over winter.My central heating has 50% anti-freeze so should be OK.

mike farmer  | 6.35PM, Friday 14 November

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