The Offshore Voyaging Reference Site

The World’s Best Bilge Pump Switch

Peter, a reader and member, related a tale of frustration with a bilge pump switch in this comment and that got me thinking about a great piece of gear that we have used on Morgan’s Cloud for over 20 years without one single failure or hint of a problem:


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Peter Naumann

Hi John

I wanted to share a recent unusual incident, with a bilge pump.

I recently fitted a new automatic bilge pump to my Catalina 309; a Rule-Mate 1100. All went well for the installation and pump worked well.
However, soon noticed the pump failing to turn off; but by switching to off then back to auto it stayed off and seemed to come on again when needed.

Yesterday decided to look more closely. I cleaned the bilge so thoroughly you could eat dinner off it and washed out the bilge pump. Using a hose I tested the pump and while at first spluttering a bit – perhaps due to soap – it was working well and switching off automatically as expected. I tested it on and off for about 5 cycles to rise out the whole bilge. Then refitted all.

Now the mystery.
Today when I returned and the pump was running again having failed to switch off. I thought I must just have a faulty pump and would replace it. But before i cleaned it all again – using the freshwater hose. AND magic – it turned off automatically every time. In fact it did this 3 or 4 more times.

I then pumped out and tested it with a bucket of clean saltwater. It failed to turn off!

It seems to me (I have yet to pull bilge pump to bits as it is all sealed) that there is an electrical switch inside the pump that makes contact when water covers it. However, as salt water is more conductive it seems that a very small amount keeps the connection active and so the pump does not respond and switch off.

I have written to Rule Inc the manufacturer of the pump but am yet to hear back.

Keith Jones

Hi John,

On Pearl our Bristol 45.5 the deep bilge is below the engine and the switch must slide into a narrow space mounted on a piece of aluminum stock. I used a 2 prong electronic switch for a number of years but one failed after about 8-9 years, but those are no longer made. About 5 years ago I replaced the switch with a Water Witch which has a great reputation and has been working well.

This switch is connected to a diaphragm bilge pump with a counter, if water gets above the “deep bilge” then there is another switch attached to a high volume submersible pump and an alarm. That pump should be replaced so it will be interesting to read your upcoming pump post.

I do think that a bilge pump cycle counter is an important safety feature, plus when I recommission the fresh water system I can figure out if there is a leak.

Martin

I see the “Water Witch” pump switch mentioned above. My experience with it about six years ago: placed it in my cockpit while I was doing work on cockpit drains, in order to pump out any rainwater that collects.
It failed to pump, so I took it back and got a replacement – failed again. Turns out that it switched fine with salt water or dirty water, but pure rainwater is less conductive and thus it would not trigger. A work-around would have been to sprinkle some salt in the cockpit while the drains were closed. So the exact opposite of Peter’s experience (see Peter’s comment above).

Larry Clough

I went through multiple “Water Witch” pump switches that failed over a three year period before finally giving up and getting an “Ulta” which has worked flawlessly for the past two years.

Bob T.

I agree with Johns assessment of this USS switch, the SR version comes with a lifetime warranty. I have two of theses stacked with the higher one used to trigger the high water alarm and pump. The lower controls the regular bilge pump. Both pumps are controlled by programmable relays that delay both the on and off functions preventing unnecessary cycling and assuring a completely dry bilge. John is correct the bilge alarm will wake the dead.