Fitted My Electronic Bilge Pump But Is It Right?

[dauntlessman]

A week or so ago I started a thread regarding bilge pumps/water and got some excellent response - thank you for that.

Anyway I fitted my Rule bilge pump with float switch this weekend and all seems to be ok apart from one thing.

I dried out the bilges completely before fitting the pump and once I had put it all together, filled the bilges with sea water to make sure it was working ok. I was a bit alarmed at how much water I had to put in before the float switch turned the system on (probably about three inches).

On the instruction they reckon the float switch should be mounted slightly higher than the pump but this just made the problem worse. So I have lowered it to the lowest point and it sits next to the pump.

The float switch works on angles so it doesn’t make any odds if I tilt the mounting plate (if you see what I mean). The only thing I can think of is trying to some how mount the pump under the planking level (not sure how I am going to do that).

What do you think or is it reasonable for this amount of water to be in the boat before the switch comes on? Other than this, it works fine and if I pull the float switch up manually, it sucks the bilges completely dry (as I thought it should do anyway).

Your thoughts would again be much appreciated...

 

[Gordonmc]

Assuming the Dauntless is a timber hull, the only reason I would be concerned about a few inches of bilge water would be if its fresh.
My boat has the pump and float switch at the same level with the strum-box of the manual pump about two inches lower. About two strokes of the manual pump and its sucking air leaving about an inch of water and that's fine. I chuck in a bucketful of sea water and pump it through now and again to sweeten things up a bit.
I don't think wood boats were ever designed to be bone dry.

 

[Casey]

My pump and float switch are fitted in a similar way to yours and I am left with about two inches of water in the bottom of the bilge after pumping out. This has been so for the last five years and I think that it is quite normal. The only thing that gets more water out is the bilge pump on the engine and that leaves half an inch or so.

An absolute must is to check the function of the whole set up frequently and particularly before leaving your boat for some time unattended!

 

[Ships_Cat]

I think the only concern with the positioning of the float switch is that it is high enuff at all angles of heel such that there is no risk of the pump pumping itself dry while the switch is still floated on, if you see what I mean (so the pump is not left running with suction dry).

If that means because of the arrangements possible in the bilge that a depth of water is left then you are stuck with it.

In my own boat the bilge pumps pump from a sump so the bilges are left dry.

John

 

[Sixpence]

Now that's one I hadn't thought of . I presume you mean the bilge is made higher than a trough that will then act as a bucket where all bilge water will naturally be drawn to

 

[Ships_Cat]

Hi Trevera25

In our case with a yacht, the top of the fin keel is not open into the bilge (as is often the case) but has a sump extending down into the keel. We just have pump suctions and a float switch in it so it is only about 150mm square and 300mm deep.

Our float switch is only used for a bilge alarm (I am not a great fan of relying on electric pumps on a yacht so ours are all manual) but could obviously operate a pump. Similarly if one used a submersible centrifugal such as a Rule then one would make the sump large enough for that.

Not quite so easy on a MoBo but doesn't need to be very deep as with a centrifigal like a Rule in it, it is not the capacity of the sump that matters but purely to get the pump able to pump out to a lower level than the bottom of the bilge. In the original poster's case where he says 3 inches of water left then a 3 inch sump would about sort it out as long as switch is placed so that the pump does not fast cycle on/off on just the water in the sump if a smallish ingress of water (that is because of the small volume of the sump the switch could be placed so that it comes on when the bilge is filled above the sump top giving the pump some run time).

John