Secondary bilge pump

[tommyh]

Getting ready to install a secondary bilge pump to get that last bit of water from the packing gland. I am using a 12 volt diaphragm pump with 1/2 hose. Two questions, should I use a check valve and where should it go also, pump location, my thoughts are to install it up high and the through hull a bit lower so I will be pumping up through the pump and then slightly down out the through hull. Any thing i am missing and is a check valve really necessary?

[a64pilot]

Only water you will have that drains back is the water in the hose from the pump to the bilge, with .5" line I don't think a check valve is warrantied, but then I don't like check valves.

[pbbmorton]

A64pilot, interesting. Can you share your reasons for not liking check valves? I am about to install several in front of my thru hulls.

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[HopCar]

Check valves should be avoided if possible in systems pumping dirty water as they are subject to jamming. Of course there are already check valves in a diaphragm pump and sometimes you can't avoid using them.

PBB, why are you putting check valves on thru-hulls?

[jkishel]

Make sure your discharge line loops well above the water line so that sea water won't flow back into the line when you're heeled over. Don't rely on a check valve to prevent this. You might also install an anti siphon valve at the top of the loop. A check valve will reduce backflow when the pump shuts off. You risk having the check valve clog or fail closed but since this is a small secondary pump maybe this is not a concern.

[a64pilot]

I don't like them as they are another failure point, and I believe can usually be eliminated by a better hose run, and as Hopcar said, you have two valves in a diaphragm pump anyway, for this reason be sure to have a good strainer, one good enough to catch hair.
This pump really isn't a true bilge pump as in high volume, gotta work pump, it's to get the last drop so to speak?
Can you do that with your manual bilge pump?

[tommyh]

My other pump is an automatic rule,
My bilge is extremely shallow so even an inch of water makes it seem real wet,
Just want to keep the moisture down to a minimum.
In a smaller boat everything counts

[HopCar]

A good option for a situation like this is the new Rule Lo Pro Pump.
It comes with a tricuspid joker valve that you can use or not at your discretion. The joker style valves are less likely to get jammed than more conventional check valves. They are also very easy to clean on this pump when it does get something caught in it.

Rule LoPro Bilge Pump