Bilge pump installation

[Strathglass]

Yes,

I have stuck with the Henderson Mk5 pumps for hand pumping and have about a 3 ft lift and 6 ft run on the inlet to the pump in the cockpit without any problems.

My electric pumps with float switches (by passable) sit in the bilge. Thus they have no inlet piping.

Iain.

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[MainlySteam]

Maybe there are a few of us been on the side wondering if there is some other problem. We have 2 manual Whale Gushers one of which has a suction lift of at least 7-8 foot plus a horizontal distance of around 15 foot from the bilge sump to the pump position (it is the one in the cockpit). The second one is mounted with only about a 2 foot suction lift and about 15 foot total horizontal run and about 4 foot total lift from bilge sump to discharge. We also have a Henderson for the holding tank pump and which has about a meter head up a siphon breaker and negligible run.

After all that, the telling comment is that I do not think any of them are any easier to pump than another, even with their varying head circumstances. I can say though, they are all very, very hard work if you have to do it for long.

I should also add, if one pumps into a loop which the drops down to exit below sea level as was suggested in an earlier post, and you put a siphon breaker on the loop as one should (I would not rely on the flap valves in the pump to stop backflow siphoning) then I believe that exactly the same will happen as if the exit was above the water line ie the discharge pipe will drain down and not provide an assisting negative head.

John



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[PaulJ]

Thanks everybody for taking the trouble to respond. I still haven't decided how I am going to do it but you have given me plenty to think about....

Many thanks.

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