bilge pump - would this work?

ghostlymoron

ghostlymoron

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I am having to replace my electric bilge pump and have discovered the old one was installed in an unusual way (to me at least). The electric pump was jubilee clipped to the end of a hose in the bilge, the other end of the hose led to the suction side of a Henderson Mk V manual pump. The delivery side of the Henderson was connected by hose to a skin fitting in the transom.
I have been thinking about this and can see that the manual pump could suck through the electric one but I can't see how the electric pump could deliver through the manual one.
Am I being obtuse?
I'm proposing to fit a new electric pump with a seperate delivery hose tee'd in to the henderson delivery hose. Any comments welcomed!
 
It may make sense, but try these things...

Fill the bilges with water.

The pump should operate if you have automatic float switch.
observe any water?

Now operate the Henderson and it should be a doddle if it isnt having to drag water up a pipe.

Now stop the electric one, and disconnect from the pipe.
Go back and have another go with the Henderson. You may find that the henderson struggles with the head of water.

If none of that is true, then run a separate hose for the leccy pump to a new skin fitting, and fit a strum box to the Henderson pipe.
 
It's not unusual as the hendersons / whales usually have flap valves in them to control suction / expelling water. So the electric pump will only have to overcome the flaps in the intake / exit of the henderson to work.

The problem comes when the flaps get old and stiff or the electric pump impellor gets damaged and cannot pump hard enough to move the flaps.

But it does save having another exit through the hull.
 
[ QUOTE ]
I have been thinking about this and can see that the manual pump could suck through the electric one but I can't see how the electric pump could deliver through the manual one.

[/ QUOTE ]If you look at the flap valves in the manual pump, you'll see that it's quite feasible to pump water through it, although the flow rate will be reduced compared with a straightforward direct pipe.


[ QUOTE ]
I'm proposing to fit a new electric pump with a seperate delivery hose tee'd in to the henderson delivery hose. Any comments welcomed!

[/ QUOTE ]If you do this, although the electric pump will work OK, it will be possible for the water coming out of the manual pump to escape through the electric pump back into the bilge rather than going overboard. You'd need to put a one-way valve in the hose from the electric pump. The best way to plumb the electric pump would be a separate hose and skin fitting.
 
Re: bilge pumps

I don't share the popular aversion for holes in the hull, and in any case they will be up under the gunnel.
My electric pump (with float switch) is one system emptying engine bay/cockpit.
And there's the original manual Whale with separate outlet - but that can only be operated by lifting a floor hatch (not clever!) so added another manual leading to yet another outlet.

Forepeak and wheelhouse bilges are common with similar to the above.
Belt 'n braces in excess!
 
Re: bilge pumps

Yup, separate systems give better failure coverage, however, I like the 'series pump' idea.
As long as the henderson's valves are supple, it will help stop backflow to the electric pump, thus reducing cycling.
Always assuming of course, that the electric pump has enough oomph to lift the debris in the first place.
 
Re: bilge pumps

Few bilge pumps are of much benefit in an "ohmigawd" emergency. The key thing is to stop the ingress. If you really want to shift water you need one of those submersible mains jobbies with a large diameter hose, going direct over the side. OK if you have gennie big enough and which hasn't flooded.
 
Re: bilge pumps

That's the set up I have modified my electric pump to. The non return valves on the hand pump allow the outlet to to be set lower in the hull side so the electric pump has less height to pump and now works a lot faster. I do also have a large Whale handpump totally seperate.
 
Re: bilge pumps

My ohmigawd quantity, about 200/250 litres in Full Circle bilges took over 25 minutes with the electric 1000gph and the manual.
And no more was coming in at the time, so that was just a static load.
Scary

We now have 2 x 3000gph, 1 x 1000gph, the manual and a further 750gph in the engine sump area. Exiting through 3 separate holes above the waterline to either side of the boat. Connected to 2 separate batteries.

I feel a lot happier now.
 
Re: bilge pumps

In that ultimate brown-trouser moment, the only thing to have is one of these:

http://www.pumpitout.nf.ca/

The ESP 308 can shift 2400 litres/min (yes every minute) with a shaft speed of 1500rpm and a 12m head!

All assuming that your main engine is running and can remain that way.
 
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