Using engine as a bilge pump?

Tim Good

Tim Good

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I'm sure this isn't a new idea but...

If I put a T-Ball value in the water line from seacocks to engine, then fed a new pipe to the bilge with a standard filter in the end and a basic check valve.... this would work as an emergency bilge pump right?

Or am I loosing the plot?
 
I think you will find that the volume rate of flow, for a sailing boat engine, is not very high - easy enough to check for your particular engine.

There have been discussions here which you may be able to find.
 
Not losing the plot, but it wouldn't pump much in an emergency. However, you could fit a new high capacity bilge pump, turned by a dedicated belt off your engine flywheel pulley, and engaged by a clutch. That would pump a meaningful amount, there's probably one in the ASAP catalogue.
You would need some sort of strum box to avoid blockages of course.
 
Not a studid idea at all. In fact I've seen it done.

As said above, it won't pump much (probably a couple of gallons per minute, but would certainly help to supplement the manual and electric pumps, and also if you had to have the electric pump on continuously, you would need to be running the engine to power it, so why not by pumping with the engine too.
 
I would be concerned if the water ran out, or the pipe became blocked for more than a few seconds because the impeller could be stripped from its shaft by the suction. Which means you have a leak and no engine as well. As others have said, the volume of water could be small anyway. Thinking out loud, if you put a bucket under the exhaust outlet and see how long it takes to fill up, the. Compare that with filling a bucket from the bilge and chucking over the side. Just a thought anyway.
 
My Dad had a boat with such a setup, a long time ago. Agree with all of the concerns above. I suppose there is something to be said for the simplicity of it though, being totally non electric and requiring nothing more than a Y valve and strum box.

Regarding engine driven pumps, the boat I worked on recently had such a thing- it could pum from a seacock or any one of the boat's watertight compartments, and could shift a huge volume of water. We primarily used it as a deck wash but it also formed part of the emergency kit for fire fighting and flooding. Somewhat overkill for a yacht I think.
 
Every time I have looked into I come to the conclusion that electric is best.

The amount of water the engine cooling would shift would be negligible (mine might be about 1 gallon per minute). Even proper engine-driven pumps have comparative small capacity compared with a cheap electric bilge pump.

If the engine is running then you have unlimited electricity and if it is not then an engine driven pump isn't going to do much good!
 
The OP says "emergency".

So I take this to mean a situation that you hope will never happen, perhaps where you have a continuous ingress of water and you're already using the manual end electric pumps and the level isn't going down.

In that situation, if something did block it or strip the impellor, you're really not going to be any worse off anyway. In that kind of situation anything you have is worth using.
 
bedouin said:
Every time I have looked into I come to the conclusion that electric is best.

The amount of water the engine cooling would shift would be negligible (mine might be about 1 gallon per minute). Even proper engine-driven pumps have comparative small capacity compared with a cheap electric bilge pump.

If the engine is running then you have unlimited electricity and if it is not then an engine driven pump isn't going to do much good!
Click to expand...

In my experience a mechanical engine driven pump can knock the socks off an electric pump (admittedly the one I was using was driven by a 6l 400hp turbodiesel!). This is also borne out by petrol powered pumps, where basic units can shift something like a tonne per minute.

Thinking out loud, could the diveter be arranged so that the engine can still draw from its usual source? Would require a tee off to a wide bore intake plus a non return valve. In theory the engine would 'prefer' the wide bore source but should this run dry it is still drawing from thr normal seacock. Of course this might be near impossible to get to work properly because you are fighting against the higher pressure of the seacock (unless the bilge water is higher than the waterline!) plus the NRV's resistance.
 
Kelpie said:
In my experience a mechanical engine driven pump can knock the socks off an electric pump (admittedly the one I was using was driven by a 6l 400hp turbodiesel!). This is also borne out by petrol powered pumps, where basic units can shift something like a tonne per minute.
Click to expand...
Looked into it again and I see I was mistaken - but they are an expensive / complex option.
 
The best type of pump to shift large amounts or water is the centrifugal pump.

This is the type the most electrical boat bilge are centrifugal pumps. These type of pumps as are the small petrol driven pumps use the motor bearings to locate the impeller and so cannot be driven by a belt from the main engine.

This is a section of and electrical driven centrifugal pump

centrifugal_pump-gza_type_coaxial_stainless_steel_centrifugal_pump-2.jpg


The type we need to drive from the main boat engine is like then

r4082e36.gif


This has a shaft supported by independent bearings that are also capable of taking the side load of a drive Vee belt.

There was/is a pump that could be fitted around the propshaft that does no need separate bearings as the impeller is supported by the propshaft bearings but is special in design as it can be split and fitted without the need to remove the boat propshaft. This makes it expensive as it is a uncommon design
 
Obviously it can work, but is it the best way to spend a few quid?
I think for a yacht engine, the litres per minute figure is just not worth the effort, better to sort out another electric pump.
A decent y valve that'd you should trust below the water line might cost as much as a Rule pump anyway.
If you've got a MoBo with 200hp in it, the sums are different.
I have a portable Rule 500 with a rigid outlet pipe, it is good for emptying tenders, deck wash, and it's another bilge pump if needed.
One point made elsewhere is that if you've made a hole in your boat, you may want to motor slowly, not use max revs to make the most of the pump.

An inverter and a 230V pump is also a lot of litres per minute for not much cash.

But in reality, the incidence of GRP yachts needing a bit extra in the pumping department is vanishingly small.
Either your normal pumps will do the job or you need a serious fire pump.
 
I wonder if the outboard could be adapted to make a salvage pump for emergencies. There's potentially a lot of power there and it wouldn't interfere with the main engine.

Perhaps some kind of cowling around the prop or replacing the prop entirely would be possible?
 
JBJag27 said:
I wonder if the outboard could be adapted to make a salvage pump for emergencies. There's potentially a lot of power there and it wouldn't interfere with the main engine.

Perhaps some kind of cowling around the prop or replacing the prop entirely would be possible?
Click to expand...

One of the small self-contained petrol pumps (the baby brother of the building-site frame pumps already mentioned) would probably be about the same size as your prop cowling contraption would end up.

Pete
 
Porthandbuoy said:
This is what you need! http://www.yachtwork.com/bilge-pump.htm

As an aside, the old Stuart Turner engine seacock had three positions: Closed (obviously), Open to the sea, and open to the bilges. Great for emptying the bilges, but you had to remember to switch it to 'sea'.
Click to expand...

That's what I remember - it rarely started but when it did you could clear the bilges really quickly
 
! installed a y valve and roaming hose on my engine input as an aid to winterizing the engine when adding the antifreeze mixture. It certainly makes it much easier to do!
Hopefully I wont have to use it as an emergency bilge pump!!
 
Moteurs Baudouin used to have a scavenge system which I think was the engine cooling pump, there was a separate outlet which just spat a little telltale water until the level rose, then it was full bore until clear. If it's a worry I would go for the belt driven Jabsco, any size you like, but bear in mind if you have an electric clutch it will give up if the electrics fail, as it will if the belt is submerged.
 
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