Bilge pumps - how many ?

roaringgirl said:
One electric whale pump with intake at bottom of keel; one manual pump in stern cabin with intake in bottom of keel; one manual pump in cockpit with intake at bottom of keel; T-valve in engine water intake, with intake at bottom of keel - if I close the engine intake seacock and throw the T-valve over, the engine becomes a diesel-powered bilge pump. I'm genuinely surprised that no-one else has mentioned this option.
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Try & keep up read post #56 it was only 2 before yours. :rolleyes:
But when you "throw the T valve over" do not throw it over the side, it does not help.:(
 
PilotWolf said:
The risk is in a panic situation the engine will run dry and overheat.

W.
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But at that point one would hope to have the situation under control, It would further suggest that the leak was not actually that bad. So as normality returned, one might expect the automatic pumps to cope. Unless shorted out , of course.
One could perhaps listen for the over heat alarm & remember to switch back. Most engines have one.
 
roaringgirl said:
One electric whale pump with intake at bottom of keel; one manual pump in stern cabin with intake in bottom of keel; one manual pump in cockpit with intake at bottom of keel; T-valve in engine water intake, with intake at bottom of keel - if I close the engine intake seacock and throw the T-valve over, the engine becomes a diesel-powered bilge pump. I'm genuinely surprised that no-one else has mentioned this option.
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The sort of throughput that would give you is tiny compared to a proper bilge pump (my engine is about 5l/min).

Doing that risks the engine (a) it may run dry or (b) the intake pipe may get blocked by debris in the bilge either of which could do a lot of damage to the engine and compound an already serious situation.
 
Daydream believer said:
But at that point one would hope to have the situation under control, It would further suggest that the leak was not actually that bad. So as normality returned, one might expect the automatic pumps to cope. Unless shorted out , of course.
One could perhaps listen for the over heat alarm & remember to switch back. Most engines have one.
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Wish it was that simple...

PW
 
RAI said:
Just a wee point about automatic electric bilge pumps. They often use float switches. The electrics of which are extremely vulnerable to failure, being often under bilge water.
Been there, got a wet t-shirt.
So I use two above waterline air pressure switches for greater reliability.
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I experimented with a dip tube with a washing machine pressure switch on the top which worked well but was awkward to install. In the end I went back to a float switch and made sure there was no debris in the bilge which could stop the float operating.
 
My first (&second) stella had an open cockpit & in severe weather it was not unusual to have to pump every 20 minutes.Fortunately the bilges were quite deep & the bunks were arranged so that they were away from the hull sides. This meant they stayed dry as the boat heeled.
I had a Henderson double acting pump bolted to the cockpit floor just in front of the cabin bulkhead & it came with a removeable long handle. The front cover had a quick release plate so the flap valves could be cleared in seconds. I could reach it from the helm position & it moved serious amounts of water. However, when I rebuilt my second Stella they were no longer available which was a pity. I suppose that in modern yacht design they do not suit the asthetics of an AWB, sitting in the floor of the cockpit.
My current boat has a Plastimo pump with a handle that folds away. It has a very sharp edge on the underside & any prolonged use would result in the user having a cut hand & being unable to use it. If I were to go for extended offshore cruise I would change for a pattern with a round handle as used by Whale. Hanse have seen fit to wire the electric bilge pump with the connections within 200mm of the pump and at the same level. If water was at a sufficient level for the pump to operate ( It never has had to work yet in 18 years) the connections would fail as soon as the boat heeled.
 
bedouin said:
The sort of throughput that would give you is tiny compared to a proper bilge pump (my engine is about 5l/min).

Doing that risks the engine (a) it may run dry or (b) the intake pipe may get blocked by debris in the bilge either of which could do a lot of damage to the engine and compound an already serious situation.
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I would not put the inlet directly in the main bilge but under another deep compartment. We are talking about a situation with serious amounts of water here. If one is able to install a byepass then one might assume that It is not beyond one's capabilities to install a decent strum box. It has been pointed out that some boats carry stores in the bilges so obviously not suited to put it there. But many owners keep their bilges clean. I would suggest that it is a matter of common sense in how one deals with the matter of water extraction in their own boat. If the engine option does not work, then do not do it.
But if the boat were to sink, then I would not give a monkeys about the state of the engine. I would be more interested in when I last had the liferaft serviced. ---------Which reminds me ;)
 
Daydream believer said:
Well it is for most people. But some ?? :rolleyes:
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It's not that's my point.

As mentioned above the risks of engine damage from debris/which engine?/both engines in case the one with the pump is disabled?/panicking non professional (or indeed professional) crew/what if you can't get to the diverter valve or PTO clutch?/what if it won't prime?/etc.

PW
 
Sorry for this question but I couldn't sleep last night and was thinking about this.

Obviously the boat would need some form of propulsion to move forward in the water, but could this be used to create suction? I'm thinking of some kind of large diameter pipe you could deploy over the back that feeds into the bilge. I keep thinking of the auto bailers in my old enterprise...

We have to be careful and add things to the exhaust system to stop a syphon happening and flooding the engine. Could the same principals but in reverse be used to empty a boat?

I might be way off the mark, physics isn't my strong suit..
 
Daydream believer said:
But you cannot sail the boat, or look for the cause of the leak, & bail at the same time, if sailing single handed.

I do recall a report of a fishing charter boat, that suffered a bad leak on charter. The report praised the skipper for having a valve that diverted the engine cooling water intake from its normal inlet to the bilges. I would consider it a good idea to get a diesel engine started early, before the electrics failed anyway. Once started, a typical yacht diesel does not need electric to run. It can also be supplying power to the batteries, thus assisting power to electric pumps to avoid flat batteries. That assumes one can keep the water level low enough to prevent them shorting out, of course.
Having the engine running allows one to drop the sails & keep the boat level for a while, which may assist the stability of the boat, once things get really bad.
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See Neeves post 26.


.
 
Daydream believer said:
I would not put the inlet directly in the main bilge but under another deep compartment. We are talking about a situation with serious amounts of water here. If one is able to install a byepass then one might assume that It is not beyond one's capabilities to install a decent strum box. It has been pointed out that some boats carry stores in the bilges so obviously not suited to put it there. But many owners keep their bilges clean. I would suggest that it is a matter of common sense in how one deals with the matter of water extraction in their own boat. If the engine option does not work, then do not do it.
But if the boat were to sink, then I would not give a monkeys about the state of the engine. I would be more interested in when I last had the liferaft serviced. ---------Which reminds me ;)
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Yes - not for me to dictate what others should do but everyone needs to make a risk assessment. But the key factor is that the amount of extra water you pump that way is so small that it hardly seems worth the effort/risk. If you want to use the engine to increase pumping then fit a proper engine-powered pump or - if you have space - one of those clever devices that fits to the prop shaft. But even for those if you look at the figures they don't really add much capacity.

For me the best solution always seems to be to buy another electric pump. A small one is less than £20 - and that is rated to pump 60x what my engine will pump - so running it for one minute will pump as much water as the engine will pump in one hour (of course it will probably only pump half the rated capacity) and even a big pump is less than £100.

Losing the engine is a major disaster - it restricts your ability to help yourself - you lose power for the pumps, VHF etc.
 
I think the people advocating using the engine saltwater pump as a bilge pump need to measure just how much water exits via the exhaust. I reckon the above estimate of 5 litres a minute is not far off for mine, a healthy 3GM30. It’s not even close to what even a small leccy pump will shift.
 
RAI said:
Just a wee point about automatic electric bilge pumps. They often use float switches. The electrics of which are extremely vulnerable to failure, being often under bilge water.
Been there, got a wet t-shirt.
So I use two above waterline air pressure switches for greater reliability.
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I have a couple of those in stock but not needed to fit them yet. My float switches are still going strong. I tested the air pressure switch and it needed quite a bit of depth of water to make it work. By comparison the float switch will activate in a couple of inches of water. They may be an issue in a shallow bilge
 
geem said:
I have a couple of those in stock but not needed to fit them yet. My float switches are still going strong. I tested the air pressure switch and it needed quite a bit of depth of water to make it work. By comparison the float switch will activate in a couple of inches of water. They may be an issue in a shallow bilge
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My air pressure bilge pump switches come with funnels on the ends of their pipes. They trigger on about 1 inch of water.
 
Gixer said:
Sorry for this question but I couldn't sleep last night and was thinking about this.

Obviously the boat would need some form of propulsion to move forward in the water, but could this be used to create suction? I'm thinking of some kind of large diameter pipe you could deploy over the back that feeds into the bilge. I keep thinking of the auto bailers in my old enterprise...

We have to be careful and add things to the exhaust system to stop a syphon happening and flooding the engine. Could the same principals but in reverse be used to empty a boat?

I might be way off the mark, physics isn't my strong suit..
Click to expand...
Sailing dinghies have such valves, but they go quite fast and have shallow draft to get them to work.
 
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