Alternative bilge pump

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robp

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Prompted by James' search for a particular pump solution, I saw this;

http://www.amazon.co.uk/gp/product/...m=A3P5ROKL5A1OLE&pf_rd_r=16B5G1A000DS6D9X1BFD

I've seen discussion on here years ago regarding using the engine to pump out in an emergency. For example flooded electrics. That discussion mentioned diverting the cooling water intake and pumping it overboard via the engine. But would one of these, (or similar), coupled to the crankshaft and run at 2,500 rpm provide some decent backup?
 
robp said:
Prompted by James' search for a particular pump solution, I saw this;

http://www.amazon.co.uk/gp/product/...m=A3P5ROKL5A1OLE&pf_rd_r=16B5G1A000DS6D9X1BFD

I've seen discussion on here years ago regarding using the engine to pump out in an emergency. For example flooded electrics. That discussion mentioned diverting the cooling water intake and pumping it overboard via the engine. But would one of these, (or similar), coupled to the crankshaft and run at 2,500 rpm provide some decent backup?
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No.

Buy a belt driven Jabsco.
http://www.jabscoshop.com/marine/pumps/bilge-pumps/bronze-engine-driven-clutch-pumps/

Deck wash, regatta water fights, emergency engine cooling, and sodding great bilge pump all in one.

Mind you, if you have elec failure the clutch will disengage.....
 
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fisherman said:
Mind you, if you have elec failure the clutch will disengage.....
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How much power does the clutch need? Could it run off a small emergency battery?

Perhaps it should be wired straight (via a switch) to the alternator? It's only any use when the engine's running anyway, and that isolates it from most electrical problems except failure of the alternator.

Or, just get one of the manual-clutch versions :)

Pete
 
http://www.amazon.co.uk/Karcher-SDP...ef=sr_1_1?s=diy&ie=UTF8&qid=1351177777&sr=1-1

A submersible pump powered by an inverter shifts a lot of water.
Until the inverter overheats or gets wet.
7000 litres an hour sounds a lot until you work out how much your boat holds.

A 500gph Rule pump is so cheap, it's hard to justify not having one aboard. I have one with long leads mounted on a rigid tube (overflow pipe), it has been used for emptying dinghies, deckwash etc, I'm sure it won't keep up with a major hole, but it might stop a minor leak from becoming a major problem by stopping the engine.
 
prv said:
How much power does the clutch need? Could it run off a small emergency battery?

Perhaps it should be wired straight (via a switch) to the alternator? It's only any use when the engine's running anyway, and that isolates it from most electrical problems except failure of the alternator.

Or, just get one of the manual-clutch versions :)

Pete
Click to expand...

Yes of course it needs disengaging! using power and probably has a relatively short running life. The Jabsco is very nice indeed - but the price? Ouch!
I think if I ever do it, I'll mount a chuck on the crank pulley.. :)
 
robp said:
Yes of course it needs disengaging! using power and probably has a relatively short running life. The Jabsco is very nice indeed - but the price? Ouch!
I think if I ever do it, I'll mount a chuck on the crank pulley.. :)
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My 1 1/4" Jabsco with electric clutch has done 11 years, not running all the time but engine has done about 7000 hours in the same period. Same impeller throughout. The manual clutch can be operated by a morse cable, but it wears and needs regular adjustment, I would have replaced it twice at least in this time. I think it should be possible to link the clutch to the alternator via an emergency connection, but if its so bad your electrics have gone does that imply the belt is under water? My service batteries are well above deck for this reason.The answer to all this is a bilge alarm so it doesn't get to that stage before you start pumping, after that if the water has risen so far that you are only delaying the inevitable, but maybe long enough for help to arrive.

A simple way is to mount the pump on a pivoting arm to tighten the belt, or as I had to run a pot hauler, a simple jockey wheel pulled up on a lever, a pump with no clutch is a lot cheaper. You can run it all the time in any case, as long as it has water, so have its own inlet and a manifold to redirect pickup.

One more thought: a layshaft to one side of the engine, driven by dog clutch/belts/whatever can be useful, you can run all sorts off it, extra alternator, pumps, and play about with pulley sizes.
 
fisherman said:
My 1 1/4" Jabsco with electric clutch has done 11 years, not running all the time but engine has done about 7000 hours in the same period. Same impeller throughout. The manual clutch can be operated by a morse cable, but it wears and needs regular adjustment, I would have replaced it twice at least in this time. I think it should be possible to link the clutch to the alternator via an emergency connection, but if its so bad your electrics have gone does that imply the belt is under water? My service batteries are well above deck for this reason.The answer to all this is a bilge alarm so it doesn't get to that stage before you start pumping, after that if the water has risen so far that you are only delaying the inevitable, but maybe long enough for help to arrive.

A simple way is to mount the pump on a pivoting arm to tighten the belt, or as I had to run a pot hauler, a simple jockey wheel pulled up on a lever, a pump with no clutch is a lot cheaper. You can run it all the time in any case, as long as it has water, so have its own inlet and a manifold to redirect pickup.

One more thought: a layshaft to one side of the engine, driven by dog clutch/belts/whatever can be useful, you can run all sorts off it, extra alternator, pumps, and play about with pulley sizes.
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Thanks for all that. Interesting.

Couple of years ago, I was helping a guy out who had run aground in Chi Harbour and was taking in a lot of water on the flood tide. I took wife and baby off the boat whilst another guy was below with a bucket. I called the harbour conservancy rib and they came down with a portable petrol driven pump. (Bit like a chainsaw engine on a pump). It was a godsend. Always wanted a decent capacity independent pump ever since - like PRV says. I know that an engine driven one might not have helped in this instance though.
 
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robp said:
I called the harbour conservancy rib and they came down with a portable petrol driven pump. (Bit like a chainsaw engine on a pump). It was a godsend. Always wanted a decent capacity independent pump ever since
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That's a good point, petrol driven pumps are relatively cheap - a fraction of the Jabsco prices for equivalent flow rates. See eg http://www.machinemart.co.uk/shop/product/details/clarke-pw2-2inch-petrol-driven-water-pump , which does 416 litres per minutes, nearly twice what the 2" Jabsco does at about a fifth of the price.

True, it's probably not good at salt water, but it only needs to save your boat once to pay its way. You'll not be using it every day to wash down a fishing boat.

The main problem is the size of the thing for stowage purposes, when the chances are you will never need it.

I have seen the much smaller "chainsaw engine" type that it sounds like the Conservancy people had, and that's potentially more stowable, though with lower flow rate and I think more expensive.

Pete
 
fisherman said:
You could use that for propulsion, given the right nozzle.
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:)

Not sure it would push the yacht very fast, but the engine is 6.5hp so even with the inefficiency of using a pump as a propeller it would probably drive the dinghy quicker than the 2hp outboard does :D

I'm almost tempted to spend the £200 just to experiment :D:D:D

(Nowhere to keep the pump if I did though :( )

Pete
 
prv said:
That's a good point, petrol driven pumps are relatively cheap - a fraction of the Jabsco prices for equivalent flow rates. See eg http://www.machinemart.co.uk/shop/product/details/clarke-pw2-2inch-petrol-driven-water-pump , which does 416 litres per minutes, nearly twice what the 2" Jabsco does at about a fifth of the price.

True, it's probably not good at salt water, but it only needs to save your boat once to pay its way. You'll not be using it every day to wash down a fishing boat.

The main problem is the size of the thing for stowage purposes, when the chances are you will never need it.

I have seen the much smaller "chainsaw engine" type that it sounds like the Conservancy people had, and that's potentially more stowable, though with lower flow rate and I think more expensive.
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Just to put this pump issue into perspective, a 1.5" hole in the boat, say 2ft underwater, will allow about 250 litres a minute to leak in. Sobering thought.
 
Most sinkings are not down to a sudden hole, more likely a failed hose, possibly the exhaust, or failed skin fitting, and the key is to know about it soonest. We always used to hear a story ending with 'by the time I got down below to look the water was x feet deep and I couldn't find where it was coming in'. All down to a seacock pipe failure which only needed the valve closing.
 
fisherman said:
Most sinkings are not down to a sudden hole, more likely a failed hose, possibly the exhaust, or failed skin fitting, and the key is to know about it soonest.
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Agree with that. My "bilge alarm" is a rather noisy auto pump, but if I didn't have that I would definitely fit an alarm.

Pete
 
fisherman said:
Most sinkings are not down to a sudden hole, more likely a failed hose, possibly the exhaust, or failed skin fitting, and the key is to know about it soonest. We always used to hear a story ending with 'by the time I got down below to look the water was x feet deep and I couldn't find where it was coming in'. All down to a seacock pipe failure which only needed the valve closing.
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Yes, so a nice big reliable pump giving you confidence to be down below for a while, let alone ferretting around for the inflow would be nice.
 
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