Recommendations for an emergency electric pump

[srah1953]

Hi all
I'm looking for recommendations for an emergency electric pump that would extract a lot of water in an emergency (eg hole below waterline) for use with a Honda EU20 generator. The generator has a rated output of 1,600 watts with a max output of 2kW. There were a number of articles last year in YM, focussing on high capacity hand pumps (eg Whale Gusher) for use in an emergency. I'm thinking that a) an electric pump worked off a small generator would be easier and b) if I were sailing alone (which is mostly the case) it would allow me to do something else like trying to identify and block the source of water.
Any thoughts or suggestions?
Thanks in advance

 

[sailorman]

Hi all
I'm looking for recommendations for an emergency electric pump that would extract a lot of water in an emergency (eg hole below waterline) for use with a Honda EU20 generator. The generator has a rated output of 1,600 watts with a max output of 2kW. There were a number of articles last year in YM, focussing on high capacity hand pumps (eg Whale Gusher) for use in an emergency. I'm thinking that a) an electric pump worked off a small generator would be easier and b) if I were sailing alone (which is mostly the case) it would allow me to do something else like trying to identify and block the source of water.
Any thoughts or suggestions?
Thanks in advance

engine driven would be more efficient way

 

[sarabande]

If you are confident that your generator will start, be fuelled for long enough, and not gas you, then I'd look at a commercial electric pump with a head capacity of, say, 5m so that it will not be overwhelmed by sitting in the bilges with the delivery pipe exiting through the hatch to overboard.

If you have 2kw available then look at a pump of no more than 1 kw to give you good starting capacity. Self priming (you can't be fiddling around) and with long run capacity (not intermittent). Avoid the 'clean water' types and look at ones for industrial sites which can cope with some muck.

We have used Italian ones on the farm; they do a good job and are relatively cheap.

Your intake will need an easily cleanable strum box - but not so big that it can't be chucked deep into the bilges. I'd be inclined to go for a fairly rigid delivery pipe, as the flexible roll up hose types can thrash around a bit when the pump is working.


here's an excellent selection of pumps:-

http://www.tidyco.co.uk/store/water_pumps/tsurumi_submersible_pumps/submersible_pumps_info.asp

 

[Cymrogwyllt]

consider a dedicated, independant, system. On my 18 ft sea kayak I had a 450 gph pump with a 12 Ah sealed cell battery. By my calculation it could have emptied the cockpit area (rest was bulkheaded and volume left in a self rescue could be less than 20 gall depending on conditions). Theoretically the battery was much over rated but rather be safe than sorry. Easy to recharge a battery before needing it.


If going this route I suggest having a spare, or two depending on how paranoid you are, set of wiring and connectors ready to go despite using waterproofing/sealants.

I refused to go to sea on a Senior instructor training course when the primary set of wires/connections failed on test leaving me with only the back up set. My boat) Far from ideal when the day was to be spent 'falling over' and swimming in a tide race for practice. I had a back up hand pump as well as a foot pump but in a tide race you do not want to use a hand to pump out if you want to stay upright

 

[srah1953]

engine driven would be more efficient way

Any particular suggestions for an engine driven pump? How might such a pump be driven directly from the engine?

[QUOTE SARABANDE here's an excellent selection of pumps:-

http://www.tidyco.co.uk/store/water_...pumps_info.asp QUOTE]

Yes indeed, these look very appropriate. If the pump will handle solids (of varying sizes, depending on the pump model) is a strum box still necessary?

 

[sailorman]

Any particular suggestions for an engine driven pump? How might such a pump be driven directly from the engine?

[QUOTE SARABANDE here's an excellent selection of pumps:-

http://www.tidyco.co.uk/store/water_...pumps_info.asp QUOTE]

Yes indeed, these look very appropriate. If the pump will handle solids (of varying sizes, depending on the pump model) is a strum box still necessary?

How might such a pump be driven directly from the engine?
most practical yachtsman would know

 

[pvb]

Hi all
I'm looking for recommendations for an emergency electric pump that would extract a lot of water in an emergency (eg hole below waterline) for use with a Honda EU20 generator. The generator has a rated output of 1,600 watts with a max output of 2kW. There were a number of articles last year in YM, focussing on high capacity hand pumps (eg Whale Gusher) for use in an emergency. I'm thinking that a) an electric pump worked off a small generator would be easier and b) if I were sailing alone (which is mostly the case) it would allow me to do something else like trying to identify and block the source of water.
Any thoughts or suggestions?
Thanks in advance

You've had some suggestions. An engine-driven pump requires a lot of engineering to mount it and drive it properly. An electric submersible pump can shift a lot of water. You can't fit a strum box to these easily - most have a built-in strainer. Many submersible pumps have a float switch which will only activate when the pump is in about 60cm of water, so you'd need to buy one without a float switch or over-ride it. I have a couple of Clarke pumps which I use in the garden from time to time (don't ask!). These are about 1kW, and will pump vigorously all day long. See here for a typical example. I'd second Sarabande's thought about a semi-rigid delivery pipe - the flat hose is hopeless at going around corners.

However, at the end of the day, I do think that the situation you fear is highly unlikely. It might be better to direct your energies to creating some sort of removeable watertight bulkhead which could block off the bow area.

 

[ytd]

I bought a submersible dirty water pump from Aldi a while back. I use it to run a large rotating sprinkler from a 10kl watertank. It has a float switch which is used to stop the tank being pumped dry. Not sure of its capacity but it moves about the same amount of water as comes in when you remove the sounder transducer from the bottom of a hull.

 

[xtiffer]

Put a T piece in the hose from your engine's salt water intake.
On the new bit attach a hose into your bilge ( with a stop-cock on it!)
and a strum box.
When the s*** hits the fan just turn off external water intake and turn on bilge hose intake. Your engine will now run on the water in the bilge.
Be sure to turn on external water when the bilge is getting dry.
So simple that I am surprised boat builders don't do this as a norm.
I am sure that more competent engineers will point out something I have missed
Cheers,
Chris

 

[pvb]

So simple that I am surprised boat builders don't do this as a norm.
I am sure that more competent engineers will point out something I have missed

What you've missed is that the volume of water pumped by the engine cooling pump is relatively small!

 

[nimbusgb]

Put a T piece in the hose from your engine's salt water intake.
On the new bit attach a hose into your bilge ( with a stop-cock on it!)
and a strum box.
When the s*** hits the fan just turn off external water intake and turn on bilge hose intake. Your engine will now run on the water in the bilge.
Be sure to turn on external water when the bilge is getting dry.
So simple that I am surprised boat builders don't do this as a norm.
I am sure that more competent engineers will point out something I have missed
Cheers,
Chris

The Perkins 4-108 fitted to our boat had a dual impeller pump atacked one behind the other, one pumped seawater as per normal. the second was there as an emergency bilge pump. Useless. Even at 2000rpm with the pump run off the end of the camshaft the pump only got 1000rpm and at that speed it would just about pump 25 litres per minute to 2.5m head. It was an unneccesary complication and just got through twice as many impellers. Replaced with a single raw water pump.

I have seen large centrifugal pumps linked to the main pulley system with either a magnetic clutch ( one ex air conditioning compressor drive ) or a simple dog clutch. A nice idea in an emergency, great for the occasional fire and perfect for season opening regattas.

 

[CAPTAIN FANTASTIC]

I have two Clarke dirty water 240v, they are used on farms and to pump out pond water etc.
I can run them from the boat inverter, 1000w,
or I can run them from my small petrol generator. If you need to pump out water, efficiency is less important, effectiveness is what you need.

 

[Salty John]

If you lose a seacock a couple of feet below the waterline you'll be dealing with around 50 - 60 gallons per minute, 3,000 to 3,600 gph.
On the popular 12v centrifugal immersion pumps you need to downgrade the published capacity to about 40% for a typical installation. This is to overcome the pressure head and the line resistance and the fact that your batteries might not be at 13.6v and the wiring might be undersized. For example, a Rule 2000 will do about 800 gph in a typical installation.
A pump such as the Jabsco 51270 series will handle 4000 gph. This is a manual clutch pump running of the boats engine. Not entirely practical in small boats, but the only way I know of handling a big leak.
A big manual bilge pump, such as the Edson, will handle 0.75 gallons per stroke, 30 strokes per minute is about normal for a fit human.
My point is, if you try to design a system that will handle the flow from a hose falling off a seacock, for instance, you'll be disappointed with the options available. Prevention is not only better than cure, it's really the only viable option.

 

[pvb]

A pump such as the Jabsco 51270 series will handle 4000 gph. This is a manual clutch pump running of the boats engine. Not entirely practical in small boats, but the only way I know of handling a big leak.

"Not entirely practical in small boats" may be an understatement! The 51270 is huge, and needs to be driven at over 1500rpm to get that sort of output - not easy when it has a 180mm diameter pulley...

 

[Poignard]

The chances of ever needing to use such a pump seem so remote to me that I wouldn't think it worth bothering with, but if you want a powerful pump I reckon the best way is to have a mechanical one driven directly off the engine. A simple diesel engine will probably keep running until the water reaches the air intake, by which time you would be thinking about an exit stategy anyway.

Several years ago there was a advertising feature in PBO for a simple centrifugal pump that fitted around the propshaft and ran continuously, even without any water in it, as long as the propshaft was turning. In the event of water reaching the level of this pump it would be drawn in and pumped overboard.

 

[pvb]

Several years ago there was a advertising feature in PBO for a simple centrifugal pump that fitted around the propshaft and ran continuously, even without any water in it, as long as the propshaft was turning. In the event of water reaching the level of this pump it would be drawn in and pumped overboard.

Often marketed under the "Fast Flow" name, this type of pump isn't as practical as it might seem at first glance. The most likely place for a big leak to occur is in the bows, as a result of hitting something. The prop-shaft pump only works once the water level in the boat reaches the pump, and then only when the engine is pretty well flat out in gear. Motoring a semi-submerged boat with a hole in the bows flat out seems like a risky thing to do.

 

[Poignard]

Often marketed under the "Fast Flow" name, this type of pump isn't as practical as it might seem at first glance. The most likely place for a big leak to occur is in the bows, as a result of hitting something. The prop-shaft pump only works once the water level in the boat reaches the pump, and then only when the engine is pretty well flat out in gear. Motoring a semi-submerged boat with a hole in the bows flat out seems like a risky thing to do.

In which case - motor astern!

Seriously, your points make good sense - and probably explain why these pumps do not seem to have sold widely.

 

[Bobobolinsky]

I've been giving engine power transmission a lot of thought lately. I've got a Beta BD3/listerCRK in my boat. It was originally a keel cooled setup, which meant that as I did not want a keel cooler, conversion to heat exchanger would be the way to go. So now my BD3 has a heat exchanger fitted from a BMC 2.5. The BD3 was fitted with a huge alternator, which between needing a great big pulley because of engine RPM, was far too large to fit with the heat exchanger in place. The Lister CRK though was a Ford mini tractor engine originally and has a standard PTO drive in the gearcase, so giving me a hydraulic power unit. The intention being to drive the big alternator and a 240v alternator, remotely from the engine (The engine set up is engine in a box, so not a lot of room.) Now the thought remains that I could fit a hydraulically driven bilge pump. Hmmm

 

[PeterGibbs]

If you lose a seacock a couple of feet below the waterline , will handle 0.75 gallons per stroke, 30 strokes per minute is about normal for a fit human.
My point is, if you try to design a system that will handle the flow from a hose falling off a seacock, for instance, you'll be disappointed with the options available. Prevention is not only better than cure, it's really the only viable option.

I think this is the approach to take. I have a very large dedicated electric pump in my bilge and have used it in anger just once in 12 years - it worked well but was not dealing with the direct inflow from a failed hull intake. The inflow from a 1-2 inch intake is breath-taking, especially if a foot below the waterline or more. You would have no time to assemble gear and clean out strum boxes, believe me, it's scary - especially to a lone sailor.

A technical point - a pump with any kind of rubber / nitrile impeller will not be reliable over time. Garden pumping gear is permanently immersed and therefore works for years. Not the situation on a boat.

I appreciate your concern to be self-reliant - totally agree, but the closest attention to all risks of innundation performed 2-3 times a season with military precision is the only way.

A true story; I was walking through the yard and met a guy standing beside his boat with a Blakes seacock in his hands, looking dumbfounded. He had just been through the boat and given it a pre-season turn when the whole thing disintegrated in his hands. He was so glad to be ashore at that moment! Stuff happens.

PWG

 

[lw395]

The old RORC requirement of a tapered wooden bung for every seacock has a lot of merits.
A tarpaulin you can drag over a hole can work.
There are limits to what can be done, but yachts sinking are very rare.
An inexpensive submersible pump might be worth carrying, good for giving the deck a good rinse if nothing else.