Are manual bilge pumps useless?

[Jigger]

Re bucket. You really need one on board for all sorts of things and as for how well they work. Anyone who has capsized an old non self bailing type dinghy will know how well a small hand bailer works, a bucket holds a lot more. You only need an inch of water to scoop up a good half bucket full at a time.
Even if you have a good hand pump or electric pump another set of hands at the bucket will help.

 

[geem]

I had similar experience as was mentioned earlier in this thread, water pump on engine broken so plumbed into the hand pump. 30 foot boat 14hp engine and it only required very slow pumping to keep normal flow of water through engine. So I am pretty sure a good diaphragm hand pump is far more efficient than an engine cooling water pump.. just look at the size of the hoses.
As for buckets, after my father had a very rough trip across the mouth of the thames in a Silhouette (17'6") when I was a kid he told me they were taking a lot of water and I said something about the bilge pump (brass things in those days). He said "nothing moves water as fast a frightened man with a bucket". I always keep a good bucket on board, it kind of depends on how much water you are looking at.

My 86 hp engine moves 21.5 gallons per minute. It would make a pretty effective bilge pump but having seen a flooded boat the amount of debris that can block the engine water intake is surprising. I wouldn't want to add failed engine to a sinking boat senario. With a running engine you can run multiple electric pumps indefinitely as long as you keep the batteries dry.

 

[LittleSister]

A friend had a high-volume Jabsco pump fitted to his engine which, in the event of flooding, you could engage. I can't remember the exact arrangement, but I think it might have required stopping the engine, putting a drive belt on, and tightening it. It was never put to use.

 

[Keith 66]

Long ago Simpon Lawrence sold bilge pumps under the Name "Vortex" they were a compact geared rotary pump beautifully built of bronze. A Tram style handle went through a thwart & into the top of the pump, gear ratio was about 15-1 with a 1 1/2" outlet.
No diaghram pump made today comes anywhere close to the output of these. They shift a lot of water very quickly. You occasionally see them at boatjumbles & they are well worth picking up if you can find one.

 

[westhinder]

The engine intake even less - I winterise my engine by diverting the intake into a bucket and it gets through about half a gallon a minute (at idle)

That will depend on the type of engine. I use the same method for winterising and when flushing the engine with fresh water a hose running at full speed does not keep up with what the engine sucks out of the bucket. A bucketful of antifreeze is swallowed in a matter of seconds. My engine is a 40 hp Yanmar.

 

[William_H]

Well much depends on your size of boat. If we are talking 20 ft class with no through hulls and outboard engine. Self righting and self draining cockpit then you are pretty safe with just a bucket. Given that the inertia of the boat at speed and strength of the hull mean a holing is unlikely.
Go up to 30ft + and situation changes with through hull liable to failure and greater total mass so inertia and hull not so relatively strong. A manual bilge pump becomes a good idea to go with an electric bilge pump.
The you have what seems to be called in politics the "optics" In other words how does it look if all sorts of safety standards for yacht racing specify a manual bilge pump and you decide otherwise. To the OP leave it there and be glad it is fitted. Even if you never use it or expect to. ol'will

 

[Kukri]

Long ago Simpon Lawrence sold bilge pumps under the Name "Vortex" they were a compact geared rotary pump beautifully built of bronze. A Tram style handle went through a thwart & into the top of the pump, gear ratio was about 15-1 with a 1 1/2" outlet.
No diaghram pump made today comes anywhere close to the output of these. They shift a lot of water very quickly. You occasionally see them at boatjumbles & they are well worth picking up if you can find one.

Yes, excellent things! As were the bigger sizes of “semi-rotary” pumps, which had about the same capacity as the big diaphragm pumps but took a lot less effort, as no energy went into distorting the diaphragm, but both these types were “non-self priming” so you had to know what you were doing.

 

[mogmog2]

Boat size seems to matter here. According to the mfr. blurb, the Whale gusher on our Centaur delivers 117lpm and the Johnson f35 water pump around 20lpm at 2500rpm.
I always thought the gusher did a good job of emptying the bilge...

There would seem a certain inevitability of the engine pump getting blocked by debris. Maybe if it is a big concern, an auxiliary engine driven pump?
Presumably several pumps and as wide a spread of types as possible would be optimal.

 

[DoubleEnder]

One good reason for having a manual pump is that it helps you keep track of how much water is coming in. I have a wooden boat and it leaks a little bit, sometimes. So when sailing we have a routine and pump manually every hour on the hour. If the number of strokes needed to clear the bilge starts to go up meaningfully then we will think about why, and what to do. An auto bilge pump would just quietly keep up with an increasing leak... until it didn’t. So the manual pump is a useful safety check, something to do every hour and a little bit of exercise.

 

[bedouin]

I would imagine that sometimes you just want to buy time rather than save the boat.

But it takes a lot of water to sink a boat and it will take a pretty big pump to make a significant impression on the sort of rate of ingress that will sink a boat in an hour or so. I would say that if it doesn't have at least a 2 inch hose then it isn't going to buy you much time.

Of course a bilge pump is essential on a boat but it should not be thought of as being much use in an emergency situation and anyone who thinks that can save their boat with anything less than a proper petrol-driven salvage pump is kidding themselves.

 

[fisherman]

Engine driven jabsco, say 1.5in driven by suitably matched pulleys chucks a serious amount of water. Can be manual clutch or electric, but the latter relies on sparks being in order, can even be a home made, pull the pump on a swivel arm tight into the belt, system. All rely on belts not being submerged.
Gilkes make rotary pumps that run all the time wet or dry, but are not self priming and cost thousands.

 

[pvb]

Of course a bilge pump is essential on a boat but it should not be thought of as being much use in an emergency situation and anyone who thinks that can save their boat with anything less than a proper petrol-driven salvage pump is kidding themselves.

Yes, a petrol driven pump is perhaps the ultimate emergency pump, but they are heavy and awkward to store. Machine Mart have a 2" pump for under £200 which is only 23kg and fairly compact, and it will shift 500 litres a minute.

https://www.machinemart.co.uk/p/clarke-pw50-2-petrol-powered-water-pump/

 

[rogerthebodger]

Yes, a petrol driven pump is perhaps the ultimate emergency pump, but they are heavy and awkward to store. Machine Mart have a 2" pump for under £200 which is only 23kg and fairly compact, and it will shift 500 litres a minute.

https://www.machinemart.co.uk/p/clarke-pw50-2-petrol-powered-water-pump/

Shame you can't get a combination pump and mains generator driven from the same engine.

 

[ghostlymoron]

I'd carry one of those on an ocean crossing if I had room.

 

[Resolution]

If you have got enough water in the boat to use a bucket in the cabin your cockpit floor will be submerged. Feel free to try it...

Not the case when my Sigma 33 stern gland failed. Arrived to find water up to bunks level inside, but cockpit drains still functioned. Even with two buckets, plus a manual bilge pump and fit young crew it took a worryingly long time to get the water out and to reach the gland. But it was fun watching the guy in the cockpit (manual bilge pump) being hit by successive bucketfuls from inside.

 

[Kelpie]

Shame you can't get a combination pump and mains generator driven from the same engine.

Well there is the 'Evo': https://www.machinemart.co.uk/p/evo...UAt50mLO9X3NYupNxyuGOJ__bi0zMqLxoCLpsQAvD_BwE
Which is an engine that comes with different attachments- generator, pressure washer, or water pump.
In theory a useful thing to have aboard, but it's pretty agricultural and hard to see how you could integrate it into a boat easily as an emergency pump.

 

[bedouin]

Yes, a petrol driven pump is perhaps the ultimate emergency pump, but they are heavy and awkward to store. Machine Mart have a 2" pump for under £200 which is only 23kg and fairly compact, and it will shift 500 litres a minute.

https://www.machinemart.co.uk/p/clarke-pw50-2-petrol-powered-water-pump/

Yes - that would save the boat - or at least buy you a lot of time. And note that has a 6.5HP engine to power it. You are not going to get that sort of power from your batteries or even by a belt drive from your main engines.

Every time I have looked into this I have come to the conclusion the best approach, short of that, is a fairly large electric pump with decent plumbing. I don't see any real benefit from an engine-driven one, If you want redundancy or more capacity fit another, and another

 

[Deleted member 36384]

...... I don't see any real benefit from an engine-driven one, If you want redundancy or more capacity fit another, and another

Once the diesel engine is running the engine driven pump keeps going, even if the electrics fail and user of the manual pump is exhausted. Maybe modern diesel engines installations require electric power to keep going but the older ones don't.

There are also the propellor shaft mounted centrifugal pumps that when submerged shift a huge volume of water, such as Fast Flow: -

https://www.fastflowpump.com/Bilge_FAQ.html On most yachts the water level will have to be around the bottom of the engine for these to work but it would do the job saving the boat compared to some electric pumps.

 

[bedouin]

https://www.fastflowpump.com/Bilge_FAQ.html On most yachts the water level will have to be around the bottom of the engine for these to work but it would do the job saving the boat compared to some electric pumps.

But it has issues on a small boat like mine. Firstly I am not sure I have space to fit it. Secondly by the time the water is high enough to reach it water will be well over the cabin sole, the engine will be up to its crankshaft in water and the air intake will actually be under water. That also implies the boat is probaly 6-12 inches lower in the water so you have probably doubled the amount of water coming in.

An average large electric pump is nothing like as good at shifting water, but gains in that it can be used in a much greater variety of circumstances. On my boat I am highly unlikely to lose all electrical power before the engine dies.

 

[pvb]

There are also the propellor shaft mounted centrifugal pumps that when submerged shift a huge volume of water, such as Fast Flow: -

https://www.fastflowpump.com/Bilge_FAQ.html On most yachts the water level will have to be around the bottom of the engine for these to work but it would do the job saving the boat compared to some electric pumps.

I can't agree with you on these shaft-mounted pumps. The Fast Flow looks remarkably similar to the Ericson pump which people were promoting about 20 years ago. Fast Flow don't seem to quote figures, but the Ericson pump was theoretically rated at over 40,000 gallons an hour. But - and this is a big but - this rated capacity was at 3500rpm (pump revs). The average 30-40ft cruising yacht has a small diesel which will do maybe 3000rpm flat out, connected typically to a reduction gearbox (say 2.4:1 ratio), meaning that the prop shaft (which the pump is clamped around) is only turning at a maximum speed of around 1250rpm. At this slower speed, the output is much less, maybe only 8000 gallons an hour.

Next problem: the pump is huge. The smallest Ericson pump was about 10” diameter and about 5” front to back. There’s no way it will fit in most 35ft yachts.

Next problem: before it will pump efficiently, the aperture around the prop shaft must be fully submerged. So there needs to be quite a lot of water in the boat before the pump will start working properly. This would affect the boat’s stability somewhat.

Next problem: it’s most likely that a dramatic leak will occur in the front part of the boat, and the pump is much further back. For it to work, it will be necessary to have a virtually open bilge right through the boat. With modern boat construction, stiffening ribs, etc, this is difficult to achieve.

Biggest problem: the pump only works well when the boat is flat out in forward gear. As “Motor Boat & Yachting” pointed out in its review of the Ericson pump “it is probably the case that most collisions involving breaches of the hull would damage the vessel's forward sections. In this case, driving the boat forward would tend to fill her and negate the usefulness of the pump”.

So, if you could fit one in, and if you could open up your bilges right through the boat, and if you thought that motoring flat out with a hole in the hull (and a lot of water sloshing around in the bilges) wouldn’t be a problem, then this sort of pump might shift 8000 gallons an hour. Why not get 3 or 4 big 12volt bilge pumps instead? They’d be cheaper, they’d work as soon as water got in, they’d chuck out at least as much water, and you wouldn’t need to be motoring flat out in order for them to work.