Engine Powered Bilge Pump?

[fisherman]

I have a 1.5 in Jabsco for deckwash and bilge, probably 200 litres a minute, depends on pulley sizes. What you have is a manual clutch so you would have to get down to the engine to engage it, and repeated engagements will wear the clutch until you have to unlock the ring and move it round. I used to have that, operated by a morse cable, now I have the electric clutch version, not touched it since 2001. BUT, that one relies on the electrics being intact to keep the clutch engaged. Drawing through a manifold from either seacock, engine room or forward bilge. I also have a Johnson L 4000 electric pump. Bilge alarm is most important, just a magnetic reed/float switch to a buzzer, forewarned is forearmed.

 

[Robin]

Many years ago in true 'Blue Peter' fashion PBO published an article showing how to make bilge alarm from a simple smoke alarm, just by taking two leads to the bilges such that if they contacted water it closed the circuit between them to turn on the screaming alarm. I even made one, tested it too but never got around to fitting it in the then owned boat.

 

[Tim Good]

Many years ago in true 'Blue Peter' fashion PBO published an article showing how to make bilge alarm from a simple smoke alarm, just by taking two leads to the bilges such that if they contacted water it closed the circuit between them to turn on the screaming alarm. I even made one, tested it too but never got around to fitting it in the then owned boat.

Wouldn't it just be a case of running a wire from the bilge pump so that when it activated from the water switch it also set off an alarm? I'm assuming that 99% of boats over 30ft boats have an automatic bilge pump switch that is hard wired into the batteries to be constantly on.

 

[Robin]

Wouldn't it just be a case of running a wire from the bilge pump so that when it activated from the water switch it also set off an alarm? I'm assuming that 99% of boats over 30ft boats have an automatic bilge pump switch that is hard wired into the batteries to be constantly on.

Quite probably but when PBO ran the article boats were less likely to have auto leccy pumps, besides not everyone has a boat over 30ft. My last two UK owned boats only had manual bilge pumps, my current USA boat has a small leccy pump in the enclosed engine bilge area but otherwise the important one is a hand one. There was a leccy bilge pump but the float switch failed and it was removed. There was also a 120VAC pump ( we have a 3KW inverter) but the Previous owner, kleptomaniac as he is, took it with him along with a lot of other gear listed on the inventory. Memo to self " never trust anyone".

 

[lw395]

.... I'm assuming that 99% of boats over 30ft boats have an automatic bilge pump switch that is hard wired into the batteries to be constantly on.

You are possibly assuming wrong.
A lot of places it would be very foolish to automatically pump oily bilge water.

 

[fisherman]

No, I don't like leaving anything live in the bilge, my alarm is the only thing left on, live to the bleeper, neg via the bilge switch.

 

[fisherman]

A friend has a simple alarm/actuator, a vertical wire, such as a morse cable core, in a tube attached to a bulkhead, bottom has a large float, top is visible and operates a switch. Worth remembering a simple switch is not ideal for a pump as it will be on/off every few seconds, that's why rule switches are of the mercury type, stay on for a good while.

 

[Tim Good]

You are possibly assuming wrong.
A lot of places it would be very foolish to automatically pump oily bilge water.

Agreed so you need to keep a clean bilge and turn it off in places when it would be very bad news but I wouldn't want to leave my boat for any length of time without an auto bilge pump in place. Once when there were a succession of tropical storms and the gator on my mast developed a small leak, you'd be amazed at how much water built up with the mast acting as a catchment.

 

[fisherman]

That's the trouble in the tropics, all those pesky 'gators.

 

[pmagowan]

One of the things about leaks is that many of them are from the same cause; failure of a through-hull fitting. I thing most are related to the heads. The most important thing, I would have thought, is to know immediately you have a leak and where it is located. I would think it should be easy enough to locate sensors at all the through-hulls, perhaps in a mini-bilge around each one. It could also be possible to locate all through-hulls in a watertight box to give a double protection, or even to extend them beyond the waterline. It seems to me that most people find out they have a leak when they step into a puddle of water from the gangway. At that stage the water is likely to be covering the ingress point and as such it is much more difficult to find it. If you had an alarm which went off and told you the leak was from the starbord heads through-hull then you could simply walk up and put your hand over it. In general I think bilge pumps should be looked at as a way of bailing out water once any leak is dealt with. Time spent working at pumps is time lost from repairing the breach.

 

[prv]

One of the things about leaks is that many of them are from the same cause; failure of a through-hull fitting. I thing most are related to the heads. The most important thing, I would have thought, is to know immediately you have a leak and where it is located. I would think it should be easy enough to locate sensors at all the through-hulls, perhaps in a mini-bilge around each one. It could also be possible to locate all through-hulls in a watertight box to give a double protection, or even to extend them beyond the waterline. It seems to me that most people find out they have a leak when they step into a puddle of water from the gangway. At that stage the water is likely to be covering the ingress point and as such it is much more difficult to find it. If you had an alarm which went off and told you the leak was from the starbord heads through-hull then you could simply walk up and put your hand over it. In general I think bilge pumps should be looked at as a way of bailing out water once any leak is dealt with. Time spent working at pumps is time lost from repairing the breach.

A lot of sense there - especially the fact that it's difficult to find a leak once the water in the hull has covered it.

I'm not sure about the idea that most leaks are skin fittings though, at least not directly. I suspect that a lot are due to internal plumbing failures - hoses coming off fittings etc - which might be some distance away from the fitting that needs to be turned off. Leaks in and around the engine exhaust are a common theme too.

We had a minor flood in Ariam earlier this year when the inlet hose to the calorifier softened in the heat and popped off the fitting, spraying the whole contents of our full water tank around the engine bay. Obviously no danger of sinking from your own freshwater, but the time it took to figure out what had happened was instructive.

Pete

 

[pmagowan]

In the research I did the number one cause of sinking was from the heads. Then it was through-hulls but that also includes hoses comming off a through-hull etc; essentially a leak where the water is entering through a through-hull. The least common was some kind of hull failure. Essentially the idea is that your hull is watertight and will remain that way unless you really batter it repetitively. The problem is that your hull has lots of man-made holes in it. Through-hulls, prop-shaft, rudder stock, keel bolts. It is these man made holes that are vulnerable. It should not be beyond the wit of man to either put a second layer of defense or to have an early warning system in place. It could be as simple as having a water sensor in the bilge forward, aft and midships so that you can narrow it down. I think one of the major concerns is that so many people immediately think about pumps when they have water in their boat when they would be wiser to think about where the water came from and how to stop it. The pump is there to clean up afterwards.

A lot of sense there - especially the fact that it's difficult to find a leak once the water in the hull has covered it.

I'm not sure about the idea that most leaks are skin fittings though, at least not directly. I suspect that a lot are due to internal plumbing failures - hoses coming off fittings etc - which might be some distance away from the fitting that needs to be turned off. Leaks in and around the engine exhaust are a common theme too.

We had a minor flood in Ariam earlier this year when the inlet hose to the calorifier softened in the heat and popped off the fitting, spraying the whole contents of our full water tank around the engine bay. Obviously no danger of sinking from your own freshwater, but the time it took to figure out what had happened was instructive.

Pete

 

[Strolls]

These figures demonstrate that its more important to have an alarm than more pump capacity.

Dunno about you, but to me 11,000 litres per hour sounds deceptively a lot more than 2906 gallons per hour.

That will indeed swamp a Rule 1500 12v bilge pump, by a factor of 2 over the manufacturer's claimed throughput.

On the other hand, any of the 4-stroke garden / agricultural pumps would cope with the largest hole in the examples given by Simondjuk, if we take the manufacturer's claims at any value.

I don't advocate carrying an extra pump as the answer to all problems - clearly the goal is to stop the water coming in.

But it seems to me like a crew member should be able to start an LPG pump in minutes, whilst you head below decks to find the source of the leak.

I think in such a terrifying situation, with water around my ankles, I'd be very reassured as the hose fell down the companionway behind me, knowing it has 10x the capacity of the overburdened electric bilge pump.


http://www.wolframalpha.com/input/?i=11000+litres+in+gallons

 

[Kelpie]

The boat i work on has a Jabsco engine-driven pump, used as a wash down and fire hose primarily. Very powerful bit of kit. We have it plumbed in so that it can draw from either a through-hull or from each of the boat's watertight compartments. I don't really see the need to have one on a pleasure boat, though.

Recently whilst I was shopping around for a generator I looked at Screwfix's 'Evo' range- an engine that can be fitted with three attachments: generator, pressure washer, and dirty water pump. The pump claims 1000l/min which is a staggering amount of water. However i can't think of a practical way of operating such a pump on a relatively small boat. Being petrol driven, stowage would need to be carefully considered, and getting it up and running would inevitably take a while.

Personally I think the best answer is to have all of your through-hulls etc easily visible, and be familiar with them so that you can catch any deterioration early.

 

[AntarcticPilot]

You are possibly assuming wrong.
A lot of places it would be very foolish to automatically pump oily bilge water.

It is against marina rules to pump bilges where I am (James Watt Dock, Greenock). And that isn't imposed by the marina; Clydeport (the owners of the dock) imposed it on the marina. I suspect the rule is aimed at the tugs and other ships that use the dock, but it applies just as much to us. I did pump them a week or two ago - but then I knew I was pumping out fresh water from a mishap in the water system!

 

[ghostlymoron]

If my boat were sinking, I'd be inclined to break the rules and take the consequences.

 

[AntarcticPilot]

If my boat were sinking, I'd be inclined to break the rules and take the consequences.

Of course. But I was thinking of those who advocate automatic bilge-pumps - they would not be allowed in our marina. And there is an argument against them; the scenario where a serious leak is missed because the boat is unattended but the automatic bilge-pump keeps it under control UNTIL the batteries/solar panels/whatever run out of steam and the (apparently) perfectly fine boat sinks. Without the automatic bilge-pump, routine checks by a marina or whoever would have detected the problem before it became serious; the automatic bilge-pump might mask a problem until it became terminal!