Modern Bilge Pumps?

[Tim Good]

Ok so my Jabsco 1750 has died after 20 years of service. It was install in the bilge with a check valve next to it and up to an antisphon loop and out at a scupper vent via seacock at the waterline.

What is the modern day thinking of bilge pumps? Is it still good to have the pump down in the water like my 1750 or can I install a pump up further up in the system dry? I do this for my grey tank.

What about diaphragm vs impeller or centrifugal? Pros and cons?

I was considering putting in a whale gulper as all my other pumps are whale and it would limit spares. But even the best whales don't shift a huge about of water.

Thoughts?

 

[pvb]

I was considering putting in a whale gulper as all my other pumps are whale and it would limit spares. But even the best whales don't shift a huge about of water.

How much water do you want to shift? I reckon it's worth remembering that few bilge bumps could cope with more than a very gentle leak. Centrifugal pump ratings are hugely optimistic; they're based on zero-head open-flow conditions usually. Something like a Gulper IC could be a very satisfactory solution in most situations.

 

[Minchsailor]

I am faced with the same question. A pump down in the the depths of the water does not seem a good idea - I have no great faith in integrity of waterproofing of something that is (relatively) cheaply mass produced. Also had problems with the quite low pressure of the pump getting flow past the NRV.

My thoughts are for a Jabasco grey water diaphragm pump, controlled by float switches. Would welcome opinions.

 

[pvb]

My thoughts are for a Jabasco grey water diaphragm pump, controlled by float switches. Would welcome opinions.

The Gulper IC system I suggested is better in that it has a solid-state switching sensor, rather than float switches. It also has a run-on timer to get as much water out as possible.

 

[fisherman]

I can only suggest that for a bilge clearing submersible pump I prefer a Johnson, available at ASAP, but if your Jabsco has done 20 years that's pretty good. I also have an engine driven electric clutch Jabsco for deckwash, firefighting and emergency use. Pros: it pumps a lot and self primes. Cons: when the water reaches the drive belts or electric feed to the clutch it's dead. Mechanical clutch available also, but needs regular adjustment and ( expensive) replacement if used as I do.

 

[Billjratt]

Experience persuades me to aim for the largest capacity that : - space, power (electrical capacity), wiring size, plumbing size, and money will permit.
It's also worth remembering that submersibles are cooled by living in the cold water they are shifting, any that run dry will self destruct the motor as well as the impellor (unless centrifugal).
A washing machine level sense switch arrangement will keep the wiring above water level, and a car courtesy relay will control recycling without the need for valves.

 

[wombat88]

I would add that from experience automatic submersible pumps that sense the water without a float do not work once the have been covered with a thin film of oil...

 

[ghostlymoron]

Experience persuades me to aim for the largest capacity that : - space, power (electrical capacity), wiring size, plumbing size, and money will permit.
It's also worth remembering that submersibles are cooled by living in the cold water they are shifting, any that run dry will self destruct the motor as well as the impellor (unless centrifugal).
A washing machine level sense switch arrangement will keep the wiring above water level, and a car courtesy relay will control recycling without the need for valves.

I'm interested by the recycling control. How does it work?

 

[lw395]

Ok so my Jabsco 1750 has died after 20 years of service. It was install in the bilge with a check valve next to it and up to an antisphon loop and out at a scupper vent via seacock at the waterline.

What is the modern day thinking of bilge pumps? Is it still good to have the pump down in the water like my 1750 or can I install a pump up further up in the system dry? I do this for my grey tank.

What about diaphragm vs impeller or centrifugal? Pros and cons?

I was considering putting in a whale gulper as all my other pumps are whale and it would limit spares. But even the best whales don't shift a huge about of water.

Thoughts?

Is this an emergency pump? Or one for a boat that leaks regularly?

 

[geem]

I would fit the largest capacity bilge pump I could on the basis that it will function as an emergency pump if needed and it gets regularly use as a bilge pump if you get water in the boat routinely.
We have 19000 litres of pumping capacity installed ( and allowing for approximately 2m head) via four pumps with float switches. A Rule 2000gph pump sits in the main bilge sump. The same pumps in the shower sump and engine room plus a Rule 3700gph pump as an emergency pump where the original manual bilge pump used to be located. We carry a couple of spare float switches.

 

[Tim Good]

Sorry for the delay on this one. To answer some of he questions. It is a 43ft Seastream with 4 separate compartments. Lazarette is emptied by an auxillary pump but it never gets used as no water gets in. Main bilge is the one in question which had the Jabsco submersible centrifugal pump. Galley area is seperate and also has a working Jabsco centrifugal. Then bow/forward cabin also a sealed bulkhead and can be pumped seperately.

So this replacement is for the main bilge which hoses the engine and where most seacock would fill if they were to blow. In this compartment I have a high capacity hand pump and low volume auxillary pump already but I suppose I want a high capacity main electric pump to replace my existing Jabsco.

I see Rule do quite a lot. Does anyone rate these particularly or are the submersible pumps like my Jabsco all pretty much the same?

 

[zedcell]

I am faced with the same question. A pump down in the the depths of the water does not seem a good idea - I have no great faith in integrity of waterproofing of something that is (relatively) cheaply mass produced. Also had problems with the quite low pressure of the pump getting flow past the NRV.

My thoughts are for a Jabasco grey water diaphragm pump, controlled by float switches. Would welcome opinions.

Just a thought but modern day aquarium pumps are very cheap the magnetic impeller ones I use in my aquarium rated at 2000 lph have no issues at all with the quality of waterproofing and like most things these days are manufactured in china.

 

[fisherman]

I have had to replace my Johnson L4000 submersible pump once since before 1992, when I bought the boat, in 1014. Used once daily, 120 days a year.

 

[Billjratt]

I'm interested by the recycling control. How does it work?

Well, when the pump stops because the level sensor has 'flipped' , all the water up the pipe falls back and the level sensor trips to start the pump again.
The delay relay (which keeps the courtesy light on in your car for a few seconds after you've closed the door) will keep the pump running to get that little bit more water out of the bilge so that the fallback doesn't trip the switch and start the process all over again. Non return valves would be a solution but the commonly found solids in the bilge tend to render them useless.

 

[pcatterall]

I have had 2 submersed pumps fail in about a year each. The failure was due to corrosion of the impellor shaft where ordinary rather than stainless steel was fitted.
Fortunately these were just small pumps located in the deepest part of the bilge. I have a larger pump located out of 'normal' bilge water level and this has been ok for 5 years.

 

[Tim Good]

I have had 2 submersed pumps fail in about a year each. The failure was due to corrosion of the impellor shaft where ordinary rather than stainless steel was fitted.
Fortunately these were just small pumps located in the deepest part of the bilge. I have a larger pump located out of 'normal' bilge water level and this has been ok for 5 years.

Care to name the brand which failed?

I just got a Rule 2000 submersible and removed the check valve that was there previously. A lot of people seemed to rate Rule but there branding and products done look amazing. The plastic looks cheap and the logos on the product are smudged. Anyway I hope the mechanism and motors speak for themselves.

In

 

[ghostlymoron]

Thanks for the explanation.

Well, when the pump stops because the level sensor has 'flipped' , all the water up the pipe falls back and the level sensor trips to start the pump again.
The delay relay (which keeps the courtesy light on in your car for a few seconds after you've closed the door) will keep the pump running to get that little bit more water out of the bilge so that the fallback doesn't trip the switch and start the process all over again. Non return valves would be a solution but the commonly found solids in the bilge tend to render them useless.

 

[fisherman]

I have had to replace my Johnson L4000 submersible pump once since before 1992, when I bought the boat, in 1014. Used once daily, 120 days a year.

That's not very clear! I bought the boat in 1992, with a pump which was OK until 2014.

 

[aidancoughlan]

I've got a single manual Bilge pump in my "new" this season M35, and was reading around recently.

I don't have any particular product recommendations since I've not had much experience of them, but for general info (if you need it, I did !) this seems worth a read for general info
http://www.marinesurvey.com/yacht/bilge_pumps.htm

I was taken by the suggestion in that article of something hooked up to the engine. For a really useful emergency bilge pump, how bout one of these ? http://yachtwork.com/product-bilge.htm or something like this http://www.threefools.org/catspaw/BoatDetails/EngineBilgePump.htm
Does anyone have one of these type of engine-driven bilge pumps, any feedback ?. They seem relatively expensive, but I'll bet we would be happy to have it if the floor boards start floating !

 

[pvb]

I was taken by the suggestion in that article of something hooked up to the engine. For a really useful emergency bilge pump, how bout one of these ? http://yachtwork.com/product-bilge.htm or something like this http://www.threefools.org/catspaw/BoatDetails/EngineBilgePump.htm
Does anyone have one of these type of engine-driven bilge pumps, any feedback ?. They seem relatively expensive, but I'll bet we would be happy to have it if the floor boards start floating !

The first one you linked to is often suggested, but it's far from practical. Firstly, the pump is huge, and not many yachts would have space to install it. Secondly, it only starts to pump once the prop shaft is submerged, by which time there'd be a lot of water in the boat. Thirdly, in order to pump much water the boat has to be in gear, at high revs. As most likely scenarios of major water ingress would involve damage in the bows, this isn't a great idea.

The second one you linked to is a better solution, but not easy to engineer in most yachts.