Hydraulic water pump for stabilizers

[Arthurc]

Hi, I have the Multisea ii stabilizers and my 12v water circ pump failed (groco vp-20-bbwa). I’m talking to Don on Starr he suggested moving to a hydraulic driven water pump to eliminate the 12v pump. Does anyone have a hydraulic driven cooling pump on similar sized stabilizers and can you share the model/make?
For the rest of the trip I’m using my spare 110v reverse cycle circ pump so have some time to design a better solution.
Thanks much!
Arthur

 

[mvweebles]

Do you have wet exhaust? Is it possible to put your cooler inline with your raw water and eliminate the pump altogether?

Another option would be a 120vac pump such as ones used for A/C. The Iwata pumps are fairly reasonably priced so its practical to carry a spare.

Peter

 

[O C Diver]

I'm having a hard time understanding the advantage of a hydraulically driven water pump. Seems that it would add a significant amount more failure points between a shaft seal, hoses and the control mechanism. Curious what the advantages over picking a different type of electric pump are?

Ted

 

[Arthurc]

Maybe I don’t fully understand the idea to tap into the raw water for the main, it is a wet exhaust but has a much larger inlet and outlet, I’m not sure I’d want to mess with that, also that would run hoses in inconvenient places.
The AC pump is fine in an emergency but I’d rather not have my inverter become a critical system….

 

[Arthurc]

I'm having a hard time understanding the advantage of a hydraulically driven water pump. Seems that it would add a significant amount more failure points between a shaft seal, hoses and the control mechanism. Curious what the advantages over picking a different type of electric pump are?

Ted

I am not an expert on hydraulic systems but I believe the pumps are significantly more reliable, it also eliminates the need for an extra relay, etc to turn on the electric pump.

 

[twistedtree]

I like the Primetime pumps. SS, non-contact impeller so no maintenance, and available with Hydraulic, DC electric, or AC electric power. Not cheap, but very high quality.


I think adding hydrauic drive would be complicated and expensive. You need valves, pressure reducers, flow reducers, etc. It's a nice way to go if built that way from the factory, as many ABT systems are. But I expect as a retrofit it would be very expensive above and beyond the pump cost. The advantage is that if the hydraulics are flowing and creating heat, the cooling pump is also running.


I have heard that the DC pump motors don't last too long, so I would avoid that. My own preference is an AC version. You just need to somehow switch it via a relay or such so that whenever the hydraulics are on, the pump runs. Mine uses a pressure switch, but there are other ways too.

 

[mvweebles]

Maybe I don’t fully understand the idea to tap into the raw water for the main, it is a wet exhaust but has a much larger inlet and outlet, I’m not sure I’d want to mess with that, also that would run hoses in inconvenient places.
The AC pump is fine in an emergency but I’d rather not have my inverter become a critical system….

See attached. The white item is the Wesmar water cooler. It has 2-inch NPT in/out. You can see my 2-inch sea strainer in the background. I have the opposite challenge you have - my 75hp Perkins has a 3/4" raw water inlet which I stepped up to 1" at the pump, then adapted to 2" at the cooler.

Peter

 

[Arthurc]

Thanks for the lead on primetime pumps, I’m going to talk to the tri county folks about the complexity of adding to the hydraulic loop otherwise will likely go with the dc version. I don’t have redundancy in my 120v system so trying to keep all critical operating systems off of it.

 

[O C Diver]

How many GPM is needed?
How high is the through hull discharge above sea level?
Is the pump mounted below sea level or does it have to lift?
12 or 24 volt?

Depending on the above, there should be a number of choices in pumps. To me, probably one of the important considerations is how quickly and easily it can be changed out. I don't see swapping a hydraulic motor out as being quick.

Ted

 

[Arthurc]

See attached. The white item is the Wesmar water cooler. It has 2-inch NPT in/out. You can see my 2-inch sea strainer in the background. I have the opposite challenge you have - my 75hp Perkins has a 3/4" raw water inlet which I stepped up to 1" at the pump, then adapted to 2" at the cooler.

Peter View attachment 141623

Ahh ok, so is that a heat exchanger/cooler, what I need is a raw water pump that can run the loop that feeds my naiad internal heat exchanger.

 

[Arthurc]

How many GPM is needed?
How high is the through hull discharge above sea level?
Is the pump mounted below sea level or does it have to lift?
12 or 24 volt?

Depending on the above, there should be a number of choices in pumps. To me, probably one of the important considerations is how quickly and easily it can be changed out. I don't see swapping a hydraulic motor out as being quick.

Ted

I believe the old pump was rated for 17gpm, it’s mounted below the water line, the exit is a few inches above but does go though an anti siphon loop.
Good point in changing it quickly. While I could easily switch the water lines hydraulic adds to the complexity.

 

[O C Diver]

I believe the old pump was rated for 17gpm, it’s mounted below the water line, the exit is a few inches above but does go though an anti siphon loop.
Good point in changing it quickly. While I could easily switch the water lines hydraulic ads to the complexity.

If there's a siphon break before the pump, that eliminates centrifugal pumps. 17 GPM and 12 volt really reduces the options. Was the Groco a vane or impeller pump?

Ted

 

[Arthurc]

It’s after so it’s a centrifugal.

https://www.fisheriessupply.com/gro...nd-automotive-circulation-pump/cp-20-bbwa-12v

 

[twistedtree]

What failed on the Groco pump? Is repair or replacement with the same pump an option?

 

[O C Diver]

It’s after so it’s a centrifugal.

https://www.fisheriessupply.com/gro...nd-automotive-circulation-pump/cp-20-bbwa-12v

On the below page is a graph of flow against head pressure.

https://www.groco.net/cp-20-12v

It might be worth measuring the actual flow at discharge to see what you really need.

Ted

 

[Arthurc]

What failed on the Groco pump? Is repair or replacement with the same pump an option?

The electric side, it’s looks like the cost of the motor isn’t much different than a whole new unit. I was inspired by Don yesterday to switch to hydraulic but the more I read the more I’m thinking about just buying 2 pumps and making the electrical a bit easier to swap underway. Likely not worth the hassle to change the design at all.
It’s my fault, I’ve been so busy with other projects we haven’t really used the boat for a year and that seems to have been particularly hard on the electric motors that sat for an extended period. (Had the warn hoist motor fail as well).

 

[Arthurc]

On the below page is a graph of flow against head pressure.

https://www.groco.net/cp-20-12v

It might be worth measuring the actual flow at discharge to see what you really need.

Ted

I think my AC pump is overkill right now as it was sized for 3 heat pumps, I’ve never had overheat issues before so that groco flow was fine. Once I get a replacement in I’ll measure as it would be good to know.

 

[Bmarler]

What Peter showed was a way to plumb the cooler in series with the raw water loop for the engine. No extra pump required as the one on the engine is doing the work already.
You may want to consider a shaft driven pump like this one: https://www.oberdorferpumps.com/en-us/centrifugal-pumps/end-suction/60p
Can be pulley driven, or coupled to any motor using a jaw coupler or similar.

 

[mvweebles]

What Peter showed was a way to plumb the cooler in series with the raw water loop for the engine. No extra pump required as the one on the engine is doing the work already.

You may want to consider a shaft driven pump like this one: https://www.oberdorferpumps.com/en-us/centrifugal-pumps/end-suction/60p

Can be pulley driven, or coupled to any motor using a jaw coupler or similar.

I'm not familiar with how Naiad does their system, but my guess from the OPs response is the Naiad reservoir tank has a tube-stack heat exchanger integral or something. Not a remote heat exchange I showed. Guessing it simply is not practical to change that configuration. I agree that the Wesmar setup I showed makes a lot of sense. My prior system - circa 1970 Vospers - had a small generic oil cooler inline too, but it was a fraction of the size of my Wesmar cooler.

OP - I'm curious about how the coolant water circulates in your system. Any pictures or diagrams?

Peter

 

[Arthurc]

What Peter showed was a way to plumb the cooler in series with the raw water loop for the engine. No extra pump required as the one on the engine is doing the work already.
You may want to consider a shaft driven pump like this one: https://www.oberdorferpumps.com/en-us/centrifugal-pumps/end-suction/60p
Can be pulley driven, or coupled to any motor using a jaw coupler or similar.

Right, but in my case the naiad cooler is 1/2npt, in series it would cut down flow way too much considering my whole engine raw water loop is 2” (I’d need to confirm that but it’s significantly larger)

 

[Arthurc]

I'm not familiar with how Naiad does their system, but my guess from the OPs response is the Naiad reservoir tank has a tube-stack heat exchanger integral or something. Not a remote heat exchange I showed. Guessing it simply is not practical to change that configuration. I agree that the Wesmar setup I showed makes a lot of sense. My prior system - circa 1970 Vospers - had a small generic oil cooler inline too, but it was a fraction of the size of my Wesmar cooler.

OP - I'm curious about how the coolant water circulates in your system. Any pictures or diagrams?

Peter

Correct on the naiad system (I believe), adding a much larger hydraulic heat exchanger would work fine as I’m guessing the naiad one could simply be capped at the water inlet and outlet. That would require new hydraulic lines plus some creativity in the raw water lines to the main as I’m tight on space. Advantage as you said is it’s always going to work as long as my main does and if the cooler didn’t have a zinc that’s one less to deal with…
Right now I have 4 raw water loops in the boat
1. Main engine which also does the transmission.
2. Naiads powered by the now failed groco 12v pump
3. Heat pumps powered by an AC pump
4. Genset

Each has its own thruhulls and are self contained.

 

[Simi 60]

Thanks for the lead on primetime pumps, I’m going to talk to the tri county folks about the complexity of adding to the hydraulic loop otherwise will likely go with the dc version. I don’t have redundancy in my 120v system so trying to keep all critical operating systems off of it.

You are worried about redundancy for your 120v system
Do you have redundancy for hydraulics?

Fwiw we run multiple inverters onboard 24/7 365 days a year for 7 years without a hiccup.
Some of the smaller inverters onboard are leftovers from her commercial trawlering days and are decades old.

 

[O C Diver]

I think my AC pump is overkill right now as it was sized for 3 heat pumps, I’ve never had overheat issues before so that groco flow was fine. Once I get a replacement in I’ll measure as it would be good to know.

Any idea how long the first pump lasted? If you got good life out of it, it might makes sense just to have a spare instead of re-engineering. I have an all plastic engine room blower to ventilate the engine room whenever the engine or generator is running. It lasts a year (1,000+ hours of use) and costs $35. Not worth looking for an alternative as it works so well. Keep a spare onboard and swap it out in 15 minutes.

Ted

 

[mvweebles]

How long did the Groco last? They also make an impellor model of similar quality. $400 for a pump is a lot, but in the big scheme of a boat, carrying a spare and swapping isn't the worst expense (assuming access is okay).

Sort of depends on how you plan to use the boat. If crossing an ocean, it might make sense to convert to an inline cooler. Bowman, who makes exhaust manifolds, also make generic oil coolers for hydraulics. As you say, would be a bit of a project to rerun hoses and such, but reliability would be improved.

Peter

 

[Arthurc]

Any idea how long the first pump lasted? If you got good life out of it, it might makes sense just to have a spare instead of re-engineering. I have an all plastic engine room blower to ventilate the engine room whenever the engine or generator is running. It lasts a year (1,000+ hours of use) and costs $35. Not worth looking for an alternative as it works so well. Keep a spare onboard and swap it out in 15 minutes.

Ted

I’m leaning this direction, I can see in my desire to make things easier I could make it a lot more complicated. The one change might be to switch to 120v AC, it’s a fair point that inverters don’t fail often and I could use the DC signal to activate a relay/switch. Since I doubt there is a downside to a bit more flow as long as it doesn’t significantly increase pressure I could likely use the same exact pump I have for the heat pumps and keep only one spare.

 

[Arthurc]

How long did the Groco last? They also make an impellor model of similar quality. $400 for a pump is a lot, but in the big scheme of a boat, carrying a spare and swapping isn't the worst expense (assuming access is okay).

Sort of depends on how you plan to use the boat. If crossing an ocean, it might make sense to convert to an inline cooler. Bowman, who makes exhaust manifolds, also make generic oil coolers for hydraulics. As you say, would be a bit of a project to rerun hoses and such, but reliability would be improved.

Peter

Not as long as it should have, it looks like it might have had a slight shaft seal leak which I never noticed, my guess is sitting for 10 months plus that did it in.

 

[mvweebles]

..... my guess is sitting for 10 months plus that did it in.

I was going to ask if it was in constant service. Long periods of sitting seems to be hard on pumps especially.

Peter.