Hydraulic backup on a Perkins generator?

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LeoKa

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Apr 15, 2017
Messages
1,169
Location
USA
Vessel Name
Ironsides
Vessel Make
54' Bruce Roberts steel sailboat hull, coastal LRC, 220HP CAT 3306.
I need advice, or opinion, on an idea, which was recommended to me by a friend. His engine died on anchor and could not pull the anchor up to move.
He is thinking about a generator hydraulic backup solution.

Since I also have hydraulic steering, windlass, autopilot, I would not mind a backup solution for emergencies. I have replaced most of the hydraulic system I have a couple years ago. My hydraulic pump is on the main engine and handles the bow thruster and the windlass. The steering hydraulics is a separate setup with the autopilot. Even if I do not care about steering, I do need the anchor to be pulled up in all cases.

My generator is an old Perkins and it works fine. I rarely use it and mostly just run it for maintenance. I will post some photos of the pulley setup on it and the manual I have. Would it be possible to add a hydraulic pump by replacing a pulley? If yes, how? I can buy the parts and do the work, but I am not a mechanic.
All advice is appreciated.
 
Here are some old photos, when the belts were replaced.
 

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Another option might be to install an electrically driven hydro pump as a backup. Then you can power it from the generator, inverter, shore power etc. as needed. No need to fire up an engine to test things at a dock, for example.
 
Another option might be to install an electrically driven hydro pump as a backup. Then you can power it from the generator, inverter, shore power etc. as needed. No need to fire up an engine to test things at a dock, for example.


I like the idea. It would be more simple for sure. Do electrical pumps have limits? How much current an electrical hyd pump will require?
 
I like the idea. It would be more simple for sure. Do electrical pumps have limits? How much current an electrical hyd pump will require?

That depends on how much pressure and flow your hydro system needs and whether the electrical pump needs to flow enough to run more than 1 item at a time. Same way the pump size was determined for the engine driven pump, as you can get as big or small a pump as you need.

Power draw will depend on the size of the pump.
 
If indeed you have a reliable 208 V. 3 phase 7.5 kW Gen. Set with unused capacity, I would consider powering the hydraulic pump with an electric motor of sufficient size.
This way you can locate the pump/motor closer to the loads (wire should be cheaper than hose and it typically does not leak) and you would not have to fool with the pulleys or belts.

As always, a proper system can only be determined once you know all of the conditions.
 
It can certainly work, but you will need to do all the power calculation to size everything, not stall the generator, and see how slow the hydraulics will be with the alternate power source.
 
Power draw will depend on the size of the pump.

This is the pump on the engine. It is a clutch pump. I cannot find this model on the manufacturer website. I might need to contact them directly.
 

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Googling the model number yields this as the first hit

https://forceamerica.com/products/h...r-pumps/cast-iron/p350/cast-iron-323-9110-523

Guessing that your thruster is (or needs to be) about 15hp, that's how much power you will need from a generator driven pump, plus a bit more for losses. 15hp is 12kw, so you are already well past you generator capacity. As a rough estimate, you will be able to get 1/2 to 1/3 of the hydraulic performance from your generator compared to what you get from your main today,
 
Googling the model number yields this as the first hit

https://forceamerica.com/products/h...r-pumps/cast-iron/p350/cast-iron-323-9110-523

Guessing that your thruster is (or needs to be) about 15hp, that's how much power you will need from a generator driven pump, plus a bit more for losses. 15hp is 12kw, so you are already well past you generator capacity. As a rough estimate, you will be able to get 1/2 to 1/3 of the hydraulic performance from your generator compared to what you get from your main today,

I agree with the above, 15hp would be an awfully big demand for that generator. With a 7.5kw rating, I'd expect the engine on the genset is good for somewhere in the 12 - 16 hp range total, so if you wanted to come close to having as much hydro output available as the main provides you'd need to have the generator producing no power while using it for the hydro pump.

For a reference point on genset output vs engine hp, my 6.5kw genset has an engine rated for 13hp. Somewhere around 2:1 is common on smaller gensets, typically a bit less as they get larger.
 
I agree with the above, 15hp would be an awfully big demand for that generator. With a 7.5kw rating, I'd expect the engine on the genset is good for somewhere in the 12 - 16 hp range total, so if you wanted to .

Good points.
I am only thinking about this for emergencies. If the main fails and I am on anchor, I need to. pull it up, if the boat is being towed.
I am not planning to use this to maneuver and using the thruster. Yes, I can manually pull the anchor up with some help, but using the existing hydraulic system could simplify it. Particularly in blowing weather.
Here is a photo of my generator's manual page.
 

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The Kubota D950 that powers my 8 kW Onan Genset is rated at 11.5 (SAE Cont.) HP. at the speed of 1800 RPM to output power at 60 Hz.

It is true that the engine will produce 17 HP, but you need to be running it at 3000 RPM.
Don't know if the armature or it's mounts would like that, nor would I want to have to reset the governor each time I wanted to use the engine mounted hydraulic pump at full output to drive the thruster, only having to go back and find 60 Hz again.

How to get 15 HP to drive the pump off of the front end of that small of an engine would certainly be a challenge.

If the goal is back up hydraulic power for only the windlass, your genset's electrical output may be enough to drive a motor driven hydraulic pump of suitable size to power the windlass at it's rated speed and power. Adding in the thruster at likely twice the power rating is likely not doable at any acceptable speed.
 
How to get 15 HP to drive the pump off of the front end of that small of an engine would certainly be a challenge.

If the goal is back up hydraulic power for only the windlass, your genset's electrical output may be enough to drive a motor driven hydraulic pump of suitable size to power the windlass at it's rated speed and power. Adding in the thruster at likely twice the power rating is likely not doable at any acceptable speed.


Great info, thanks!

Correct. My main goal is just to be to handle the windlass. I have the option to separate the thruster and the windlass hydraulic circuit, if needed. In case of emergency anchor pull up, I agree that a good size of electric pump could be enough to handle. Do you have any recommendations for a 12V hydraulic pump, which can be strong enough?
 
Great info, thanks!

Correct. My main goal is just to be to handle the windlass. I have the option to separate the thruster and the windlass hydraulic circuit, if needed. In case of emergency anchor pull up, I agree that a good size of electric pump could be enough to handle. Do you have any recommendations for a 12V hydraulic pump, which can be strong enough?
I had a 24 VDC hydraulic power unit on my last boat to raise the centerboard.
If you can determine the maximum operating pressure your windlass needs,
almost any electric powered hydraulic pump of equivalent minimum output
pressure will drive it. The main variable will be the speed it does the job.

I found this 12 VDC one in my first online search and offer it only as an example:
https://www.hydraulic-supply.com/12vdc-motor-pump-assemblies-1152.html
There will be engineering considerations like minimum flow required and
the type and placement of diverter and control valves.
 
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I have no idea what HP rating your windlass motor is, but just spitballing lets say 5 HP.

Thats 3750 watts (HP/0.00134 = W) which at 12 V is an outrageously large 312.5 Amps
Perhaps a motor off of an electric windlass would work, but likely would be expensive and you would have to work out how to couple it to the hydraulic pump.
Plus where are you going to get the 312 Amps from and how are you going to get it to the motor?

In my mind you would be far better off to use the 120 V ac output from the generator, (about 4000 W) run the wiring from the generator to the motor that is close coupled to the pump that resides close to the windlass's hydraulic motor.

If this is a back up, I would want it truly independent of the existing hydraulic system, save the windless's motor, which means it's own reservoir, cooler, (maybe) valving and lines. That will get expensive.

An alternative, nowhere near as elegant would be to install a mount someplace as far back as possible, but reasonably in line, to mount an electric hoist (they have brakes on them) that you may be able to string out the hoist's cable, hook the anchor chain and pull it up 15'+/- at a time.
It's not perfect, a lot cheaper and serves as a back up regardless of what breaks on the original system. The key is the cable route and any guides that are needed as to not damage the topsides.
 
I have no idea what HP rating your windlass motor is, but just spitballing lets say 5 HP.
.

There is not much documentation on this boat, but I found the installation manual. This is what I think I have. Windlass VRC3500HYD / MUIR and T25 Hydraulic 25 HP WESMAR thruster.
See photos.
 

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An alternative, nowhere near as elegant would be to install a mount someplace as far back as possible, but reasonably in line, to mount an electric hoist (they have brakes on them) that you may be able to string out the hoist's cable, hook the anchor chain and pull it up 15'+/- at a time.
It's not perfect, a lot cheaper and serves as a back up regardless of what breaks on the original system. The key is the cable route and any guides that are needed as to not damage the topsides.

Elegant is not my concern. I need something I can work with in ugly weather, if needed. I will look into this idea. Mounting a hoist in the bow area will be a challenge. Unless, I will be able to mount a long enough boom to my mast? Or adding a shorter mast in front of the PH and mount a boom there? A boom which could serve dual purpose; a hoist base and a steading sail boom.
 
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That's a winch handle socket on top of the windlass, so you can operate the windlass manually in emergency. If you want power for it, there are a number of companies which make purpose built power winch handles and others that adapt power tools for the job. Much cheaper than anything you could do with the hydraulic system and perfectly satisfactory for emergency use.


Here's the adapter: WINCH BIT HOME



Jim
 
That's a winch handle socket on top of the windlass, so you can operate the windlass manually in emergency.

Here's the adapter: WINCH BIT HOME

Jim

I knew I had something for this purpose. I just found this. This is for the windlass from Muir.
I might still build something at the bow for a motorized solution.
 

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That's a winch handle socket on top of the windlass, so you can operate the windlass manually in emergency. If you want power for it, there are a number of companies which make purpose built power winch handles and others that adapt power tools for the job. Much cheaper than anything you could do with the hydraulic system and perfectly satisfactory for emergency use.

Here's the adapter: WINCH BIT HOME

Jim
My only thought is that, yes, while that windlass can be manually operated in a
pinch, and you could even grab and haul the chain by hand, a system providing
the full lifting power at a reduced speed on battery power alone is affordable.

An off-the-shelf DC solution to this could probably be bought for under $2k.
 
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a system providing
the full lifting power at a reduced speed on battery power alone is affordable.

I completely agree.
If you have info on a complete setup, please share.
 
Be glad you have a Muir vertical which accepts a sailboat winch handle. The more common horizontal Muir is a lot harder to deal with in a windlass failure. Manual chain retrieval led to some foul language, I bought leather gloves to keep onboard after that, and had Muir rebuild the windlass.

I suggest you try a retrieve using the handle and see how it goes. It may be sufficient for you as back up. The alternatives under discussion don`t sound encouraging.
 
I completely agree.
If you have info on a complete setup, please share.
I don't know your knowledge and capabilities but the basic idea is to add the
DC hydraulic pump in parallel with the existing engine driven hydraulic pump.
The DC pump draws fluid from the reservoir either from the same port as the
existing pump via a tee fitting or one that is available and unused.
The DC pump output should pass through a check valve and then tee in before
the control valve.
A check valve should be added between the existing pump and this tee fitting,
so the DC pump output doesn't back-flow through the existing pump.
The DC pump I posted earlier would work but is by no means the only option.
 
You need to make mounting brackets and probably need dual belts. Hydraulic pumps take a lot of power.

SeaDrive makes a PTO that drives off the front and leaves the pulley so you still have your belt. It has a clutch so the PTO doesn't have to run all the time. Do a search for Sea Drive PTO. There's a dealer in Seattle.
 

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You need to make mounting brackets and probably need dual belts. Hydraulic pumps take a lot of power.

SeaDrive makes a PTO that drives off the front and leaves the pulley so you still have your belt. It has a clutch so the PTO doesn't have to run all the time. Do a search for Sea Drive PTO. There's a dealer in Seattle.


I did look at this. They have a dealer in Astoria, OR and I will plan to visit the are soon. I will talk to them about my situation. Based on the photo, it is possible that I do not have enough space to mount this in front of the engine. Maybe a small version. I suspect, this cannot be too far from the engine, if it is belt driven. Let's see what they say.
 
This seems like a lot of work for a backup option. It might be easier to replace the hydraulic windlass with an electric one if you are that concerned with a potential failure. Don't get me wrong, I'm a big fan of hydraulics, my entire boat is power with them, but what if your failure is actually in the hydraulic system like a blown line or broken fitting? The extra pump isn't going to do you much good then.

That winch handle or as someone posted, an automated version is looking more practical.
 
but what if your failure is actually in the hydraulic system like a blown line or broken fitting? The extra pump isn't going to do you much good then.

Yes, things can happen. Even with electric winches.

I had to replace the engine mounted pump, so it is new. At the same time, I replaced the expansion tank, added valves, filter, new hoses. So, the system should be fairly reliable. Of course, things can happen.

The manual option is good to have. Last resort. I
f I can figure out something in addition, I would feel much better. To me, another source of hydraulic pressure, fitted in/valved in to the existing circuit with a clutch, is a more attractive way to go. If that is not possible, I will try an electric winch solution.
 

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