Hydraulic Bow Thruster Problem

[Ski in NC]

If there is a filter in the supply line from tank to pump, it could be worth changing that. maybe when pump tries to transition to full flow it gets a pressure drop that slows the swash plate actuator. Turns into a "chicken and egg" sort of thing with regards to what causes the low pressure.

Does problem show up more when fluid temp is low?

 

[sunchaser]

Of the many possibilities for troubleshooting a hydraulic system, pressure gauges in a few key areas are helpful. One important place would be pressure checks at the thruster inlet, any motor bypass lines and outlet.

A hydraulic shop should be able to supply a guy with the right gauges and know where to install quick connect fittings for the gauges to get plugged in for system checks. This then allows you to isolate problem area which could be the main valve block, check valves, manual valves, thruster motor or hydraulic pump.

Possibly the original install or design is at fault and problems have existed since day one. Wesmar should be able to proved an ideal install schematic to compare to actual.

Yes, everybody claims to love hydraulic thrusters. I am not one on smaller vessels. Electric thrusters are not the menace some say and even Nordhavn equips the vast majority of their sub 60 footers with electric. I debated this issue a few years ago with my vessel and ended up with electric which can run uninterrupted for in excess of one minute, that was the extent of my test. I also went through this with Nordhavn when specing out a new build. If per chance you need some expensive repair parts, it would be nice to have the cost of a 8kw or so electric thruster in your back pocket. The hole is already there.

Last but not least get a really bright flashlight and look at all the system's valve bodies and fittings for hairline cracks and fluid loss.

 

[Britannia]

If there is a filter in the supply line from tank to pump, it could be worth changing that. maybe when pump tries to transition to full flow it gets a pressure drop that slows the swash plate actuator. Turns into a "chicken and egg" sort of thing with regards to what causes the low pressure.

Does problem show up more when fluid temp is low?

There is a filter - a huge one. I have a spare too. At that point I should probably flush and service the whole system when I change the filter. Who knows when it was last done.

Richard

 

[Britannia]

Of the many possibilities for troubleshooting a hydraulic system, pressure gauges in a few key areas are helpful. One important place would be pressure checks at the thruster inlet, any motor bypass lines and outlet.

A hydraulic shop should be able to supply a guy with the right gauges and know where to install quick connect fittings for the gauges to get plugged in for system checks. This then allows you to isolate problem area which could be the main valve block, check valves, manual valves, thruster motor or hydraulic pump.

Possibly the original install or design is at fault and problems have existed since day one. Wesmar should be able to proved an ideal install schematic to compare to actual.

Yes, everybody claims to love hydraulic thrusters. I am not one on smaller vessels. Electric thrusters are not the menace some say and even Nordhavn equips the vast majority of their sub 60 footers with electric. I debated this issue a few years ago with my vessel and ended up with electric which can run uninterrupted for in excess of one minute, that was the extent of my test. I also went through this with Nordhavn when specing out a new build. If per chance you need some expensive repair parts, it would be nice to have the cost of a 8kw or so electric thruster in your back pocket. The hole is already there.

Last but not least get a really bright flashlight and look at all the system's valve bodies and fittings for hairline cracks and fluid loss.

Thanks for the suggestions.

I'm not an evangelist for hydraulic bow thrusters. It just happens to be what's on my boat. Is 8kW enough for an electric replacement? Mine is rated at about 25HP and even then has a hard time if there's much wind. The boat is 80,000lb loaded, full keeled and the bow is about 10' off the waterline. Lots of mass and lots of windage.

Richard

 

[sunchaser]

Thanks for the suggestions.

I'm not an evangelist for hydraulic bow thrusters. It just happens to be what's on my boat. Is 8kW enough for an electric replacement? Mine is rated at about 25HP and even then has a hard time if there's much wind. The boat is 80,000lb loaded, full keeled and the bow is about 10' off the waterline. Lots of mass and lots of windage.

Richard

The standard specs for a N55/60 show a 15 HP Sidepower 24V. Boat weighs around 120K lbs with considerable windage. I've operated them and no doubt it moves the vessel quite handily. Hard to know how many HP your setup is actually putting into the water at "idle".

I'm not saying it is necessarily a good idea, just saying nice to have a price in your back pocket.

 

[Britannia]

The standard specs for a N55/60 show a 15 HP Sidepower 24V. Boat weighs around 120K lbs with considerable windage. I've operated them and no doubt it moves the vessel quite handily. Hard to know how many HP your setup is actually putting into the water at "idle".

I'm not saying it is necessarily a good idea, just saying nice to have a price in your back pocket.

Interesting - that's certainly plenty of boat to be swinging around. Yes - I don't really know what the output of mine really is. I don't know how often I have encountered the low power output problem and not noticed. Now I'll be more aware.

I do know that increasing the RPMs makes a marginal difference to the sound (speed) of the thruster. Also, I think the JD 6068T puts out something like 40HP at idle. I have the curves at my boat.

Richard

 

[Capt.Bill11]

Have you tried contacting the manufacturer and running it by them?

 

[Britannia]

Have you tried contacting the manufacturer and running it by them?

Not yet - I will do that when I get chance during the day - probably next week. Good suggestion.

Richard

 

[Mule]

I have a hydraulic stern thruster, belt driven pump. It has occurred to me hydraulics are really nice. This just an intellectual exercise. The question is this, is it feasible, reasonably workable to have a 12volt powered pump perhaps off the house bank.
Thoughts??

 

[Ellebo]

Hi there How do i set up my hydraulic thruster to run off generator

 

[Shoalwaters]

Hi there How do i set up my hydraulic thruster to run off generator

What does it run off now and what problems does that give you?

 

[Mule]

I have looked into it. 1st and foremost, limber up your wallet. Second, find a company that specializes in hydraulics. They have various power pack pump assemblies powered by electricity.
I suppose you could get an electric motor and gear or belt and pulley to rig up something that might eventually work. The very fact that you and I have ask the question, at least in my case, pretty well elimates the shade tree option. I have done those types of projects in the past and in the end could have paid the money up front and saved a bunch in the long run. Not to mention aggravation.

 

[Capt.Bill11]

Hi there How do i set up my hydraulic thruster to run off generators Z

Either via an electric hydraulic pump or PTO mounted pump on the genset engine.

 

[Phil Fill]

Variable psi hydraulic pumps have a vane internal valve that opens closes to vary the psi flow. So it sounds like the actuator that opens closes the valve vane is not working properly. If you c an see the pump there is a nut lever that turns to open close the vane. I don't think its the hydraulic but the actuator controlling the vane valve.

The psi or and flow is dirrctly related to rpm, if the vane valve is open, so if the rpm is constant the same its probably the vane valve actuators for the pump. I installed a nanual push pullcable to control the opening closing of the vane from 0 to 1800 psi. The gen set does not have enough hp to maximize the pump or thruster. Any way I would see if the vane actuator is working properly.