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Hydraulic system pros and cons


OCM

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Nanni hydraulic drive 62hp w hydraulic gearbox and bow thruster

Any information on this would be helpful.

Is it something to avoid? Or would it be better/safer to stay with mechanical/normal diesel?

Thanks

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Makes no sense. A hydraulic gearbox is not a hydraulic drive unless you have hydraulic thrusters or pumps. In my view, hydraulic gearboxes are the more reliable, but there is one hydraulic box maker that is a bit suspect.

 

If it is  a hydraulic bow thruster it is likely to be/cause fewer problems than an electric one.

 

More info or photos would help identify what you have and make better comments.

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There were a number of discussions one here (?) and an article in WW.  AFAIR the conclusion was that the system at that time was not very reliable AND very expensive. IM untutored O hydraulics are great if the motors need to be remote from the power source and connected via a flexible hose (ie cranes, some agricultural devices). In a boat there's norrra lot that move (the main drive shaft is fixed as is a bow thruster.

It's difficult enough finding mechanics who can fix conventional boat engines / drive - let alone anything hydraulic.....

 

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1 hour ago, OCM said:

Nanni hydraulic drive 62hp w hydraulic gearbox and bow thruster

Any information on this would be helpful.

Is it something to avoid? Or would it be better/safer to stay with mechanical/normal diesel?

Thanks

I think confusion is arising from your use of the term “hydraulic gearbox”. Many conventional gearboxes are hydraulic - this means that oil pressure is used to select the gear. I suspect you mean hydraulic drive rather than hydraulic gearbox? This would comprise a hydraulic pump on the engine and a hydraulic motor on the prop shaft.

 

As has been mentioned, hydraulic drive adds complexity and inefficiency. There is only any point if eg you want to put the engine somewhere where direct drive wouldn’t be feasible. Also the hydraulic drive systems I’ve come across often seem to have an annoying whine which is much more irritating than a conventional Diesel engine noise.

 

Hydraulic bowthrusters are better than electrical ones, but then for any normal narrowboat a bowthruster isn’t necessary.

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1 hour ago, Tony Brooks said:

 

If it is  a hydraulic bow thruster it is likely to be/cause fewer problems than an electric one.

 

 

I'm not sure why that would be? I've personally seen problems with hydraulic bow thrusters and also electric ones of course. But since there are more electric BTs on the inland waterways then we would expect to see more issues with them. The point is unless they are correctly installed, and just as importantly correctly used, problems can occur with both.

18 minutes ago, nicknorman said:

 

Hydraulic bowthrusters are better than electrical ones, but then for any normal narrowboat a bowthruster isn’t necessary.

 

Better because you can keep your finger on the button for longer? But then one isn't supposed to do that anyway...

 

As long as an electric bow thruster isn't overused then I'd say it's as good as a hydraulic unit.

 

Edit: I once steered a 72 x 13ft barge with a hydraulic BT and to get the thing to work you had to rev the engine to get enough pressure in the hydraulic system. Going into neutral and revving the engine is the last thing you want to be doing when maneuvering. At least with an electric BT it's largely independent of engine revs. 

Edited by blackrose
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13 minutes ago, nicknorman said:

Also the hydraulic drive systems I’ve come across often seem to have an annoying whine which is much more irritating than a conventional Diesel engine noise.

 

 

 

Increasingly, I hear the same from a small subsection of boaters, when discussing the shortcomings of CRT.

 

 

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@ditchcrawler has had hydraulic drive for a few years now so could be well positioned to post pros and cons.

My only thought on hydraulic bow thrusters is that they need the pump to be running hard when in use which is not what you need when trying to manoeuvre in tight spaces using the prop as well which needs to be running slowly.😱

Edited by Loddon
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10 minutes ago, blackrose said:

[snip]

 

Edit: I once steered a 72 x 13ft barge with a hydraulic BT and to get the thing to work you had to rev the engine to get enough pressure in the hydraulic system. Going into neutral and revving the engine is the last thing you want to be doing when maneuvering. At least with an electric BT it's largely independent of engine revs. 

 

Exactly my experience with the 57' x 10' widebeam I hired this year which had a hydraulic bow thruster. Not impressed. And as for the wheel steering... 😞

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Have had two ARS systems on different boats. One whined although not overly itimidating and did not distract from the 3LW, but there nonetheless. The other was quieter, more of a subdued hum that was drowned out by the JD3. Yes, thrusters can be used for longer but not a deal-breaker at all. A benefit of the hydraulic thruster is being less prone to blocking due to the screw being narrow as opposed to a propeller (guards can only prevent so much getting through), at least with the ARS version (made by Parker hydraulics IIRC). On the downside, you have very long, high-pressure hoses (20,000 psi?) which could burst and make one hell of a mess thoughout your boat so future servicing/inspection should be a criteria when making a decision. The main benefit of a hydraulically driven prop is that the engine can be sited anywhere as no need for a propshaft. This also provides for greater headrooom in any cabin aft of the engine.

 

Overall I liked the hydraulic drive due to the full headroom in the engine room and boatmans cabin. But now, I like the simplicity of a PRM gearbox hanging off the end of my 2LW.

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There at least a couple of members on here that have hydraulic drive boats.  I had one and like everything there are pros and cons.  

 

When I first got the boat there was no information with it on how to maintain/repair the system, so I ran Peachments (I think) who installed it.  Simply, the guy explained that these drives are designed for hard working commercial craft so in a leisure boat are usually effectively maintenance free.  He said to just keep an eye on the reservoir level, but the indicator on the filter would probably never get to the stage where it needed changing.   The boat also had a PSS stern gland, so virtually maintenance free transmission.

 

I wouldn't be at all concerned about these horror stories of pipes fracturing etc.

 

The other big advantage is you have a free hand where to put the engine, but on some of the other boats I've looked at this created as many problems as it solved.  One, for example had the engine right up in the bow compartment which obviously made it very quiet for the steerer, but because of the restricted room it looked like an absolute nightmare to maintain, I couldn't even see the fuel filter let alone get at it..

 

The whining noise from the pump/motor can be really annoying, depending on how you react to noise.  

 

My main concern would be the power losses involved.  When you research this you get all sorts of estimates and some say you can lose up to 30% compared to conventional shaft drive.  So I would only consider it on a narrowboat if the engine was plenty big enough.   

 

 

 

 

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They're a bit specialist hydraulic drives. Sometimes seen on motorised butty's where fitting a conventional stern tube etc is awkward, sometimes seen with front engined boats, e.g. engine under a tug front deck with hydraulic motor at the back and sometimes seen on boats with transverse engines or engines mounted to one side. All these are compelling reasons to fit hydraulic drive but apart from that a straightforward engine and gearbox makes more sense. Hydraulic bow thruster? no idea.

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51 minutes ago, Neil2 said:

There at least a couple of members on here that have hydraulic drive boats. 

. . . 

My main concern would be the power losses involved.  When you research this you get all sorts of estimates and some say you can lose up to 30% compared to conventional shaft drive.  

I’m one of the members here with an ARS hydraulic drive fitted to a butty.  See https://www.buttyhampton.com/undercloth-conversion-2005

 

Pros:

Pretty well maintenance free.  I just change the oil about once every five years.

I've  renewed all the hoses after about ten years – merely as a precaution.

ARS provide excellent service and will design a system for you that matches your engine.  There are also specialist engineers around who will come out to your boat.

Very simple to fit to a bog standard engine like my 1.8 BMC. 

Can be fitted anywhere on the boat where it’s convenient.  Very useful if there’s low headroom in the back cabin because of a conventional prop shaft running under the floor.

 

Cons:

A bit of a whine.  Not really a problem.

Expensive when things do go wrong.  I had a log trapped in the propellor and for some reason the safety valve didn’t actuate.  Blown oil seals resulted in rebuild.

 

I am told that they are efficient, but I’ve never been able to verify this.  There's certainly no lack of power on our 70' boat.

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Thanks looking at 62bhp on 59’ boat

1 hour ago, Neil2 said:

There at least a couple of members on here that have hydraulic drive boats.  I had one and like everything there are pros and cons.  

 

When I first got the boat there was no information with it on how to maintain/repair the system, so I ran Peachments (I think) who installed it.  Simply, the guy explained that these drives are designed for hard working commercial craft so in a leisure boat are usually effectively maintenance free.  He said to just keep an eye on the reservoir level, but the indicator on the filter would probably never get to the stage where it needed changing.   The boat also had a PSS stern gland, so virtually maintenance free transmission.

 

I wouldn't be at all concerned about these horror stories of pipes fracturing etc.

 

The other big advantage is you have a free hand where to put the engine, but on some of the other boats I've looked at this created as many problems as it solved.  One, for example had the engine right up in the bow compartment which obviously made it very quiet for the steerer, but because of the restricted room it looked like an absolute nightmare to maintain, I couldn't even see the fuel filter let alone get at it..

 

The whining noise from the pump/motor can be really annoying, depending on how you react to noise.  

 

My main concern would be the power losses involved.  When you research this you get all sorts of estimates and some say you can lose up to 30% compared to conventional shaft drive.  So I would only consider it on a narrowboat if the engine was plenty big enough.   

 

Thanks that’s reassuring 

 

 

 

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13 minutes ago, OCM said:

Thanks looking at 62bhp on 59’ boat

 

 

I would have thought that would be ample even taking into account the possible power losses.

 

I would certainly want to have a proper "sea trial" before buying another hydraulic boat, you need to get the engine under load in order to be able hear the whine, and remember you have to listen to it for hours on end.  

 

One other thing is I suspect such boats are going to be slightly lower in value just because they are different.  So a good thing when buying, a bad thing when selling.  

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1 hour ago, koukouvagia said:

I’m one of the members here with an ARS hydraulic drive fitted to a butty.  See https://www.buttyhampton.com/undercloth-conversion-2005

 

Pros:

Pretty well maintenance free.  I just change the oil about once every five years.

I've  renewed all the hoses after about ten years – merely as a precaution.

ARS provide excellent service and will design a system for you that matches your engine.  There are also specialist engineers around who will come out to your boat.

Very simple to fit to a bog standard engine like my 1.8 BMC. 

Can be fitted anywhere on the boat where it’s convenient.  Very useful if there’s low headroom in the back cabin because of a conventional prop shaft running under the floor.

 

Cons:

A bit of a whine.  Not really a problem.

Expensive when things do go wrong.  I had a log trapped in the propellor and for some reason the safety valve didn’t actuate.  Blown oil seals resulted in rebuild.

 

I am told that they are efficient, but I’ve never been able to verify this.  There's certainly no lack of power on our 70' boat.

 

That's really interesting.  

 

The motor being submerged would help with the whining noise, IIRC most of it comes from the motor..?

 

I would have though Hampton was a lot more efficient through the water than a modern narrowboat, so you would have no issue with power, and I do like the idea of having a "big outboard" on a narrowboat, it must be a lot of fun!   

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37 minutes ago, robtheplod said:

Hydraulic bow thrusters don't have the limitation on usage like electric ones.... great if like me you're cr@p at steering!

The newer electric ones like the Vetus Pro can run non-stop for 10 minutes, which I'd have thought was sufficient even for you 😉

 

They're more expensive than cheap electric ones but still cheaper than hydraulic ones, and work with the engine at tickover...

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7 hours ago, IanD said:

 

Exactly my experience with the 57' x 10' widebeam I hired this year which had a hydraulic bow thruster. Not impressed. And as for the wheel steering... 😞

Wheeled steering is easy after a while, real plus you can go to toilet and put kettle on and it goes in a straight line whilst doing it!¬ Shame about those rowers though 😔

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4 hours ago, robtheplod said:

Hydraulic bow thrusters don't have the limitation on usage like electric ones.... great if like me you're cr@p at steering!

You would be even worse if you tried to use a bow thrust for steering..They are not intended to be used as a steering substitute, getting progressively more ineffective the faster you go and virtually useless around 2 mph or so. They are really there to provide a push to get out of a tricky situation if required.

 

Howard

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I had a fun conversation this year with the owner of this boat. The engine (air cooled, Lister I think) is in the bow locker (lid open for added cooling ...) and drives the prop via a hydraulic pump. The owner said it worked very well, and was quiet (at the stern!)
 

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19 hours ago, robtheplod said:

Hydraulic bow thrusters don't have the limitation on usage like electric ones.... great if like me you're cr@p at steering!

 

But your steering won't improve if you keep using the BT.

 

I had been boating 41 years before I got a boat with a BT.

 

It is currently not working again, and unless it is a cheap fix will stay that way.

 

That said it does come in very useful for long reverses.

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