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I believe that the PRM150 can be run either way. The only issue is that the fail safe facility ,where you can lock the gearbox in drive to get you home,only works with a right hand prop(unless you want to get home backwards,of course)I have been using a PRM150 with a left hand prop,for 2,200 hours with no problem.(I converted from Lister to Isuzu)

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I believe that the PRM150 can be run either way. The only issue is that the fail safe facility ,where you can lock the gearbox in drive to get you home,only works with a right hand prop(unless you want to get home backwards,of course)I have been using a PRM150 with a left hand prop,for 2,200 hours with no problem.(I converted from Lister to Isuzu)

Hello, I never knew gearboxes had this get-home facility. Mine is a Hurth 150, does it have this ability, and if so how would I engage it?

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Hello, I never knew gearboxes had this get-home facility. Mine is a Hurth 150, does it have this ability, and if so how would I engage it?

 

Afraid not.

 

Some boxes are deigned to be in forward if something goes wrong. The Lister LH150 does this, the hydraulics pulling it out of forward and engaging reverse

 

Some PRM boxes have this kind of facility - the PRM150 has an Allan key in a pocket behind the oil pump. Some of the bigger boxes have a blade on one of the covers that locks the box in forward when repositioned. On any of theses gearboxes, once you have used the 'get you home', the box needs to be rebuilt

 

Richard

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To add to what Richard said. The "get you home" device/design is only appropriate on hydraulic gearboxes where a hydraulic failure (low oil/pump fault etc.) would jamb the box in neutral so as the Hurth is a mechanical box (like the PRM 80 & 120) it does not need such a device.

 

I am not sure about the TMP hydraulic box but I do not think it has a get you home device and I am sure the Velvetdrives do not.

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And just to point out that the get-you-home facility is intended for sea-going craft where a gearbox failure could have serious consequences and an inability to go into neutral and reverse isn't an issue. Its not much help on the cut, particularly if there are locks between where your gearbox hydraulics fail and home.

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And just to point out that the get-you-home facility is intended for sea-going craft where a gearbox failure could have serious consequences and an inability to go into neutral and reverse isn't an issue. Its not much help on the cut, particularly if there are locks between where your gearbox hydraulics fail and home.

I know what I'd rather do on a canal, use the forward gear get you home device on the gearbox rather than man haul my boat back home or leave it in a dodgy place. Surely its not much of a problem not to have an astern gear and neutral. You simply gauge your stopping distances, cut the engine in time and drift gently into locks arresting the boat forward movement with a turn of a stern rope around a handy bollard if necessary, restart the engine and drive out. Boatmanship all good practice. smile.png

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I know what I'd rather do on a canal, use the forward gear get you home device on the gearbox rather than man haul my boat back home or leave it in a dodgy place. Surely its not much of a problem not to have an astern gear and neutral. You simply gauge your stopping distances, cut the engine in time and drift gently into locks arresting the boat forward movement with a turn of a stern rope around a handy bollard if necessary, restart the engine and drive out. Boatmanship all good practice. smile.png

 

Yup, Got Lutine from Fradley to Great haywood like this when the gear cable came off and I had no tools to get the control off and reattach. Worked fine for the five locks

 

Not so good when I turned the corner onto Rugeley Aqueduct and found a boat mid channel on the aqueduct coming the other way though...

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On the subject of incorrect handed props. When I bought my yoghurt pot it's performance was pathetic (although fitted with a new diesel engine with tiny hours on the clock)

It was obvious to me that it was incorrectly propped. On lifting out I discovered that not only was the prop the wrong size and pitch but was also the wrong hand, The connections in the Morse control had been swapped to compensate. The gearbox was a small Hurth and AFAIK this has a smaller thrust bearing in reverse than forward, fortunately no damage seems to have been caused

 

 

14362623381_5728c90d69_b.jpgimg459 by mudlarker2, on Flickr

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On the subject of incorrect handed props. When I bought my yoghurt pot it's performance was pathetic (although fitted with a new diesel engine with tiny hours on the clock)

It was obvious to me that it was incorrectly propped. On lifting out I discovered that not only was the prop the wrong size and pitch but was also the wrong hand, The connections in the Morse control had been swapped to compensate. The gearbox was a small Hurth and AFAIK this has a smaller thrust bearing in reverse than forward, fortunately no damage seems to have been caused

 

 

Like many gearboxes, it has a different ratio in reverse

 

Richard

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Like many gearboxes, it has a different ratio in reverse

 

Richard

 

Yes ...noticed that as well......knew pitch was wrong, guessed size was wrong but was actually shocked hand was wrong....I mean there are bodges and there are bodges! fancy installing a brand new engine and gearbox and not spending the extra hundred odd quid on a prop....unbelievable

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There should be a plate on the gearbox somewhere. It would be handy to know the model number

Hi it's a prm 150 , nebulae says he has run his prm 150 backward for 2200 hours with no problems so I am guessing I should be ok till I find a 18x14 1 1/2 prop ,thanks

 

Richard

I believe that the PRM150 can be run either way. The only issue is that the fail safe facility ,where you can lock the gearbox in drive to get you home,only works with a right hand prop(unless you want to get home backwards,of course)I have been using a PRM150 with a left hand prop,for 2,200 hours with no problem.(I converted from Lister to Isuzu)

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On the subject of incorrect handed props. When I bought my yoghurt pot it's performance was pathetic (although fitted with a new diesel engine with tiny hours on the clock)

It was obvious to me that it was incorrectly propped. On lifting out I discovered that not only was the prop the wrong size and pitch but was also the wrong hand, The connections in the Morse control had been swapped to compensate. The gearbox was a small Hurth and AFAIK this has a smaller thrust bearing in reverse than forward, fortunately no damage seems to have been caused

 

 

 

Although there may be an issue with the thrust bearing possibly the more serious problem on the mechanical boxes is the lubrication of the extra gear(s) needed to provide reverse. This is far more important on the old boxes using planet gears for reverse but can also be an issue on the more modern boxes with a single idler gear. This is small in comparison to the other gears so will spin fairly fast and only relies upon splash lubrication. Hydraulic boxes tend to use force fed lubrication so the lubrication is more assured.

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