Opinions Regarding PRM120 Gearbox

[Guest]

My Vetus is fitted with a Technodrive box, on which I am not over keen. I have learned from PRM that their 120 box is a direct fit for the Techno. So I wondered if any members had experience of the PRM 120 and would they recommend the purchase of one?

Many thanks

[Big COL]

My Vetus is fitted with a Technodrive box, on which I am not over keen. I have learned from PRM that their 120 box is a direct fit for the Techno. So I wondered if any members had experience of the PRM 120 and would they recommend the purchase of one?

Many thanks

 

Hi Cat

 

PRM, dogs doo dars in my opinion, engineering spot on.

I had a PRM delta box on my first boat and these were considered an economical box never had any trouble whatsoever gear change smooth as you like no thump as the gear engaged.

As a result of using the delta box when it came to specifying the gear box for my new sailaway the only instruction to the builder was the gearbox had to be a PRM.

5 years on from that decision I still think, well I know there is no better .

[mrsmelly]

Hi Cat

 

PRM, dogs doo dars in my opinion, engineering spot on.

I had a PRM delta box on my first boat and these were considered an economical box never had any trouble whatsoever gear change smooth as you like no thump as the gear engaged.

As a result of using the delta box when it came to specifying the gear box for my new sailaway the only instruction to the builder was the gearbox had to be a PRM.

5 years on from that decision I still think, well I know there is no better .

 

Hi

 

I had the 120 on a previous boat it worked fine if a little more clunky than the 150 250 etc etc...it depends what size ur engine/prop boat is ? if u have a seventy footer with a clunk clunk engine swinging a 26 inch prop then the 120 will give up the ghost very quickly. If u have the bog standard 57 footer with a modern sewing machine engine then the 120 will do fine.

[david and julie]

I have a Beta 38 sewing machine and a PRM120 gearbox. Its done about 1200 hours and hasn't given any problems - yet. Definately very clunky though - its been like that since new and hasn't changed one way or the other.

 

Next time I would still have the Beta but would probably go for the PRM150 instead because I'm not keen on the clunks.

[alan_fincher]

I have a Beta 38 sewing machine and a PRM120 gearbox. Its done about 1200 hours and hasn't given any problems - yet. Definately very clunky though - its been like that since new and hasn't changed one way or the other.

 

Next time I would still have the Beta but would probably go for the PRM150 instead because I'm not keen on the clunks.

We have the older Delta box, presumed 13 years old, and it's still very smooth, (on a BMC). None of the paint is broken, so I doubt it's ever been apart.

 

I know there is a considerable cost saving on a 120 versus a 150, but if I was making a point of upgrading for smooth operaion, I think I'd try and find the extra cash for the hydraulic offering.

[David Schweizer]

Well as we are all vying for brownie points, I have a PRM 160 on my boat, it is 27 years old, and has given nearly 21,000 hours service.

 

When the engine was re-built three years ago, I asked for the gearbox to be examined and re-built at the same time if neccessary. The engineer dismantled the box, cleaned all the parts, and declared that everything was in perfect condition, but that he would replace the oil seals as a precaution even though it was not strictly necessary.

 

Now that is a recommendation.

[chris w]

My Vetus is fitted with a Technodrive box, on which I am not over keen. I have learned from PRM that their 120 box is a direct fit for the Techno. So I wondered if any members had experience of the PRM 120 and would they recommend the purchase of one?

Many thanks

I too have the PRM 120 and, as you may probably be aware, it is a mechanical box rather than an hydraulic box. This is why it clunks when you move it into gear. Other than that engagement clunk it makes no noise. I only have 400 hours on mine but it has been trouble-free so far.

 

Chris

[mrsmelly]

Well as we are all vying for brownie points, I have a PRM 160 on my boat, it is 27 years old, and has given nearly 21,000 hours service.

 

When the engine was re-built three years ago, I asked for the gearbox to be examined and re-built at the same time if neccessary. The engineer dismantled the box, cleaned all the parts, and declared that everything was in perfect condition, but that he would replace the oil seals as a precaution even though it was not strictly necessary.

 

Now that is a recommendation.

 

Hi David

 

I would say that the reason ur box has lasted so well for so long is the way u use it, u must be very good and gentle without thrashing it, its a shame more boaters did not boat the same way And totaly off topic a good friend of mine bought a new escort and never had the head off or indeed changed the clutch in over 400 thousand miles !!!

[David Schweizer]

Hi David

 

I would say that the reason ur box has lasted so well for so long is the way u use it, u must be very good and gentle without thrashing it, its a shame more boaters did not boat the same way And totaly off topic a good friend of mine bought a new escort and never had the head off or indeed changed the clutch in over 400 thousand miles !!!

It would be nice to think so, but it actually spent it's first 15 years as a corporate boat and then a hire boat, so it will have had a fair bit of heavy handedness. The people at Newage told me that as long as it has oil in it, it will stand any amount of heavy treatment. Apparently the 160 (now called the 260) was designed to operate in sea going fishing vessels, so a narrowboat is considered to be light duty.

[sociable_hermit]

Mine is a PRM 'box, not sure of the model but it's described as a "PRM Delta" in the engine manual.

 

Boat is 14 years old, gearbox is fine. A little noisy when first engaged, i.e. at very low revs, but not intrusive. Very quiet at normal revs. No oil leaks. I have every confidence of it outliving the hull.

 

They are very solidly engineered and work well.

[Keeping Up]

Mine is a PRM 'box, not sure of the model but it's described as a "PRM Delta" in the engine manual.

 

Boat is 14 years old, gearbox is fine. A little noisy when first engaged, i.e. at very low revs, but not intrusive. Very quiet at normal revs. No oil leaks. I have every confidence of it outliving the hull.

 

They are very solidly engineered and work well.

The Delta is similar to the PRM150 although the latter is an uprated version. When my Delta, which had leaked since new, needed new shaft seals at about 6000 hours it wasn't worth refurbishing it because it was worn out - especially the input shaft, which on the 150 is much chunkier.

 

PRM gearboxes are very good, I now have a PRM 150; I just wish I could have one that didn't leak (preferably accompainied by an engine that didn't leak - or is that wishing for the impossible?)

[Speedwheel]

If I was going to have a modern 'box I wouldn't chose anything other than a PRM.

However for me, nothing can beat a Parsons. I love the noise they make in reverse.

Edited March 28, 2009 by Satellite

[PeterG]

My gearbox is a PRM 120 attached to a Beta 38 and yes it does go clunk when you engage gear which it has done from new, but it just works well.

 

Probably with a bigger engine under rated but with the B38 it seems well suited.

[churchward]

I don't think I have ever been on a boat that has used the mechanical PRM120, I have either used boats with a mechanical Hurth box or a hydraulic PRM. The Hurth's are fine in my experience at least, last well but the PRMs (hydraulic) are quieter and very good. My present boat has a Hurth but should it go west before the engine needs changing (BV1505/B38) I would definitely consider a PRM 150 as a replacement.

Edited March 30, 2009 by churchward

[Smelly]

We've a PRM120 gear box as standard fit on our Isuzu 35, poor engine alignment's menat it was abused for the first few hundred hours use, but it's survived quite happily.

 

I always wonder whether it's wise, considering these smaller boxes are working toward the top of their tolerances, compared to fitting, say a 260 hydraulic jobbie. However in my little corner of existence I couldn't afford one anyway so it's hypothetical, maybe in 7 years or so when the mortgage is paid...