Drive Plate Routine Replacement

[beerbeerbeerbeerbeer]

Tony,

Out of curiosity, and should the day come when I need a new gear box,

Is a PRM 150 gear box a straight swop for a Delta 20?

 

It looks as though refurbished Delta 20’s are hard to come by now.

And I understand the 150 is an updated version of the Delta 20

So is it designed so one can simply unhook the old and replace with the new?

 

(last question honest, I’ve a bottle to drink 👍)

Edited January 2, 2023 by Goliath

[Tony Brooks]

3 minutes ago, Goliath said:

Tony,

Out of curiosity, and should the day come when I need a new gear box,

Is a PRM 150 gear box a straight swop for a Delta 20?

 

It looks as though refurbished Delta 20’s are hard to come by now.

And I understand the 150 is an updated version of the Delta 20

So is it designed so one can simply unhook the old and replace with the new?

 

No idea, you do know it must be about 50 years ago when I practically dealt with PRM boxes.  I think Tracy can probably answer that, plus a few other regulars. If all else fails ask PRM

[enigmatic]

On 01/01/2023 at 18:34, Wanderer Vagabond said:

I'm probably tempting fate here by commenting, but as an example on my boat we got it at 1100 hours on the meter and have now run it up to 9,200 hours without a whimper from the drive plate. It is regularly serviced (by me) and the gearbox oil changed every year (not sure if that has any relevance) but I'm of the mindset of 'if it ain't broke, etc'.

 

For those who have had drive plate failure, does it just go 'clunk' and the boat doesn't go any more? (a bit like a clutch plate on a car) or do you get a bit of warning to be able to get somewhere to get it fixed?

From personal experience, the warning is when you get a rope/coat/tarp wrapped round your prop the week before that does the majority of the damage. Apparently sometimes it makes a lot of noise when it's almost completely wrecked and about to fail, but with mine it didn't. 

 

And when it fails properly, you might be getting some rotation in the correct direction from the prop at high revs, but not enough to properly move the boat

 

Most recently, I noticed because I was on the River Thames, and whilst my engine was running smoothly enough, I was going backwards  

[beerbeerbeerbeerbeer]

19 minutes ago, Tony Brooks said:

 

No idea, you do know it must be about 50 years ago when I practically dealt with PRM boxes.  I think Tracy can probably answer that, plus a few other regulars. If all else fails ask PRM

Yes , I was gonna email them, 

thanks

[Wanderer Vagabond]

40 minutes ago, enigmatic said:

From personal experience, the warning is when you get a rope/coat/tarp wrapped round your prop the week before that does the majority of the damage. Apparently sometimes it makes a lot of noise when it's almost completely wrecked and about to fail, but with mine it didn't. 

 

And when it fails properly, you might be getting some rotation in the correct direction from the prop at high revs, but not enough to properly move the boat

 

Most recently, I noticed because I was on the River Thames, and whilst my engine was running smoothly enough, I was going backwards  

We travel the BCN quite a lot so I'm kind of used to stuff round the prop, and can usually react quick enough to knock it into neutral before any real harm is done. I did think I'd probably stuffed the drive plate when I trapped a log between the prop and skeg going into Gorsty Tunnel and stopped the engine dead. That was however five years ago now and we still seem to be trundling along.

[Tony Brooks]

On 01/01/2023 at 18:34, Wanderer Vagabond said:

For those who have had drive plate failure, does it just go 'clunk' and the boat doesn't go any more? (a bit like a clutch plate on a car) or do you get a bit of warning to be able to get somewhere to get it fixed?

 

To a degree that depends upon the type of drive plate. They will all start to chatter at idle in neutral but go quieter as they go into gear and are revved up.

 

The all metal ones tend to make the most noise because it runs metal to metal and eventually bits will fall off so the flywheel bounces them about - just before total failure.

 

The rubber bush ones are likely to be the quietest but if the bushed disintegrate you are back to metal on metal. The plastic web ones probably fall some way in between but in the early stages you may get more of a clonk when going into gear.

 

The latter types will probably drive for longer once they get noisy.

 

I advise physically checking every so often specifically because the more modern plates tend to make much less noise and some may still drive with broken plastic or rubbe rparts.

 

 

[cuthound]

On 01/01/2023 at 18:34, Wanderer Vagabond said:

For those who have had drive plate failure, does it just go 'clunk' and the boat doesn't go any more? (a bit like a clutch plate on a car) or do you get a bit of warning to be able to get somewhere to get it fixed?

 

I was on my second shareboat when the drive plate failed. It had done over 10,000 hours.

 

Usually they start to get noisy, making clunking sounds on gear engagement, but this one made a tinkling sound as soon as I picked the boat up

 

When the gearbox was removed, two of the nuts were being circulated around the bell housing, having been torn from the driveplate. The boat was still moveable, but I don't know how long it had been making the sound. Some of the other co-owners had less mechanical sympathy than me.

Edited January 3, 2023 by cuthound
Spillung

[Tracy D'arth]

14 hours ago, Goliath said:

Yes , I was gonna email them, 

thanks

The PRM150D is the recommended Delta 20 replacement but it is not dimensionally a direct swap.

[beerbeerbeerbeerbeer]

6 hours ago, Tracy D'arth said:

The PRM150D is the recommended Delta 20 replacement but it is not dimensionally a direct swap.

I’ve sent off an email asking.  
 

👍