Disappointment after buying a narrow boat

[Till Hoffmann]

 

I doubt it. I repair gearboxes for a living, unsticking those cones is a challenge.

 

This sudden failure of a PRM120 is very typical. When the end comes, they either stick in gear or slip because all the lining falls off. You get no warning of either of these beforehand

 

Richard

 

Ah, right, that shows my ignorance of the matter.

[bizzard]

Entering a lock? There's the possibility that the transmission was damaged whilst doing that, if the prop clouted something really sold, like a log floating about in the lock entry, but I'm sure the OP would have mentioned it if it had happened. A novice may not be fully aware of floating rubbish that can hang around at lock top and bottom gates. Its wise to coast in neutral in and out of locks if there's rubbish about for this reason, with a keen eye on the look out for it.

[MtB]

 

Ah, right, that shows my ignorance of the matter.

 

 

Keep reading and keep asking questions. This will change rapidly!

[RLWP]

 

Ah, right, that shows my ignorance of the matter.

 

Nothing to be ashamed of, Tim.

 

Just to echo what others have said. The driveplate was probably like that for ages, and has a lot of life left in it. I would still replace it if I was replacing the gearbox because it keeps the labour costs down. The PRM120 gearbox will fail suddenly and catastrophically.

 

Your surveyor would not be able to spot either of these in a normal survey

 

Richard

[David Schweizer]

 

Ah, right, that shows my ignorance of the matter.

 

Not at all Till. Driveplates have a tendancy to suddenly give up with very little prior warning. I had an almost new one fail after only a few months work, and that had been fitted by a very well respected person. He came out immediately with a new one which he fitted under warranty, and six years later it is still fine (he said with fingers crossed!)

 

The gearbox is a different issue and the PRM 120 is a box I have no experience of. Our boat has the massive PRM 260 in it, and they have a reputation of going on for ever.The one in our boat is 35 years old, and when it was stripped down during the engine re-build six years ago, there was no wear in any of the components.

Edited July 12, 2016 by David Schweizer

[gazza]

Point of order Dave...

 

I think that's not the only function of the drive plate, or even the main one.

 

As an engine rotates, its angular velocity varies as it progresses though the 720 degrees of rotation comprising the full cycle of a four stroke engine. Each combustion event speeds up the flywheel, and each compression stroke slows it down. This all happens very rapidly but the effect becomes more pronounced at low engine speeds and tickover.

 

The principle of inertia means the gearbox, shaft and blade attempt to rotate at a constant speed. However, the engine would be constantly trying to speed them up and slow them down if rigidly coupled to the flywheel. The drive plate is elastic to smooth out these rapid changes in angular veloctity of the engine flywheel, to save rapid and constant reversing of stress on the gearbox gears and drive train components that would otherwise result, I suggest.

 

This is the reason they now fit dual mass flywheels to many car engines too, I suspect. (Although Dave - DMR may know otherwise!)

 

 

DMF's are fitted to reduce NVH. amongst other reasons, that and to increase the cost of clutch replacement.......

https://www.valeoservice.co.uk/en/dual-mass-flywheels-dmf

 

our gearbox is coming off this winter to aid keel bolt replacment, it will give me a chance to see how our 5 year old 800+ hour R&D drive plate is looking

Edited July 12, 2016 by gazza

[Laurie Booth]

They even do one where you pay £150 plus parts and show you how to service your own boat. A wise investment if you are not sure what to do.

 

 

 

Well worth the money.

[MtB]

 

 

DMF's are fitted to reduce NVH. amongst other reasons, that and to increase the cost of clutch replacement.......

https://www.valeoservice.co.uk/en/dual-mass-flywheels-dmf

 

our gearbox is coming off this winter to aid keel bolt replacment, it will give me a chance to see how our 5 year old 800+ hour R&D drive plate is looking

 

 

What does NVH mean? A brief google and I can only find the acronym widely used, but never explained!

[gazza]

 

 

What does NVH mean? A brief google and I can only find the acronym widely used, but never explained!

Noise, Vibration & Harshness.

 

Improvements in which mean a Vauxhall Corsa no longer feels like it's going to shake itself apart at 90 mph

[MtB]

Noise, Vibration & Harshness.

 

Improvements in which mean a Vauxhall Corsa no longer feels like it's going to shake itself apart at 90 mph

 

Ah I see, thanks.

 

NVH is probably another manfestation of the effects of the variations in angular velocity of the flywheel I described earlier, given a DMF fixes it.

[gazza]

 

Ah I see, thanks.

 

NVH is probably another manfestation of the effects of the variations in angular velocity of the flywheel I described earlier, given a DMF fixes it.

 

Yes, but the DMF masks it rather than fixing it - we used to put up with notchy gear changes and buzzy clutch pedals and only slight rip off garage prices.

 

not any longer, cars can be driven by weaklings and bills are now stratospheric for a clutch change.

Several fit old style (so called Single Mass) flywheels in a bid to reduce costs, some reports of gearboxes going pop with a SMF though.

 

What has been a revelation for me is the 'box in the Alfa, the 140/180 bhp Multi Air only comes with what Alfa call a TCT box, its a dry multi clutch sequential box, flappy paddles, 3 different engine maps, choice of auto, paddles or sequential stick shift. Changes in 8 m/s - awesome bit of kit, no aching left leg in traffic. Cant believe i would enjoy a car without a h pattern box, its the future!!

[dmr]

Point of order Dave...

 

I think that's not the only function of the drive plate, or even the main one.

 

As an engine rotates, its angular velocity varies as it progresses though the 720 degrees of rotation comprising the full cycle of a four stroke engine. Each combustion event speeds up the flywheel, and each compression stroke slows it down. This all happens very rapidly but the effect becomes more pronounced at low engine speeds and tickover.

 

The principle of inertia means the gearbox, shaft and blade attempt to rotate at a constant speed. However, the engine would be constantly trying to speed them up and slow them down if rigidly coupled to the flywheel. The drive plate is elastic to smooth out these rapid changes in angular veloctity of the engine flywheel, to save rapid and constant reversing of stress on the gearbox gears and drive train components that would otherwise result, I suggest.

 

This is the reason they now fit dual mass flywheels to many car engines too, I suspect. (Although Dave - DMR may know otherwise!)

 

If I remember my history right, the desire for better fuel consumption lead to slower tickover speeds and thinner oils in the gearbox so the speed fluctuations caused gear rattle (the meshed gears separating then impacting back together) and so the twin mass flywheel was seen as the solution. It actually created a whole load of new problems but that another story, however it did create a lot of lucrative work for me!

NVH is Noise Vibration and Harshness.

I have measured the instantaneous flywheel velocity on our JD3 which shows why a flexible driveplate is required. Might post it later but are currently in Liverpool so more exciting to be doing just now.

 

..............Dave

[alan_fincher]

@alan_fincher, yes, we have asked the RCR to replace the gear box and the drive plate. They are charging us 460 for the refurbished box but I don't know what their definition of refurbished is.

 

Well you could ask them what "refurbished" means I guess.

 

If the box is in good order, that doesn't sound too bad.

 

Do you get any guarantee on it?

[Joe the plumber]

Did the brokerage own the boat outright or was it for sale with them on behalf of a customer? If it was theirs, you should have the Sale of Goods Act to cover you if you want to grumble to them, but if it was just on brokerage (ie like a house with an estate agent), there's little come back.

 

Looking on the bright side, you're about to have a good gearbox and a new driveplate fitted which should keep you going for a long time.

 

Incidentally, if you want a brand new gearbox, Calcutt Boats sell them:

 

http://www.calcuttboats.com/gearbox.html

[Machpoint005]

 

Ah I see, thanks.

 

NVH is probably another manifestation of the effects of the variations in angular velocity of the flywheel I described earlier, given a DMF fixes it.

 

Not to mention the huge out-of-balance forces when pistons thump up and down hundreds of times a second?

And light stuff that isn't glued down rattles about?

 

>>. Cant believe i would enjoy a car without a h pattern box, its the future!!<<

 

Same here -- three years with a VAG DSG box, I wouldn't willingly go back to a handraulic clutch (OK, footdraulic) when the car can be in the right gear before I've even decided which gear I need!

[Chewbacka]

 

Not to mention the huge out-of-balance forces when pistons thump up and down hundreds of times a second?

.......................

Some engines also have a balancer shaft to reduce those vibrations.

[gazza]

Some engines also have a balancer shaft to reduce those vibrations.

Power sapping nasty things. Again, they are a mask for not having the right engine layout, all things being equal we should be driving v12's

 

Inline motors you'd be hard pushed to beat a six for creamy smooth power delivery.

[gazza]

 

Not to mention the huge out-of-balance forces when pistons thump up and down hundreds of times a second?

 

And light stuff that isn't glued down rattles about?

 

 

Same here -- three years with a VAG DSG box, I wouldn't willingly go back to a handraulic clutch (OK, footdraulic) when the car can be in the right gear before I've even decided which gear I need!

I've driven both variants of the VAG box, mated to both petrol and diesel, they matched the cars well, haven't driven one in a VRS though.

Having lived with the Alfa for nearly two years I'm a convert, there is no way you can get as much out of the car with a manual box.

I tend to drive it in Dynamic (sport) manual using a combination of paddles and the gear lever, no missed gears, no lifting between changes, it's bloody ace!

 

When not driving like my hair's on fire or in town I stick it in Natural (normal) auto and let it do its thing with no input from me.

 

They have come a long long way from the slush boxes of old

Edited July 12, 2016 by gazza

[Bobbybass]

In my experience..(and this is only mjine)...nobody ever seems to agree on blacking.

 

Each time I have had a boat surveyed....or out of the water...boat yards....and surveyors talk of 'dodgy blacking'.

Whether this is to encourage you to pay them to reblack I don't know.?

 

I blacked mine once...3 coats of Comastic..nice and thick...but a year later....the combination of diesel in the water...diluted by by marina neighbour's frequent use of Fairy liquid for his washing up..had stripped large part of one sde of the hull.

 

As for drive plates...I replaced one......on a Beta 43 that was linked to a PRM150.

I had to take the old plate to Beta in Gloucester..for them to identify (Adrian)...as there was no 'official' drive plate for my boat...with that engine/box combination.

The one that Adrian supplied had to had the lugs cut off with a hacksaw to make it fit...which (apparently) was the standard way that Beta made it fit. Adrian cut it off for me.

Don't forget that many canal boat engines are 'adapted' units that are more commonly found in plant....so cobbling them to a marine gearbox is not what they were intended for.

 

I would think that there are many boats with no 'official' drive plate...as so many are put together based on the builders preference.

 

I would 'guess' that

[Chewbacka]

In my experience..(and this is only mjine)...nobody ever seems to agree on blacking.

 

Each time I have had a boat surveyed....or out of the water...boat yards....and surveyors talk of 'dodgy blacking'.

Whether this is to encourage you to pay them to reblack I don't know.?

 

I blacked mine once...3 coats of Comastic..nice and thick...but a year later....the combination of diesel in the water...diluted by by marina neighbour's frequent use of Fairy liquid for his washing up..had stripped large part of one sde of the hull.

 

As for drive plates...I replaced one......on a Beta 43 that was linked to a PRM150.

I had to take the old plate to Beta in Gloucester..for them to identify (Adrian)...as there was no 'official' drive plate for my boat...with that engine/box combination.

The one that Adrian supplied had to had the lugs cut off with a hacksaw to make it fit...which (apparently) was the standard way that Beta made it fit. Adrian cut it off for me.

Don't forget that many canal boat engines are 'adapted' units that are more commonly found in plant....so cobbling them to a marine gearbox is not what they were intended for.

 

I would think that there are many boats with no 'official' drive plate...as so many are put together based on the builders preference.

 

I would 'guess' that

I would have thought a Beta43 linked to a PRM150 is fairly common. Surprised Beta don't have a drive plate 'on the shelf'.

[RLWP]

I would have thought a Beta43 linked to a PRM150 is fairly common. Surprised Beta don't have a drive plate 'on the shelf'.

 

Or just about any chandlers

 

Richard

[nebulae]

Not an expert on marine gearboxes,but I was advised to go for a PRM 150 when re engining the boat ,It is the smallest hydraulic box from PRM. The 120 is a mechanical box .Have had a lot of problems with gearboxes in previous boats so took the advice, Have given it some welly for ten years,so far so good. If I manage to total it,it will get replaced with a new unit.