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This is the coupling that's causing me grief. The only way to get the thing off was to cut of a couple of the bolts holding it in place (Lister SR2), one at each end. As far as I can tell, it's been put back without replacing the missing bolts. I was hoping to have got it replaced (as it was chopped about a bit while getting at the bolts) but the boatyard seem incapable of doing it, so my first concern is replacing the bolts that are missing.

Is it likely to be possible to do this with the thing in place or will I need to dismantle it a bit first? Alternatively, as there at least four and possibly five bolts in place at each end, does it matter much if one is missing?

And while I'm here, any ideas as to how many hours work it would be for a boatyard to take it off, replace it wit a new one, possibly also replacing the propshaft?

post-14319-0-14820900-1486228668_thumb.jpg

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This looks very like an industrial Fenner or Renold drive coupling.

If you can furnish some dimensions, ie coupling outside diameter , overall length of the coupling, prop shaft diameter as well as some close up pictures of the connection to the prop shaft I will look for you.

When I had a Lister gearbox, with the drop box, I used the standard Cetraflex coupling to connect to the prop shaft.

This required a bit of modification to the drive flange on the gearbox, I may still have details of this but it was not difficult - if needed I can machine parts for you.

I no longer have the Lister setup but still have this coupling on my PRM 150, so can give you the lengths/diameters and pictures.

You should be able to fit this without removing the prop shaft, just ease the gland packing a bit and move the shaft into the bearing, then slide back into the new coupling ( assuming all dimensions are OK and you can get the old coupling off the gearbox).

The Centraflex uses a taper clamping onto the shaft.

PM me if you want to discuss etc

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If that half coupling on the reduction box is the standard Lister 6 bolt one which it looks like, and the one the propshaft ''which we can't see'' is the same then, I think I've mentioned it before, that the Ford Granada propshaft rubber doughnut couplings fit perfectly at a fraction of the cost of marine couplings. You couple them alternately 3 and 3, 3 bolts towards the gearbox and nutted and 3 bolts facing the other way nutted on the propshaft side. using appropriate spacer washers to give clearance for the bit of fore and aft thrust movement. You might need two of them bolted through together to get the the thickness of what you already have unless you are having a new shaft fitted which can be cut to length to fit just the one doughnut. You would need long shank high tensile bolts, nuts, plus a load of washers.

I fitted one to my Lister ST2 in 2004 and its been excellent and absolutely trouble free. I fitted another to another old boat here with a Lister SR2, also a sound job. They were £12 odd each when I bought them, probably £15 or £20 each now.

QH part No is QL9000.


If that half coupling on the reduction box is the standard Lister 6 bolt one which it looks like, and the one the propshaft ''which we can't see'' is the same then, I think I've mentioned it before, that the Ford Granada propshaft rubber doughnut couplings fit perfectly at a fraction of the cost of marine couplings. You couple them alternately 3 and 3, 3 bolts towards the gearbox and nutted and 3 bolts facing the other way nutted on the propshaft side. using appropriate spacer washers to give clearance for the bit of fore and aft thrust movement. You might need two of them bolted through together to get the the thickness of what you already have unless you are having a new shaft fitted which can be cut to length to fit just the one doughnut. You would need long shank high tensile bolts, nuts, plus a load of washers.

I fitted one to my Lister ST2 in 2004 and its been excellent and absolutely trouble free. I fitted another to another old boat here with a Lister SR2, also a sound job. They were £12 odd each when I bought them, probably £15 or £20 each now.

QH part No is QL9000.

If your interested I can take a close up photo of the arrangement and stick it on here.

  • Greenie 1
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If that half coupling on the reduction box is the standard Lister 6 bolt one which it looks like, and the one the propshaft ''which we can't see'' is the same then, I think I've mentioned it before, that the Ford Granada propshaft rubber doughnut couplings fit perfectly at a fraction of the cost of marine couplings. You couple them alternately 3 and 3, 3 bolts towards the gearbox and nutted and 3 bolts facing the other way nutted on the propshaft side. using appropriate spacer washers to give clearance for the bit of fore and aft thrust movement. You might need two of them bolted through together to get the the thickness of what you already have unless you are having a new shaft fitted which can be cut to length to fit just the one doughnut. You would need long shank high tensile bolts, nuts, plus a load of washers.

I fitted one to my Lister ST2 in 2004 and its been excellent and absolutely trouble free. I fitted another to another old boat here with a Lister SR2, also a sound job. They were £12 odd each when I bought them, probably £15 or £20 each now.

QH part No is QL9000.

If your interested I can take a close up photo of the arrangement and stick it on here.

 

 

They appear to be discontinued but there's one on ebay at the moment.

 

s-l1600.jpg

 

 

http://www.ebay.co.uk/itm/Flexible-Drive-Coupling-QL9000-Brand-New-QH-Ford-Granada-Sierra-Transit/252316829673?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140107083358%26meid%3Dc74e296c49c24f759e859d0dd3bdfe9c%26pid%3D100011%26rk%3D1%26rkt%3D6%26sd%3D272304163912

Something similar but possibly a bit smaller used to be fitted to Triumph Sptifire and Lotus Elan driveshafts.

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The early original Fenner coupling that Lister included in a complete engine, gearbox, stern gear, propeller, exhaust, electrics installation package that boat builders like Harborough Marine and others fitted was like a hefty wheel barrow tyre with its beads sandwiched clamped between grooved plates which bolted on between the gearbox half coupling and the shaft half coupling. They were quite simple and brilliant, still a few around on old boats.

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I've got a Fenner on our boat, its actually a Fennerflex (Fennaflex?), they are good things and as far as I know are still available. I don't think it would work on your installation though as they don't like thrust, in reverse they will pull the tyre beads out of the clamping rings and going forward the tyre squeezes and its not good for it, smell of hot rubber and things.

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I've got a Fenner on our boat, its actually a Fennerflex (Fennaflex?), they are good things and as far as I know are still available. I don't think it would work on your installation though as they don't like thrust, in reverse they will pull the tyre beads out of the clamping rings and going forward the tyre squeezes and its not good for it, smell of hot rubber and things.

I fitted one on my drive, they wont take any forward thrust, you need a thrust bearing for that

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I fitted one on my drive, they wont take any forward thrust, you need a thrust bearing for that

Yes, I forgot, a Dodge Fenner thrust plummer block would have been included in the package too, although I've seen one old Harborough boat without which seemed to get away without one, albeit it only had the 13hp Lister SR2.

Edited by bizzard
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That's the kiddie. I don't remember Triumph Spitfires having them, like Heralds they just had single Hardy Spicer joints. Hillman Limps had them as well as the Elan which had 4, 2 each side but both smaller. The Elans got through them at quite a rate, them along with Ford Cortina Mk3, 4 and 5 rear suspension void bushes paid for my garage rent, food bill for the week with a slap up Sunday roast.

Edited by bizzard
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I assume the Lister is solid mounted?, if you are having a new shaft, why not have A. a R&D isolating coupling or B. just a standard 1/2 coupling and have the engine aligned to suit.

Mostly because I don't know what I'm talking about! I am relying on the boatyard (or a different boatyard, as the case may be) havign the expertise to advise me what it the easies thing or them to fit. I have a vague memory (all my memories are getting vaguer) of someone mentioning an R&D coupling before - can you give a link? The alternative seems to be a standard Centraflex with an attachment to fit it from metric to the imperial of the Lister doofer, which Adrianh has described above.

PS it is solid mounted.

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To be honest, on the solid mounted Listers a flexible coupling is only there to suppress transmitted noise a little although I prefer one more for in case the propeller receives a serious hefty clout, it will absorb some of the sudden shock, and hopefully nothing busts. Otherwise align and couple direct half coupling to half coupling, most sea boats would be done like it.

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To be honest, on the solid mounted Listers a flexible coupling is only there to suppress transmitted noise a little although I prefer one more for in case the propeller receives a serious hefty clout, it will absorb some of the sudden shock, and hopefully nothing busts. Otherwise align and couple direct half coupling to half coupling, most sea boats would be done like it.

I'd assumed that it was there to protect the gearbox from a jammed prop and to even out any slight misalignment.

What do you think about running it with a bolt missing at each end? Is this likely to cause problems or not?

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I'd assumed that it was there to protect the gearbox from a jammed prop and to even out any slight misalignment.

What do you think about running it with a bolt missing at each end? Is this likely to cause problems or not?

How many on each side is there? If there's 3 or more on each side preferably in triangular fashion I would say OK. Can you not fit a couple of new bolts in the vacant holes. You could remove one of the others as a pattern.

Edited by bizzard
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How many on each side is there? If there's 3 or more on each side preferably in triangular fashion I would say OK. Can you not fit a couple of new bolts in the vacant holes. You could remove one of the others as a pattern.

Theres five out of the six - I think I'll just stop worrying about i. Thanks.
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I recently had coupling problems and tried to run with only 3 out of 4 bolts fitted. The vibrations set up (at cruising revs) made it impossible to use/live with. I got over it temporarily by removing a second bolt so that I had alternate bolt and space. This worked perfectly with no vibration because the system was now balanced. Later the job was fixed properly.

My pictures at: http://nbconstance.blogspot.co.uk/2017/01/it-is-2017-now-where-did-time-go.html about 2/3rds of the way down. HTH

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Mostly because I don't know what I'm talking about! I am relying on the boatyard (or a different boatyard, as the case may be) havign the expertise to advise me what it the easies thing or them to fit. I have a vague memory (all my memories are getting vaguer) of someone mentioning an R&D coupling before - can you give a link? The alternative seems to be a standard Centraflex with an attachment to fit it from metric to the imperial of the Lister doofer, which Adrianh has described above.

PS it is solid mounted.

 

I can't see what's wrong with the one in the picture. you probably won't get it off the shaft it will be seized on but if you remove the bolts from each side -- I think there is three each side -- you can separate the shaft and pull out the rubber insert.

 

that's the only piece that fails and I seem to remember they were it was fairly easy to obtain a spare.

 

Brinklow boats would be my first port of call

why are you replacing it? i haven't understood.

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I'd assumed that it was there to protect the gearbox from a jammed prop and to even out any slight misalignment.

What do you think about running it with a bolt missing at each end? Is this likely to cause problems or not?

The one i had ( fairly standard on grand union boats ) had one bolt that was sacrificial on the forward flange and nothing on the other side. The rear flange was seized to the shaft but that's not a problem. you can separate it so you have a flange on each shaft.

 

As you say it's there to absorb shock from the prop hitting something. I've only ever seen them on longer shafts so i'm not aware of their tolerance to mis-alignment.

 

There's nothing to go wrong except the rubber part which on your photo looks fine so i'm a bit mystified why you want to replace it.

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The picture was taken before we hacked it about. We had to chop some of the rubber out to get at the nuts/bolt heads which spun when we tried to undo the bolts, some of which had to be cut off, which is why some are nkw missing. There's so much rubber there we reckoned it was OK the first time, but it's now been done twice.

Assuming the yard have still done nothing with the boat after a month, I'll just fill it with the stuff they mend tractor tyres with and carry on. Wish I'd never bothered to take it there in the first place.

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