Prop shaft coupling removal - any suggestions?

[NigelChattin]

Hi

I am currently have an issue with one of the stern glands on my Broom 44. The boat is now out of the water, as I need to remove the gland nut. I've disconnected the shaft from the gearbox but I can't get the half coupling off the inboard end of the shaft so that I can slide the gland nut off the shaft

The shaft is 2 1/4'' and the coupling is tapered with a key (no roll-pin). I've removed the two big retaining nuts and washers from the end of the shaft and I can see the end of the key when looking down the coupling.

I've tried various pullers on the end of the shaft and I've tried heating the coupling but the coupling will not move. So far I've broken 3 pullers in my attempts to get the coupling to come off but I've had no luck.

Does anyone have any suggestions of how else to remove the coupling off the end of the shaft? Alternatively could anyone recommend a marine engineer in or around Gosport who might be able to help?

I'm guessing I need a hydraulic puller and I've contacted a couple of marine engineers but I can't find anyone with a big enough puller. The only suggestion I've been offered so far is to cut the coupling off the end of the shaft or even cut the shaft in half and replace everything, but given the likely cost of replacing a 2 1/4'' shaft I definitely want to avoid going to that extreme!

It looks like the couplings on both shafts have been off at some time in the boats history as I can see where the couplings have been heated previously, so I'm sure there must be a way.

Does anyone have any suggestions or recommendations? I'm stuck!

Thanks
Nigel

 

[jfm]

You may have already tried this but I would use

Sykes pickavant hydraulic puller
Engage with the half coupling using not puller claws with a metal lip on the end, but a proper backing plate bolted together behind the half coupling with 3 or 4 m12 puller studs
A lot of heat

2.25 inch isn't big so the engineers who didn't have a big enough puller must have been very small boat guys. A Sykes pickavant big puller set will easily do 2.25 inch

 

[Elessar]

Hi

I am currently have an issue with one of the stern glands on my Broom 44. The boat is now out of the water, as I need to remove the gland nut. I've disconnected the shaft from the gearbox but I can't get the half coupling off the inboard end of the shaft so that I can slide the gland nut off the shaft

The shaft is 2 1/4'' and the coupling is tapered with a key (no roll-pin). I've removed the two big retaining nuts and washers from the end of the shaft and I can see the end of the key when looking down the coupling.

I've tried various pullers on the end of the shaft and I've tried heating the coupling but the coupling will not move. So far I've broken 3 pullers in my attempts to get the coupling to come off but I've had no luck.

Does anyone have any suggestions of how else to remove the coupling off the end of the shaft? Alternatively could anyone recommend a marine engineer in or around Gosport who might be able to help?

I'm guessing I need a hydraulic puller and I've contacted a couple of marine engineers but I can't find anyone with a big enough puller. The only suggestion I've been offered so far is to cut the coupling off the end of the shaft or even cut the shaft in half and replace everything, but given the likely cost of replacing a 2 1/4'' shaft I definitely want to avoid going to that extreme!

It looks like the couplings on both shafts have been off at some time in the boats history as I can see where the couplings have been heated previously, so I'm sure there must be a way.

Does anyone have any suggestions or recommendations? I'm stuck!

Thanks
Nigel

Colin Ryan did mine (col on here). I have access issues due to an act cabin as I suspect you do. Col had to fabricate a bespoke bracket for mine for his substantial hydraulic puller. He did this in his workshop at home then bingo.

 

[jamie langstone]

This just a thought i had a coupling that was bolted by four bolts to hold it on to the shaft but i had the same issue i could not move it. But after many attempts to remove the coupling i noticed a hole in the coupling of with further investigation i found an Allen key grub screw that was screwed in to the hole to which it locked on to the shaft. Once i took the grub screw out the coupling it almost fell off.

 

[aquapower]

Hi

I am currently have an issue with one of the stern glands on my Broom 44. The boat is now out of the water, as I need to remove the gland nut. I've disconnected the shaft from the gearbox but I can't get the half coupling off the inboard end of the shaft so that I can slide the gland nut off the shaft

The shaft is 2 1/4'' and the coupling is tapered with a key (no roll-pin). I've removed the two big retaining nuts and washers from the end of the shaft and I can see the end of the key when looking down the coupling.

I've tried various pullers on the end of the shaft and I've tried heating the coupling but the coupling will not move. So far I've broken 3 pullers in my attempts to get the coupling to come off but I've had no luck.

Does anyone have any suggestions of how else to remove the coupling off the end of the shaft? Alternatively could anyone recommend a marine engineer in or around Gosport who might be able to help?

I'm guessing I need a hydraulic puller and I've contacted a couple of marine engineers but I can't find anyone with a big enough puller. The only suggestion I've been offered so far is to cut the coupling off the end of the shaft or even cut the shaft in half and replace everything, but given the likely cost of replacing a 2 1/4'' shaft I definitely want to avoid going to that extreme!

It looks like the couplings on both shafts have been off at some time in the boats history as I can see where the couplings have been heated previously, so I'm sure there must be a way.

Does anyone have any suggestions or recommendations? I'm stuck!

Thanks
Nigel

I have a round plate drilled the same as the R&D coupling with 6x 1/2" unf bolts and think about an M24 in the middle, you bolt this in place of R&D with the centre bolt touching the centre of shaft, you then tighten up the 6 bolts evenly and then it should pop off, occasionally you need a bit of heat but usually once you have applied pressure all round it breaks free. I must have done a hundred plus with this and never has it not worked. There's not usually a lot of room to play with between gearbox and coupling which in most cases the Sykes Pickavant puller won't fit in.

 

[burgundyben]

For the heat source use a MAPP torch with a puller as described above.

 

[superheat6k]

I was at the point of chopping my shaft on my former Turbo 36 last year, with somewhat restricted access to boot.

Measure the PCD of the bolts or use the R&D coupling joint piece as a guide if you have one fitted.

Obtain a piece of steel plate about 12 mm thick just bigger than the coupling, drill holes to match the centres and diameters of your coupling.

(If yours is the same as mine you can borrow it, but I suspect yours will be larger as my shaft was only 1 3/4" (something of an admission I suppose)).

Place a suitable socket that will just fit into the recess, bearing on to the shaft end, then assemble the plate pressing onto the socket, preferably using fine pitch bolts as these will transmit a far higher torque per part turn than a standard pitch bolt. I used the bolts from the coupling joint to the R&D Coupling.

Wind these bolts up evenly until you think the threads are about to strip.

Then thump the coupling with a large copper mallet. For this task do not spare the weetabix - let it know you mean business.

If it doesn't come free then heat the coupling as rapidly as possible with the improvised puller under hard tension - you want heat into the coupling fast to expand it, but not the shaft. Then thump again, although I found once it was really tight the heat was not needed. If its warm where you are, then wrapping ice bags around the coupling for a few hours before injecting the heat will certainly help the expansion procedure.

When I tackled the port this winter and went straight into this procedure the coupling decided not to argue at all, as clearly it had witnessed the abuse its stbd mate had received 6 months earlier !

The force I applied formed a permanent deflection around the socket in the 1/2" plate I used. I reckon a press would have registered at least 10 tonnes to do that.

If you want the PCD of my puller plate let me know.

 

[Croftie]

Endorse all the above, Sometimes just leaving it a few hours under pressure will work rather than expecting immediate results.

 

[PCUK]

Oxy-propane will get it hot enough to drop off once it is glowing. A blowlamp won't.

 

[NigelChattin]

Thank you to everyone who made a suggestion

We ended up making a plate the same size as the half coupling and using a hydraulic ram to push the coupling off the shaft - it came off a treat and we didn't even need to heat it up. After spending all last weekend fighting it without success, now we have the right tools it was off within an hour!

First Marine Propulsion sorted the stern gland for us and we're now back in the water.

Thanks again

Nigel