Stiff shaft

superheat6k

superheat6k

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Not intending to be rude here.

Last haul out in August the port shaft was stiff to turn by the prop, no notable play in the cutlass bearing, no underwater strike damage, and no notable loss of power relative to the stbd engine underway.

Boat out at the weekend for wipe and a swipe plus anodes if needed.

So do I need to disconnect the gearbox shaft coupling and see if the engine has moved out of alignment ?

Or am I answering my own question - if so looks like the Houdini course at the weekend.
 
If its just stiff it could be an engine out.

Undo the coupling bolts slide it the depth of the register back and see if it turns easier.

Also as you push it back it should push back on easily.

Carry on Houdini.:encouragement:

Keep the cutlass bearing lubed, Swarfega is good.
 
You are running a Fairline Turbo 36 so a minimum of 20 years old , do I assume original engine never been out of boat ?

How long have the lower an upper cutless bearing on the stiff side been in place?

Options
1 Bent shaft
2 Incorrect cutless bearing material used, size or material
3 P bracket has moved
4 Engine has moved out of alignment
5 Engine mounts have sagged with age
6 Engine mount bolts have slackened off
7 a sheared mounting stud

If it were me:

A inspect all engine mounts for movement or sheared stud, if the latter you may see dust from the fretting surfaces

B inspect stern seal and coupling for sign of movement

C take the boat out of the water but have it blocked off high enough so you can draw the shaft if you have to

D split the coupling and see if the shaft turns freely and is there any obvious displacement of the shaft and coupling/ gearbox ?

E if the shaft is still stiff when uncoupled suspect its bent or P bracket has moved, draw the shaft and have it spun in a lathe to check for truth check alignment with a wire or laser with shaft out

F while shaft out consider replacing both cutless bearings on each shaft, if a packed stern gland clean out and inspect, repack and refit or if a proprietary stern seal neat 5 years old consider replacing, if replacing consider tides marine.

G consider age of engine mounts they do sag with age and go off, consider replacement
 
superheat6k said:
Last haul out in August the port shaft was stiff to turn by the prop, no notable play in the cutlass bearing, no underwater strike damage, and no notable loss of power relative to the stbd engine underway.
Click to expand...
By "no notable loss of power", do you mean that both engines reach their max rpm as they should?
I'm asking because the answer to your doubt depends also on how stiff is "stiff" - I mean, the prop isn't supposed to spin freely, with your setup.
If it does in stbd engine, it might well be that something is wrong (too loose) on that side....
...just a thought. :)
 
Have a very close look at the bearing, there should be a clearance and if everything is straight the shaft will sit in the bottom of the bearing at rest, so you should be able to see clearance at the top both front and rear. If as an example you have clearance on the left at the rear and on the right at the front of the bearing the bearing carrier P bracket is not straight....or the engine/coupling is pulling the shaft to one side. Disconnect and check everything, ideally chock shaft so it is central in the bearing/bearing carrier. Can be a long fiddly job so expect to spend a few hours on the boat if you're doing it yourself.
 
++ 1All of what Bandit said.
If the engine mounts are faulty, make sure that the shaft is drawn back before you start anything.
The weight and leverage is enough to bend the shaft if it comes into contact with the coupling. [ obvious I know ]
But a surveyor I was working with once pushed the shaft in whilst the alignment was being done on the engine, with disastrous effect.
Good set of feeler gauges an asset as well. Plus a good idea of where the engine is now. Either by measurement or a block of wood and a wedge to engine beds and down onto the hull.
 
One of my shafts is def "tighter that the other".
When moored one shaft happly will turn under tidal flow the other will not.
 
Bandit said:
You are running a Fairline Turbo 36 so a minimum of 20 years old , do I assume original engine never been out of boat ?

How long have the lower an upper cutless bearing on the stiff side been in place?

Options
1 Bent shaft
2 Incorrect cutless bearing material used, size or material
3 P bracket has moved
4 Engine has moved out of alignment
5 Engine mounts have sagged with age
6 Engine mount bolts have slackened off
7 a sheared mounting stud

If it were me:

A inspect all engine mounts for movement or sheared stud, if the latter you may see dust from the fretting surfaces

B inspect stern seal and coupling for sign of movement

C take the boat out of the water but have it blocked off high enough so you can draw the shaft if you have to

D split the coupling and see if the shaft turns freely and is there any obvious displacement of the shaft and coupling/ gearbox ?

E if the shaft is still stiff when uncoupled suspect its bent or P bracket has moved, draw the shaft and have it spun in a lathe to check for truth check alignment with a wire or laser with shaft out

F while shaft out consider replacing both cutless bearings on each shaft, if a packed stern gland clean out and inspect, repack and refit or if a proprietary stern seal neat 5 years old consider replacing, if replacing consider tides marine.

G consider age of engine mounts they do sag with age and go off, consider replacement
Click to expand...
Thanks for the thorough answer and suggestions. I do regularly inspect the mountings, which are clean and dry and definitely not oily. I would describe the stiffness as moderate but not hard and binding. I will break the coupling and see if the engine has dropped or otherwise moved.

The boat already has Tides or similar Deep Sea type seal from about 6 years ago. No signs of any underwater strikes. No excessive vibration underway, and no apparent loss of power port compared to stbd (both sluggish presently due to the hanging gardens the boat is carrying).

I will update after the weekend's activities - so check shaft alignment on the port shaft; then if mostly OK adjust engine, one coat primocon, 2 coats Micron Extra 2, scrub and polish topsides (2 coats wax only this year), anodes if required. If not OK boat staying out for pulling of the port shaft and full checks for the reason.

Can't wait ! Anyone feeling bored and wanting something to do for the Bank Holiday Weekend - volunteers most welcome.
 
MapisM said:
By "no notable loss of power", do you mean that both engines reach their max rpm as they should?
I'm asking because the answer to your doubt depends also on how stiff is "stiff" - I mean, the prop isn't supposed to spin freely, with your setup.
If it does in stbd engine, it might well be that something is wrong (too loose) on that side....
...just a thought. :)
Click to expand...
Wouldn't describe the stbd as loose - about what I would expect, turns with light hand pressure on the prop blades, but the fast running tide at Foulkes wouldn't spin it.
 
A lovely Bank Holiday weekend, just perfect for boating, so just spent most of yesterday and all of today trying to get to grips with the root of the stiff shaft problem, and still not there yet.

But having initially thought the engine had sunk into its mountings, once I separated the coupling it became obvious the problem was with the shaft itself and its cutlass bearings. Alignment was spot on.

So by late afternoon and with my arms and chest smothered in bruises clambering / crawling into the back of the engine bay, I have got as far as undoing the large nut retaining the shaft coupling to the shaft itself.

Now I need to make a puller plate to detach the coupling from its taper, plus find a large three legged puller to get the prop off.

The possibilities left are: mis-aligned cutlass bearings, badly worn upper cutlass or a bent shaft.

Deep joy - the intention was out for a wipe and a swipe, looks like it will be several weeks before this one is sorted.
 
Is the front coupling on a taper? If it is you can put the nut back on, but with a couple of turns still to go, and bolt up to the flange, it'll break the taper, you may a spacer, its how I did it before I bought split half couplings.

I have a prop puller which way fit, its in the back of the Morris parked out the front, not locked, pop round and help yourself, its in the rusty canvas bag under all the other junk! LOL.

I have a biggish 3 arm puller too, welcome to borrow them both, I'll dig them out tomorrow for you.
 
Thanks Ben - PM sent for your address.

I will try the flange method, but will need to remove it from the gearbox output flange otherwise with the R&D cush coupling removed it won't pull up close enough - more bits & bolts !!!
 
Having spent 6 hours today in and out of the engine bay I finally managed to get the shaft coupling half to release from the shaft. In the end a piece of 1/2" steel plate with holes drilled to match the PCD of the coupling, and a 22mm socket as a bearer piece placed inside the securing nut re-affixed a couple of turns, which acted as a guide.

How much force does it take to permanently warp a piece of half inch steel plate - six bolts all pulled to the point of stripping the threads, then one clout with the lump hammer and off it came.

Proceeded to pull the shaft to find the problem was the outer cutlass bearing. As it was drawing I used washing up liquid to lubricate the shaft passing through and noted the black slurry coming from the cutlass bearing, even when the shaft had dis-engaged the upper cutlass the lower was still tightly gripping the shaft tightly the whole way out.

Anyway time for a new PSS seal anyway (6 years recommended life).

Can't wait to do the stbd !
 
So you are replacing your PSS seal ? Why? If you need to replace a sterngland seriously consider a Tides Marine a better unit.

Was your shaft in line with the gearbox flange?

It seems unlikely that a stern seal would make the shaft " Stiff"
 
Bandit said:
So you are replacing your PSS seal ? Why? If you need to replace a sterngland seriously consider a Tides Marine a better unit.

Was your shaft in line with the gearbox flange?

It seems unlikely that a stern seal would make the shaft " Stiff"
Click to expand...
The problem was the outer cutlass disintegrating - not alignment. It had swollen and was gripping the shaft tightly, even after the shaft had left the upper cutlass it was still v tight, even using plenty of washing up liquid, and the black slurry on the shaft as it withdrew was a giveaway.

Due to its location right under a bulkhead the rotating part of the PSS had to be drifted back with a screw driver on the edge of the critical face, plus I expect the seal has been installed for at least 8-10 years, if not longer - recommended life is 6 years for the bellows. No specific damage to the rotor, but and the seal faces are not that pretty anyway.

After all this effort to get the shaft out I think not replacing both cutlasses and the seal would be a folly, however I have asked Tides for a quote for their equivalent seal. If their's compares favourably on price or availability then Tides it will be, although the PSS seems a very well designed seal, and at no stage has either ever so much as dripped, nor caused me any trouble at all.

I would like to thank Fairline for installing an upper cutlass bearing housing that is so made that it is not possible to replace this bearing without completely removing the housing from the boat - 2 lock grub screws, both centre popped on a 3.5" long cutlass bearing, one of which is impossible to access with the housing installed, plus for good measure there is a register preventing this bearing being withdrawn outwards, the natural direction to pull the thing and there simply is not space to withdraw it inwards with the housing mounted.

Once the Port is sorted I will be doing same to the stbd, but that will be a scheduled Winter job, as for now the stbd is free and seems OK.
 
Tides is first class Kit.

If you buy one or two make sure both engines supply each stern seal in case of single engine running.

If you get a Tides marine seal ( recommended ) against PSS, get a second seal and fit it above the one in use so you can if required cut the old seal and slide the new one down.

You can in theory change a seal in the water but you need to be sure of yourself and have big balls, see the video on you tube.
 
Bandit said:
Tides is first class Kit.

If you buy one or two make sure both engines supply each stern seal in case of single engine running.

If you get a Tides marine seal ( recommended ) against PSS, get a second seal and fit it above the one in use so you can if required cut the old seal and slide the new one down.

You can in theory change a seal in the water but you need to be sure of yourself and have big balls, see the video on you tube.
Click to expand...

How do you achieve a cross connection without any risk of pumping seawater back into the non running engine - small NRVvs in each line - the PSS has only one water injection nipple ?

The awful access and lack of spare shaft space i think would rule out having a second seal set mounted on the Turbo 36.

Whereas size has been commented on in the past, mine are not that big to test that theory !
 
Any back flow will only go out of the injection bend into the exhaust of the non running engine which is open to the sea anyway or out of the seawater intake ( unlikely).

The width of a Tidesmarine spare seal is only about 6 or so mm.

A colleague of mine who is involved with seal, shaft and cutless work replaced the old PSS seals on his boat and he could not achieve a dripless fit and was fed up with water in his engine room so he replaced them at two years old with Tidesmarine
 
I fitted another PSS seal kindly provided at short notice by Aquafax via Foulkes.

Despite helpful noises on the phone and promises an email would follow with the details of the Tides Seal I would require, I heard nothing more from them, so I will not know whether their seals are any good or not. I hope their seals are more effective than their customer service !

Besides, the PSS I removed has been there for at least 10 years without a drip, and appears to be well engineered.

The PSS seal is fine below 12 knots without a cross connection feed, and there is no way OB would go above that on one engine.

I now know precisely what is required to change the cutlass bearings on a Turbo 36, and I can't wait until Winter when I will be tackling the stbd !

Following on from a thread a long while ago I have painted the props with Hammerite Special metal primer - can't do any worse than the udder cream (lanolin) i trued last year. I will feed back next haul out on its success or otherwise. Rest of the bottom this time has primocon plus two coats Micron CSC Extra 2.
 
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