Prop shaft wrapped in cable ties.... ?

[bigolslabomeat]

Looking at buying our first boat, survey booked for next week but had a good look over today. She's a tug style so has a long prop shaft through the boatman's cabin. Thought I'd take a look at it and noticed this, which seems kind of odd as layman.

 

Is this "normal" or some kind of temp repair that's been left for a while?

 

Hopefully the surveyor will notice and confirm but my curiosity is piqued and don't want to have to wait a week 😂

 

 

[Tony Brooks]

I can't work out what the idea of that would be. The half coupling looks very much like a shrunk on one (rather than a modern clamp on) so it should be solid on the shaft and a beast to get off, but if the coupling was moving on the shaft that would hide any signs of it.

 

It might be intended to absorb any excess grease leaking from the bearing block to stop it being thrown about by the revolving shaft, but there is no sign of this happening around the bilge and swim sides. I don't think it would be effective it this was the intention.

 

The only other thing that I can think of is to try to damp noise or vibration, rather than find the source and rectify it.  This might be from a worn bearing in the shaft support plumber block or the needle rollers around the spider in the universal joint. It is also worth noting that if the universal joint has been misaligned with its pair that is under the floor you will get noise/vibration as speed increases, however the grease nipple on the joint end suggest it was a sliding fit on the shaft, but it looks as if it may now be welded.

 

Please note that my suggestions are pure conjecture. I would suggest that you insist that it be removed for the survey and ask the surveyor to pay special attention to that area.

[blackrose]

Maybe it's broken and that's someone's idea of a bodged repair? 😋

[NB Alnwick]

Clearly some sort of bodge! When one finds a bodge like this one has to wonder what else may have been bodged.

Walk away - there are plenty of good boats out there and the right one will come along eventually . . .

[magnetman]

Interesting that they are releasable cable ties .

 

Perhaps this is where the powdered rhino horn is kept. Valuable stuff. 

 

Nobody would think to look there. 

 

 

[GUMPY]

Wild guess

The half coupling is not tight on the shaft and the ties are there to stop the shaft coming out of the half coupling when running  in reverse.

 

[magnetman]

Also maybe the grub screws locking the shaft to the inner race of the plummer bearing tend to come loose n

 

 

Interesting to see if they are done up tight. 

[MtB]

My own guess is the cardan shaft has a sliding spline on the far end (out of view) and the cable tie wrapping is a monumental bodge-up of a thrust bearing the prevent the shaft moving too far back when astern is engaged. 

 

Or possibly the engine is a Kelvin and someone has mistaken the back-and-forth movement of the prop shaft as a fault and tried to stop it happening. 

[Bee]

I think I would remove the cable ties and rag and have a look, it could be that the shaft is free to slide through the plummer block and underneath the gubbins is some sort of home made clamp to stop it doing that. If that shaft with the universal joint retains the sliding part from the vehicle it came off then the prop could pull out and foul the rudder. Apart from that then I dunno. Edit, Post crossed with others.

Edited November 2 by Bee

[magnetman]

Yes a Kelvin, a Sabb or a Gardner. Or a Volvo? All of these had cone clutches in some circumstances. 

 

 

Is this one of the slightly silly situations where someone has deliberately put the engine out of the centre line for convenience thinking it is clever? The cardan shaft seems to go off to one side. Could be the camera effect. 

[NB Alnwick]

Just now, MtB said:

Or possibly the engine is a Kelvin and someone has mistaken the back-and-forth movement of the prop shaft as a fault and tried to stop it happening. 

 

Unlikely - most Kelvin set-ups are properly aligned with a solid shaft - no universal joints.

[magnetman]

Just now, NB Alnwick said:

 

Unlikely - most Kelvin set-ups are properly aligned with a solid shaft - no universal joints.

I've seen a J2 in a forward engine room with a long cardan shaft. Yes it did cause problems with staying in gear. 

 

 

[MtB]

1 minute ago, magnetman said:

Yes a Kelvin, a Sabb or a Gardner. Or a Volvo? All of these had cone clutches in some circumstances. 

 

 

Is this one of the slightly silly situations where someone has deliberately put the engine out of the centre line for convenience thinking it is clever? The cardan shaft seems to go off to one side. Could be the camera effect. 

 

Yep I thought that too. The builder with an unholy habit fitting engines off to one side and in weird, hard-to-find places (like under the bed) was Orion Boats. They also liked fitting Kelvins so speculating wildly, is this an Orion tug perhaps? (I have one myself!) 

 

 

[NB Alnwick]

3 minutes ago, magnetman said:

Is this one of the slightly silly situations where someone has deliberately put the engine out of the centre line for convenience thinking it is clever? The cardan shaft seems to go off to one side. Could be the camera effect. 

 

That is a very good point! Another reason to walk away . . .

[MtB]

2 minutes ago, NB Alnwick said:

 

Unlikely - most Kelvin set-ups are properly aligned with a solid shaft - no universal joints.

 

Most but not all. My previous boat has a Kelvin with a cardan shaft. Worked fine. 

[NB Alnwick]

Whatever the reason - it looks like a bodge of some sort! And the whole area looks messy - buyer beware!

[magnetman]

So lets just imagine it was a Kelvin Diesel unit. Cardan shaft. The issue which occurs in forward gear is that the cone clutch disengages into neutral. Some people use weights on the speedwheel. 

 

Maybe someone has spotted this and thought putting some sort of 'spring loading'  in the gap there would tend to stop the creeping into neutral effect but still allow use of reverse which requires slight movement astern of the propeller. 

 

 

[GUMPY]

Hope @bigolslabomeat comes back and tells us what the surveyor says about it.

[MtB]

 

 

 

11 hours ago, bigolslabomeat said:

Is this "normal" or some kind of temp repair that's been left for a while?

 

Hopefully the surveyor will notice and confirm but my curiosity is piqued and don't want to have to wait a week 😂

 

 

Just to clarify, no this is NOT normal and yes it is probably some sort of ineffectual repair, long abandonned.

 

And don't stress out waiting for the survey report, it will say something like "Problem with prop shaft noticed, advise getting some expert advice", or something equally slippery!

 

 

[NB Alnwick]

It would be helpful to have more information:

• What engine is fitted and is it offset from the centre?
• Whate gearbox is fitted?
• Who built the boat?

[LEO]

Interesting replies, but to me it all looks slightly out of alignment, the bolt on the coupling, the label on the bearing...and the nuts on the packing seals are well screwed down...........the general condition of the steel work and presentation of this area is causing concern... it will be interesting to learn of the outcome.

[MtB]

3 minutes ago, LEO said:

Interesting replies, but to me it all looks slightly out of alignment, the bolt on the coupling, the label on the bearing...and the nuts on the packing seals are well screwed down...........the general condition of the steel work and presentation of this area is causing concern... it will be interesting to learn of the outcome.

 

You're right, it does all look a bit pished doesn't it? The stern tube isn't welded in straight so the shaft leans to starb'd, and the plumber bearing is consequently also offset to starb'd. Most plumber blocks hold the bearing inside a spherical housing so this takes up the misalignment. 

 

It won't really matter in terms of how well the boat works or steers but it suggests a sloppy attitude and lack of attention to detail by the shell builder. Probably not an Orion boat after all then! 

 

And yes the packing gland has all but run out of adjustment, as far as I can see in the dim light. 

 

 

 

Been leaking too, judging by the rust on the baseplate!

 

 

[magnetman]

It seems to be pipe insulation. 

 

Maybe it was getting a bit cold. 

 

 

Woodruffe key which was sliding out? 

 

It seems to be a not particularly technical solution to a problem. The cable ties are completely random and it doesn't seem like something which had a method statement or diagrams. 

 

It could even be something hastily cobbled together by a Boat mover just to get to the destination. 

 

 

 

Something failed. 

[David Mack]

7 minutes ago, MtB said:

And yes the packing gland has all but run out of adjustment, as far as I can see in the dim light. 

 

Been leaking too, judging by the rust on the baseplate!

But the area is bone dry, so if this boat is in the water the gland must be completely watertight.

[magnetman]

Just now, David Mack said:

But the area is bone dry, so if this boat is in the water the gland must be completely watertight.

Sponge ? 

 

There are obvious signs of a large amount of bilge water in there.