Can anyone identify this?

[Serendipity]

Sorry about the quality, taken last night in the shed.

 

Long story short - my rubber tube on my stuffing box needs replacing. The yard reckon there is a little play on the prop and are concerned about what they find when the shaft is removed. They would prefer to cut out and replace with a traditional unit, but apparently they don't come in the size of my shaft. So new shaft, centerflex, stuffing box, shaft bearing and prop.

 

Apart from a small amount of play on the prop shaft, it seems to me that the log containing the prop shaft is separate to the hull flange and has some play within this. Is this by design?

 

What is the screw for on the top?

 

If anyone can identify this for like replacement, or service details, it'll save me a shed load.

 

Cheers

 

[RobinJ]

If anyone can identify this for like replacement, or service details, it'll save me a shed load.

Never seen anyhting like that before?

There seems to be some sort of castelated tube around the shaft?

If this forms the support/seal for the shaft, are those metal wedges to centre it?

I'd hate to have to remove stuff from that prop!

[the grinch]

to me it looks like a anti foul attachment over the top of the shaft

[Ratzend]

Could it be a rope cutter?

[larkshall]

Not any rope cutter I'm familiar with. Strange assembly though

[Serendipity]

There seems to be some sort of castelated tube around the shaft?

If this forms the support/seal for the shaft, are those metal wedges to centre it?

I'd hate to have to remove stuff from that prop!

 

Yes, and that tube seems to have a little movement within the flange on the hull, but whether by design who knows.

 

If you rotate the prop you hear a rubbery groan/squeak, so I reckon there is a rubber or is it neoprene cutlass bearing inside.

 

Actually it's not too bad getting a rope off the prop, though I did crack a rib as I was laying across the hospital silencer to do it

 

Could it be a rope cutter?

 

No, deffo not.

[RLWP]

Could you post some bigger, clearer pictures? I'm having trouble working out what's what

 

Richard

[Chalky]

It's not a conventional stern gland fitted in backwards is it?

[Davidss]

The title of the thread carries the description 'shaft log arrangement'.

In the context of a boat moving through water I know what a 'log' is (and what a shaft is!), but I wonder what Serendipity (the OP) meant by 'shaft log'?

 

I agree the pictures could be better. Possibly a couple of the inside of the shaft bearing / seal arrangement might help, at least in a process of elimination, 'of what it is not'.

When posting, put a line space between pictures.

 

So far, I have some understanding (if not sympathy) of the boatyards approach.

(Never seen one before, don't understand it, don't want to understand it, as we don't see them on a regular basis, so let's cut the labour costs and brain exercise, and fit a complete arrangement we think we understand and have fitted before).)

The validity of the approach is that it's cheaper for them, and for you if you let them do the work.

Your cheaper alternative is to get the collective CWDF mind involved, where your only 'cost' is sifting the dross from the jewels!! (Vision here of Customs Officers waiting for a mule to displace whatever they might have swallowed).

 

HTH, although tea time might not be the best time to post :-))

[Chris Pink]

What size is the shaft?

[Thewatchmaker]

Sacrificial anode for the prop?

[Teadaemon]

To me (and bearing in mind that the pictures aren't very large or clear) it looks like a fairly normal housing for a Cutless bearing.

 

Since you'll have to withdraw the shaft (at least partially) to get the new rubber tube on, I would recommend taking the opportunity to take a good look at the whole thing. If it all looks ok, then replacing the Cutless bearing is probably a good idea while you're there, but I wouldn't replace the whole lot unless there's good reason to. How much play is there? A mm or so would be fairly normal, much more than that and you might have a more serious problem.

[Serendipity]

To me (and bearing in mind that the pictures aren't very large or clear) it looks like a fairly normal housing for a Cutless bearing.

 

Since you'll have to withdraw the shaft (at least partially) to get the new rubber tube on, I would recommend taking the opportunity to take a good look at the whole thing. If it all looks ok, then replacing the Cutless bearing is probably a good idea while you're there, but I wouldn't replace the whole lot unless there's good reason to. How much play is there? A mm or so would be fairly normal, much more than that and you might have a more serious problem.

 

Thanks for that. Any idea what the screw on the top is for? I can't take any better pictures as she's back in the water now. I didn't think the play was excessive, but I guess they are concerned what it might be after being disturbed.

 

I think I'm just gong to get them to replace the rubber tube, and then if they find a problem whilst doing it then we'll get the whole lot changed.

 

ETA - Same pics, but they might be clearer viewing at source:-

(That's a tiny mussel on the left side of the hull flange)

Edited May 31, 2012 by Serendipity

[Teadaemon]

Thanks for that. Any idea what the screw on the top is for? I can't take any better pictures as she's back in the water now. I didn't think the play was excessive, but I guess they are concerned what it might be after being disturbed.

 

I think I'm just gong to get them to replace the rubber tube, and then if they find a problem whilst doing it then we'll get the whole lot changed.

 

ETA - Same pics, but they might be clearer viewing at source:-

(That's a tiny mussel on the left side of the hull flange)

 

I'm afraid I don't know what the screw at the top is, I'd need to examine things in person to see what was going on.

 

If you're going to get the rubber tube replaced, it might be worth replacing the Cutless bearing while you're at it, as they do wear out, particularly in water with a lot of suspended particles (which is most canal water), and they're not that expensive. As the prop shaft will need to be uncoupled and at least partially withdrawn, take the opportunity to examine the shaft for scoring and wear. I would also note that the Cutless bearing housing does seem to be fairly corroded in the pictures, so it might be worth cleaning it off and examining it to see if it's still capable of doing it's job (supporting the prop shaft).

[RobinJ]

ETA - Same pics, but they might be clearer viewing at source:-

Aha!

What appeared to be a shaft and tube held in with wedges, now appears to be all part of the same casting!

It almost looks as though something is designed to fit over that?

Why would you have both castellations and lugs to undo it?