Edited: Many thanks for the help

[Seaworthy Lass]

25th July: Thread title changed from “Urgent help needed” to “Many thanks for the help”.

Dockhead has asked me to post this on his behalf, as he is unable to post while on passage. Could anyone help please? I will relay all responses:


We've developed a technical problem I need some advice on.* I can't post to CF so I wonder if maybe you could do it on my behalf, and email me what people say?

The problem is a loudish tapping sound from my shaft seal or shaft log.* I have no idea and in fact cannot even imagine what the cause of this could be.* It's not a good time -- to say the least -- to have a problem with the shaft, as there is no lift out within hundreds of miles, and the engine is mission critical in the ice.*

The shaft seal is a Tides Marine (similar to a PSS) one, which has been excellent, performing flawlessly for 3000 hours, with the seal ring replaced purely prophylactically in May when we were getting ready, since I needed the shaft out anyway for a cutless bearing.* The engineer who did it is a very reputable and obvious very skilled person. He didn't get the seal right the first time -- he mounted it just on the spot where the shaft had worn into the old one.* So he had to take it out with the boat in the water and install a new one, positioned a little differently. I have had no further problems with it, no leaks, and it doesn't run hot or anything. When I squeeze the bellows, it is obviously full of water.

So what can this tapping be?* I started to notice it as we were leaving (motored 12 hours in a calm), couldn't figure out what it was, and then knew for sure when we started sailing and I forgot to lock the shaft -- the shaft turned and I could hear the noise in slow motion -- tuk tuk tuk tuk tuk tuk.* It can't be anything good, but I cannot even imagine what it might be. Maybe someone has some insight?

[estarzinger]

We had a tide marine seal - is he sure it is coming from there? I was a champion at getting things to fail and we never had that issue

If he has an autoprop, I would suspect a seal is broken and one blade wobbling a little.

Or perhaps a piece of rope caught in the prop (that would sure be the easiest to fix of the causes I can think of).

[Seaworthy Lass]

Originally Posted by estarzinger

We had a tide marine seal - is he sure it is coming from there? I was a champion at getting things to fail and we never had that issue

If he has an autoprop, I would suspect a seal is broken and one blade wobbling a little.

Or perhaps a piece of rope caught in the prop (that would sure be the easiest to fix of the causes I can think of).

Thanks for the quick response.
I have emailed him your post.

[belizesailor]

Could it be as simple as something fouled on prop/shaft?

A bit chilly to jump in and look there.

Folding prop or fixed?

[Seaworthy Lass]

Originally Posted by belizesailor

Could it be as simple as something fouled on prop/shaft?

A bit chilly to jump in and look there.

Folding prop or fixed?

I have done a search of what prop Dockhead has and I think it is a Bruntons. I presume an Autoprop?

[belizesailor]

Does he have a dry suit/survival suit...maybe he could pop in and look?

[Bleemus]

Does he have a waterproof GoPro on a stick he can stick under water and view what he sees on his phone? Sounds like something has fouled the prop.

[Seaworthy Lass]

Originally Posted by belizesailor

Does he have a dry suit/survival suit...maybe he could pop in and look?

Yes, he does have a dry suit, but I guess that is a last resort. An underwater camera taped to a pole set on video may be a better option.

[Seaworthy Lass]

Originally Posted by Bleemus

Does he have a waterproof GoPro on a stick he can stick under water and view what he sees on his phone? Sounds like something has fouled the prop.

Snap.
I just posted a similar suggestion.

[belizesailor]

Originally Posted by Bleemus

Does he have a waterproof GoPro on a stick he can stick under water and view what he sees on his phone? Sounds like something has fouled the prop.

Sure would beat a dip in the Artic!

[sy_gilana]

Here is what I would do.
If you have a stethoscope, pull off the diaphragm, use the hose end to accurately find the source of the noise. If not, use a length of plastic hose stuck in your ear, and block the other ear. This is important.


A folding prop can transmit noise up the shaft to a log, especially in a metal boat.


Your shaft brake could be the culprit.


Your output flange or keyway could be the culprit.



FEEL and LISTEN to identify it without prejudice, close your eyes, move the hose around.



I cannot see how a lip seal could generate that sound. A face to face seal yes.


I have looked at both models of this seal online, and place the cause elsewhere.

[atoll]

sounds like fishing line or polyproplene in the prop, it will eventually disintegrate,in the mean time as long as the shaft seal is not leaking nothing really to worry about.

[belizesailor]

Originally Posted by Seaworthy Lass

Yes, he does have a dry suit, but I guess that is a last resort. An underwater camera taped to a pole set on video may be a better option.

Absolutely.

[Seaworthy Lass]

Originally Posted by sy_gilana

Here is what I would do.
If you have a stethoscope, pull off the diaphragm, use the hose end to accurately find the source of the noise. If not, use a length of plastic hose stuck in your ear, and block the other ear. This is important.

A folding prop can transmit noise up the shaft to a log, especially in a metal boat.

Your shaft brake could be the culprit.

Your output flange or keyway could be the culprit.

FEEL and LISTEN to identify it without prejudice, close your eyes, move the hose around.

I cannot see how a lip seal could generate that sound. A face to face seal yes.

I have looked at both models of this seal online, and place the cause elsewhere.

Thanks everyone.

I have emailed all the responses to Dockhead.

A little more information I can provide:
- Dockhead’s boat is a Moody 54, not a metal one.
- I think the prop is a Brunton’s Autoprop, which is a feathering not folding one.

SWL

[atoll]

Originally Posted by Seaworthy Lass

Thanks everyone.

I have emailed all the responses to Dockhead.

A little more information I can provide:
- Dockhead’s boat is a Moody 54, not a metal one.
- I think the prop is a Brunton’s Autoprop, which is a feathering not folding one.

SWL

i had this same thing with our 22 inch max prop when plastic or nylon got caught in it, he could try going from forward to reverse to try and clear it.

otherwise as long as the prop is giving proplusion and the shaft seal is not leaking the nylon trapped will eventually melt due to friction.