Repacking a stern gland

[PeterWright]

I understand that the current Volvo glands have copied the Radice / Orbitrade approach and have a vent which you just need to route to a position well above the waterline. With that approach, no burping required - any air in the seal will just flow up the vent.

Peter.

 

[PeterWright]

Hi Tillergirl.

Unusually, I must disagree with you.

If you cut the turns as described above while wrapped tightly around the shaft, each turn will come out the right length. To introduce each turn into the gland simply wrap it around the shaft right next to the gland with the two 45 degree cuts overlapping and push it into the gland housing, no taper exposed as it's butted up against the taper on the other end. Take care when pushing the turn to the bottom not to undo the overlap of the ends - this is best achieved by using the gland follower to push each turn in as it pushes uniformly all round. I first packed a stern gland in 1962 in my Uncle's Stella while she was building in his yard and have packed countless numbers since, always with the turns cut at 45 degrees. Never heard a complaint about the result.

Peter.

 

[tillergirl]

Well opinions will have to differ. I admit I have little experience. I did it on two boats cut at 90 degrees. Never had to do them again over 40 years. Perhaps I should rake out the packing on Sea Dog. I inherited the set-up; it drips; it doesn't improve via adjustment but frankly it doesn't drip much and is inconsequential. Perhaps I should look and see whether the packing is cut square or 45 degrees? PS, is that a Deckhand job?

 

[Colvic Watson]

Update. Collar thingy that pushes in to compress the packing is now removed. A couple of hours and we got the packing out. Five b***** rings of it. Then we discovered there’s an actual tool for £3 for getting it out.

Hi hum. Now it’s cutting the rings and putting them in. One quick question:

45 degrees or not? Some say cut at 45 others say not.

 

[AntarcticPilot]

Update. Collar thingy that pushes in to compress the packing is now removed. A couple of hours and we got the packing out. Five b***** rings of it. Then we discovered there’s an actual tool for £3 for getting it out.

Hi hum. Now it’s cutting the rings and putting them in. One quick question:

45 degrees or not? Some say cut at 45 others say not.

While I admit getting the boatyard to do the job, until this thread I'd never heard of it NOT being cut at 45°, the problems @tillergirl describes being avoided by cutting it on the shaft.

 

[Rappey]

Wrapping the packing around the shaft tightly then cutting could result in each ring springing back leaving a small joining gap.
Wrapping loosely then cutting will make each ring slightly oversize resulting in the cut ends forced together when inserted regardless of cutting at whatever angle but a 45 degree cut will give more chance of a seal along the cut.

 

[Plum]

I've always cut ar 45 degrees and not had a problem.

Www.solocoastalsailing.co.uk

 

[AntarcticPilot]

Wrapping the packing around the shaft tightly then cutting could result in each ring springing back leaving a small joining gap.
Wrapping loosely then cutting will make each ring slightly oversize resulting in the cut ends forced together when inserted regardless of cutting at whatever angle but a 45 degree cut will give more chance of a seal along the cut.

I think you're supposed to wrap it snugly, but not tight. I did (honest) seriously look into doing it myself before chickening out and letting Halls do it!

 

[LittleSister]

The packing is quite soft and flexible. Provided it's put in evenly, I doubt it would have any problem conforming to whatever space, or lack of space, was available as a result of being slightly too long, too short, etc.

Having carefully reviewed the above arguments for 45 degree versus 90 degree cuts, and the reported success of both approaches, my considered opinion is that it probably doesn't matter, and if it does it almost certainly doesn't matter much!

Without knocking 'modern' proprietary shaft seals (I've got one on a different boat), I have to say that the traditional packing gland shaft seal is a brilliant, reliable, low-cost, low-tech boat of kit, and at least for me, pretty much the only trouble with them is they live in usually rather inaccessible places on small boats.

 

[ex-Gladys]

Well opinions will have to differ. I admit I have little experience. I did it on two boats cut at 90 degrees. Never had to do them again over 40 years. Perhaps I should rake out the packing on Sea Dog. I inherited the set-up; it drips; it doesn't improve via adjustment but frankly it doesn't drip much and is inconsequential. Perhaps I should look and see whether the packing is cut square or 45 degrees? PS, is that a Deckhand job?

Deffo not, I'm only employed to steer accurate courses, nuffink technical...

 

[Colvic Watson]

Thank you!

We very nearly chickened out but in the end ploughed on and fitted it all. Cut at 90 degrees because we were paranoid about getting the length right. Five rings all with offset joins. How tight to start with? We just guessed thinking loose was better.

Launched on Thursday and not a drop. Yikes, we’ve done it too tight. Checked in gear and it started to drip once every 30 seconds, running cold and stopped with a half turn of the grease gun thingy. Same after a few hours of motoring since.

So this time we got a boat job right - touch wood - and learnt a lot. Thanks everyone!