Volvo stern seal guidance required.

[Pete735]

I'm looking for a reasonable solution to the leaking stern gland on the boat. It's leaked consistently since I owned the boat despite being repacked twice (and it's a pig to get at). Boat went back in the water onto a swinging mooring this week and seems to be letting water in at the rate of 0.5 inches per 24 hours. Short term the boat yard have keys and instructions to keep an eye on it and go on board and use bilge pump if necessary. Longer term I need a more practical solution.

The volvo seal looks an economic and effective way to if not solve problem at least get it more manageable. Problem is I have a 1 inch prop shaft and 42mm od stern tube. V-P website says a metric 25mm seal needs 42mm stern tube and the imperial 1 inch prop shaft needs 1 3/4 inch (44.45mm) stern tube. Neither is technically a straight replacement. I'm tempted to fit a metric unit and get the stern tube dimension correct. My feeling is that worst case is the propshaft will get minor wear ridges in it over time. I've not seen an actual v-p seal, but from photos there are 2 or 3 lips inside seal. My first question is has anyone fitted metric seal to imperial p/shaft and if so was all ok?

Second question, if there are 2 of us, can we safely do this whilst boat remains afloat? Me changing seal for stern gland whilst another pumps bilge? Naturally this would be done after carefull check - as far as possible - that everything fits.

I appreciate that stern glands are an effective way to keep water out of the boat, but either I'm not doing mine correctly or there is a fault somewhere. If nothing else I'd like some short term breathing space and the ability to use boat this summer without wondering if it's going to be afloat when I get to it - it's 100 miles away.


Anyone got any experience of taking this route or any good reason why I should not give it a go? My thoughts are worst case a little shaft wear and possibly it's replacement in 4 or 5 years with stern gland/seal set up becoming more ideal at the same time

As always thanks for any assistance..

 

[theoldsalt]

Have a look at a recent thread

"Can one change a shaft seal on the water?"

Last posting 29th April

One posting has a link to a video.

 

[MoodySabre]

The Volvo stern tube sizes are the maximum that the gland can fit over. Buy the right size for your shaft - a 25mm will be too tight on a 1" shaft and won't last any time. A 1" size on to your 42mm stern will be ideal.

The important thing is that your shaft is in good nick where the seal will lie.

 

[Tranona]

Are you sure it is a 1" shaft? Unlikely on a French boat (assuming you still have the Evasion in your profile).

Anyway as Moody Sabre says get the right size for the shaft. If the stern tube is too small diameter,build it up with self amaglamating tape. Although changing in the water is possible, would not risk it if you areuncertain about whether it will fit.

 

[johnalison]

I had a Volvo 2.5cm seal on a 1" shaft on my Sadler 29 for many years, after taking advice on the subject, without a problem, though the advice above seems to discourage it. Absolute magic though: a completely dry bilge forever.

 

[awol]

The Volvo bumpf gives 25.0mm +0/-0.1 as the shaft size and tolerance but previous threads with a variety of posters have claimed that a 1" shaft in the 25mm gland causes no problems. I took the plunge with my 42mm/1" combination in 2006 and precautionarily replaced the Volvo seal last year after a rope wrap and the shaft with marking tape was pulled into it. On measurement, the shaft showed no wear though the surface was more polished where the seal had been. The seal was visually indistinguishable from its replacement but I haven't dissected it to check further.

As to doing it while in the water - you've seen the video, what could possibly go wrong? ......... other than things like not enough clearance on the end of shaft to get old gland off or new gland on; prop shaft goes for a wander out the stern tube; stern tube is a different size under the present gland fixing; the pump valve gets blocked by a bit of detritus from the bilge; etc. All of these and anything else can be catered for but it could be less stressful doing it on a drying wall. Have fun!

 

[Bosun Higgs]

The Volvo seal is not just a series of lips inside the rubber - it also incorporated a water lubricated bearing. Now whilst you might get away with a 0.4mm difference on the sealing lips, I'm not sure I would want to try it with the bearing. On the other hand, the difference in tube diameter between what you have and what volvo say they need seems big to me. You really do need to talk to Volvo and get an official answer.

Dont worry about the lips wearing grooves in the shaft - they will do that anyway. The soft always wears away the hard.

You may like to consider using the one inch and building up the stern tube diameter in which case I would do it with epoxy resin and a layer of woven roving. It need not be absolutely precise - there is reasonable give in the seal.

 

[Pete735]

Thanks for all the comments. Awol and Johnalison in particular, as people who have done what I am contemplating.

The existing set up was apart only 10 days ago, so I know clearances will allow me to remove and replace everything and I used the time to put vernier calipers on both shaft and stern tube, just in case I continued to have problems. Boat is still Evasion, and whilst a french built boat, I have an invoice that came with a mountain of details showing the purchase of a s/s shaft of 1 inch od. some 15 years ago. together with a new prop, so I'm confident on dimensions.

Boat is equipped with 3 bilge pumps - all working, I checked last weekend so I've got backup. Video was interesting so thanks for pointing me in that direction theoldsalt, it's that initial spray of water that will be unnerving, but my intention even before seeing video was to get a rag to hand to smother sterntube/shaft as I slide stern gland off. Hopefully it will be an exciting 15 minutes only.

As always most helpful everyone, thanks.

 

[philip_stevens]

it also incorporated a water lubricated bearing.

I have my old Volvo shaft seal in the garage, and there are only two lip seals and no water lubricated bearing. The inner lip is grease lubricated, and the outer is water lubricated/cooled.

 

[Tranona]

I have my old Volvo shaft seal in the garage, and there are only two lip seals and no water lubricated bearing. The inner lip is grease lubricated, and the outer is water lubricated/cooled.

Well, the one in my garage definitely has a fluted rubber bearing aft of the seals - about 50mm long. That is the bit that needs water lubrication and makes the noise if it runs dry. Grease covers both seals but of course the aft one is in contact with water.

Have another look inside your seal.

 

[vyv_cox]

I have my old Volvo shaft seal in the garage, and there are only two lip seals and no water lubricated bearing. The inner lip is grease lubricated, and the outer is water lubricated/cooled.

Please have a look at the one shown sectioned on my website here. If yours is different I would be very pleased to have a photograph of it, especially if you can take the time to section it in a similar way.

Thanks

Vyv

 

[Ruffles]

Please have a look at the one shown sectioned on my website here.

Brilliant website!!!

 

[Bosun Higgs]

I'm looking for a reasonable solution to the leaking stern gland on the boat. It's leaked consistently since I owned the boat despite being repacked twice

Personally I dont like the old style shaft seal but even this type should not leak the way that yours is doing.

Might be financially painful but I would hand the job over to the yard. It doesnt sound as if its the seal that is wrong unless you re-packed it yourself and did something consistently daft. So a change of seal to a Volvo might well leave you with the same problem. A fresh pair of eyes on the situation might help

 

[vyv_cox]

Brilliant website!!!

Thank-you