Stern Gland Problems

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Stern Gland Problems

Postby Bob Hine » Wed Jun 13, 2007 8:48 am

Model: Seahawk 34 (1985/6)
Problem: Sea water leaking into engine bilge whilst motoring.

Whilst I have always had some leakage into the engine bilge this has increased recently to become concerning. I have regularly pumped grease into the stuffing tube both before and after a trip but this now seems to be ineffective. The stuffing tube has never been changed (22 years now) and does feel quite soft and spongy. I could just change the rope inside but feel that this would probably only delay the inevitable.

Questions.
1. Is the stuffing tube likely to be the main cause?
2. Is this a Volvo part or a Westerly part and where can I get one?
3. How easy is it to change?

Can anyone out there advise please.
Bob Hine
 
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Postby ex-Stormy Monday » Wed Jun 13, 2007 6:15 pm

Not sure why you feel that you need to change the entire unit and I'm no expert on the subject because I have a Volvo shaft seal rather than the traditional stuffing box. However, there is a lot of knowledge on the subject on the Westerly Owners' email discussion group, including recommendations as to how to change the stuffing as well as replacing associated rubber hose if required.
If you are already a member of the group, clicking on the link below should take you straight to the results of a search on the subject. If you're not yet a member, it will probably take you to a sign-up page.

http://groups.yahoo.com/group/Westerly- ... ndows-1252
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Postby cpedw » Thu Jun 14, 2007 9:46 am

Bob,
After 22 years I expect the stern gland probably needs re-packing. I think that would be a fairly straightforward process, though much easier done when ashore. If nothing is significantly damaged, it should give another 20 years service using the occasional squirt of grease.
As the owner of a Falcon (aft cockpit version of the Seahawk) of a similar age for 4 years, I would recommend changing to the Volvo shaft seal. This is a single rubber moulding that has a manufacturer's quoted service life of 7 years I think but anecdotes tell that it can continue for much longer. i suppose your sailing environment may affect that - muddy, silty water may wear it out quicker, as I guess will drying out onto mud.
To fit it, you need to disconnect the prop shaft from the back of the engine, remove the old stern gland, check that the shaft is undamaged at the seal area, fit the new seal (2 Jubilee clips secure it) taking care to protect its lips with the supplied tool, give it a wee squirt of the special grease, reconnect the prop shaft and continue.
It's more than a 5 minute job but not a terrific amount of work, and well worth it for drip free sailing, I think.
You need to get a seal of the correct size, involving measuring both the shaft diameter and the stern tube diameter. Volvo places can supply them, such as http://www.volspec.co.uk/ and http://www.keypart.com/.

Hope that helps.

Derek
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Postby ex-Stormy Monday » Thu Jun 14, 2007 11:14 am

If you do go the Volvo shaft seal route (as previously mentioned, I have one and it is excellent), be aware that it requires venting on launching and after drying out.
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My stern gland problems.

Postby Bob Hine » Thu Jun 14, 2007 2:09 pm

Thanks to both of you for the replies and the info. Have looked at the Yahoo forum and it would appear that the shaft seal route is extremely popular with those who have converted over. I will investigate the equivalent for the Seahawk with it's longer shaft and gland and see how cost effective it will be against the straight replacement of the existing stuffing tube.
Bob Hine
 
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Postby rhumlady » Sat Jun 16, 2007 8:16 pm

Hi,
Have you tried tightening the nut and locknut on the shaft seal you have? if it is leaking then usually all that is required is to loosen the locknut and tighten the main nut but not too much or you will cause heating of the shaft because of friction. Then lock the two nuts and see how it goes. Check for heating of the shaft and gland once done.

Derek
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Further info.

Postby Bob Hine » Tue Jun 19, 2007 10:33 am

Have spoken to others on this subject and majority feel that I should go the simple route of repacking the tube and readjusting before taking any more expensive steps. I have had a quote from Volvo for a shaft seal of £65.00. I assume this is ex VAT plus any other addons that might be incurred. Thanks to all for your help and interest. I'll keep you all posted as to how I progress from here.
Bob Hine
 
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Further Info.

Postby Bob Hine » Tue Aug 21, 2007 12:10 pm

Have had the boat out of the water and have repacked the stern gland. Not as difficult as I feared but had a job getting old packing out, it was really tight inside the gland and I ended up trashing it somewhat to get it out. Repacked it with 1/4" packing (three strips) and bags of grease. So far it seems OK but like most things time will tell!! Thanks for everybodys help. Bob Hine.
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