All Forums › Boat Talk › Stern glands
- This topic has 6 replies, 3 voices, and was last updated 6th Nov 2007, 1:35 pm by .
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- 14th August 2007 at 5:52 am #10975
I have just had to replace for the 2nd time my starboard stern gland due to serious water leakage. They have both bean Deep sea seal. The boats is a Ht 27 with Hydraulic drive units . The prop shaft is not fully central in the stern tube and so sets up a eliptical surface area on the two deep sea seals mated surfaces.
Has anyone suffered similiar problems or used a different make of stern gland for this type of installation?23rd August 2007 at 12:33 pm #11527Dave,
i don't know much about these seals but with exactly the same set up I am interested to know anything about them. It seems you're shaft must be well off line to be wearing out the seal rings so fast (costly). It makes me wonder what condition your cutlass bearings are in! Is there much movement there? Sounds like your shaft has a twist in it. Should you remove it and have it assessed? I'd be pleased to hear if you solve the problem and how.
Good luck,
Alastair2nd November 2007 at 12:53 pm #11528Hi Dave,
I saw your string on the HTOWOA web site and replied. Now I have a leaking deep sea seal!! I think they are both (I have two hydraulics like you) 15 years old and so I have decided to replace both of them. You seem to have done this (at least once!). Can you advise how to do it. Can you pull the shaft out of the hydraulic pump connector and then pull the whole thing through to the outside, without taking the prop off? On my set up the shafts go into a cast iron or steel jaw crimped together with 4 nuts with Allan Key hexagonal heads. If you loosen these does the shaft simply pull out or is it bolted on the end or have a cotter pin?
Otherwise I take it you have to take of the props (probably incredibly difficult after 15 years afloat), split the shaft from the pump (four standard bolts on the circular plate of the joint), remove the pump from the bilge cross plate and then pull the shaft through into the bilges, a lot more work! Can you advise?
Have you solved your problems yet, are you happy with the deep sea seals, I gathered your replacements wore out very quickly- how quick was that, did you find out why?
Hope you can help and all is going well with yours.
Best wishes,
Alastair
2nd November 2007 at 6:37 pm #11529Hi Guy's
These mechanical seals are basically the same as we now use in standard pumps in Hotels or we used to use on Subs. The only difference is the pressure they are up against.The two most important things are.
1: They must be completley alligned (spelt wrong I know) Both vertically and horizontaly .Within half a milimiter is almost to much.
2: Dont touch the face with your hands. Any grease or oil will completely screw them up.
Steve
4th November 2007 at 11:34 am #11530Steve,
Interesting what you say about grease, because when the seal began to leak the bilge had oily water in it, coming from outside. So does that mean that if you sit on an oily spot in a harbour or dock youmay ruin your seals?? Can they be recovered by cleaning with solvent? Surely that's a problem with the design then.
Alastair4th November 2007 at 4:57 pm #11531Hi Alastair
The problem always used to be that one face was carbon so it would bed into the other face. ( Originally both faces were carbon but they often use one ceramic now) The carbon is absorbent, when u get oil or grease on it it wears uneven.Steve
6th November 2007 at 1:35 pm #11532You obviously know a lot about these seals Steve. Thanks for the info. I emailed Dave and he has gone for PSS seals to replace the deep sea seals, because they are apparently more giving for misallignment. Also, he says they have one carbon and one stainlesss steel disc now, better as you say.
Cheers,
Al. - AuthorPosts
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