Deep sea seal versus traditional packing box and greaser

In the past few weeks I have been expanding the stern gear section of my website with considerable input from many posters, to whom I offer thanks. I am pretty much up to date with the stern glands section and now have photos and information on almost all of them. I am still working on couplings and some other stern-gear aspects.

I am now turning my attention to calorifiers.

If you wish to look at the various designs available please do. Any further offerings are very welcome although there is not much space for duplication, unless there is something unusual about your design. Failures, problems and solutions are always welcome. If you have any comments, criticisms or anything else to add, please PM me or submit mail and photos to engineer33@btinternet.com

Once again, thanks to all those who have or will contribute.
 
laurance said:
Worried now, there are posts suggesting that peoples' packing glands don't leak much. The old boy that taught me the basics 20 years or so ago told me the worse thing was to over-tighten them, you want to see a drip every couple of minutes with engine at rest I was told. I have dutifully set them that way ever since. I am also sure I read the same advice in the instructions of one I installed not so long ago. Wrong?
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I've always understood that 2 drips per minute when running was about right. I wouldn't want any drips when stationary.
 
silver-fox said:
What about the safety of a traditional stern gland but without the drips?

http://www.defender.com/realproduct.jsp?path=-1|311|53222|292328&id=569190

i have used this for the last year and am very pleased so far.....
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Once you accept the drip, there is very little wrong with the traditional stuffing box, particularly on small HP and low shaft speed applications (eg yachts). Problems arise when they are not adjusted properly or are overstuffed with grease which reduces the flow of cooling water. Their bad name comes from neglect rather than any fundamental design fault.

However, lip seal designs are more tolerant of neglect and many have two seals for extra security.
 
stick to the original I had a seal fail and lost the boat which was sitting on her moorings I heard that the newhaven lifeboat had a failure about the same time 7or 8 years ago
 
parsifal said:
In what way did the stern gland fail?
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Rough passage en route for home - we arrived late at night in a harbour and found a mooring that we could leave the boat on and return to complete the passage home a couple of weeks later. I hadn't realised that the packing was wearing thin and I certainly forgot to give it the extra grease it required as it was dark, raining and late at night and I was dog tired.

When I returned a week later, the boat was nearly flooded. All the batteries were written off and the engine didn't enjoy the partial submerging either.

Lots of pumping and bailing and the boat floated to her lines again. Couldn't start the engine as the batteries were all duff.

Towed her into harbour using the dinghy alongside and bought a new battery for the engine etc. Repacked the stern gland and the problem was solved for the time being.

Of course this was user error, but I am a bear of little brain and when I have the chance of a seal that simply doesn't leak. I fit one of the said seals. I know that there is the possibility of catastrophic failure, but I will take the chance. PSS seals seem pretty well engineered.
 
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