What type of prop shaft seal is this...

Nauti Fox

Nauti Fox

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The starboard one has started to drip, I've only had boats with stuffing glands before, so what is it and what can I do?
Thanks.
Sorry for the missing photo, working on it.

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I had one of those and the mating surfaces corroded and wore out. They have a service life of 5 years IIRC though ours had done at least 10. Nothing to be done so I have now replaced it with a PSS seal that is a lot more robust.
 
I can confirm its a Deep Sea seal, and yes they are the pits. I had one that dripped from new. If the bearing face is undamaged, you are supposed to be able to reseal them by moving the sleeve down the shaft a little way to increase the pressure on the seal. But if as Hoolie says, the mating surfaces are not perfect it never will seal properly.
 
oldharry said:
I can confirm its a Deep Sea seal, and yes they are the pits. I had one that dripped from new. If the bearing face is undamaged, you are supposed to be able to reseal them by moving the sleeve down the shaft a little way to increase the pressure on the seal. But if as Hoolie says, the mating surfaces are not perfect it never will seal properly.
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Check ASAP's Orbitrade range-delighted with mine.
 
Thanks Gentlemen, looks like a lift out and replace with a different type then, I'll have a look through the archive to see what people suggest.
 
For that size shaft a Tides Marine is probably the best replacement. Fitted as standard to many larger power installations, particularly in US. Uses replaceable lip seals and is very well engineered and robust.
 
I seem to real that deep sea was one of the makes where you could install a spare on the shaft ready to go. I wondered if that was what was on your shaft.
Possibly you could try to improve what is there first by increasing the bellows pressure.
I did work on my Tides marine seal while the boat was in the water as the ingress was not so rapid. In my case there was crevice corrosion just at the lip I was able to saw 1/4" off the back of the bellows which moved the seal to 'a better' place on the shaft and the drip issue was solved. ( when next out of the water we replaced the seal with a PSS which does not rely on shaft condition).

If that is a spare seal on the shaft then you should be able to replace while in the water but, of course, be certain you have the means to restore the situation or have an emergency lift out plan in mind!
( for information we now believe that our crevice corrosion issue was due to the very poor/stagnant water condition in a Cagliari marina … no oxygen and long period unused.

Good luck
 
Don’t rule out the LasDrop Gen2 seal. It’s another variant of a face seal but uses a stainless spring to maintain pressure rather than a rubber belows so possibly more durable. At least I hope so having fitted one 4 years ago.
 
We also have one of those Deep Sea seals fitted. Interested to read about the rather short service life, as we've had this boat for over 10 years. No idea how long b4 that it was fitted. It still appears to have plenty of bearing surface material.
Apart from the ONE time I pulled it back to have a look, it's never allowed a single drop of water into our dry bilge.
 
Well, waited for a good low tide and replaced the seal, did all the preliminary work the weekend before and then again the day before just to recheck...
Slid the old seal back and cut it off with a dremel, surprisingly tough material and took a while, cleaned up the face of the static seal and then came to the only problem which was trying to get decent tension with the new seal, the only way I could do it was using the nylon insert from the old seal to hold it square.
Lying on your belly, wedged between bits of pointy metal while trying to reach down to the seal and compress it with the bellows and get it all square was a bit of a task....and then get the clips done up.
I ran it for about half an hour to start bedding it in but am still getting an occasional drip so I'll make up a "special tool", a section of mini guttering downpipe which is the correct size, cut in half then clipped together fitted over the shaft and long enough to get a good purchase to set the seal to the recommended compression.

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Special tool.....https://www.diy.com/departments/flo...gclsrc=aw.ds&dclid=CMTq_7Ppst0CFUsUGwodqhoHQQ
 
Tranona said:
For that size shaft a Tides Marine is probably the best replacement. Fitted as standard to many larger power installations, particularly in US. Uses replaceable lip seals and is very well engineered and robust.
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One data point -- I finally replaced the lip seal in our Tides Marine shaft seal this April, after 17 years of completely trouble-free service and 3000 engine hours.

Replaced it just prophylatically -- it was still working fine.

One of the few bits of original wearing gear on my boat which had not been replaced by now. Seems like good kit to me.

It is possible to change the seal without lifting out or removing the shaft. As noted above, however, the seal is made between the lip seal and the shaft, so wear or corrosion on the shaft can thwart the sealing. In practice maybe not a big deal since the design of the seal allows you to move it up and down to vary the position of the seal on the shaft to choose a nice clean place for it.
 
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