Water Lubricated Shaft Seals

I have fitted two Deep Sea Seals. Not cheap (£130-ish plus VAT each), but they are simple, have minimum set up requirements, require no-maintenance – & they seem to work. The only significant hassle fitting them was detaching the prop shafts from the gearboxes, when this had not been done for over 15 years. But that's another story. They are lubricated directly by seawater ingress thru the stern tubes – no need for any take off from the engine (although there's a connection to do this if required). My seals don't even get warm. You'd be amazed at the amount of water that flows through the tiny openings between the shaft 'bearing' and the shaft. Not sure how this works with a central diesel though). My research seemed to show that only faster revolving shafts (>3000/4000 rpm) require the fancy cooling arrangements. Look in PBO under T Norris – good range of products on website. For Deep Sea Seals, I used Lancing Marine (www.lancingmarine.com) – very efficient and quick. Hope this helps.
Nick, HT Gee Bee.

Nick,
I have an newly acquired HT 27 with deep sea seals. Like you have done, the seals although attached with tubing to the engine compartment, are not supplied with water from the engine pump (as recommended). They work well without the water supply as far as I can see, but I was worried about this since reading the manufacturers installlation manual it said water supply was necessary; so I am pleased to read you came to the same conclusion. When I ran the engine on purchase I noticed water in the pipes, a good check I think that the seal is being supplied by water from it squeezing past the cuttless bearing.
A worry for me though is that when I put the boat on the hard for the winter I inspected everything on the boat (as you would on a new purchase). I naively found the (emergency) red jubillee clips on the seals were loose and so tightened them. Subsequently, having read the installation manual acquired from T. Norris, I realised my error and loosened them again (never ran engine with them tightened). I am hoping that the emergency contraction of the gland is reversible when you loosen off the jubillee clips (T. Norris didn't know). Hve you any idea if it's reversible? The boat goes in the water this Saturday (21st) so I suppose I will soon find out! I will go with a thick plastic role and ties to shut off the seal if it leaks!

Nick,
Thanks for that. I was hoping you might have inspected an old seal during your change over. Anyway I launched and haven't sunk yet. You're right though I pulled back the seal to seee if water was coming up the stern tube and wow it fairly flows in. A complete failure would be catastrophic if unattended, but I think this would be very rare, more likely a gradual leak with excessive wear would be likely and now with the knowledge you've supplied the answer I think probably would be to tighten the emergency ring when unattended until sorted.
Happy sailing (afloat!), Alastair