Dripless shaft seals - the forums recommendation in this situation......

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PetiteFleur

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We want to fit a dripless shaft seal on my friends Contessa 28. Had the original conventional stuffing box on a length of rubber tubing, now unclamped and slid along the shaft. Shaft diameter is 1" Dia. and the stern tube is 42/42.5mm Dia. (difficult to measure at full arms stretch with calipers). I have a Volvo rubber seal on my boat and it's fine, no leaks after 8 years. Volvo say the standard 1" /1.75" seal won't compress down to seal the 42/42.5 stern tube and it's not recommended to use the 25/42mm metric seal as you'll have excessive wear on the lip seal. (Although I am pretty sure my Volvo seal is the metric 25mm version on a 1" shaft and it does not leak).
Oh, and the shaft is not concentric with the stern tube.
Also spoken to dealers about Deep Sea Seals , PSS seals and Tides Marine. I realise we will have to align the shaft with the stern tube to get them concentric for all these seals, hopefully not a big problem. There is a P bracket externally.
Has anyone any experience of the Volvo seal and fitting to undersized stern tube? The volvo seal appeals due to cost and my experience on my boat.
Any other recommendations ?
 
You could try a Radice RMTA seal, which is much like the Volvo seal in principle, but comes with a bleed tube (so no need for 'burping'). It's had many recommendations in threads on dripless seals (so much so that I have one ready for fitting.)

It's available for 1" shaft and 42mm tube.

You can find it on page 16, here: http://www.sillette.co.uk/pdf/sillette_marine_propulsion_catalogue.pdf

Not sure about the concentricity issue, though. Wouldn't that need fixing whatever type of seal is employed?
 
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Last winter I fitted a Tides Marine seal to my Fulmar. The reason I chose it was it does not need to be burped as it is water fed from the engine. Very easy to fit provided you have sufficient length between the gearbox and stern tube. There is no need to align it as it is so flexible it self aligns, so this may be of help for you.
 
I have just changed my Tides for a PSS. The Tides requires a pressurised water feed. If that fails due to a blockage or impeller fail then the Tides will soon overheat and wreck itself (see my comments on the seals section of coxemgineering website).

The propshaft was worn but a PSS bridged the worn bit and does not rely on a lipseal to the shaft unlike most others.
I hope it lasts as long as those here have experienced.
 
What was wrong with the traditional stuffing box. With modern packing and correct adjustment there is very little leak from them. If it was me I would repack with PTFE or graphite impregnated packing, replace the stuffing box hose if necessary and get the shaft centred in the tube.
 
Spyro said:
What was wrong with the traditional stuffing box. With modern packing and correct adjustment there is very little leak from them. If it was me I would repack with PTFE or graphite impregnated packing, replace the stuffing box hose if necessary and get the shaft centred in the tube.
Click to expand...

Fewer suppliers for PTFE now in view of the problems with it. Neither ASAP nor T Norris stock it.

Stuffing box is OK, I have it on one boat but the PSS on the other requires less attention. In something like eight years the PSS has been faultless and requires nothing other than pouring water over the faces in April and October.
 
vyv_cox said:
Fewer suppliers for PTFE now in view of the problems with it. Neither ASAP nor T Norris stock it.

Stuffing box is OK, I have it on one boat but the PSS on the other requires less attention. In something like eight years the PSS has been faultless and requires nothing other than pouring water over the faces in April and October.
Click to expand...

I've read about the problems with PTFE and experienced a "hot box" when first used however I found with careful adjustment it can run cool and be almost drip free.
 
PSS for me every time now. Excellent piece of quality engineering. Water feed not mandatory below 12 knots.

www.pyiinc.com

The one I have just changed on OB was tired out, and still not a drip from it. Important feature that the wear takes place on the seal parts not the shaft.
 
A wee question. Is the Volvo seal available in a 1" version, or can i just put a 25mm on instead?
I can get an 'orbitrade' copy of the Volvo for about £50, but only in 25mm.
 
vyv_cox said:
Fewer suppliers for PTFE now in view of the problems with it. Neither ASAP nor T Norris stock it.

Stuffing box is OK, I have it on one boat but the PSS on the other requires less attention. In something like eight years the PSS has been faultless and requires nothing other than pouring water over the faces in April and October.
Click to expand...

I notice that ASAP are supplying ptfe again so not sure if it was down to problems that they stopped.
 
RivalRedwing said:
Not much of a saving really given the importance of the item and the good reputation of the original...
Click to expand...

I have heard very good things about the Orbitrade. Also ASAP happen to sell it and I need to get some things from them anyway. Unfortunately they don't appear to do a 1" and I can't seem to find a 1" Volvo anywhere either.
 
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