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We are laying up ashore this winter so I am planning to get some below waterline mods done. We want to replace our existing stuffing gland with a shaft seal and also fit a rope cutter. For the shaft seal there doesn't seem to be much room betweem the stern tube and the universal joint. Can anyone recommend a suitable seal that will fit? I was also hoping that by disconnecting the universal joint and removing the prop that I can draw the shaft inwards to facilitate fitting the seal. Is this possible or am I being naive? As for the rope cutter I have always been impressed with the Spurs scissor type cutter -- until I saw the £500 price tag!! The circular blade type are much cheaper but I am not convinced that they can be effective. Does anyone have any experience of this type in action?
SeaDog Name (if owner or crew) Star Dog
Graham
Sep 2, 2009 - 12:07PM
Re: Prop Shaft
Hi,
No info about the shaft seal, we still have the original stuffing box.
Re the propshaft, you will almost certainly find that you will need to disconnect the universal joint (both bits) so that you can remove the propeller anyway. the shaft needs to move forwards to give enough room in front of the rudder.
We have had an Ambassador 'Stripper' on Dougal for several years now, it is similar to the 'spurs' and seems to work well, no evidence but since fitting we have not suffered from a fouled prop. Previously seemed to happen at least once each year.
all the best
Graham
SeaDog Name (if owner or crew) Dougal
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Alan and Deb
Sep 2, 2009 - 1:05PM
Re: Prop Shaft
Thanks Graham. Hope you are having a good expedition this summer. Interested to hear that you still have the original stuffing box. the main reason that we are thinking of changing to a shaft seal is that despite having repacked the stuffing box two years ago (with traditional packing not PTFE and as per Peter's instructions in an earlier journal). We still get quite a drip, 3 or 4 a minute, enough to need a good 100 pumps on the bilge after three or four weeks away. I have taken to tightening the gland slightly before we leave every time using the benchmark that I must be able to turn the shaft easily by hand to avoid overtightening. Even so after a couple of hours motoring it's back to dripping merrily, always more than the one a minute usually quoted. Be interested to hear other views as I am actually reluctant to fit a seal and thereby rely on a rubber bellows but am fed up with constantly monitoring the stuffing gland.
SeaDog Name (if owner or crew) Stardog
Graham
Sep 2, 2009 - 1:27PM
Re: Prop Shaft
Afternoon Alan,
We are presently on Ile D'olleron and planning the last stage of this years cruise to take us back ro Rochefort, should be home in a week or two after settling Dougal for the winter.
We re-packed the stuffing box about 7 or 8 years ago and since then I have tightened it about half a turn each year after launch, seems OK, though I admit that because of our aft cabin king-size bed I rarely check. We do have a bit of a leak on the rudder gland, mainly due to the extra weight we carry on our long cruise (wine in the aft cabin!)
I tend to switch on the electric bilge pump for a few seconds every couple of days and it spits out about a cupfull.
regards
Graham
SeaDog Name (if owner or crew) Dougal
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Russell Stevens
Sep 2, 2009 - 3:36PM
Re: Prop Shaft
Hi Alan and Debbie
I would be very careful with shaft seals in general. I had a 'deep sea' seal on a prvious boat and it developed a slight leak. this was lucky because these seals rely on the two seal faces mating closely together under pressure. If anything gets between the two faces it could cause a catastrophic leak. My advice is to repack the old stuffing box.R
SeaDog Name (if owner or crew) Spinner
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Graham
Sep 2, 2009 - 4:01PM
Re: Prop Shaft
Interesting discussion on shaft seals on the ybw forum http://www.ybw.com/forums/showthread.php?p=2225868
Another option for StarDog might be to fit a remote greaser, then a squirt of grease before you leave her might save all that pumping on your return?
SeaDog Name (if owner or crew) Dougal
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Eric Richardson
Sep 2, 2009 - 6:14PM
Re: Prop Shaft
Hi Alan & Debbie
Seems like long time no see, Hope youare both ok.
Re the shaft seal. In my opinion a deep sea carbon face seal could not work on a Seadog which has the intermediate short drive shaft. the reason for this is that over the years the neck ring in the stuffing box is bound to have worn a bit and the shaft is undoubtably being held in position by the gland packing. With the packing removed shaft whirl would occur and swiftly Knacker the seal faces.
If you are having problems with gland packing there could be a number of causes, the most likely being the surface of the prop shaft. Taliesin used to eat packing when I bought her, this was due to crevice corrossion in the gland area of the shaft due to being packed with graphite packing. Incidentaly many marine stockist sell graphite packing which is far to nobel a product and causes the shaft to fail.
If you are having to keep tightening the packing and it seems to be disapearing its a neck ring problem which can be sorted but its a bit of a bugger to do though this is unlikely.
The problem today is that asbestos packing is no longer available, it would give a good ten years life in most of our boats.
The best thing to do is to speak to Walkers Packings at Leeds, I know they do a replacement for the asbestos packing which was called SEXTANT if my memory is ok, it's not as good but will give reasonable service.
An old dodge is to buy packing one size up and hammer it to fit thickness when fitting, making sure that joints oppose or are stagered by at least 120deg.
I packed Easy Go this way in 2005 and have not had to touch it since, it only gives the occassional drip when running and is dry otherwise but not running hot.
Regards Eric
Eric Richardson
Sep 3, 2009 - 9:25AM
Re: Prop Shaft
Hi Alan
Gland Packing, Walkers Packing details, Lion Works, Woking. The technical dept is very helpful, unfortunately you can only buy packing by the box!
Eric
Graham
Sep 3, 2009 - 9:36AM
Re: Prop Shaft
website for Walker is http://www.jameswalker.biz
SeaDog Name (if owner or crew) Dougal
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