Stern gland tighten or not?

whiteoaks7

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Joined
29 Nov 2002
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570
Location
South Wales, UK
www.seasolutions.co.uk
Moody Eclipse 33 stern gland - one big cap nut (47mm across the flats) through which the shaft runs, plus a locknut. The gland has started dripping enough to need bailing once every couple of days and I want to tighten it down a little (it's already had all the grease I can pump in there). Point is I'm a little worried about tackling the job here while I'm floating around in a foreign harbour. The nuts seem pretty well welded together and are going to need a stillson or something to shift them, so the question - what is the risk? I don't want to take any risk that might make the leak worse until I can be sure I'm near a haul-out facility. Or am I being paranoid?
 
I suspect that the nuts probably look worse than they are. Your words suggest quite a flow of water? If that is right, you wil probably make a little more when the shaft is spinning. I would be tempted to see if the lock nut backs off easily and then tighten up the cap nut. The advantage of doing it in the water is that you will be able to see the drip reduce - or not. If it doesn't repacking is going to be required and you'lll need to dry out. But you have packing in there, you grease it regularly, chances are that a very small turn of the cap nut will have results. The only real hazard as I see it is the whole lot is seized so solid that you have to use serious wellie to shift it and thereby run the risk of sheering something. So a gentle test.....

To put another way. You have a glass boat and therefore are not used to water in the bottom. I have a wooden boat that tried to sink on launch this year. It took up of course but for 6 hours there were 'jets' of water in one of two places. Not the best but the pump kept up with it very easily. I have since strained a seam trying to make a 45 year old cruiser act like a dinghy in some strong winds. There's a tiny dribble as a result but it can wait until the end of the season..... Pumping every couple of days to keep her dry isn't the end of the world. Mind you pumping her every two days to keep her afloat would, I suggest, indicates the need for action.
 
first can you dive under the boat safely,if yes pass a line around the shaft twice and push in the hole around the shaft then push in greased cloth around the shaft this will stop the flow of water ,when you need to remove it just pull out the rope,If there is a rubber pipe between the hull and the shaft seal have a good look at the hose and clips make shore you are happy with it all before doing anything,it is important not to twist the rubber tube when undoing the lock nut,if the nut will not move hold a large hammer under the nut and hit the top with anuther hammer this will spread the nut, to much will split it so gently gently
 
You should have no problem at all. It sounds as if you do not have suitable thin spanners, they are worth acquiring or having made to fit. I would avoid Stilsons if possible.
 
Since you can seal the shaft from the outside as Oceanpilgrim says you could fit a dripless seal(Volvo is the best) with the boat still afloat.I've done it at least three times ,twice just replacing a similar worn seal and once for replacing a stuffing box like yours.That included fitting a rubber hose and a bit of stainless tube to take the seal itself.That meant some preparatory work but the fitting time was so quick that all it took to stop water coming in was a simple rag around the shaft as I slipped the seal onto the shaft tube.
 
You will probably need the stilsons to release the lock nut, before you start treat with wd40 for a day or two, as for the packing if required we do ours whilst in the water, before you undo anything lay the packing around the shaft and cut to lenght, do 2/3 of these, then undo the gland push it out of the way, get in the tube with a hook and remove the old stuff, then replace it with new packing alternating the position so that the joints are staggered. Not much water will ingress, you will be amazed how little gets in. But as already stated maybe a small inward adjustment of the gland nut will suffice.
 
If yours looks like this!
You will need two sets of stiltsons.
Mark with a felt tip the top of both the nuts
Loosen by turning both spanner in opposite direction,(looking at this picture the nearest nut goes anticlockwise)
Turn nut nearest aft so it goes onto gland further about 1/4 turn and retighten.
Try engine, if still drip re do again.
Check for overheating if ok later.
DSCN1629.jpg
 
agree that stilsons are 'blunt instuments'. if you can get large open ended spanners that would be better, but use what you've got. Agree that the nuts may well look worse than they are. Suggest a bit of common sense about trying to loosen them. Try to back off the lock nut, and then tighten the cap nut. If it all seems stuck don't try too hard - put some penetrating oil on and try again later. If its really stuck, put up with the leak until you can get dried out, but at least have a go.
 
My aft nut is the locking nut - it's the fwd one of the two that compresses the packing.

Second I wish I had such room around my gland nut ! I have about 1" either side preventing any spanner from getting in there. So I have to use blunt chisel and hammer to 'knock' the nuts round. Terrible I know but there just is no room to move.
 
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