Re: Send packing the stuffing gland..
Yesterday I lifted out into the boatyard here in Portugal after a fraught 18 hours nursing a leak from the stern tube fitting. I think its Vetus and the it's the second potential sinking failure I have sustained in 3 years.
The original problem occurred during the short journey from my mooring to the boat yard. As I went below to turn off the engine, I noticed the cabin sole bubbling under rising water. When I opened the engine bay, it looked like the inside of a washing machine. So I umm .... shut it again quickly. It's kind of like when I used to fly small planes. The advice goes..If you have an engine failure at night, turn on your landing lights. If you don't like what you see......Turn them off again!
The Stern tube rubber is held on with 2 hose clips and the tube had come off.
Inspection suggested that the two rear engine mounts had sagged/failed and allowed the rear of the engine to drop down so that the shaft came into contact with the rubber hose and made it come off.
Solution was to fit new engine mounts and align. fit new rubber with bigger hose clips on both ends. I replaced the stuffing with that black Teflon stuff.
Re-launched boat 1 year ago. took some time to get the new packing to settle in as sometimes the drip would be too much and still leak when the prop wasn't turning and some times there was no drip at all when not moving or almost none when moving. I figured that in the end I would probably put another ring of stuffing in.
During the year I noticed that sometimes when I engaged gear forward the drip would stop and stay stopped so I made a habit of giving a little forward power just before shutting down. Two days ago I ran the engine to charge my batteries. when I stopped the engine I noticed that the previously dry engine bay now had water in it and was still coming in a bit too much so I employed the forward gear principle. Hmmm bad idea. When I shut the engine down I could hear the water coming in fast and saw it rising. I quickly deployed emergency pump no1 into the engine bay. It's a Rule submersible pump runs of the standard cigar lighter supply. I recommend one of these as its a fast way of making a start. Next In deployed he generator and emergency pump no 2 which is a Karcher garden pump. During this my partner was making access possible to the hatch that would allow me to get to the stern gland. but at least by this time we had the rising water under control.
On inspection it appeared that the rubber hose had rotated 180 deg and moved forward as there is no collar on the shaft forward of the stuffing box.
I did consider fitting one of these after the last fiasco but was advised that it might score the shaft. (Um would that matter there?)
anyhow so the upshot is that the rubber hose was on the cusp of coming off and water was coming in at the rear (aft) of the stern tube rubber and I was able to push it back on. However, when I tried to tighten the clips it got worse each time I tried. I took stock. It was 5 hours before high water (at night) and I had a long time to wait before I could get a haul out. I figured that if I continued to try and fit it back more securely it might come off completely.
I therefore elected to leave it trickling in at a 1/2 litre a minute which was better than 10 litres a minute I had not-so-long-ago. We took shifts and pumped with the rule pump alone for 2 mins or so every 35 mins. for the next 18 hours. I reckoned if I put the boat into gear then the tube would deffo come off so I arranged a tow to the yard about a mile away. Of course we had 30Kt winds to make things more fraught.
So now I am here in the yard, wondering If I can find a solution here to my problem. I have looked at the PSS seal video and think that it might be the way to go. Not least of which because the metal disc screws into the shaft a little and I could,would, WILL fit a shaft collar forward of that.
If those O rings ever failed it could be bad I agree but it would be possible to make a rubber washer that butted up to that thing between it and the shaft collar perhaps?
My original stuffing box greaser actually fitted to the stern tube and I was advised to lock it off so grease couldn't get into the rubber hose. That's why I fitted the Teflon braid. But I wonder if any residual grease got pushed by water pressure to loosen the grip of the hose clips holding the tube to the stern fitting. The stuffing box is bronze about 4 inches long and has a knurled hand tightening collar with a locking tab. (Poss Vetus?)
The rubber tube says Vetus 30 on it.
Sorry for the enourmous post but would be grateful for any suggestions as to why it came off as well as what would be the best solution now.