Dampness under prop shaft, not packing leak

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Hawkeye

Hawkeye

Veteran Member
Joined
Jan 15, 2016
Messages
82
Location
USA
Vessel Name
Happy Clown
Vessel Make
Heritage 45 Europa
Just noticed seepage under the packing gland hardware, maybe called the shaft log? It is wet under the bronze piece that the packing gland collar tightens into. How is this piece attached to the hull and is it common that after 32 years I should expect water intrusion at that point? (This area behind the other engine is dry.) What kind of fix is required for this problem, average cost, specialty yard required, etc? Any help much appreciated.
Ted
 
A picture would help. What you are calling a packing gland collar can be interpreted in very many ways. You may just need to tighten your packing. Alternatively you may need to do something with what you are calling a collar. For certain when sitting quiescent there should be no leak.:D
 
I have dripless logs now, but previously had "stuffing boxes". I was always taught that you tighten them to the point where you get a small drip about once every 30 seconds to a minute when sitting.
 
I understand both responses above, Poach and obthomas. This dampness is apparently coming up under the "unit" (includes packing gland, collar, etc.) that takes the prop shaft thru the hull I think I've heard it called the shaft log or the sleeve (through which the shaft goes after, as in behind, the packing gland.) Any other thoughts about this?
 
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Never mind, I don't know what I was talking about.
 
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The stuffing box (packing gland) is attached to the shaft log by a short length of heavy duty hose. Those hoses do need to be replaced periodically. Check the hose for soft spots. It may not be the hose, the clamps holding the hose to the shaft log or the stuffing box may simply need tightening/replacing.
 
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Sounds similar to a problem I had on my boat a few years ago. The stern tube had perforated and water was seeping into the bilge. The stern-tube was encased in concrete and it was quite a job to chip it out. Never did get it all, without dismantling the boat and was unable to replace the tube, which was some form of stainless. This was on a 33 year old boat.
BTW the seeping accelerated dramatically, necessitating an emergency haul-out. Yard slipped a FG tube over the original and encased the whole thing in Resin and some form of sand.
Pretty pricey but it included new shaft and dripless seal and cutlass bearings.
 
Borrow the brides hair blower and slowly dry the area .

Find what is actually allowing the moisture to seep .

Bring a cushion , it may take a while.
 
Following FF's advice dry the area, then lay strips of cardboard around the suspected moist area. The cardboard with darken and provide a visual moisture indicator. By using strips, you can more easily check each and try to localize the problem.
 
I second FF's idea. Also consider condensation. Not uncommon in the winter time for metal parts exposed to cold water to form condensation inside the hull. Of course that is ruled out if you have a steady stream...

If you do have a leak around the shaft log thru-hull or fixed bronze packing gland attachment you will most likely need to haul your boat to fix it. The fixture will have to come off to check for corrosion or worn out sealer then a proper repair made.

If your prop shafts are original their is also a chance you may find problems there too. Angus99 recently posted a thread that shows what crevice corrosion looks like on rudder shafts. It is likely on original propeller shafts in a boat the age of yours.

Check the whole underwater gear if you have to haul to address the leak. Strut bearings, shaft & engine alignment, propeller shaft and whether to go back with same type seal arrangement. Once you start repairs or replacement of some or all may be necessary. Planning for that eventuality can help avoid unexpected expenses. Not that you should avoid them just be prepared if they are necessary.

FF said:
Borrow the brides hair blower and slowly dry the area .

Find what is actually allowing the moisture to seep .

Bring a cushion , it may take a while.
Click to expand...
 
Not all packing is designed to drip. I assume that you are not the original owner as I don't think any packing lasts 32 years.
 
The Eagle had a leak be hind shaft log where the log connects to the shaft tube. Had to pull the boat, pull back the shaft, take out the log, cut out the punk wet wood, fill with area with epoxy, install a new SS backing plate, reinstall the shaft log. Took about two weeks most of the time was drying time. Cost 2 to 3 grand.
 
This is TF at its best! The info is exactly what I need to figure out next steps. The problem is clearly not the packing gland, the dampness is behind (downstream) that unit. I hope it is the hose that TDunn mentioned. Access to that requires removing the large s/s water lift muffler that is mounted on the diamond plate right over the hose area. I'll try to unfasten the muffler and peer in that space, avoiding taking off the 8" very stiff exhaust hoses. Wouldn't you know that all of this came to light a month after my 3 year haul out routine. Nothing turned up with the running gear then. Murphy....I really worry about what ianonhercules said--that his problem "dramatically worsened." At 33 years old, and my owning and maintaining it for 25, I thought I knew, or should have expected, it all. I'll let you know what I find. Has anybody other thoughts on this?
 
In that case you really need to dry the area and watch for the first drop. I have seen weeping actually through fiberglass. Strange as it sounds.
 
Got to the boat this weekend and pulled out the tools. First thing I noticed was that the nuts holding the entire prop log/packing gland "system" in place were a bit loose. Took up almost a half turn on the four 3/4" nuts and the dampness soon dried. While under the the diamond plat n that area (removing bits anchored on them) I also got an easy quarter turn out of the nuts holding the prop support in place (home of the cutlass bearing,forget the name of this piece.) I did the same on the starboard side. In all, 16 3/4" nuts were each a bit loose. Lesson learned: there a plenty of places in the engine room that are completely out of sight...look around, regularly.
Ted
 
Great news. I had missed the fact that your boat has twins....which is an entirely different situation to a single engine installation, which was my case.

Ian Munro
Carver 350 Voyager
ex Hercules(DeFever type 39' trawler)
 
Sounds like what I just went thru. Took our 37 ' Pacific Trawler to have a packless system installed. they found that both seals on the shaft were leaking. plus corrosion to the shaft. ended up having to have both bearings replaced as well as the SS shaft. I was glad I had a co-owner to share the cost with. Lots of issues with ours. $5000+. Modutech Marine in Tacoma did the work. that also answered the question of why we had so much vibration anytime we got above 1750 RPM.
 
Ouch! But I don't understand where the seals that went out were located. I thought that the packing material was the seal. And the corrosion on the shaft where was it located? Caused by crevice corrosion I;m guessing. I don't have any vibration all the way up to WOT at 2800 RPM but am always worried that something completely out of sight is going south on me.
 
one seal is where the shaft exits the hull. if that seal is compromised then water enters into the shaft area. the second seal is the one where the shaft enters into the bilge area. the packing gland may be fine but the seal holding the packing gland is not.
 
Thanks 37Pacific. I wonder if most trawlers (or boats in general) have these seals? I've always thought that water was kept out of the boat because of the tight packing material forced tight by the packing gland collar. Can anyone shed light on this? It is important because several people have commented that the shaft log, cemented or glassed in tight, could be failing due to material/bonding failure of the log where it enters the hull, none mentioning "seals."
 
I have had boats with seals on the outside or the inside never both.




Double seals is a new concept to me. Sounds like the trapping of water in between with no flow would encourage corrosion.
 
I found this thread and will add to it here since I searched "shaft log" and this thread seemed the most appropriate. On The Promise I pulled the sole up in the aft cabin to inspect something else and notice the shaft tube looked a little cruddy. Feeling around it I noticed it was moist on the underside, and using a rag to clean it up a but came away with some rust.

Forward of this, through the bulkhead is the stuffing box, and all that looks fine. The engine turning 1200rpm produces one drip every 4-5 seconds. So I'm not sure where the moisture on the shaft tube/log is coming from. The tube was painted at some time in it's life, where the paint had peeled off I can see it appears to be some kind of stainless, so I'm not sure why its rusted.

And this situation may have been going on for years.

Any thoughts?

https://youtu.be/cbP7bd0Mx8w

https://youtu.be/jC_B8WiszNY
 

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Stainless will rust if it does not have a supply of oxygen. If it is submerged in stagnent water, the water oxygen content will drop and then the stainless will rust.
 
Thanks Dave. I'm trying to understand what I'm looking at. It seems at the aft the shaft log slides into the end of the square bronze plate, as can be seen on the forward side. Could it be that the end of the shaft is not what the hose clamps are clamping to as is what should be typical? Does that make sense?
 
Not sure. I have not seen a shaft log like yours before. There are a bunch of different types.
 
Most likely the stainless section threads into the square bronze fitting where the hose attaches. Interesting there is no water supply plumbed into the shaft log. Typically some raw water from the engine is diverted to flow through the shaft log.

The shaft log pipe is likely corroded through in a spot and oozing. It is not under any kind of load so you could seal it and go on with your life unless probing indicates the pipe might crumble and fail. If that is the case you will need to replace it.
 
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