prop shaft leak

[Canopus]

Hi all,
I was checking out the ol' diesel and noticed more water under the engine than I thought should be there. looking around back I see a steady drip from the shaft just forward of the nut indicated in the pic


Is this indicative of anything bad or do I just need to tighten said nut?

 

[KWay]

Give it a 1/8 to 1/4 turn and see what happens; If you can not turn the nut most likely it is bottomed out and you will need to repack the shaft log.
Not something to do in the water; so then you have to decide if you what to go with the drip for rest of the season or fix it now. Not sure where you are located so I have no idea if you girl is pulled every winter or not.
Kent and Linda

 

[tenders]

That is the “packing gland,” or “stuffing box.”

Either that nut needs to be tightened a little (note that it should be locked against the thin nut directly behind it, so you’ll need to unlock it, adjust it, and relock it), or it needs to be unspun, the flax packing around it dug out with a dental tool while water sprays in around the shaft, and the packing replaced before retightening the nut so the drip almost stops.

This may sound more difficult than it actually is. It’s a simple system but it is very important to understand how it works and that it’s adjusted correctly. You should probably have a complete replacement of the packing in your spares kit.

Edit: you can do it in the water If you have spares on hand. In fact you should, because the final adjustment is supposed to allow a very slow drip during operation. There isn’t much space between the rotating shaft and the inner radius of the gland, although the water will spritz pretty convincingly when you’re doing the work. You can also have a diver stuff clay, or a trash bag, around the shaft to nearly stop the flow, and then remove it when you’re done.

 

[Canopus]

Thanks for the replies. I'll try to tighten it and hopefully that will do the trick.

 

[Loren Beach]

W

Thanks for the replies. I'll try to tighten it and hopefully that will do the trick.

Tighten a little and run it in gear a short while. Then feel the stuffing box for warmth. A little is acceptable but if it is hot, that's not good. Unless you have a record of the engine hours at the last time the packing was changed, best assume that this is one more item that falls under "deferred maintenance" and is overdue.
When we acquired our (well) used boat, the packing was hard and I would tighten and loosen (an eighth turn) and track the drips and the friction heat in the bronze coupler nuts.... and finally I replaced it all with a PSS Shaft Seal, back in '95 or '96. We still have that seal and have replaced (per the manufacturer's instructions and also caution) the bellows every 9 or 10 years.
If I were a more skilled mariner, I would doubtless have kept and learnt the arcane secrets of the packing gland, and also learned the zen of acceptance of sea water sloshing around in our shallow bilge....... but I was and am determined to have a dry bilge. Dust, if anything.
Best of luck to you. The 35-3 (and near-sibling the 34-2) is a great design!

 

[Canopus]

... but I was and am determined to have a dry bilge. Dust, if anything.
Best of luck to you. The 35-3 (and near-sibling the 34-2) is a great design!

My bilge until this past week was staying dry as a bone unless it rained (water comes down the mast). I suppose our more frequent excursions recently have gotten the leak going.

 

[debonAir]

Now that I have a flexible shaft coupler, repacking the gland in the water is not an option. There just isn't enough prop shaft to back the nut all the way off (which in some respects is comforting!). The flexible coupling didn't get rid of the vibrations I hoped it would fix so it might come back out.

I've heard of, but not tried using a bees wax toilet ring to squeeze around the shaft/log from outside the boat to seal it while repacking in the water, and even as an emergency patch for a lost shaft. Having installed a fair number of toilets and stepping on a few of those rings I can easily picture this working well but perhaps hard to clean up from.

 

[1911tex]

Now that I have a flexible shaft coupler, repacking the gland in the water is not an option. There just isn't enough prop shaft to back the nut all the way off (which in some respects is comforting!). The flexible coupling didn't get rid of the vibrations I hoped it would fix so it might come back out.

I've heard of, but not tried using a bees wax toilet ring to squeeze around the shaft/log from outside the boat to seal it while repacking in the water, and even as an emergency patch for a lost shaft. Having installed a fair number of toilets and stepping on a few of those rings I can easily picture this working well but perhaps hard to clean up from.

debonAir: way back on April 23 I did a test with flex-seal tape...keep a roll on hand...it may work fine for this purpose?

 

[paul culver]

I've been very pleased with my dripless PSS system.

 

[Canopus]

Today finally had a chance to address the drip. I was able to loosen the locking nut with my fingers so I guess the stuffing box nut vibrated loose.
I put about an eighth of a turn on it and the drip stopped. Put the locking nut on tight then cranked it up and put her in gear for a while. Everything stayed cool to the touch .

 

[debonAir]

That's scary. The nut should have a little nub on it with a hole that you can put a safety-wire through and wrap tight onto something close by to keep the nut from turning even if it vibrates loose.