Shaft packing replacement

[wayneking]

I'm looking for some advice. The boat is hauled out getting the bottom painted. I'm wondering if I should change the shaft packing while it's on the hard. I don't have much history on it. The engine/transmission only had 30 hours on them when I bought the boat almost 3 years ago so presumably the packing was relatively new then. About 120 hours now +/-. There was a bit of a drip while idle when I bought it. I tightened it a small amount a couple of times and it's been fine since. Doesn't drip while idle, drips a small amount when the shaft is turning. I don't have any experience on when to change the packing. Is it OK if it's not dripping or should I change it as a matter of practice when it's out of the water?
Thanks,
Wayne King

 

[G Kiba]

Packing should not have to be done every time you haul the boat and I am told you can repack in the water but it is a risk. Packing should last years and if it was recently done may only need periodic adjustments to control drips. I think your question about this will get a lot of varied responses that will all make sense.
I recently adjusted my packing to drip less than it was. I know that if you over tighten the packing you risk damaging the shaft. So I used one of those an inexpensive infrared thermometers to help find the right tightness. I tightened the gland and checked temperature until I found the leak stopped or was very slow at a low temperature after running for 5 -10 minutes in gear at higher RPMs. Use the dock lines to hold you in the slip. You can really dial it in by watching the shaft/stuffing box temperature.

 

[Alan Gomes]

Doesn't drip while idle, drips a small amount when the shaft is turning.

This is a perfect adjustment. I'd leave it alone. Just have some packing on hand for when you do need to change it. It is no problem to do it in the water if you need to. Your bilge pump should keep up with the flow just fine.

 

[frick]

Packing should not have to be done every time you haul the boat and I am told you can repack in the water but it is a risk. Packing should last years and if it was recently done may only need periodic adjustments to control drips. I think your question about this will get a lot of varied responses that will all make sense.
I recently adjusted my packing to drip less than it was. I know that if you over tighten the packing you risk damaging the shaft. So I used one of those an inexpensive infrared thermometers to help find the right tightness. I tightened the gland and checked temperature until I found the leak stopped or was very slow at a low temperature after running for 5 -10 minutes in gear at higher RPMs. Use the dock lines to hold you in the slip. You can really dial it in by watching the shaft/stuffing box temperature.

great advice

 

[Pete the Cat]

I second all that is said here. A little drip underway on a conventional packing is just fine and, for goodness sake, leave it alone. I use the green clay stuff on my boats to achieve dripless results that has lasted for years, but I don't actually recommend it to most folks because it requires a very clean and entirely smooth shaft (new is best) and quite a bit of fussing with nut tension to get it perfect (completely dry and not producing heat). In Maine, this is the preferred solution for the lobster boats (which is where I learned to do it--though the instructions in the kit are clear and correct). Once set, mine has been running cool and dry for the last 10 years. I could do a video on this (I don't think there is one on Youtube yet) but I really do not want to deal with folks with scored shafts and those who are not willing to fuss with the settings for the first 30 hours--it is a fussy job requiring patience. Sounds like you have a well set, very traditional packing situation and I would stick with that for now. If you have to replace it, I have done it in the water. It is a bit wet (use a towel) and a terrible time to be learning how to do it (there are excellent videos on Youtube about how to remove ALL the old packing--which is the key). For some reason the Ericson Owners manual specifies 1/8"packing on a 1" shaft--I know of no professional boatyard that would agree with that. On a 1" shaft you need some 3/16" rings (I carry them pre cut as spares) and some Syntec grease. It would be good to cut some rings that fit your shaft and watch a Youtube video as a kind of safety drill--to be prepared. I have no safety advice for folks with the PSS mechanical seals. You just need to have a towel to sacrifice (been there done that) and hope you are near a Travel lift before the leak overwhelms your bilge pump. I understand the new models of PSS seals are significantly improved, but they still are not adjustable or repairable underway. I believe the packing gland should be checked as a regular part of start up and shut down--generally the designers make sure to make this extremely difficult if not impossible, a huge problem in production yachts.

 

[Christian Williams]

The PSS, should it fail, should be surrounded by latex cloth, or a thick plastic sheet, and the wrap held by hose clamps. I carry such a kit on board and my tests give me confidence it will work.

Sailing is then the only means of propulsion, since the engine can't be put into gear. But it can still run in neutral to charge batteries.

 

[Christian Williams]

This offhanded discussion caused me to check the dripless emergency kit, where I found the latex had deteriorated and gummed up after 10 years. Hmmm. Oops.

I replaced it with four feet of Sunbrella fabric, which I think will serve the same role of emergency PSS wrap when secured by the hose clamps.

 

[AK67]

Packing should not have to be done every time you haul the boat and I am told you can repack in the water but it is a risk. Packing should last years and if it was recently done may only need periodic adjustments to control drips. I think your question about this will get a lot of varied responses that will all make sense.
I recently adjusted my packing to drip less than it was. I know that if you over tighten the packing you risk damaging the shaft. So I used one of those an inexpensive infrared thermometers to help find the right tightness. I tightened the gland and checked temperature until I found the leak stopped or was very slow at a low temperature after running for 5 -10 minutes in gear at higher RPMs. Use the dock lines to hold you in the slip. You can really dial it in by watching the shaft/stuffing box temperature.

I like the science-based approach and get the part about checking for drips at various revolutions, but how did you determine the acceptable temp range?

 

[Pete the Cat]

I like the science-based approach and get the part about checking for drips at various revolutions, but how did you determine the acceptable temp range?

You generally don't want it over 140°F or hotter than you can hold onto it at cruising speed. Be very careful working around a spinning shaft.

 

[G Kiba]

So right about working around spinning shafts Ray. I didn't come up with any specific number but thought if it was cool to the touch, after shut down of course, and after being engaged for 15 to 20 minutes and not dripping, It would be fine. So maybe less than body temp? So far so good.

 

[Pete the Cat]

So right about working around spinning shafts Ray. I didn't come up with any specific number but thought if it was cool to the touch, after shut down of course, and after being engaged for 15 to 20 minutes and not dripping, It would be fine. So maybe less than body temp? So far so good.

The instructions and the folks who work with the clay and synthetic flax say it can be warmer than packings that drip, but not too hot to touch. I have had dripless in my Tartan for well over 1500 hours. But it requires an unscored shaft and a bit of break in and adjustment in the first few hours to set it. Then don't mess with it. The shaft on my Ericson was scored by the PO overtightening conventional flax and I have had a harder time getting that set--it will work for 30 hours and then start leaking--my option is probably to replace the shaft at some future date. There is not room for a PSS even if I wanted one.