Shaft seals

N

northern

Well-Known Member
Jan 17, 2007
3,526
Anacortes Washington
Boat Info
380 Aft Cabin 1989 Charts Timezero radar Furuno
Engines
Twin 454 strait shaft
We have a 1989 38 aft cabin with twin 454s. Hours on engines 1200. Boat runs in west coat salt water. We run between 1200 and 1600 RPM most of the time. The shaft seals seem to work well. We have never had any problems with them. Does any one know if they require inspection and or maintenance? If so how often and what is maintenance required?
 
Are yours dripless? Mine are not - they are old fashioned stuffing boxes with packing inside. If you have the old type like me, they should drip every now and again to cool the rotating shaft. If they drip too much, you tighten the big nut and reset the cotter pin. If you bottom out the nut and it still drips too much, you need to pull out the old packing and replace. Do NOT do this with the boat in the water. You could sink!

If you have dripless wait for someone else to respond b/c I know nothing about dripless. :grin:
 
Tanks for the reply. The mechanic called them dripless, but they drip a little when the shafts are turning and stop when the engines are off. They both seem to drip about the same. Drip rate is very slow as you do not see drips, just acumulation of water over time.
 
Northern:
I was under the impression that dripless are designed to NOT drip. They are an elaborate mechanism that pumps water in to cool the shafts. If they drip than I believe something is wrong. Hopefully others will respond to this.
 
rondds said:
Northern:
I was under the impression that dripless are designed to NOT drip. They are an elaborate mechanism that pumps water in to cool the shafts. If they drip than I believe something is wrong. Hopefully others will respond to this.
Click to expand...

You're correct. Dripless seals-well, they're not supposed to drip. They need to be serviced or replaced. Your boat is from the same era as mine- you may have the Tides Strong Seals. If so, you might get lucky and have a spare seal already in place on the shaft ahead of the seal. If you have the spare seals in place, you don't need to haul-out to replace them.

You'll need to post a pic or find out what you have for specific advice.
 
When you remove the worn dripless seal, make sure you do not scratch the shaft, otherwise the new seal will not work properly and could get ruined very quickly.

Mr Salt
2001 640 CPMY
Caterpillar C-12s
Cape May, NJ
 
tobnpr said:
You're correct. Dripless seals-well, they're not supposed to drip. They need to be serviced or replaced. Your boat is from the same era as mine- you may have the Tides Strong Seals. If so, you might get lucky and have a spare seal already in place on the shaft ahead of the seal. If you have the spare seals in place, you don't need to haul-out to replace them.

You'll need to post a pic or find out what you have for specific advice.
Click to expand...

Lets see/ I have found out my Starboard is a "Tide" and the port is a PSS with the crossover hose disconnected and a bolt stuffed in the end.

The PSS has a slow drip (only during use) which my marina believes they can stop.

I believe soemtime next year I am going to maybe get both replaced with the same type and have the crossover connected.

So I now have a question

How many members here have there seals dripping a bit during operation?

Here is a link to some answers about one brand

I am curious about this answer?



Q. Do I need water lubrication?
A. At hull speeds of 10 to 12 knots and above, a vacuum is created in the stern tube that draws the seawater used for cooling and lubrication. At slower hull speeds, no water lubrication is necessary. The supply hose can instead be used to purge the air out of the seal when the vessel is put back in the water.
Click to expand...
 
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I have a 340 '89 searay express. 3 yrs ago, my shafts were dripping excessively, so my mechanic redid them in august while in the water. and no the boat didn't sink. very little water actually came in. However, the next summer they starting dripping to fast again, and I had to keep tighting up the nuts on both shafts. So last winter I restuffed the boxs myself while on land and this past summer I had no problems, and never had to tighten them. However, now my rudder boxs are leaking to fast and I want to repack them but they look imposible to get to, and look very different the the shaft boxs.. any one repacked the boxs on rutters before ??
 
Should be similiar design to your shaft stuffing, loosen one nut,tighten the other then resnug the first.(shaft stuffing boxes should drip a little in order to keep them cool, on the other hand the rudder posts don't need to drip as there is no heat)
 
If you can't see them drip, but water is just accumulating, you may very well not have a shaft seal problem at all. Look for other sources. Check for water stains along the bilge below the shaft seals. Check for changes over time. Clean the area and look for new stains. Rain water can collect in the bilge. Hoses loosen up and leak (especially when it gets cold out).

If you can, have someone drive the boat and observe the shaft seals under way. Mine were actually leaking at about 1200 RPM and above, but barely dripping at rest.
 
Have finnally got around to restuffing the rutter stuffing boxs. I found that I can hang upside down and reach in and have undone the top nut. I was hoping the area to be stuffed would be on the bottom and visible but instead are in the top nut and so can't be seen. so will be digging the old stuffing out without seeing it. was thinking i'd just put more in and leaving the old in as it seems to be just about gone. any ideals, also wants a good "digging" tool to dig the old stuffing out?
 
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Next time you're in for a dental visit just ask the dentist or staff if they have a spare "pick" or two. Most dentists are only too happy to donate an old or damaged instrument. Usually one end breaks from a scaler or explorer and it's useless to the office, so they'll sterilize them and keep them around for mechanics, wood carvers, hobbyists. They're great for removing Racor "O" rings. Just ask.

James
 
Assuming the boat's on the hard, I'd block the rudders, remove the rudder shelves and pull the packing nuts.

You mentioned in your previous post that they had been leaking for a while- no doubt the tube and packing nut could be all crudded up inside. Then you've got the issue of hanging upside down and trying to get a few turns of packing in there properly- meaning splices staggered 180 degrees. Without cleaning you run the risk that you could do all that and it might still leak. Not saying it won't work without doing this, but if it were me I'd go the extra step...

How difficult would it be to remove the shelves and pull the packing nuts?
 
I have the same shafts. I do not have a cotterpin to lock in place. Had the packing nuts repacked near the end of the season as I had tightened the nut to the max. I was still having problems getting the shafts to drip just right. I believe the manual says one drip every 20 seconds. Once I set them while at the dock and everything looked good, I would return and see them running like a tap. I would continue to try to set, but still was having trouble finding the right setting. You ever have this problem?
rondds said:
Are yours dripless? Mine are not - they are old fashioned stuffing boxes with packing inside. If you have the old type like me, they should drip every now and again to cool the rotating shaft. If they drip too much, you tighten the big nut and reset the cotter pin. If you bottom out the nut and it still drips too much, you need to pull out the old packing and replace. Do NOT do this with the boat in the water. You could sink!

If you have dripless wait for someone else to respond b/c I know nothing about dripless. :grin:
Click to expand...
 
Do you know what they used to re-pack? If was the old wax rope stuff, you need the drip. If they used the Gore product, you don't. There is no friction from GORE stuff and somehow they remain cool all the time, even after a long run. So you no longer need a drip. With the waxey stuff, you need a drip and after a run, at least during the adjustment phase, they will drip A LOT. Ask your mechanic what product was used.

Since I repacked with Gore, mine do not drip. I found it hard to believe that I wasn't doing damage so when returning to the dock I immediately climbed down and felt both shaft logs. Cool to the touch, even on a hot day in the sauna that my bilge becomes. I'd done this several times until I felt comfortable that nothing was amiss.

http://www.gore.com/en_xx/products/sealants/packing/gfo_packing_fiber.html
 
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Thanks for your reply. I believe the stuff he used was the wax type, but I will ask. Sure like the idea of no drip, or very little. I dont want to spend nor think I need to spend money on installing dripless shafts as I can think of better things to spend that money on when it comes to the boat.
The boat does not leak antwhere else and I dont mind a bit of water in the bildge as I am a believer in a little water down there can be a good thing when it comes to discovering an oil leak. That happened last year when I seen some oil in the bildge and found out it was a transmission bolt that had a steel washer on it rather than nylon and it started to leak just enough to show oil in the water in the bildge. Probably wouldn't have discovered that for a while as the transmissions are more up front. I checked the tranny oil regular and it wsn't down enough to to tell me there was a leak. Bottm line, I will stay with these shafts and try the Gore material.
rondds said:
Do you know what they used to re-pack? If was the old wax rope stuff, you need the drip. If they used the Gore product, you don't. There is no friction from GORE stuff and somehow they remain cool all the time, even after a long run. So you no longer need a drip. With the waxey stuff, you need a drip and after a run, at least during the adjustment phase, they will drip A LOT. Ask your mechanic what product was used.

Since I repacked with Gore, mine do not drip. I found it hard to believe that I wasn't doing damage so when returning to the dock I immediately climbed down and felt both shaft logs. Cool to the touch, even on a hot day in the sauna that my bilge becomes. I'd done this several times until I felt comfortable that nothing was amiss.
Click to expand...
 
If you have straight shafts and the stuffing boxes are accessible, there is absolutely NO reason to convert to dripless unless you want to stimulate the economy. This material has been used in industry for many years under much more extreme conditions than our boats can muster and is tried an true. You probably need 1/4" packing material (please check with SR or your mechanic!) - this is the best price I could find. I just ordered more for my rudders.

http://www.e-marine-inc.com/products/gfopacking/packing.html
 
Thanks,excellant, am going to order now so I will have available for launch. I'm in Ontario Canada so its going to be a while yet. Still looking at about 2-3 feet of snow outside. You have been a GREAT help.
rondds said:
If you have straight shafts and the stuffing boxes are accessible, there is absolutely NO reason to convert to dripless unless you want to stimulate the economy. This material has been used in industry for many years under much more extreme conditions than our boats can muster and is tried an true. You probably need 1/4" packing material (please check with SR or your mechanic!) - this is the best price I could find. I just ordered more for my rudders.

http://www.e-marine-inc.com/products/gfopacking/packing.html
Click to expand...
 
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