Stuffing Box

[ELECTRA VI]

I was out a week ago and had a nice run offshore to blow out my diesels. When I returned to the dock, the stuffing box on my port engine was streaming water. I had tightened the stuffing boxes on both engines until a got a drip about every 50 seconds two weeks prior to the trip offshore. I checked them again this weekend and that box has slowed to a single drop every 24-25 seconds. New flax was installed when the new engines went in in 2003. Is this normal?

 

[(Nobody You Know)]

Shaft log packing I think is a very fickle thing. Have had em on two boats. Basically what is happening is somewhat normal (in my experience and I am no expert). It is important that you have adequate water flowing while underway - lubricates and cools the shafts. And the packing should slowely dry out after docking over a day or so. Excessive continued dripping (say a drop every couple of seconds) could mean they need further adjustment - not unusual for new packing - or, if it continues, they were installed wrong, or installer used the wrong size flux). Unfortunately I have experienced both of these. Be reminded that you are probably going to get many opinions on just how much dripping at the dock constitutes an acceptable rate, But I think you are on the right track.

If you ever have the need to have a shaft(s) removed (and I hope you don't!), it would be a good time to invest in dripless seals. I did and they work great.

Good luck,
Bill

 

[67hat34c]

Sounds normal. think mine drip at same rate. may tighten them a little to get it to 60 sec drip. how many windings are in yours. we have original stuffing box' and they take 4 cords. i think next time we replace the packing we will try the dripless stuff., prior thread. stuff sounds good and other boaters on this site seem to like it.

george your packing being 3 yrs old should be changed, i think. know you dont put many hours on it but it is cheep insurance once again. by the way did you change shafts when you repowered? if not what condition is the wear surface in. ours was real pitted, could not get a good seal so we extended the wet tube and put in new packing, been good since.

 

[ELECTRA VI]

Steve, no, I did not change shafts, but now that I think of it, the packing may be only two years old. That is the first time since I had the boat (13 years) since the stuffing boxes were repacked. The mechanic that did it did not comment on the surfaces being compromised. I will ask him if he thinks that it needs to be changed again.

 

[67hat34c]

you may be able to extend the wet tube and get the nut over clean shaft as we did unless it has already been done. of course boat will have to be out of the water for that. ours had been over tightened before, the packing was so hard that it could not be picked out. they had to dig it out once the gland was removed and put on the bench. we have not adjusted it since it was done in august, first hurricane, believe it was katrina when it was hauled. i think we need to look at it and possibly adjust it since packing has been broken in.

 

[Genesis]

Get thee over to eMarine and buy the GFO packing.

I am JUST changing it on my mains now - 5 years of service, no problems. It still was working but was actually leaking underway (it had been DRY for the previous four seasons) so what the heck - I'll change it.

Do not overtighten the GFO stuff though - it takes a bit for it to "run in."

I love the stuff - oh, my rudder stuffing boxes have been done once - when I got the boat - and not touched in over two years. No leaks. At all.

The GFO packing is more expensive but IMHO worth every dime.

Dripless seals sound good but IF they fail they will sink your boat. A stuffing box that fails just drips some water at a reasonably slow rate. You choose.

 

[ELECTRA VI]

Thanks Genesis. I have already chosen. When they put the new engines in, the yard manager told me he intended on putting in dripless seals and I told him no. Rather go with something I know and have control over. I will get the GFO packing. I assume that it goes in much like the flax packing.

 

[Genesis]

Yep.

Just don't overtighten it. You have to run it in before you can set the boxes - set 'em up loose and let 'em drip until the boat has run a couple of hours.

 

[ELECTRA VI]

OK thanks. Will do.

 

[Maynard Rupp]

I have asked lots of folks up here and they all look at each other and shrug their shoulders. I have found no one, including myself, that changes the shaft packing unless they can't stop the flow. Our 36C has never, (to the best of my knowledge), ever had the shaft or rudder packing changed. The boat is an '86 so do the math. We have never considered well cared for and well adjusted packing as a wear item. Am I wrong??

 

[Fanfare]

Run it until it starts to leak or you have to pull shafts for cutlass bearings or other reason. Then change it. They don't leak much at first, gradually increase. Even a slight drip gets thrown around the engine room as the drops hit the moving shaft. The spray is atomized by the motion, so the first clue may be finding gritty salt on everything in the engine room. On many boats a shield of split hose is set up around the stuffing box to contain spray.

On my boat one shaft didn't leak, one couldn't be kept from leaking. Tried everything to stop it, but it was tighten, run a few hours, tighten again as a few gallons per hour would come in. Flow would stop after a day or so, probably as crud washed through and plugged the gap. Pulled shafts, repacked stuffing box, checked shafts for straightness, etc. Finally put in dripless seals last year, and so far so good. Sure wish I could have figured it out, but had spent too much money with no solution.

 

[ELECTRA VI]

I clamped half of a gallon laundry detergent containers on each shaft log to help contain the spray. Seems to be working. Packing was just replaced two and a half years ago.

 

[first230sl]

Dripless seals sound good but IF they fail they will sink your boat.

I have had dripless seals on my current and all past boats. I've never had a problem, but the sample size is, of course, small.

Looking at these, they seem unlikely to fail, but I agree - it could let a lot of water in if it failed in a severe way.

My question is - does anyone know of the frequency & mode of failures of dripless seals? That kind of data is probably hard to come by.

If not - has anyone had one fail - or first hand seen a failed one? What was the mode of failure and the result? I am trying to get a sense of how much to trust these, how often to inspect or replace them, etc.

Take care - Murray

 

[Genesis]

The bellows can tear, which is an immediate "you're dead" sort of problem. If you inspect it regularly you should see any sort of checking before it gets serious.

A stuffing box hose can tear too, but they're a LOT thicker and better-armored than a dripless bellows - the stuffing box hose doesn't have to provide pressure for the seal.

(I'm speaking of the PSS design - others may vary.)

I personally find the idea of a "dripless" shaft log amusing, considering that I take considerable water from storms that comes down my exhaust blower vents. That's where the majority of my bilge water comes from, and its both fresh water and gets nasty in a HUGE hurry if I'm not running the boat all the time to make sure it gets back into the engine room sump and out.

 

[first230sl]

The bellows can tear, which is an immediate "you're dead" sort of problem. If you inspect it regularly you should see any sort of checking before it gets serious.

Makes perfect sense. I am still wondering, though, if anyone on this forum has had it happen, or seen one. Hardly a scientific survey, and does not reduce the need for inspection (not to mention ensuring that nothing is close to it that could rub or tear it), but it would be interesting to know if it seems to be a common, uncommon, or exceedingly uncommon occurrence.

Take care - Murray

 

[Beckytek]

There was an article in passagemaker magazine about a failure of a dripless log that was caused by a blockage in the cooling water. Don't remember the circumstances but they put a flow indicator in line so they could see if the water was flowing.

 

[fixin-to-cruise]

I converted to stainless/carbon dripless seals and they have been trouble-free and completely dry for 3 years. I looked at the "lip seal" type also, and went to the manufacturer's HQ in Deerfield Beach, FL where there were several failed seals on a table near the reception area.

The failure mode of the lip seal type were caused by heat and friction from either a lack of cooling water or a misalignment or friction on the plastic bearing that keeps the lip seal riding at 90 degrees to the shaft. This plastic bearing is like a mini cutless bearing that is part of the seal retainer.

I went with the stainless/graphite seals because they don't need that plastic thing to align the seal. After seeing how well they work you would all be impressed!

The lip seals also wear the shaft as they seal directly to the rotating prop shaft. The carbon/stainless seals only slide against each other.

The lip seal company makes some rudder post shaft seals I installed that leaked a little at first but are now dry. The combination of these two sets of seals gives me a 100 percent dry bilge...that is until the plumbing starts leaking, but that's another story!

 

[mike]

FWIW here some info from boatdiesel website..... mike



have the "old type" of shaft seal in my Albin trawler. So there is always some water in the bilge. Was checking on the internet for "dry shaft seal" and there seem to be various manufacturers of mechanical seals in the market and they all promise "perfectly dry" seal. Any of you guys tried some of those companies? Which one do you recommend?


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Section: Stern Gear:Shafts By: chuck basil
Level 1 Member

Topic: Shaft Seals
Subject: i just had pss shaft logs installed on my ocean 48
Date: May 11, 2003 06:15 PM
Viewed: 480 times
i just had pss shaft logs installed on my ocean 48. about $1500 installed. i just purchased the boat and was surprised to see the old packing seals on a late model boat. its a no brainer. i think they pay for themselves with a clean, dry engine room. not to mention one less thing to maintain/adjust.


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Section: Stern Gear:Shafts By: Jack Sardina [email]
Non Member

Topic: Shaft Seals
Subject: I also have the pss shaft seals in my boat. Insta
Date: May 12, 2003 11:50 AM
Viewed: 455 times
I also have the pss shaft seals in my boat. Installed last year when I repowered and the seem to work great. I've been told that your shafts need to be in near perfect shape in the area of the shaft seal in order for a dry fit. Jack


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Section: Stern Gear:Shafts By: john lewis [email]
Level 1 Member

Topic: Shaft Seals
Subject: i´m on my second set of pss seals and they are gre
Date: October 17, 2003 09:47 PM
Viewed: 365 times
i'm on my second set of pss seals and they are great. cut a flap of vinal or rubber sheet and secure it with a hose clamp to the non rotating part with it extending over the rotating part. now it wont mist the stuff around it with salt spray. they do sling a very small amount of water at speed. maybe they will read this and include them with their seal kits? good company,good products



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Section: Stern Gear:Shafts By: Steve Amick [email] MORE...
Level 1 Member

Topic: Shaft Seals
Subject: I´ve had the PSS seals for over 5 years (1000+ hou
Date: October 18, 2003 04:36 AM
Viewed: 364 times
I've had the PSS seals for over 5 years (1000+ hours) now with no problem. I do notice a few salt crystals around the seal occasionally but that thells me there's virtually no water coming through at cruise speed. The extra rubber flap around this area does sound like a good idea though in case a little seawater is being thrown off. --Steve



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Section: Stern Gear:Shafts By: F.C.Lowell [email]
Level 1 Member

Topic: Shaft Seals
Subject: I have a Lasdrop seal (10 years, 1100 hours) and i
Date: October 18, 2003 05:42 AM
Viewed: 361 times
I have a Lasdrop seal (10 years, 1100 hours) and it came with a piece of 3-4" tube to act as a splash guard, clamped to the fixed part as you describe. I took it off because I couldn't monitor the seal easily with it on and there was essentially no leakage. That was until recently when I had some leakage problems. It turns out this was a self inflicted problem, however, too long to explain here. Not a fault of the seal.
pete

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Section: Stern Gear: General By: tony browne [email]
Non Member

Topic: dripless Shaft Packing
Subject: Try P.S.S. its good quality and really is dripless
Date: January 15, 2006 09:34 PM
Viewed: 116 times
Try P.S.S. its good quality and really is dripless. Mine took a lot of abuse because the bearings ran dry one time after a haul out when the idiot contractor fouled up the flutes in the cutlass bearings and the litle water that was left in the tube actually boiled, when I pulled the boot back to bleed water in to the tube the steam burst out... it was damn hot!! and the seal system handled it all with ease. I would advise getting the one with a water injection into the seal area to flood the tube and keep the debris out by continually flushing the tube and keeping the water fresh and the bearings cool. I plumbed my injection off from the main cooling water pipe after the sea water pump.





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Section: Stern Gear: General By: ralph pratt [email]
Level 1 Member

Topic: dripless Shaft Packing
Subject: Hi Jim, I used PSS. I chose it because a friend th
Date: January 16, 2006 03:36 AM
Viewed: 109 times
Hi Jim, I used PSS. I chose it because a friend that has a 30 knot harpoon boat converted his and spoke well of it. Others in my harbor now have it and I have not heard of any failures. I converted mine at the time of repower 4 years ago (almost 5000 hrs). The boat stays in 12 months and fishes winter and summer.

 

[Fanfare]

When I investigated dripless shaft seals I phoned both Hatteras Yachts and Hargrave Yachts. Both now use Tides Marine seals. (www.tidesmarine.com) That seemed about the best recommendation I could think of. I have about 50 hours on mine with no problem so far.

 

[Genesis]

The PSS design is a carbon face seal. These are commonly used on things like submarine shafts and other similar applications, have a proven history, and work well.

I do not like and would NEVER install anything that depends on the SHAFT ITSELF for part of the seal (e.g. anything that actually runs ON the shaft.)

My issue with things like the PSS system is common to any similar design - the utter inability to do anything about it in the water IF it starts leaking badly or worse, if the boot rips. With a stuffing box if it starts leaking like a sieve you can repack it in the water - no big deal. That's just simply not possible with the dripless systems.

If I had an otherwise dry bilge I might see them of value. But I don't - I've got major rainwater that comes in any time I have winds from astern in heavy rain, right down the bilge blower chutes. In fact, we just (a couple of days ago) had a huge line of boomers come through here, and the result was the usual couple of gallons of water blown in through the vents.

The only real solution to that I can come up with would be to get rid of the clamshells and do something else instead (they act like scoops when the wind blows rain up into them), or figure out a way to make a dorade box in the middle and drain it to the centerline ER bilge. I may do the latter - this issue is one I've had since I got the boat and its on the of the few things that really pisses me off about it.