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 Post subject: Stuffing box question/advice
PostPosted: 10 Nov 2014 11:35 
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Joined: 24 Sep 2013 09:20
Posts: 393
In my quest for a dry bilge, I came to the stuffing box and found it to be most of, if not all of, the problem. I was getting one drop of water every 6 seconds without the engine on. This small amount seems to be enough to fill the little bilge area and start the auto bilge pump going in less than 24 hours. Also, you can see there is corrosion in the area around the shaft from increased salt water intrusion while under way. So, I went about trying to tighten the packing nut (keep in mind I am a complete novice and may not be doing anything right here). Tried to hold the packing nut still while trying to turn the lock nut clockwise. After a couple of hours, I had managed to increase the drip rate to about once every 3 seconds while seemingly not getting either of the nuts to budge. Wonderful! Frustrating Anyways during hour number 3, I think (but I'm not positive) that on two separate occasions both the locking nut and the packing nut moved in unison clockwise. Certainly less than a quarter of a turn total. Also, the dripping stopped. I tested with the engine in gear at 1200 RPMs and wasn't seeing the 2-3 drips per minute that I thought I was supposed to be seeing. I let the engine run for 10 minutes, stopped everything, and felt zero heating of either the shaft or the stuffing box. So, that seemed better than things heating up due to too much friction in there. I plan to test for drips when I'm back at the boat next weekend. I also sprayed everything down with T9 Boeshield and scrubbed at it with a brush to help with the corrosion (should have taken an after picture. was a little better). Any thoughts on the above info. I wouldn't be surprised if it starts to drip a little again. Especially while under way, and I plan to continue to monitor this going forward and check for any excess heat. What about the condition of everything from the pictures (hose, stuffing box, shaft, rusted thingy shaft goes into, etc)? I certainly would be happier if it looked more like the "good" picture than the "bad" picture in Nigel Calder's book. Do other's look about like this on a 1980 boat. Should I get in there and really try to clean the corrosion off? I wasn't planning to haul out this year. Was thinking about having all of this looked at and the stuffing box repacked next Winter (end of 2015/beginning of 2016). I REALLY want to learn to do all of this stuff myself, but every time I start a project, I end up getting stumped and confidence is rarely going up. A little over dramatic there. Smile But wish I could become experienced without having to gain experience and worry that I may sink the boat/ destroy expensive parts of the boat Very Happy


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Zach Duncan
SV Holiday
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 Post subject: Re: Stuffing box question/advice
PostPosted: 10 Nov 2014 14:40 
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Joined: 10 Nov 2006 22:56
Posts: 171
Location: Portland, Oregon
Your photos are what Betty Lou looked like when we first brought her home 5 years ago. The first time we hauled out for bottom paint I noticed that the prop was loose on the end of the shaft, and asked the yard to tighten it up. That led to the discovery that the end of the shaft was out of true and the prop could not be tightened. The yard guys then looked at my cutlass bearing and showed me that it was worn out and needed replacement. We pulled the shaft to send it out to get the prop end fixed, but the heavily corroded shaft coupling (looked just like yours in your photo) had to be cut off and replaced. The shaft turned out to be beyond saving so we got a new shaft. Tired of messing with the stuffing box, we installed a dripless shaft seal. And finally, the yard recommended replacing the engine mounts as they were pretty well shot and new mounts would make realignment much easier.

Final result: new shaft, cutlass bearing, shaft coupling, dripless seal, motor mounts (oh, and the bottom paint job). It all added about $4k to the haul out, but now have an all new drive train, peace of mind, much less vibration, and the shaft seal never drips.

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Tartan 37 Betty Lou (formerly Rainbow)
Hull # 118, fin keel
St. Helens, OR
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 Post subject: Re: Stuffing box question/advice
PostPosted: 11 Nov 2014 16:04 
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Joined: 09 Jul 2008 12:51
Posts: 251
Sometimes just a good hammer will do the trick. Knock the hell out of the nut to break it free. Most of the old salts that I talk to use that trick.


 
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 Post subject: Re: Stuffing box question/advice
PostPosted: 12 Nov 2014 09:16 
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Joined: 24 Sep 2013 09:20
Posts: 393
Jay, I can certainly see myself doing those things you mention in the future. I would like to delay it as much as possible though while at the same time maximizing safety and the likelihood of things breaking all together at some inopportune time. One thing I have learned in my short time owning Holiday: Even things that aren't broken may break when you start to try to take it all apart or at least you find that while you have it all apart, things are worn to the point where you might as well replace so you don't have to pull all apart again for as long a time as possible. I can imagine that the next time something has to be done with that rusty coupling will be when it all gets done. I did just have a new prop installed without issue. So, the problem you had there, I have avoided for the time being. I feel like from what I have learned here and other reading that a lot of problems can be avoided with correct alignment. I haven't taken any measurements yet, but I did observe that while bouncy upon first cranking and putting in gear at idle, the shaft and engine in general look very smooth at high idle (1200 RPMs or so). I haven't really gotten my head or a mirror in behind the shaft, but from up top, it isn't visibly off to any side. I can do more checking there and also check on my mounts. What other preventative maintenance would anyone recommend? Do I need to replace that hose? Wonder if I could make it to next Winter to repack the stuffing box and then keep going with what I have there for some time after that? Or am I risking the coupling breaking apart, the stuffing box/hose failing, shaft freezing, wife and I in a life boat Smile etc?

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Zach Duncan
SV Holiday
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 Post subject: Re: Stuffing box question/advice
PostPosted: 12 Nov 2014 09:17 
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Joined: 24 Sep 2013 09:20
Posts: 393
Mike, I didn't take a hammer to it. If I need to adjust when I check on it again, I'll add that to my repertoire for sure!

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Zach Duncan
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 Post subject: Re: Stuffing box question/advice
PostPosted: 29 Jan 2015 10:53 
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Joined: 09 Jul 2008 12:51
Posts: 251
Here's some good instruction on repacking or just tightening a stuffing box,,, most of you already know about Pdase.com/mainecruising

http://www.pbase.com/mainecruising/stuffing_box

For those of you that have never done this.......To Start....when loosening the stuffing box nuts,,,, view the instruction on the website.... both wrenches need to move in the opposite direction. Once the locking nut is broken free, the locking nut can be moved down the shaft and the stuffing box tightened to it. He advises using PB Blaster if they do not break free and gives a word of caution before using it. He also states that WD40 will not do the trick... (but I've successfully used it to help break them free, and a few taps with a hammer).

He warns about tightening a stuffing box loaded with Gore GFO, Ultra-X or GTU materials too tight because even if it doesn't get hot, without some water drips, it could be damaging the shaft. He also warns against using "West Marine Moldable Packing Kit". He gives real picture examples showing the potential shaft damage that can occur.


 
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 Post subject: Re: Stuffing box question/advice
PostPosted: 31 Jan 2015 09:42 
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Joined: 29 Dec 2006 09:38
Posts: 656
While I generally agree with Mainsail's website advice he is wrong about this tightening with GFO. It does not require any dripping if you are using the genuine GFO. I have been using it for 15 years and 30K miles of cruising with NO drips. It does take some adjustment when first installed and you do not want to crank it down initially like with the old flax stuff. Youi install the GFO and hand tighten the outer nut. then crank it 1/8 of a turn with a wrench, set the locking nut and drive the boat a bit 10 to 30 minutes and it will probably start to drip just a bit. Turn it another 1/8th until it just stops leaking. Lock it. Repeat until it stops leaking. The engineers at a defense plant that supplies seals to Navy ships has told me you should never have to adjust it again if done properly and it does not leak. As you can imagine, nuclear subs do not have drips inside. I have gone as long as five years with no drips and took the coupling apart and there was no indication that the packing needed replacement or shaft scoring. It makes the old mechanical seals (PSS and Lasdrop) and flax stuffing history and eliminates the significant maintenance headache and, in IMHO the danger, of them. The Navy has been using this GFO stuff for years before it was commercially available. So have the lobstermen of Maine.
I also agree that you should think about preemptive replacement of the down tube hose (this is special stuff, do not use a substitute) and the packing nut hardware every decade or so--or when you go through a shaft or cutless bearing replacement. The stuffing box will last a long time, but maybe not indefinitely when corrosion is an issue, and it is not fun to have a failure at sea. Cheap insurance.
I have mentioned before the importance to the life of your engine, transmission and drive train of periodically checking your alignment. This cannot be done by eyeing it, you need a feeler gauge (.003 limit) and a fair amount of patience. I suggest you hire a mechanic to do it with you the first time and then do it at least semi annually. The "shaking" of the engine and drive train is not really an indication of the alignment. Yanmar engines have more shaky mounts (their theory is that their engines will then transfer less vibration to the boat) and watching the engine and drive train in a Yanmar powered boat will make you think the engine is horribly out of line, when it is fine. The only way to check alignment is to loosen the coupling and carefully measure the gap all around.

I believe what we are talking about here is perhaps the most ignored maintenance tasks in boat ownership. Considering the consequences--and I had some very bad experiences when I used to deliver boats for others--it deserves serious attention.


 
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 Post subject: Re: Stuffing box question/advice
PostPosted: 02 Feb 2015 09:24 
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Joined: 09 Jul 2008 12:51
Posts: 251
Well where's a nuclear submarine engineer when you need one... to ask questions and get advice..... I do know what I've seen from marine repair facilities and heard opinions from repairmen. The pictures of scarred shafts from using the drip less products as if they were drip free is a little scarey. I'm old school and will stick with traditional flax. At least I know what to expect and how to adjust it and know when it is adjusted too tight. There's enough material on the harmful effects of using GFO or should I say misuse of it that the recommendation of checking the shaft every time the boat is pulled; maybe every one-two years when getting a bottom job is a good advice.

It would be great to do things on my boat once and forget about it. So far I haven't seen anything that falls into that category.


 
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 Post subject: Re: Stuffing box question/advice
PostPosted: 26 Feb 2015 15:24 
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Joined: 14 Jul 2012 20:36
Posts: 495
Location: Norfolk, Va
Well I'm a Elec Eng who's work on nuc subs for +30yrs and I stayed at a Holiday Inn last night so I guess that's close as we're getting.

I'm scared to death of drip-less (PSS) stuffing boxes. Was racing on a boat where one ripped apart from heat and fiction, we came so close to losing the boat. Had water 6 inches over the floorboards. That was 25years ago and the system wasn't installed properly. I've also seen boats sink with std stuffing boxes too, they just leak at a slower rate and usually can be tighten up.

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 Post subject: Re: Stuffing box question/advice
PostPosted: 04 Apr 2016 14:03 
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Joined: 24 Sep 2013 09:20
Posts: 393
Update to an old thread. Attached are the after pics, and you can look back up for the before pics. I did pretty much the same as Betty Lou above, but I also got a new strut (before and after pics attached). For everyone's info, mine also came out to a little over 4k. Going to give this PSS a try with a sharp eye on it. Can always go back to traditional if I don't like it (and don't sink). So far so good. I am extremely happy with a bone dry bilge and feel confidence to hunt down any new water (before I just attributed any to the stuffing box). I do respect the opinions above about the PSS and don't disagree with any of the advice about the newer packing materials that can make a traditional non drip. Just the decision I made.


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Zach Duncan
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