Stuffing box challenged!

[gonesail]

Originally Posted by Vasco

No, no water comes in once the shaft log is wrapped where the shaft enters the boat. Water pressure will depend on how deep your hull is. On my CS36 Merlin it's not a lot. You can stop it by wrapping a rag around it but I find the rubber a lot better. Once you turn the box off the shaft log, the clearance between the shaft and the shaft log is very small. I'm guessing but on my boat it's less than an eighth of an inch.

OK now I think understand after seeing the parts on the buck algonquin site!! the box spins off and moves forward ... then you wrap the shaft. then you take the packing out and put more in the box. when done take the wrap off and screw the box back on. then tighten lock nut.

[Vasco]

gonesail,

I think you've got it!!

[Maine Sail]

But I would practice on a boat out of the water before doing it in the water. besides the rubber hose connecting your stuffing box to the shaft log most likely is due for a replacement. I would use Gore GFO when you do it.


Directions:

Measure your shaft with a set of calipers. If it's 1 inch, 1 1/8, 1 1/4, 1 1/2 go to a local canvas shop and ask for a scrap pice of stainless tubing the same OD diameter of your shaft and use it to make your rings on. Or if the boat is out of the water go outside the boat and clean a portion of the prop shaft with scotchbrite and cut the rings on it.

Cutting the rings:

Wrap some packing around the shaft or piece of scrap so the ends over lap each other by about 2 cm or so but are side by side on the shaft tightly. Then take a new razor blade and make a 45 degree slice through both ends, where they meet, in center of the area where the ends overlap. Now remove the flax and you have a ring that will fit perfectly on your shaft and the ends butt together with a perfect 45 degree scarf joint. Make three, or two depending on your stuffing box, rings and insert them into the nut, after cleaning out the old flax with a dentist pick or similar, with the 45 degree cuts offset from each other. You don't want the 45 degree cuts all in a line they need to be off set from each other! Tighten packing nut by hand and allow it to drip for a few hours of engine run time with the shaft spinning. Then re-tighten & adjust it to a point where the stuffing box is slightly warm to the touch and you're done. Use GFO packing and no grease it will drip much less than standard packing but you should still get a couple of drops per minute... I find it's a lot easier to pre-cut the flax rings before you start the job and maybe even have a couple of extra rings if you're not so good at it!


Warning:

Be very careful with the Teflon grease mentioned in an above post. I used teflon flax, non GFO, and the grease for two seasons on one of my boats. Towards the end of the second season my stuffing box was running very, very hot. When I took her out of the water, and took apart the stuffing box I noticed a mass of teflon grease and teflon flax residue clogging my stuffing box between the shaft and the inside of the bronze stuffing box! The spinning of the shaft & tightening of the gland nut had squeezed & spun a coating of the teflon grease onto the inside of the stuffing box log until it built up enough to slow the cooling water flow to next to nothing! The water that did drip out was boiling hot because not enough cool water could flow around the shaft. Stuffing boxes were never designed to have grease in them and the cheap teflon flax (imitation Gore GFO) with the grease is a band aid approach at minimizing water ingress. I learned the hard way on this one as I had to pull my shaft to fully clean out the stuffing box. I actually figured while I had the shaft out to put in a PSS and love it!! No water, simple and easy!

If you want a good flax for a traditional stufing box buy the Gore GFO packing it does not require a grease like the cheap Gore knock off flaxes do and when adjusted properly it drips very minimally compared to other flaxes.

In contrast to what others have said about GFO it is NOT deisgned to be entirely drip free. Even the GFO instructions do not say it's drip free. You can however adjust it to get less dripping than you can with the imitation GFO packings. GFO takes considerably less water to cool it than the West marine Teflon flaxes do but it IS designed to drip slightly when the shaft is spinning. Mine was dry when the shaft was stopped but dripped a little when spinning and did not get to hot.

Installing the PSS:

[ssullivan]

Thanks, everyone. Great responses! I'm not coming out of the water this spring: will either dive to do zincs and knock off some growth, or try and find somewhere to careen or tie up to lie on the keel.

This means I'll probably wait another season to do the stuffing box, based on Acoustic's advice. It's not exhibiting any bad behavior, but I like to keep on top of things.


Acoustic: What sort of megayacht were you on? Sail?? I was exclusively on power.

[never monday]

Sean,
Want to come down and intern?

[Maine Sail]

Large sport fishing yachts but one Broward and one 90 foot Hatteras. I've been sailing and around boats my entire life though. I just spent four summers during college crewing on the big boats. I also did a bunch of moonlight work on the side doing some detailing/varnish on these boats as well as some electrical trouble shooting.

[Jon D]

Originally Posted by Vasco

Jon,

Mine works on my B393 too but I worry about it. I know how to deal with a traditional stuffing box but these patented dripless ones scare me. I have been on boats where they leaked (worn, seals?)and there is no cure but to replace them. If I remember right my warranty says to replace the thing after 500 hours!

Rick

all in all I've put over 1500 hrs on one and never had any issues. My current one has about 1000 hrs on it [different boat] and looks and works like new. PYI suggests examining the bellows and make sure not getting brittle. That's the major concern as far as I know. I have had nothing but solid performance from mine so I'm a happy guy...

[skipperaris]

I no longer have stuffing box issues as I have replaced mine with a Volvo seal which is supposed to last for five years at least.

When I had my old stuffing box I had all the problems you mention in this thread except I changed the packing when there was the first suspicion of a heavy drip, on the next haul out. I also fitted first a grease nipple and then a pemanent grease press to the body of the stuffing box and this would cure any small drips.

I also had the tightening problem and used all sorts of methods, large pipe wrench and the like.. One of the more successful were a hammer and wide blade screwdriver to knock on the protrusions of the nut. The absolute best was a length of webbing (the kind sailmakers use to strengthen the corners) wrapped a couple of times round the nut and then gripped by a wrench. Incredibly powerful and no fear of damage to anything. The catch was that I could only turn the nut a little at a time and had to redo the wrap round.

All these were used until I discovered a wonderful tool at my local mechanic's which I borrowed whenever I needed it. In fact he had a whole set of them for different sizes.

Those were the days...

Now it is enough to remember to let the air trapped behind the seal out, when I launch.

I don't know what I'll do if I ever get a leak but I'll think of something.
Did anyone have such an interesting experience?

[Vasco]

Originally Posted by skipperaris

I no longer have stuffing box issues as I have replaced mine with a Volvo seal which is supposed to last for five years at leas

I think my Volvo seal says to replace the whole thing every five hundred hours. Seems an awful short lifetime for a seas considering the expense of installing it.

[skipperaris]

Originally Posted by Vasco

I think my Volvo seal says to replace the whole thing every five hundred hours. Seems an awful short lifetime for a seas considering the expense of installing it.

If I were Volvo selling seals I would probably say the same.
My five year estimate is from my boatyard man who has fitted them to many yachts, many of them charter yachts which do clock up the hours.
My seal has done about 2000 hrs so far.

As for the expense of installing I installed it myself. The only other expense I remember was €100 for a new shaft just in case the old one was scored to below the nominal diameter of 30 mm.

Another thing is that I am very careful to use that special tool every time I have to remove and refit the shaft and add a little of that special grease that came with the seal.

[44'cruisingcat]

I couldn't find decent stuffing box wrenches either, so I made my own. It's fairly easy, I used 10mm aluminium so they wouldn't rust, and they work fine. I usually adjust till there is a drop about every 5 seconds when motoring. It has worked pretty well, the packing lasts for years, and there is virtually no dripping when the shaft isn't turning.