stuffing box conundrum *o

[Manny]

Well, I can't figure out what is going on. I replaced the packing in my stuffing box this winter. I was able to place three rings of packing in the nut, I wanted to place four but it did not leave much thread on the nut. It was a nice, snug fit to the prop shaft. I slightly hand tightened the nut and when the boat was launched on Thursday it was dripping slightly, about 1 drop every 15 seconds. I went ahead and tightened it just slightly but I was still getting a drip about once an hour. On Saturday I went back and started the inboard and ran it at idle in gear for a few minutes tied up to the dock to start the adjustment process. I tightened it so it would drip once every 15 seconds in gear but as soon as I took it out of gear it was dripping once a minute. Very strange. I then tightened it some more (about a tenth of a turn) and it started dripping alot without the engine running. I was really confused at this point. I ran the engine some more in gear and was able to tighten to the point that I was getting about one drip every 45 seconds which I felt wasn't enough but the stuffing box wasn't getting warm. Once I took it out of gear it was dripping about a drop every 15 minutes. I'm baffled. I don't want to overtighten the stuffing box and I guess maybe it needs to be broken in. Has anyone experienced this?Oddly I received a frantic call today from a sailing buddy of mine. He was called by our marina manager today telling him that his boat was taking on water and his boot stripe was submerged at this point. He had also replaced his packing. He went down to his boat which had about 5 inches of water in it *cry and pumped it out. He had taken his boat out on Sunday and had motored for a whileThe cause - his stuffing box was leaking. He told me he had to tighten the nut substantially to stop the leaking...

 

[Maine Sail]

Not all...

not all stuffing boxes will be dry without the shaft spinning. It irks me that people mislead others and boldly state that it should not drip at rest. Many, many stuffing boxes will drip some at rest this is the reality of a traditional stuffing box.Here's the point. All traditional stuffing boxes, including ones packed with Gore GFO, must drip slightly when the shaft is spinning. If water does not drip you can ruin the shaft. Gore GFO can drip as little as 1 drop per two even three minutes and still run cool to the touch but traditional flaxes need to drip more like 3 to 10 drops per minute when the shaft is spinning. The closer you get to three drops per minute, with standard flax, the more shaft wear you will get. Never adjust the stuffing box with a wrench unless you have to! Always hand adjust then lock the nuts against each other with wrenches. If you over tighten you run the risk of ruining the packing as it does not have much rebound and does seem to have a memory.So in short break the large nut from the lock nut with wrenches then adjust by hand a 1/8 turn at a time until you get the minimal drips and still have a cool to the touch stuffing box. Traditional flax boxes should run cool to the touch not warm. GFO can run slightly warm unless you are in a high silt area then more cooling water is necessary. Some folks claim drip free operation with GFO but it is not designed for this and the Gore directions are clear on minimal dripping not NO dripping.If you get it adjusted properly when spinning, not too warm to the touch, you'll have to live with the drips. It's possible you did not cut the rings correctly too..Here's a photo how to guide to repacking a stuffing box:http://www.pbase.com/mainecruising/stuffing_box

 

[frank balcer]

Anti Seize

Manny, having owned a Shamrock center console cuddy for 5 years prior to moving UP to a sailboat and keeping it in the water year round, i replaced a lot of packing. About twice a year as i fished it a lot. The one thing i do remember about this is that each time i thought i had it figured out as to the amount of squeeze on the compression nut, it was never right. The one thing that did help was to make sure i rubbed all pieces of packing real good with anti seize! Is messy at first but the packing rings don't quite glaze as bad as if installed dry. Good luck Manny! Frank

 

[Ross]

I have no idea if this is useful but I use a

teflon based pipe joint compound that is slow setting. Perhaps it would be useful in this situation. I suppose that with an automatic bilge pump one or two drops per minute would be a problem unless you left the boat all summer.

 

[Benny]

Stuffing boxes are very simple.

The purpose of the drip is to maintain lubrication to keep the shaft surface cool. My experience has been that a mininum drip of once per every 15 seconds will do the job. Up to a maximum of a drip per second should not be a problem as the the bilge pump should easily handle it. If it does not leak when the shaft is not turning then again no problem as no lubrication is required. These are simple devices that do not require close tolerances nor fine tunning. Having replaced the packing visually inspect it after 2 hours and adjust it again in 20 hours if necessary. Don't follow the point the you are trying to make with your friend's story. The packing has to be the right size and installed in cut ring pieces with the joints overlapped; the nut has to be tightened and the drip set with the engine running and the shaft turning. If installation is not properly done catastrophic failure may result otherwise these things are very forgiving.

 

[Manny]

Thanks for the input

Maine Sail - Last year I was able to adjust the old packing so I would get 3 to 4 drips a minute running and cool to touch, without drips out of gear. The old packing was pretty beat and oddly enough, it was just one long piece. I cut the new rings with the correct angle (nice site by the way) and staggered the joints 120 degrees.Frank - what type of anti sieze did you use? By the way, nice avatar! Is that the boat you moved up to from the Shamrock?Ross - I'm not sure if I understand, did you use pipe dope instead of packing or just on the threads?Thanks all,Manny

 

[Manny]

Benny, no point to my friends story

just thought it was ironic considering I was having difficulty with my stuffing box.Manny

 

[Ralph Johnstone]

If You Check the Archives ........................

......... for "packing" you will find a somewhat different opinion than what has been posted so far. Many (including myself) have written to say that simple, cheap teflon impregnated flax is the answer to truly dripless packing. This is also cheaper and safer than a mechanical shaft seal.I have been using this system for six years on our '99 H310 and have NO dripping when the shaft is turning and NO dripping when the shaft is at rest. Of course proper packing technique must be used as has been mentioned here and that includes a smooth, clean shaft and a well aligned shaft coupling. I have changed the packing every two years and noticed that the shaft still has a mirror polish on it.As far as the need for dripping for lubrication goes, teflon is slippery enough. As far as the need for dripping for cooling goes, a 1" dia. SS shaft will conduct a lot of heat into cold sea water. Out shaft is always COOL to the touch after hours of running at top speed. Now I can imagine this will really launch a fusillade of testy replies but I must say that things were getting a little too quiet here as of the last few days. Try the teflon impregnated flax and you'll never go back.Best regards,s/v Island Hunter

 

[Maine Sail]

Well...

While I'm glad you could stop the leaking with Teflon even the Marine Gore GFO site still does not say it's leak free. There is NO doubt, and no question, that the Gore GFO is a far better and far more slippery product than "teflon impregnated" flax. In the GFO marine instruction they just say to adjust it to the desired leakage. No where in the instructions does it say drip free or dry! My mistake, when I installed my GFO, was that my desired leakage was none and my expectations were incorrect of the product. The bottom line is it still needs a little water to lubricate and running cool is not the only indicator of potential problems especially in the very cool waters of BC. PS: If you're going to stay with a traditional flax based system the GORE GFO is by far the best flax you can buy. The actual fibers the flax is woven from are slick not just the coating of teflon.Marine Instructions straight from the GFO instructions:AFTER THE LAST RING IS INSTALLED, take up bolts finger tight. Do not jam the packing into place by excessive gland loading. Make sure gland bolts are taken up evenly. STOPPING LEAKAGE ENTIRELY WILL CAUSE THE PACKING TO BURN UP. Runthe vessel for 5-10 hours and readjust packing to get desired leakage.Desired leakage is the key phrase. Not dry or drip free.. It's your boat and your shaft so do as you please...I've said it before and I'll say it again more boats have sunk, according to the Boat US insurance division, with regular stuffing boxes than with the so called "dangerous" dripless shaft seals. Both systems use a rubber hose to connect to the hull in 85% of sailboats made. The rubber is the weak link in both types of seal & needs to be replace periodically on both systems! If the rubber hose fails on a traditional stuffing box is it any different than it failing on a PSS or Last Drop?? I've had a rubber hose on a traditional stuffing box fail and they are not as fool proof as some would make you believe. If this type of seal is good enough for the US Coast Guard, they use Lasdrop, it's safe enough for the average boater. Even the US Navy uses Duramax Dripless Seals that are very similar in design and concept to the PSS and Lasdrop.Given time I think you will see dripless seals mandated for environmental reasons. No bilge water means no oily discharge and politicians, the Navy and US Coast Guard are all aware of the benefits of dripless seals and make mention of the environmental aspect of this type of seal in many publications..

 

[Paul Akers]

Requires break-in.

As your friend did, take the boat for a run. The packing requires a break-in run to set the packing. You shouldn't have to "fiddle" too much once this occurs. And just "hang around" your boat for a little while afterward - just in case. To keep an "eye" on things.

 

[Warren Milberg]

I installed a new

conventional bronze gland on my boat over the winter. It has impregnated flax packing material. I hand-tightened the packing nut and locked the lock nut to it. When my boat was launched in early April, there were no leaks at all with the engine off. When I ran the engine in gear, it leaked a lot and so I tightened the compression nut a couple of flats. I was able to get it drip only a few drops per minute in gear. After a few weeks and a few sails involving using the motor about 5 hrs, I was still getting too much leakage. So I tightened the compression nut again, about a flat. No leaks at rest; a few drops per minute in gear now. I expect to have to keep an eye on the gland and to perhaps make a few more adjustments, as the packing material settles in. This is normal, IMHO. I check the gland each time I'm at the boat and after each sail. I suggest you may want to do the same thing as it sounds like you'll just need to keep tightening the packing nut a flat at a time until your reach equilibrium -- the state we all want to be in.

 

[Bill Roosa]

Packing placement

You might have placed the packing in incorrectly. The ends of three packings should be spaced at 120 degrees to one another. If you line the ends up you will get more of a leak in all conditions.