Conference unifix::sailing

    I repack my stuffing box every other year.
    
    Hardest part is digging the old flax out (wish I had a dental pick)
    and cutting the new flax to fit.
    
    I DO NOT tighten the packing nut other than minor adjustments after
    repacking and subsequent launching. Tightening only risks further
    dripping because the flax becomes compressed; and more critically,
    risks scoring the shaft if you overtighten.
    
    I don't recall any dripping as a result of this process and therefore
    haven't felt the need to do this job every season.
    
    Total process time is probably only about 20 - 30 minutes which
    includes the following:
    
    Loosen packing nuts - 5 minutes
    Dig out old flax - 5 minutes
    Polish shaft with bronze wool (I also grease shaft with white lithium
    grease too as I recall) - 5 minutes
    Measure and cut new flax - 5 minutes
    Wrap flax inside packing nut - 5 minutes
    Tighten nut (2X) to set flax - 5 minutes
    
Better Boat has a fairly good article about how to perform the process
if you want step-by-step instructions with pictures.

    
    JC
    

re .0:

>>>    	How often do you repack your "shaft" stuffing box?

Never. I use a Lasdrop.    	

>>>    	Do yours leak at all while docked/moored?
    
No. Doesn't leak when using the engine, either.

    
    re .0:
    
    >>>	   Do yours leak at all while docked/moored ?
    
    The packable stuffing boxs are SUPPOSED to leak, they must stay
    wet to work as a bearing as I understand it. A drip rate of 1 drop
    every 12 minutes I seem to remember being told was an ideal rate.
    
    
    re .2:	Alan, I've been thinking about upgrading to a Lasdrop.
    		Did your boat come with one or did you add it later?
    		Their adds have always sounded intriguing to me, but
    		I wonder about price, retrofitting difficulty, and if
    		one isn't trading for another set of problems with
    		rubber seals/O-rings ? 'Guess it would help to educate
    		myself on how exactly they DO work !
    		
    		Any other PRO's or CON's out there ?
    
    		John 

re .3:

We installed a Lasdrop in (I think) 1983 after far too much fussing with
the original stuffing box. Removing the transmission coupling from the
propeller shaft took longer than installing the Lasdrop. The
installation of the Lasdrop itself was much easier and faster than
repacking the original stuffing box. The Lasdrop leaked a bit at first
until the mating faces wore together (in a few hours of engine running).
Since then it has leaked nary a drop and has required no maintenance at
all. All of the wear is between a plastic ring (clamped into a rubber
bellows) and a stainless steel ring clamped to the propeller shaft.
There is an improved design available (about $100 for a 1" shaft). The
Lasdrop is one of few technological improvements that is a genuine
improvement. 

Anyone want to buy a traditional bronze stuffing box for a 1" shaft?

Back to the traditional stuffing box, and a few comments. 

The packing material MUST be cut into separate rings, usually three, and placed
so the cut is spaced 120 degrees apart. NEVER wind 2-3 turns of packing around
the shaft- it will twist tighter and thats what scores shafts.

A properly packed shaft need not drip- steam valves are packed in the same 
manner and leaks there are not tolerated!

Packing is a maintenance item- Id say a couple times a season it needs 'snugging 
up'- not horsing it tight with a 3 ft wrench, but snug enough to stop leaks.
After several adjustments, it needs to be replaced.

Of course stuffing boxes are always in the most totally unreachable spot, where 
you must stand on your head to reach them. There is a special wrench made to fit
them which  can help make the job eaiser.

    
    Two years ago, when I purchased my boat (Cape Dory 28), we aranged
    for the previous owner to fix some serious problems with stuffing box
    and cutlass bearing.   To make a long story short, new cutlass bearing,
    new shaft, everything fine.
    
    Now, after 2 seasons, based on advice read here, I figured, time to 
    repack the stuffing box.
    
    Access is a test of your ability to contort your body.   Inside
    cockpit lockers you remove panels, and slide in.  Turning sideways
    your shoulders are wedged between the cockpit deck and the bottom.
    The packing nut is in a small opening between both sides of the
    full keel.   Looking aft view approximated below (if you could put
    your eyes where the shaft exits transmission).
    
    
             side of keel \ X / side of keel
                           \ /
    
    
                     X = shaft / nut
    
    The clearance on either side of the packing nut is perhaps 1/2 - 1/4".
    
    I was able to back the nut off with locking pliers with the chain
    attachment.  All manners of wrenches did not clear the side of the
    keel.  The chain, just barely fit.  I was able to do this carefully
    without stripping the nut, etc.  
    
    Any suggestions for the best tool...do you have better?   No, the large
    adjustable wrenches for plumbing do not work.
    
    Now, just pick out the flax, and replace.  For my next question, refer
    to this view looking down at the shaft (if you could look thru the deck
    in the cockpit):
                             ____  _
                            |  __||_|_____________________
                ____________|________________________
         shaft  ____________________________________       prop-->
                            |  ---------------------------
                            |____||_|      hard stuffing box
                         packing  locking
                         nut      nut
    
    My question is, should I expect to find flax behind the backed
    off packing nut or in the stuffing box, now accessible with the
    nut backed off?
    
    If I reach into the space between
    the shaft and stuffing box with a wire, everything feels hard, so I
    quit immediately...afraid I may be picking at the cutlass bearing.
    But, my recollection is: that's the right process.  
    
    All advice appreciated...including appropriate exercise program for
    weight and flexibility necessary to work in small spaces.
    
    Thanx
    
    Gary
        

re -.1:

My only advice is to install a Lasdrop (see previous replies to this 
note and also Note 443). I replaced the rubber bellows on our Lasdrop a 
couple of years ago, a matter of 10 minutes work at most. Other than 
that I've quite ignored the thing since installing it in 1983 or so. It 
still doesn't leak. Lasdrop has improved their design since we bought 
outs, and they now has some competitors. Still, it is the way to go, I 
think.

    The fixed part of the stuffing box should have a V shaped lead-in, the
    underside of the nut has a similar V. The packing goes in this V and is
    compressed onto the shaft as the two V's tighten together. The old
    packing is likely to be quite hard and compressed into the joint.
    
    Do NOT put the packing in as a continous wound strip. it MUST be
    installed as short, single turn segments. Usually three segments are
    used, with the joint staggered around the circumfrence. Cut the joint
    to a neat square joint just butted together, not overlapped.
    
    Tighten the nut firmly, but no more than necessary to get down to just
    a drip every few seconds. A shaft can be cut nearly in half by two
    tight packing, or by a packing strip wound around several turns.
    
    The LasDrop is a nice way to do a $1 job with a high-tech $150
    'solution'. 
    
    Building a Steam Boat teaches a lot about packing joints!

    Thanx for the advice.
    
    Alan,
    I have read your stuff about LASDROP.  Sounds terrific.  Assume if I
    choose this path I need to disconnect the shaft from the coupling to
    install it.  This was also necessary when the boat was first purchased,
    as the locking nut had broken off.   Shaft removal, involved cutting
    the shaft in 2, at the previous owner's expense.   I recall this action
    being choosen, as the lesser of 2 evils.   Damage to the transmission
    from a shaft puller vs. cost of new shaft.  Hopefully, doing
    this now would be easier.   
    
    Ron,
    
    Just making sure I understand.  I think I could see the V shape in
    the stuffing box.  I should expect to find the packing in the packing
    nut.   The packing will be against a matching V within the nut, that
    compresses against the V in the stuffing box when tightened.
    
    Thank you both
    Gary
    
               
                  
                 
                   
                          

re .9:

Yes, you do have to remove the propeller shaft from the transmission 
coupling to install a Lasdrop. Once the set screw that locks the shaft 
into the coupling has been removed, you have to push the shaft out of 
the coupling. On our boat, the shaft hole in the coupling is a through 
hole, ie, you can see the end of the shaft. The transmission output 
shaft flange is solid. Find a socket wrench or a length of pipe or 
whatever a little smaller than the diameter of the shaft. Put the 
whatever between the transmission flange and the end of the shaft. Using 
long bolts you can reconnect the shaft coupling to the transmission 
flange. As you tighten the bolts, the shaft will be pushed out of the 
coupling. If there is rust or corrosion, good luck. (This small problem
is discussed somewhere in SAILING). Before you put the coupling back on
the shaft, remove all corrosion/rust and burrs with fine wet sandpaper.
Then liberally slather Never-Seez (or similar) on the shaft and coupling
bore. This will reduce future corrosion problems. 

re back a couple: 

Yes, a Lasdrop is an approximately $100 alternative. For me, it is far 
preferable to the pain (want to see my scars?) of installing new flax 
packing every two years or so. And, too, with a Lasdrop there is no risk 
of damaging the propeller shaft from over-tightening the stuffing box. 
Our shaft showed obvious wear from the flax packing.

    
    	Hmmmm- the cutlass bearing is mentioned up front. Is there a
    	cutlass in the Cape Dory? I always thought you only needed 
    	these things stuffed into struts...?
    
    	Mr_Full_Keel_Clueless

    .11
    
    I think so scott, I saw them push this thing into the stuffing box,
    looked like a pipe with rubber insides.....they called it a cutlass
    bearing.   
    
    Apparently this sits in the stuffing box just before it exits the end
    of the keel.  
    
    

    
    Yup- that's a cutlass all righty! Perhaps it's for the length the shaft
    must travel thru the keel, and/or vibration damping.
    Thanks for the scoop! Now I know a little more.
    Scott

    	Whoops- my boatyard friend vociferously corrected me, and I 
    	forgot already- it's a cutLESS bearing cuz it doesn't cut into 
    	the shaft-
    	Sounds good to me- tho much less pirate-inspired!
    	S.

Well, time passes and technology (hopefully) improves. Tides Marine 
(800-420-0949) has developed a new propeller shaft seal that is 
self-aligning, non-corrosive, maintenance-free, ABS-certified, and a few
other things. (Tides' has two catalogs -- power products and sail
products. They make other interesting things such as rudder bearings. I
assume they'll send a catalog upon request.) 

The shaft seal is basically a one-piece housing of ultra-high molecular
weight polyethylene (very strong, very slippery) plastic that is both a
water-lubricated shaft bearing and a carrier for a nitrile rubber shaft
seal. The seal is similar to the shaft oil seals used in engines, etc. 

The housing is connected to the shaft log by a short length of very high 
quality (and very expensive -- $2 to $3 per inch depending on size) 
silicone hose. Should the shaft seal cause wear on the shaft, just shift 
its position a fraction of an inch as the seal edge is quite narrow. 

The water for lubrication is taken from the outlet of the sea water 
engine cooling system (between the outlet of the heat exchanger and the 
exhaust elbow). 

Tides claims that face seals (eg, the Lasdrop and others) may leak due to 
vibration, misalignment, and excessive water pressure. Over the last few 
years I have found that our Lasdrop did leak occasionally and was not 
quite as wonderful as I thought. 

I saw the Tides shaft seal at the Maine Boatbuilders Show last March, 
thought it was a nifty idea, and bought one. About $200 including a spare 
seal, an extra length of hose, and the T-fitting for the water 
lubrication. The Tides people were most helpful -- one phone call for
both ordering and technical advice and everything shipped that day COD.

Installation was easy and mostly problem-free. I did modify the T
fitting that goes into the engine sea water hoses a bit (having a metal
cutting lathe can be useful). 

So far we've run the engine maybe 10 hours this year and I've not 
noticed any leaking at all. The oil absorbent drip pad under the engine 
is still quite dry. 

Tides does say that their seal is recommended only for stainless steel
shafts meeting ABYC specifications and top-grade bronze and monel
shafts. 

So far, I'm happy.

Alan