Stuffing Boxes
from the
Sailnet Tayana List
I'm trying to get some sales/technical/installation info on Drip-Free
Packing, the blue Teflon/grease that was the subject of a thread on this list a
month or so ago. I've contacted the company several times and the info was
promised, but nothing has shown up. Does anyone know if the company is having
problems or what might be going on?
Second, since this packing seems to
stop circulation along the shaft, does this place the shaft in an anaerobic
environment that could lead to wastage?
Thanks, Coleman S/V Traveler February 2000
__________________________________________________________________________________________________
WEST
MARINE sells this packing under their own label, you
might contact them for info. I just repacked my stuffing box with it and so far
it has worked great; no drips and the shaft is not
heating up.
Jim S/V SMILES (T37 Hull 407) February 2000
__________________________________________________________________________________________________
Subject:
Shaft and stuffing box
After rebuilding my
4-108 and dropping it back in with only removing, not changing the old rusty
coupling. I have been able to move back the shaft sufficiently to
install the new coupling. I want to get the engine aligned so I can test all is
working well under load. The problem is
now to get the shaft and the coupling to slide back toward the motor. I tried diving the boat and working it over with a four-pound hammer
and a block of wood but it did not budge.
Question: if I remove/replace the
packing in the stuffing box will the shaft loosen up enough to be moved fairly
easily? (not sure how old the packing is and should
probably be replaced anyway). Has anyone
tried the dripless packing I have been reading about, and how well does it
work? How difficult is it to replace the
packing in the water?
Phill T 37 #101 October 2001
___________________________________________________________________________________________________
Phill,
Sorry for the misunderstanding. I think I
wrote out a overly long description of repacking the
stuffing box a few years ago, and at risk of excess redundancy, it's pretty
straightforward. It is easy to replace the stuffing. But you are raising two
different issues. One is how to get the coupling back to the engine, and the
other is how to replace the stuffing. Although they are possibly related, as
you indicate, I would not completely remove the stuffing until you get the
shaft back to where it can be re-connected to the transmission.
Thus, you can "loosen" the
stuffing box collar, but do it very carefully, making sure that your bilge
pumps are working reliably. Applying equal pressure on both side of the flange
(i.e. on port and starboard sides) with a small jack, you should be able to
gradually push the flange towards the engine.
This is the point at which you should now carefully re-align your engine
mounts. (I assume that you replaced the old mounts with new ones when you
re-installed the rebuilt engine.)
Prepare to spend a few hours doing
this the first time. Best to get someone who has done it to help, to avoid the
possible disconcerted reaction some people have when they suddenly see large
quantities of water pouring into your beloved boat.
Make sure that you have adequate
electric bilge pump capacity, and that the bilge pumps are all working. Test
them repeatedly to give you confidence in their performance.
Based on the age of your boat, I
suspect that the stuffing box is built in a manner similar to ours. There are
two bolts coming forward from the fixed part of the stuffing box. There is a
collar with two ears that slide on the two bolts. The collar has a tube that
extends aft into the main part of the stuffing box. The shaft should be 1.25 inches in
diameter. The opening in the stuffing
box is approximately 1.75 inches in diameter.
The tube on the collar is slightly less than 1.75 inches in
diameter. Thus you have a space between
the shaft the inside of the stuffing box that is about 0.5 inches, or 0.25
inches all around the shaft when centered. This might lead you to assume that
the proper wax laden flax should be 0.25 inches so that is will form a snug
collar around the shaft. However, you may find it advisable to have two sizes
of flax on hand: a roll of 1/4 inch (0.25) and a roll of 3/16 inch. The small size may prove necessary to allow
you to fit the material around the shaft and still push in the collar. The 1/4
inch material may make such a tight packing that you will have trouble getting
it into place, and will have water pouring in as you find the sweat on your
brow turning to a flood with your increasing anxiety. When you push the collar
back into the stuffing box, it will compress the flax, and the 3/16 material
will be just fine most of the time.
Read Nigel Calder
or any other good maintenance manual on how to re-stuff a stuffing box.
You will cut a series of pieces of flax so that it exactly completes a single
ring around the shaft. Cut the ends on a bias so that it forms a good seal. The
length of the flax pieces should not be too long or too short. Cut at least 4-6
pieces and make sure that they are the correct length for a snug fit around the
shaft. Buy a good quality spiral tool
for removing stuffing at any good chandlery.
Have several tools at hand,
particularly a few 14-mm deep sockets to loosen and tighten the nuts on the
stuffing box.
Make sure that you have lots of light
down below.
Put several drops cloths under the
prop shaft forward of the stuffing box. This will trap any tools or nuts that
you may drop, and prevent them from sliding all the way down into the bilge. But
keep the cloths loose enough to allow water to drain down into the bilge.
Test your bilge pumps again. The boat
won't sink, but you will think things will get out of control as you are deep
in the bilge and have fantasies of drowning in the lazarette as your boat
sinks. Relax. Don't take a drink at this time. You will need all your
faculties.
NOW:
Carefully lay out your various tools.
Loosen the nuts on the stuffing box.
Place them in a very secure location. Do not drop them into the trough leading
to the bilge. But if you do, remember, I suggested that you put some drop
cloths in there to catch them.
Carefully slide the collar forward on the
shaft. You may find there is an
increasing drip of water. Relax, take a
deep breath, and let it drip. If all the bilge pumps are working, you are in
good control of the situation.
Before you remove any of the
stuffing, check to see if the flax you previously cut in careful lengths really
will fit. Put a piece around the shaft and push it into the stuffing box with
the collar.
Take the spiral tool (looks like a
miniature corkscrew) and carefully slide it into the stuffing box. Turn it to
snare the piece of stuffing. Pull out the stuffing. You now know how to proceed. Now reach in and using the spiral tool,
remove one of the older pieces of stuffing. The rate of flow of water will
increase. Take comfort in the operation of your bilge pump. Probe
for any additional material. Take
a deep breath. No rush.
Now put flax into the stuffing box
one ring at a time. After each insertion, tamp it in with the tube extending
aft from the collar. Each ring should form a nice snug complete circle. Each
circle should start at a different point on the shaft so that the ends are not
all at the same point on the shaft to avoid leakage. When you have put in about
3 or 4 rings, make sure that you can still slide the collar on far enough to be
able to secure it on the bolts.
Now tighten down the collar, and it
should be about 3/4-inch gap between the collar and the fixed portion. If you
have to add more rings of flax, do so.
If you can't get even three rings in, then you didn't remove all the old
flax.
Lean back and relax.
Check
engine alignment. This is critical. Secure the coupling flange with the four
bolts.
Start the engine and let it warm up. Leave it in neutral. Make sure you are securely tied to the
dock.
Have
a second person in the cockpit.
You should now go back into the
lazarette. Have them put the tranny in
gear. Be very careful that you don't have any clothing that could be caught in
the rotating shaft before you do that.
Watch the shaft and stuffing box. There should be a slow dripping from the
stuffing box. If there is none, the stuffing box may be too tight. Put the
tranny in neutral.
Loosen the nuts on the stuffing box ever so
slightly. Put the boat in gear and check
for dripping. As the flax settles in, it will increase the rate of drip. Now
carefully tighten the nuts. It should drip about 2-8 drops per minute.
Do not rush.
Now
climb out of the bilge.
Now
you have that beer.
regards,
__________________________________________________________________________________________________
Just at the
local boat show. The Shelter Island Boat Yard people had a large booth where
they were displaying the PYI PSS dripless stuffing box. The exhibitor then
suggested that rather than spending several hundred on the PSS and its
installation, I should try out the GFO Gore-Tex and Teflon stuffing material.
About $20 worth of material would be enough for the T-37. Very interesting material.
I mentioned it to a friend with a big ocean fishing boat, and he said that he
had been using it for 4 years, and it ended the Too-Loose/Too-Tight sequence of
repeated adjustments immediately. He received a free sample directly from the
manufacturer and ended years of fiddling with the stuffing box.
Anybody else had any experience with this
material? As with many of the Gore products, they are based on very clever
design and application of materials sciences to deal with the various aspects
of a problem.
regards,
__________________________________________________________________________________________________
Bob,
Just managed to find more info on the GFO at the webpage for E.F.
Gore, Co.
http://www.gore.com/en_xx/products/sealants/packing/gore-tex_valve_stem_packing.html
I also include a quote from their page on packings.
"Packings"
W.
L. Gore & Associates manufactures a full line of high-performance
compression packings. These materials are chemically
inert, highly abrasion resistant, and able to withstand temperatures up to
550°F (228°C). Our packings can be used in virtually
any static or dynamic application requiring compression packing in your
facility.
GFO® Packing - Unexpected packing
failures are a thing of the past. Reduce downtime and cut maintenance costs
with compression packing made from long-lasting non-asbestos GFO® fiber. Chemically inert, with few exceptions, over the entire 0-14 pH
range. Withstands temperatures from -400°F to +550°F (-240°C to +288°C).
For any type of pump - centrifugal, rotary, turbine, reciprocating. For valves, agitators, mixers, dryers, and refiners.
GFO® Marine Service Packing - Ideal
for use in stern tubes and rudder posts.
It runs virtually leak free and does not damage expensive propeller
shafts. Helps keep bilges dry and lasts longer
than flax. GFO® marine service packing cuts easily and is easy to install. When
it is time for haul out, GFO® marine service packing is easy to remove from the
stuffing box. Used by the U.S. Coast Guard, specified by the U.S. Navy, and
approved by the American Bureau of Shipping. "
__________________________________________________________________________________________________
I found a place in Ft. Lauderdale that
sells the GFO. Emarine.
$17-$56 depending on shaft size, etc.
http://www.e-marine-inc.com/products/gfopacking/packing.html
John
Reynolds January 2002
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Alan,
We had persistent problems with our
stuffing box, with continuous leaking, etc. I was planning to put a PSS seal on
our shaft, but the shop that installs them on Shelter Island suggested that I
first try using the GFO Teflon braid from Gore-Tex. This is completely
different product from the Teflon Stuffing material sold at West Marine and
most other places. I've now had it in place for about 1.5 months, and it has
finally controlled the leakage, while keeping the shaft cool. The cost of the
GFO packing was a total of about $20. The mechanic could have sold me the more
expensive PSS plus the installation charges, so this was a trivial cost for a
successful (so far!) experiment. You can track down the Gore Company website
and find their web page about their GFO packing.
You might try that route. The other
advantage of GFO is that this can be repaired even at sea, if it did start
leaking. The concern about the PSS expressed by several mechanics is that you
have to haul the boat to install it, and if it blows out, you are in real
trouble. The PSS/PYI people clearly state that the PSS has to be put in place
with the boat on the hard. On the positive side of things, I have not
personally heard of any reports of it blowing out. But I did wonder what is
wrong with the PSS on Charles Freeman's T37?
regards,
__________________________________________________________________________________________________
Can you provide the dimension on the Gor-Tex packing that you used? I understand that 1/4 is
recommended but I understand that others have found 3/16 more user friendly.
Sid
Rubin February 2002
__________________________________________________________________________________________________
Alan
and Sid,
The dimension I used was the 3/16". I
had to go to the slightly smaller size as our shaft is somewhat eccentrically
placed within the stuffing box. The
1/4" couldn't fit fully around. That meant that I had to use an excess of
3/16" to compensate for the greater gap on one side, but it fit perfectly
on the other side. The company says that you should be able to restuff using a single small pack of material. But since I
had to use one size smaller, I needed two packs. So far - it works well.
Alan - as far as the vibration is concerned, check several things:
1) Condition of motor mounts. If they are more than 10
years old, they should probably be replaced.
2) Remove all the material from the stuffing box and
replace it completely with the GFO Teflon/graphite braid stuffing.
3) Very carefully align the motor relative to the shaft and
stuffing box. If you haven't done this before, I suggest that you hire a
friendly and skilled mechanic who will show you how to do it properly.
4) After the initial alignment, install a PYI isolation
coupler. This serves two purposes - it reduces the prospect of shaft damage in
the even that your prop snares an object, and it helps reduce vibration.
5) Check your shaft to make sure that it is true, check
the cutlass bearing for wobble
6) Check the prop for imbalance. Once you have the vibration under control, I
would also check the accuracy of your Tachometer. We found that after replacing
our alternator with a new unit, that our tachometer is reading 20% lower than
the actual value.
7) At that point, depending upon the present material
used, consider replacing the sound insulation material. Our engine box was
"insulated" with cheap acoustic tiles made of some sort of wood
particles. The wood fragments dropped into the bilge, and were a source of
potential problems for the bilge pump. We replaced it with a modern sound
insulation material with foam, weighted middle layer and aluminum reflective
foil. I still don't like to motor, but at least it no longer jars my teeth nor
deafens me. Engine efficiency has improved.
regards,
__________________________________________________________________________________________________
I bought from: http://www.e-marine-inc.com/
Jim (SMILES) February 2002
__________________________________________________________________________________________________
http://164.109.56.82/english/ipd/sealants/packing_GFO_Marine.cfm
Alan Jett Alliance Studios February 2002
__________________________________________________________________________________________________
Hi Rich
Thanks for
the information but my shaft does not have a nut on it at the flange end. There
is a keyway that I managed to get out yesterday but the flange still eludes
me. I am getting to the point that I
will probably cut the shaft and have the flange pressed off. After 18 years
it's unlikely it will come off any other way.
Andy Windy
Blue April
2002
Andy
The shaft is secured to the coupling
with a set screw and a key. The coupling is in two parts. One side is secured to the shaft and the
second part is secured to the transmission. he two
halves bolt together. I have a 4-108 and
the flange has 4 bolts that hold the two halves together. These four bolts are
the ones being described for removal.
Slide the shaft aft with the coupling attached and place a 1/2-inch nut
between the two halves of the flange. Using longer bolts,
tighten the 2 halves of the flange together. The shaft will move, providing the
set screw is removed. Repeat the process with a socket next (a little longer
than the nut), then possibly the socket and a nut. The process is tried and it
works. It will save a few hundred
dollars for a shaft.
Joe Sprouse Sojourn Deltaville,
VA April
2002
__________________________________________________________________________________________________
We have now had the GFO Teflon packing in
place for a few months. Continues to perform well. Shaft remains cool, and almost no
moisture comes in through the stuffing box. (Of course the stanchions, chain
plates, hawse pipes, and ports left open are another matter!).
After the first week or two as the
stuffing was settling into place, I have only had to occasionally touch the
adjustment nuts on the stuffing box by less than 1/8th of a turn. The bilge
pump rarely goes on any longer. All that money wasted on bilge pumps! (Ha!
That's challenging fate!) On a more serious note - assuming that the shaft is
OK, I have decided against installing a PSS dripless seal. The problems
associated with removing the flange from the shaft,
and the recommendation that the PSS only be put on when the boat is on the
hard, combined with the uncertainty about difficulties of emergency repairs in
the event the bellows leaks when offshore, prompt me to decide in favor of the
GFO. The PSS is not Fail-Safe, though it is highly reliable. But if it goes,
there is big trouble. The worst that could happen with GFO is that I might have
to add some more material. In addition, the price differential is substantial
($20 versus $400 - including parts and labor, but not the cost of hauling the
boat). I can recommend GFO highly to those of you who are still considering
installing a PSS to avoid the perpetual problem of a leaking stuffing box.
Harvey April
2002
__________________________________________________________________________________________________
There was a thread on this bulletin board
about a location in Florida that sells it for a reasonable price. About $20
buys enough to do the whole stuffing. I bought it at one of the small shops on
Shelter Island. It is made by the Gore
Company (of Gore-Tex fame).
I used the 3/16" wide
material. Get a diver to pack some wax
around the cutlass bearing. Make sure your bilge pump works well. Remove the
stuffing box flange, and slide it up the shaft. Remove all the old stuffing.
This might test the reliability of your bilge pump.
Put in several rings of the GFO. Push the flange back in, and tighten. If it
goes too far in to the point that the flange is almost all the way in, remove
the flange and add more stuffing.
Follow the directions about adjusting
the stuffing box. After the initial
settling in period when you may get a bit of leakage, you can eventually
completely stop all leakage, but adjust it so that there is no overheating of
the shaft.
That's all that there is to it.
regards,
___________________________________________________________________________________________________
By the way, I am only referring to the GFO
Teflon material from Gore-Tex people.
There are other brands of Teflon stuffing material. I found that they
were not very good, leaked after a short period of time, were very expensive,
and finally had to be pulled out and completely replaced with ordinary flax
stuffing.
The Teflon stuffing at West Marine
and at Boat/US is not recommended - the GFO is a very intelligent combination
of materials and design.
Harvey April
2002
__________________________________________________________________________________________________
To
buy:
http://www.e-marine-inc.com/products/gfopacking/packing.html
To Install:
ftp://ftp.sailnet.com/tayana/cutlass/GFOpack.pdf
I'm switching from the blue Teflon stuff to GFO
Ray Slaninka Red Bank, NJ April 2002
John:
I guess I'll go with 3/16. I think I could
squeeze 1/4 but it might be too tight and I don't want to risk scoring the
shaft. I think 3/16 is what most people use. And it is what the spec reads.
Ray Slaninka April 2002
I also noted that the manual says that you
should use 3/16" stuffing, not 1/4".
If the stuffing box were perfectly aligned to the shaft, 1/4" might
be preferred.
The problem with sizing is exaggerated if there is any eccentricity in
the centration of the shaft within the stuffing box.
And there definitely is in our boat. Thus, the space available on the top of
the shaft is slightly more than on the bottom. I can easily fit 1/4"
above, but barely 3/16" below. I have had the engine realigned, and have
checked the alignment on several occasions. The cutlass bearing is in good
shape, and was carefully checked during our recent haul out. The conclusion was that the original
installation of the stuffing box was not done with sufficient care and
accuracy, so it is slightly eccentric.
I suspect that leaking stuffing box
on our boat has been a problem since its original construction. That was also a
reason I was considering shifting to PSS, as it provides greater freedom to
align the shaft between only two points - the transmission coupling and the
cutlass bearing. The stuffing box intrudes into this straight line if it is in
any way not only eccentric, but if it is even slightly "off-angle"
(i.e. - not perfectly parallel to the shaft, when the shaft is properly
balanced between the transmission coupling and the cutlass bearing. Of course
this assumes that the cutlass bearing is properly aligned!).
The great virtue of the PSS is that the
shaft basically "floats" at that point, so the stuffing box does not
have to be as accurately aligned. A great concern would also be that the
stuffing box flange scrapes against the shaft, scoring it. The only saving grace
might be that the flange is made of softer material than the stainless steel
shaft, so that the flange will wear more that the shaft. But
not a happy situation.
Packing the stuffing box with
traditional flax with wax is a problem as the flax is relatively incompressible
and hard, and takes more time to seat properly. It also doesn't conform well to
the available space, and permits water to leak past it. The GFO material is
apparently made of a fiber material that is far more adaptable, and includes
both graphite and Teflon. The combination both lubes the surface of the shaft,
and the Teflon apparently seals around it.
By using 3/16" material, you can
more easily pack in and compress enough material to halt the leakage. While I
felt that I should only use complete rings of material, I found that there was
still a gap on the top of the shaft because of the eccentric stuffing box. I
therefore added a bit of extra material on the top before putting in the last
of the rings of stuffing. I compressed the collar to seat it all, removed the
collar and then added a few more rings of GFO. Had I been able to use the
1/4", then a single package of GFO would have been sufficient. But since
the 3/16" had to be used, I used two packs of 3/16" GFO. (Each pack
is about 24" of material). Just to play is safe, I ended up buying 3
packages. I still have one unopened package, as a backup. The place in Florida
sells them for about $9 a package. The place here in San Diego charges about
$12 a package (for the 3/16").
regards,
__________________________________________________________________________________________________
http://www.e-marine-inc.com/
order GFO packing on line. 2 day delivery in
Joe
Sprouse April
2002
Subject: Rusting Propeller shaft
I have just replaced the propeller shaft
and cutlass bearing because the shaft had started to rust in the area of the
stuffing gland. The rusted area was about 5" long and extended from just
out side the gland to the end of the stuffing material. I noticed last season that there was a leak
from the gland and a build-up of a rusty colored paste around the gland. I
decided that I would re-pack the gland with GFO after I read about it on this
site.
Has anyone else experienced rusting
of the shaft. Why should a SS shaft rust especially
where it is exposed to air? It has been
speculated that it could be electrically induced as followings. The shaft in my
case was not bonded since both the flexible coupling to the gear box and the
cutlass bearing are both insulating. I have also noticed that when it rains
that water leaking into the stern of the boat eventually runs down over the
stuffing gland. I have now bonded the
shaft with a copper strap across the flexible coupling.
Greg Barnicoat
__________________________________________________________________________________________________
Greg,
Did the rusting begin only after you
installed the GFO? Or did you install the GFO after the start of the rust?
regards, Harvey Karten April
2002
__________________________________________________________________________________________________
Subject:
Rusting Propeller shaft
I replaced my shaft three years ago when I
got my boat..... It probably was a 304 0R 302 series stainless and had lots of
'rust bloom' all over the in the bilge exposed area near the stuffing box. Seeing the exterior corrosion, pitting, etc. I removed the
shaft for inspection and found the area of the stuffing box packing was
severely galled, pitted and corroded (in the section that is between the
stuffing box and the cutlass).
At this time, I have the subject old
shaft / worthless paperweight in front of me at the moment and report to you
that I do have a 'rust bloom' on the area exposed in front of the stuffing box.
Testing the rusted areas shows slight magnetic attraction whereas the rest of
the shaft does not. Visually the 'rust' looks like a typical chlorine/halide
attack on stainless - as would be similarly found vs. deaerated
salt water; and, also exhibits surface cratering
(chipping/stress corrosion) under the rusted area. It was the 'chipping' that
led me to pull the shaft out and inspect it and to ultimately replace it. Fully
exposed, I found massive catastrophic surface damage.
My *hunch* (based on long, long past
engineering / chemistry experience in the foundry business, etc.) is that the
salt water enters the packing area and with poor flow of lubricating water to
keep up the needed oxygenation of the stainless surface, the fluid deoxygenates
into the surrounding fiberglass, packing material, shaft log, etc. .... and
begins fretting, etc. corrosion on the shaft. ...... and that why I prefer to
use PTFE coated FLAX packing ... because it leaks a little and such 'sweep'
volume of seawater through the packing keeps the shaft oxygenated to maintain
the proper oxide coat on the stainless, etc. I currently work with various
forms of Gore-Tex, etc. and am quite suspicious that the perfusion of oxygen
through the PTFE packing onto the shaft is quite limited - typical gaseous
intrusion pressures of such a wetted hydrophobic material are typically 25-75 psi, etc. (Sorry to again run against the crowd on this
one).
Note: If I DID install pure Gore-Tex
in future, I'd first soak the packing material in isopropyl alcohol to allow
the material to wet-out so that the necessary (I believe) perfusion of gases
would occur, .....of course it would then leak like
regular packing and I would only benefit from the low frictional
characteristics of the Gore-Tex but NOT the hydrophobicity.
Anyway it cost me over US$600 for a
new shaft .... and it all
started by seeing the rust zone on the shaft directly in front of the stuffing
box.
BTW... I
only use 3 rings of PTFE coated flax packing - 1 drip per 1-2 minutes not
running (0,25 - 0,5 Liter/day), 5 drips per minute running..
If you'd like pics of the
galling/corrosion I'd be glad to send.....
Rich Hampel April
2002
Hi
Rich,
After reading the response from Sandra
Blake I am even more convinced of the galvanic corrosion theory. In Dublin I had a swing mooring in the middle
of Dun Laoughie Harbour and thus no stray
currents. In Stockholm, I have a mooring
in a marina with electrical outlets and hence the possibility of stray
currents.
I also want to get some
clarifications from your description below.
In the stuffing gland, I had imagined that seepage of water in the
stuffing gland was essentially a boundary effect, i.e. lack of perfect seal
between the flax and shaft etc; and not the diffusion of water through the
flax.
As for GFO if you believe their
literature it has the following advantages over other
packing material:
a. high thermal
conductivity
b. low expansion
c. low friction, due to PTFE
d.
soft/pliable material, hence easily molds into the gland cavity
All of which combine to give the
gland a very low seepage rate.
I expect that the Gore-Tex fiber
gives the material the high thermal conductivity, but I have not heard of this
property before. Can you comment on this.
Greg Kish, Stockholm May
2002
__________________________________________________________________________________________________
I just installed GFO packing. I used one
package of 1/4" material and I got 4 rings out of it. Yesterday I launched
the boat and 4 rings is barely enough as I almost ran out of adjustment before
I stopped the flood. Luckily I got 2 packages and I will add more. Then I was
reading an old TOG #26 and ran across a warning from a 1984 letter not to use
graphite packing. I wonder what they meant back in 1984 by the term graphite packing? GFO has graphite in it. Also does anyone have a
copy of the ABYC standards? If so, can you look up P6-6d and look for a warning
about graphite corrosion. Derek, are you
still reading these?
Back in January 2002, I posted this
about graphite:
As far as the graphite in the
packing, maybe I'm a little out there on this one, but I was concerned about it
because of possible galvanic reactions.
Graphite is a conductor. There is a pretty big spread between Silicone
Bronze and Graphite in the Galvanic Series, although it is close enough to 316 stainless,
it is pretty far from bronze. Graphite is the most noble metal, which means
that you could start losing some of your stuffing box and even, to a lesser
degree, your shaft. But even as I write this, I have to question how much metal
would actually be lost and if it is worth worrying about.
Here's the rub, the 1984 letter warns
about the shaft and the packing. Graphite and stainless are
closer on the galvanic series than bronze and graphite. Go figure!
Ray Slaninka Tayana 37 May
2002
__________________________________________________________________________________________________
We just put new GFO packing in last
week also. One thing we discovered on our first roll of GFO was that, because
that type of packing has considerable stretch to it, we cut the first batch of
rings too short because we apparently pulled the packing a little too snug on
the shaft when cutting it. (This was evidenced by the rings not completely
joining end-to-end when installed.) We wrapped a little duct tape around the
shaft when forming our second batch of rings, and they came out perfect. You
might want to check this out before you add more rings.
Regarding your question about galvanic
corrosion, I seem to recall reading somewhere, perhaps Calder's book, that ABYC
does proscribe the use of graphite packing. I don't think GFO packing has
anywhere near as much graphite as the true graphite tape packing that caused
all the problems in the past, but I don't know for sure. This is definitely
worth checking out. The Gore Company that makes the stuff has an 800 number.
I'll see if I can dredge it up and will give them a call.
Dayton Eckerson T-37 #215 May
2002
__________________________________________________________________________________________________
The concern about the graphite is probably
something that Gore Company can answer. They claim that the U.S. Navy now uses
GFO in their stuffing boxes. I would hope that this concern was addressed in
the formulation of the MilSpecs on this material. I
would hate to think that a Destroyer would suddenly lose its prop shaft while
in the midst of a move to avoid a submarine!
Yet another month has gone by and the
stuffing box continues to work well without excessive leakage and no heat
buildup.
regards,
__________________________________________________________________________________________________
Protection is provided by the proper zinc
mounted on the shaft or prop.
Rich Hampel May
2002
___________________________________________________________________________________________________
Saga # 3: The Dripless Seal
Kamaloha had
a dripless seal which was rather tired and had no "spring" left to
the bellows, and leaked fairly prodigiously while turning. With the boat on the
hard it was time to replace it. An easy project, right?
1) Chop off and peen out the corroded split pin.
2) Borrow the world's largest spanners to spin off the
prop nuts.
3) Curse and cajole and several hours later finally
succeed in banging and gear-pulling the prop off.
4) Remove the batteries to get to the aberrant
dripless seal.
5) Try the trick of pinching a sparkplug socket
between the tranny and the propshaft to press the flange off the shaft. In your
dreams! I now know what it takes to stretch four 3/8" threaded rods to the
breaking point. Having done so, borrow the big spanner and gear puller again,
then soak the flange in cutting oil, heat with blowtorch while cooling prop
shaft. Bang, curse, repeat. Ah, a millimeter movement after only two hours!
Repeat cycle. Seven hours later, prop flange finally comes off and shaft is
free.
6) Clean up the shaft. Luckily it is corrosion-free
and looks quite good. Carefully hone prop flange corrosion out to make a nice
snug fit onto shaft.
7) Oops-- misalignment. For those that have never seen
the dripless seal, it is fitted by removing the bronze inner flange to the old
packing seal and flipping it about so the flanges are tight together, then hose
clamping the rubber bellow of the new seal to the old inner flange. Well,
careful inspection shows engine has sagged in its mounts over the years, and the hard prop shaft has cleanly worn the bronze
flange to a mere paper-thickness on the bottom side. Scary!
8) Find an old bronze pipe-fitting in the junk bin at
the machine shop and mill it to make a new cutlass bearing flange.
9) Align shaft.
10) Smooge and attach new
seal. Oops... the larger diameter bronze fitting we just made doesn't allow
enough space between the old cutlass bearing studs for the bellows to fit.
Remove, clean out the smooge, and grind off studs to
just long enough for nuts to fit.
11) Now there is just enough room to get the bellows
on. Smooge with 4200 this time
just to give it that extra little oomph to the seal.
12) Fit prop shaft, flange, and bolt it all together.
13) Hmmm, can't get the leverage required to press SS
mating doughnut the required 1" into the bellows. Fiddle with various
means of obtaining leverage for another hour.
14) Finally, refit the prop, nuts, zincs, and split
pin.
Pretty soon
my wife is going to outfit the lazarette with bedding and a stove, I spend so
much time down there...
Charlie s/v
Kamaloha January 2003
_______________________________________________________________________________
Charles,
Jeez! You really win the prize for the
nightmare story of the day.
The prospect of a dripless bellows
rupturing in the ocean was said to be unlikely - by the manufacturer. But a few
different boatwrights expressed great concern to me about this prospect. The
man I was about to contract to install a PYI dripless seal urged that I first
try the Gore-Tex dripless packing. That was a year ago. It cost about $20, rather
than $400. Worked beautifully and for the first time since we bought our boat,
it no longer produced a steady flow of seawater into the bilge. Works great, and easy to change. I keep my fingers crossed
hoping that it is not scoring the propshaft. But the bilge is almost completely
dry. (Almost, but not completely! Some comes from
rain, some from water that enters when I pull the speedo transducer to clean
off crud. )
regards,
__________________________________________________________________________________________________
I understand the angst over the PSS Seal.
However, when you take a close look at them they are essentially the same stuff
as the rubber hose used for the raw-water intake, so I figured the likelihood
of a rupture was about the same. The old one was on there for 10+ years as near
as I can tell, and the rubber had not deteriorated, just lost the
"spring" to the bellows so it was hard to put much tension on the
seal. I did have sufficient angst over the thing popping off the bronze fitting
that I used 4200 to make the connection this time; that stuff is awfully hard
to take apart. Plus, the bellows compression puts a lot of pressure on the
connection to keep it in place. I assuaged my angst that way. The scariest part
was the worn bronze fitting. I suppose you can argue that this problem was
hidden by the sealing properties of the PSS seal. Had it still been a regular
stuffing box, the wear would still have happened, but it would have shown itself
earlier due to the loss of seal and greater leak around the stuffing.
As far as the price goes, the new seal was
about $100 on eBay; plus my day's worth of time, plus $25 to mill the bronze
junk pipe fitting into a new flange.
I've got three bilge pumps; automatic,
manual-electric, and manual arm-powered. I know from experience that the
automatic can handle the full flow from a leaking prop seal. Last year the
prop-saver sheared off and the whole shaft displaced aft, forcing the SS doughnut
on the seal up the shaft and essentially opening up the seal. The bilge pump
kicked in and took care of the water flow, a little too silently actually; I
couldn't hear it running until I went below decks an hour later after running
around trying to sail the boat into a marina slip after the drive failure.
Maybe I'll wire the auto-bilge pump to the low-oil-pressure squealer (with
diodes) so I really know when it is running.
If I were to try to go back to a regular
packing seal at this point I would probably have to replace everything on the
inside end of the boat, since I have no matching bronze fittings at this point.
My bilge is not totally dry, either. I've got a very, very slow trickle from
the rudder shaft packing seal that I didn't pick up on until after we splashed
this time (it probably leaked 20ml in two days). Next time she is on the hard
I'll tackle repacking that, probably with the Gore-Tex stuff.
Charlie s/v
Kamaloha January 2003
__________________________________________________________________________________________________
Hi
Group,
I just replaced my metric (Tayana) prop
shaft with a 1 1/4" shaft with a standard marine taper
and standard threads for the nuts. It required that I also replace the
coupler. The new coupler has a keyway for the shaft and uses two, 5/16"
set screws set in dimples in the shaft to keep it from moving forward or back
in the coupler. The keyway keeps it from spinning in the coupler.
Since I intend to order an Autoprop, I had
to borrow a (power boat) three blade fixed prop until the Autoprop arrives.
When I pulled away from the boatyard the drive train was making a horrible
racket. It sounded like something was badly out of balance. I figured that it
was the prop, because I had spun the shaft while I was in the yard and turned
easily and alignment with the coupler was nearly perfect.
When
I had cleared all of the bridges on the Miami River and reached Biscayne Bay, I
decided to sail the rest of the way to the marina. After a beautiful sail of a
couple of miles, I started the engine to hold me into the wind while I furled
the sail. The engine revved all the way up but it was obvious that the prop was
not engaging.
Imagine my surprise when I checked the
shaft and saw that it had backed completely out of the coupler! The prop was up
against the rudder. Fortunately, the Gore GFO packing I had put it was keeping
any water from entering the boat. After identifying the problem, I thought it
highly unlikely that I would be able to work the shaft back into the coupling
by myself with no one to push it forward from outside the boat. I found however, that the packing, without
leaking a drop, allowed me to slide the shaft forward to the coupler from
inside the boat. Although the alignment was very close, it wasn't close enough
to allow me to push the shaft up into the coupler. After scratching my head for
a couple of minutes, it came to me that if I loosened the four bolts that
connect the coupler to the shaft saver, I might be able to move it around the
fraction needed to allow me to shove the shaft back into the coupler.
Unbelievable, it worked! It turned out that
the problem was, when I installed the shaft, I had to align the set screws with
the matching shaft dimples by feel as I couldn't see into the set screw holes.
Apparently I missed the dimples and had tightened the set screws into the
smooth part of the shaft where they quickly worked loose. As long as I was moving forward, in gear, the
shaft was being pushed up into the coupler. As soon as I stopped the engine and
began sailing, the shaft promptly slide back out of
the coupler. Anyway, any of you that have ever tried to get a shaft to slide
into a coupler on dry land know what a job it can be. It was a piece of
incredible luck that I was able to do it while alone on the water.
I owe a large part of the credit to the
Gore GFO packing which allowed me to slide the shaft forward, through the
stuffing box and cutlass bearing, without allowing a single drop of water into the
boat. I am absolutely sold on it. Good Stuff! BTW- no
affiliation with Gore. I learned about it on this list, I think it was
from you Harvey. I use 5/16"packing. It is tight but goes with just a
little coaxing.
Regards,
__________________________________________________________________________________________________
TOGgers...
FYI, I just repacked Prudence's gland
and she took about 7 rings of 1/4" Teflon.
John Kalpus Prudence Tayana 37 San Diego January 2003
__________________________________________________________________________________________________
Since the keyway guarantees that the shaft
is in the coupling in the right place rotationally, the only variable is the
depth. When I reassembled mine I carefully lined up those dimples out of the
boat where I could see them and marked the shaft with a scratch as to the
proper depth. Then when I had to reassemble it in the boat I just lined up the
scratch with the flange. Hopefully this did the trick; it's still in there for
now at least. I also safety wired the set screws using my best aviation
technique. After all the talk of
Gore-Tex packing I can envision myself switching back to a stuffing box on the
next haul; however as I mentioned I no longer have mating components of a
stuffing box, and I predict that both halves would need to be replaced. Does
anyone know if this is a "stock" item, a Grand-Deer
never-find-one-again, or what?
Charlie January 2003
__________________________________________________________________________________________________
Hi
Steve,
I used GFO packing in my Cal 31 ( my last boat) for 2 years. After 2 adjustments it never
leaked a drop. I can't wait to put it in my T-42 and dry up the bilge. Look on
the net because you can find it considerably cheaper than the West Marine
price. My link is corrupt so can't share it at the moment.
Jeff
Orca T- 42 CC February 2003
__________________________________________________________________________________________________
Nick,
Your note prompts me to add an update
and status report on the GFO packing material in a standard stuffing box. After
using GFO Teflon Packing for about 16 months, I can report that it really works
wonderfully well. I have the original material still in place, the shaft
remains cool when under power, and there is absolutely no significant leakage
of water that I can detect. There might be a bit of seepage when under power, but
the rare number of times that my bilge pump goes off could also be consequent
to the gush of water that I get when I pull my speedometer transducer to clean
it. I now monitor the bilge pump with a bilge pump counter. I installed it
about a week ago, and the bilge pump has not triggered even once during this
past week at the dock. There might be a bit more seepage when motoring, but
clearly this is a huge improvement over the problems I was having 16 months
ago, when I was using the standard flax (with or without Teflon - didn't seem
to work very well).
The GFO works so well, that I find
little reason any longer to consider installing a PSS dripless stuffing box.
For a bilge counter, I found a surplus event counter with a small battery, and
added a simple reed relay. When the bilge pump goes on it triggers the reed
relay, which advances the bilge counter. The parts were throw-aways in surplus in our electronics shop, but should be
easily obtained for only a few bucks at any electronics surplus store. Much
cheaper than the $50 or $60 for a bilge counter at West Marine.
regards,
__________________________________________________________________________________________________
We used some Greenish Blue putty, but paid
even more for it. It was a total waste of money. We ended up going back to the
regular waxed flax stuffing. But we
could never properly control the leak, which was the reason we were considering
installing a PSS dripless bellow. Fortunately for us, the man at the boatyard
who we contacted about installing the PSS suggested that we first try GFO. It
is a braided material with Teflon and carbon. He said that $20 for GFO would be
a lot cheaper than $450 for installing a PSS! If it didn't work, he still would
be glad to install the PSS. He also pointed out that if the GFO leaked, it
would be no worse than with ordinary stuffing, and I could still go to the PSS.
But as he also pointed out, even though PSS only rarely fails, when it does, it
can be a disaster to deal with at sea.
I spoke with our diver about the idea
of packing wax around the cutlass bearing, as he had once described that as a
way to stop flooding when I was working on the flexible drive shaft coupling.
He used a $2 wax package used as the gasket for seating toilet bowls in homes,
purchased at Home Depot. It almost completely stopped water flow as I removed
all the old packing. (Or at least, I HOPE I removed all the old packing). Get
one of those corkscrew like devices.
Based on the shaft diameter of
1.25" and the internal diameter of the stuffing box of 1.75", that
should suggest that we use 1/4" (0.25") GFO. But the shaft was seated
somewhat eccentrically in the stuffing box, and I couldn't fit the 1/4"
GFO around all parts of the shaft. I also noticed that the box of stuffing flax
that was originally on the boat was 3/16". The eccentricity also probably
contributed to leakage and inability to get a good seal. I then shifted to
3/16" GFO, and packed a bit of extra material on the side with the bigger
gap. Snugged it down and packed in a bit more. Removed the wax seal from the cutlass bearing. Then loosened
the nuts on the stuffing box slightly and started the engine. Made sure it was
securely tied to the dock, and then put it in gear. Initially there was a very
slight amount of seepage of a carbon Teflon mixture. I ran it for a while (?15 minutes?), snugged it down a
tad. Ran the engine again. Shaft was ever so slightly
warmer just at the stuffing box, but still quite cool.
All serious leakage has been solved
since then. After the first week or two with minor adjustment, it has not shown
any notable leak. I did let is seep ever so slowly, and the pump may come once
every few days for just a few seconds. But that happens only when I shift to a
port tack because of the location of the float switch in the bottom of the
bilge being affected by the residual water. It stays on for a few seconds. In
order to be alerted to the bilge pump going on, I bought a small piezo buzzer at Radio Shack for about $3, and wired it
across the automatic bilge pump switch (a black panel switch
with 3 positions - Auto, Manual and OFF) located near the electrical panel. It
is not very loud, but there is no mistaking it when you hear it.
Our primary bilge pump is a Rule 1100
with a built-in automatic float switch. I chose that unit rather than a
separate bilge pump with a separate float switch because I had trouble
positioning the float switch in the narrowing and curved bottom of the bilge,
in a location that would remain constant relative to the pump. The integrated
pump and float switch is a lot easier to deal with.
Harvey June
2003
__________________________________________________________________________________________________
Subject:
Stuffing box and dripless packing, bilge counter
We also have used the GFO for the
last 12 months with great success. I unfortunately failed to record the size of
the GFO we used, but I seem to recall that we ordered the 1/4" but they sent
us the 3/16" and it fit just fine. Good luck.
Dayton Eckerson T-37 #215 July
2003
__________________________________________________________________________________________________
Visit the link below to learn about GFO
packing. We used 1/4" 6 rings which is 2 packages:
http://www.e-marine-inc.com/products/gfopacking/packing.html
Joe Sprouse Sojourn July
2003
__________________________________________________________________________________________________
We ordered our GFO packing directly from
the manufacturer. Go to www.gore.com/sealants/.
They had an 800 number on that site and took our credit card order over the
phone. Good luck.
Dayton Eckerson T-37 #215 July
2003
__________________________________________________________________________________________________
Just a quick update of my stern tube and
cutlass bearing replacement project in case someone is contemplating doing it,
too.
After breaking three of the four
studs which secure the stern tube assembly to the deadwood and then removing
all parts of the broken studs from the deadwood area I found that Tayana
screwed the studs into deeply (two inches) embedded hex nuts located in the
deadwood. All four hex nuts had short pieces of metal rod welded on each side
of the nuts as anchors. They were the same deal I found when I replaced all my
chain plate studs.
I removed each of nuts and filled the
holes with thickened epoxy, a little at a time, until they were full. I am
going to drill and tap the epoxy to accept bronze hex cap screws (1/2" x
3") in lieu of the studs. Hopefully, I'll be able to replace the cutlass
bearings much easier in the future.
Again, I will post pictures on the
ftp site when it is all completed.
Regards, John Keefe CT37 ODYSSEA Youngstown, New York August
2003
__________________________________________________________________________________________________
Subject:
How to info needed - Stuffing box flax replacement procedure...
On the Norsea
it was fairly easy to reach the prop area from an inflatable, especially if I had my kids stand on
the bow. I found that wrapping the shaft with strips of old tee shirt so that
the shaft and stern tube were well covered and as sealed as possible really
helped slow the flow of water into the boat.
John,
et al...
If you can reach the prop shaft on the
outside of the boat, try covering it with a wax gasket made for a home toilet
install. They're dirt-cheap, only a couple of bucks, and are very malleable.
You can force it into the area around the prop shaft and stop most of the water
from entering while you install your new seals.
Good luck....
John Kalpus Prudence Tayana 37 San Diego December 2003
__________________________________________________________________________________________________
John,
Just to second the recommendation of
John Kalpus. I had the diver pack a $2 toilet bowl wax seal (from Home Depot)
around the shaft at the cutlass bearing. This almost completely stops the entry
of water, and will allow you to be relaxed about changing the packing. Buy one
of those things that look like a small corkscrew that will fit between the
shaft and the walls of the stuffing box. Get a few extra packs of the GFO. We
used the 3/16" rather than the 1/4", since the shaft was slightly
asymmetrically aligned relative to the stuffing box.
You want to really pull out all the old stuffing.
Pre-cut
a series of rings, with a slight bias cut to compensate for the fact that the
outer edge of the stuffing material will have a larger radius than the inner
edge.
Make
sure the bilge pumps are working, even though the load on them won't be that
serious if you use the wax sealant mentioned above.
Take off the nuts on the collar, and slide the collar forward.
Using the "corkscrew" remove all the packing
material in the stuffing box.
Pack
in the GFO rings. Start with two and then put on the collar and push the rings
back into the stuffing box. Add a few more rings, until you can barely get the
collar on far enough to put on the nuts to hold it in place.
Tighten
it down moderately.
Remove
the wax from the cutlass bearing.
Turn on the engine. Run it in gear while tied up securely to the dock. You will
get a bit of leakage. You want it snug, but not so much so that the shaft gets
too warm. As it settles in, you may get a bit more leakage.
Shut
off the engine and tighten it a bit more. Do this a few times over the next few
days. As it settles in, you will reach a point where the shaft is barely warmer
than the environment, and you no longer get any leakage. (Well, maybe a drop
every few minutes, or even less.) Once it is properly seated, you will only
have to check it every few weeks or even every few months.
GFO is really terrific stuff, and vastly better than the junk sold at West
Marine.
Harvey Karten December 2003
_________________________________________________________________________________________________
Hi Jonathon,
Before you replace your present stuffing
box setup with a PSS, if it is because of persistent leakage, I suggest that
you first try using the Gore-Tex braided packing. A number of Tayana owners
have used that, and found that it is vastly better than any other material, and
has effectively stopped almost all leakage from around the packing. It is
widely used on Coast Guard vessels these days, requires about $10-$15 worth of
material. This is not the simple (but expensive) Teflon stuffing that you
usually buy at West Marine.
The PSS is excellent, but expensive
to put in, and does have a slight risk of rupturing with age. If it does that,
you then have no way to easily control the flooding. If you are at sea, that
can be a major
disaster.
We were planning to install the PSS
due to persistent leakage, and the boatyard technician who was going to install
the PSS, suggested that we first try the Gore-Tex material (even though he
wasn't going to make anywhere near the money that he might have made by
installing the PSS).
'Twas amazing stuff.
regards,
__________________________________________________________________________________________________
Subject: Gore-Tex stuffing source
http://www.e-marine-inc.com/products/gfopacking/packing.html
Rich
Hampel April
2005
__________________________________________________________________________________________________
Jonathan,
I too see no reason to replace a conventional
stuffing box in good condition with a PSS shaft seal. I've used 1/4"
conventional or PTFE flax packing (replaced annually) for more than 20 years
with no significant leaks. The T-37's rigid stuffing box works much like the
one pictured in Fig. 9-25A in Nigel Calder's Boatowners
Mechanical and Electrical Manual (2nd Ed), page 313. The only difference is
that the T-37 uses a flanged compression ring in lieu of a packing nut and
compression spacer. If your objective is
to keep the bilge dry, why pay $225+ for a shaft seal that can fail
catastrophically, when it costs less than $10/year to maintain a conventional
stuffing box that gives plenty of warning (to anyone who looks) before it
fails?
If your OEM stuffing box is deteriorated
(due to corrosion) and it's time to replace it, then a shaft seal is worth
considering. As an offshore sailor, however, I prefer the margin of safety that
comes with a traditional stuffing box. If you've repacked and adjusted your
boat's stuffing box correctly (Calder explains how to do this in his book) and
it still leaks, it's time to pull the propeller shaft for inspection. When a
stainless steel shaft has been in service 15 years or more, it's not uncommon
to find significant pitting corrosion of the shaft inside the stuffing box (due
to the lack of oxygen). When this occurs, the shaft's roughened surface will
"chew" up the flax packing and the box will increasingly leak. Shaft
wear inside the stuffing box (from the compressed flax packing) also leads to
increased leaking, although not as much as with a seriously pitted shaft. In
both cases, the solution is to replace the shaft (not the stuffing box).
Sue
Canfield Aeolus
T37 #-305
Annapolis, MD April
2005
__________________________________________________________________________________________________
I second Sue's observation, especially
about the shafting found in Tayana’s. My shaft was probably 302 (or worse)
grade of stainless that was severely galled in the area that is encompassed by
the packing, not so much crevice corrosion but simply a very aggressive
chloride attack. After what I saw when I pulled my shaft, I would heartily
suggest that if you never pulled the shaft for inspection - that you do so.
Incidentally, I had my new shaft
polished, passivated and then electro-polished from
the stuffing box on back.
Rich Hampel April
2005
__________________________________________________________________________________________________
I'm going to be learning how to repack my
original equipment stuffing box for the first this spring prior to launch. I
want to use the Gore GFO packing material and looking through the archives it
looks like 1/4" or 3/16" is the right size depending on the condition/shape
of the stuffing box.
It appears to be sold in 2 foot
lengths and by my rough calculation that would yield slightly more than 5
rings. Is one 2-foot piece enough?
Thanks for the help in advance.
John s/v Tortuga
1979 T37 Ketch #175 April
2005
__________________________________________________________________________________________________
Hi
John,
If your flange and shaft are eccentric to
each other, you will have trouble using the 1/4". In that circumstance,
you will have to go to the 3/16", jamming in a bit extra material on one
side than the other. But with the smaller size material, we found that we
needed almost two full packages of 2 feet each. Still a hell
of lot cheaper than a PSS.
regards,
__________________________________________________________________________________________________
All you need is the 1/4". If because
of alignment/tolerance/interference, etc. you need 3/16" just lightly
"tamp" the 1/4" with a hammer etc.; but, don’t try to make 3/16"
material out of 3/4" material.
Rich
Hampel April
2005
__________________________________________________________________________________________________
Year and years is the useful life. For
packing a stuffing box, consider that GFO etc. is a permanent installation
until it ultimately abrades away. The base polymer is tetraflouroethylene
(Teflon) one of the most stable organic compounds ever synthesized. In fact
there is gaining widespread environmental concern over the stability of these
and related compounds (including Scotchguard) as they
will essentially never go away and they are rapidly 'accumulating' in the
environment.
Rich
Hampel April
2005
__________________________________________________________________________________________________
Hi
John,
I found that I had to add material after
about 2.5 years. This is probably due to the off-axis installation of the
original stuffing box, relative to the engine shaft. Assuming a cutlass bearing
in reasonable condition, and proper alignment of the engine relative to the
shaft (should be within a few thousandths), a shaft diameter of 1-1/4" and
an internal diameter of the stuffing box of 1-3/4", you should be able to
get by with 1/4" stuffing. However, our stuffing box was sufficiently off
axis that I couldn't manage to push, squeeze or pound the 1/4" stuffing
material (GFO) around all part of the shaft. I finally had to go with the 3/16".
My original notes on this (January
11, 2002):
I
bought the 3/16", rather than the 1/4", to match the present
stuffing.
If
it leaks, I may then try the 1/4". It comes in nominal lengths of 24". Then went back two more lengths. Paid $10
each for the next two pieces.
1/12/02
Saturday- Spent a few hours removing old stuffing and then installing the new
GFO stuffing. Each length was ca. 4-3/4" to compensate for the greater
outer curvature. Chris Boyd packed the outer
rim of the cutlass bearing with wax to minimize water getting in as I removed
all the old stuffing. Make doubly certain that the bilge pump is working
properly.
Two problems, as always –
1)
Shaft is asymmetric relative to the stuffing box aperture. Narrower
on the lower margin. Thus I can barely fit 3/16" stuffing below,
while the space above the shaft is roomy enough to accommodate 1/4" or
more. Removed about 5
rings of material using the corkscrew-like stuffing puller. Packed in 6 rings of GFO. Initially only
had enough for four rings, but then went to get more material. Bought two packages to play safe. Added 3 more rings, but
then couldn't insert the collar. Took one out. Total of 6 rings. As I tightened it, the collar was fully
inserted. Need to remove collar and add at least one more ring of GFO.
2)
Very difficult to reinsert the collar. Then went out to
motor. About 1.5 hrs at 1,200 to 2,100 RPM.
Only a very small amount of dripping of graphite mixed with water. Shaft is
slightly warm, but never hot. Almost a complete success, but
not quite. Have to add at least one more ring of GFO. But
looks very promising. Might have been better if i had been able to use the 1/4" GFO. Also, the
job would go much easier if I could have found my long 1/2" socket
wrench. Hope this helps.
regards,
__________________________________________________________________________________________________
Hi
All:
I, too, will repacking
my stuffing box next week. I have never done this before, and would like as
much advice as I can get before attempting it. So, all of you that have done
this one (or many times)
before, and can remember what you didn't know before you did it, please
respond.
What specifically should I look for
as I attempt this process in terms of wear, potential pitfalls, notes for future maintenance? What tools and extra's should I have handy?
Specialized? Homemade? Odd?
Can I do this with the boat in the water?
If I have to have the boat hauled, how much time should I allow for the
process (remember it's my first time)? Size/length of packing material? What am I not asking
that I should or could be important?
All your help is much appreciated.
Michael Quirk s/v Vacilando
T37, Hull 242 Minnetonka
April 2005
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Hi
Michael,
Brace yourself if this is the first time
you are about to repack your stuffing box. Do it on a day when you have LOTS of
time. There is no need to haul out your boat in order to change the stuffing in
the
stuffing box. A very simple solution is to go to Home Depot and buy a wax ring
used for the base of a toilet bowl. Assuming that the water
is reasonably warm, dive the boat, and stuff the wax around the exit point of
the shaft at the cutlass bearing. Don't push it in too far, the goal is to minimize the flooding of water when you
remove the stuffing. Water pressure will help hold the wax in place. When you
are done, remove the wax. This was is so soft that it should not cause a problem,
and comes off in a single piece. The wax ring costs about $2.50 - easily the
best bargain in boating for reducing stress.
MAKE SURE YOUR BILGE PUMPS ARE ALL
WORKING CORRECTLY BEFORE YOU START. I even suggest that you test the ability of
your bilge pumps to handle large quantities of water by turning on a hose into
the bilge. At the very least, it will help clean out your bilge.
Get all the pieces together before
you start:
Wrenches for the nuts on the stuffing box. Note - I used the plural! You are almost sure to drop
a wrench at a critical moment, and you don't want to try to find it in the
depths of the bilge as water is flowing into the boat. Make sure that the
wrenches you choose can actually fit in the available space.
A block of wood and
a rubber mallet to tap the flange. Not a good thing to do, but ... Do
not hit the flange with a metal hammer when you are trying to get the flange
back in place or compressing the stuffing.
The wax ring (see above).
Stuffing hook from your local marine supply store. Get
one that is narrow enough and long enough to reach into the depths of the
stuffing box.
A flashlight and a small mirror on a rod to try to peer into
the stuffing box.
Suitable stuffing material, and enough to finish the job.
Get two packs of the GFO. If you don't need it all this time, you will have
some extra available for the next time you do it (in about 2-3 years or more).
A wooden stick to push stuffing into the box.
Pre-cut lengths of stuffing material.
Spare nuts to replace those you drop down the bilge while working.
Tape and a felt tip marker
Pre-cut pieces of stuffing to make a snug ring around the
shaft.
Lots of good light. Lots of clear
space around you with good access to the stuffing box. Lay your tools
out in a
neat and orderly manner.
Make yourself comfortable. You will be leaning over in a very contorted
position, and you don't want to find yourself worrying about drowning while
uncomfortably squeezed in the lazarette. Make sure that the hatch to the
lazarette is securely held in the open position. It would not be pleasant to
have it suddenly slam closed over you from a passing speedboat's wake, with
water surging up from the stuffing box, as the bilge pump plugs and your head
is barely above water. Not a bad idea to have a friend sitting in the cockpit
to hand you items that you forgot, and also to provide reassurance. If you have
a bad back, I strongly suggest that you hire someone else to do this. You have
to remain in a painful bent over position for at least 20 minutes.
The rest is easy:
1)
Pack the wax around the outside of the cutlass bearing.
2)
Remove the nuts holding the stuffing box flange.
3)
Make a mark on the top surface of the flange so that
you will know the original orientation. The flange may have been distorted over
the years, and may only fit in a specific orientation.
4)
Remove the flange and slide it up the shaft. Test to see how difficult it will
be to get it back into place.
5)
Tape the flange high on the shaft to keep it out of your way.
6)
Use the stuffing hook to remove the old stuffing. This is actually one of the
worst parts of the job, as it requires a unique body shape to be able to get
your arms down where they have to be to do this properly.
7) Water will now be flowing in. DO NOT PANIC. Remind yourself that it will be
better to let the boat sink, rather than drowning in a dark lazarette. (I hope
that your boat and life insurance are paid up!)
8)
Fit in the pre-cut pieces of stuffing. Push them in with a small wooden coffee
stirrer.
9)
After you have put 3 rings of stuffing in place, try to reinsert the flange.
You may have to tap the forward face of the flange with the block of wood and
mallet, in order to push in the flange and get it to compress the stuffing. If
you still have lots of thread showing on the flange bolts, remove the flange
and add more rings of stuffing.
10)
Snug down the nuts on the flange bolts, but not too tight.
11)
Make sure that your boat is well secured to the dock.
12)
Remove the wax ring from the outside of the
shaft/cutlass.
13)
Make sure that you didn't leave anything around the
shaft that will foul it when you put the transmission in gear.
14)
Start the engine and let it warm up.
15)
Cautiously put the engine in gear. Take it out of gear. Were there any unusual
noises?
16)
Now you will need to have someone you trust in the cockpit. Climb back down
into the lazarette.
Position
yourself safely. Do not wear clothes with material hanging off.
17)
EXTREMELY carefully look at the stuffing box and flange.
18)
Have your friend in the cockpit make sure the engine is at idle speed.
19)
Put the boat in gear.
20)
Is water leaking in?
21)
If it is, have your friend put the boat in neutral.
22)
Tighten the nuts symmetrically on the flange.
23)
Go back to step "16)". Turn off the engine. You should be able to
turn the prop shaft without trouble by grabbing the coupling with the
transmission.
24)
If there is no leakage, does the shaft get hot when rotating.
25)
It may take a bit of fiddling, but the shaft should stay barely warm to the
touch after it has been running. If it gets hot (and especially if it so hot
that you can't hold your hand on it) loosen the flange a bit.
26) Stop.
27)
Take the boat out for a short ride around the harbor to help seat the stuffing.
28)
Check to see if it is leaking. If so, tighten the flange nuts a very small
amount.
29)
Nothing wrong with slight seepage of water. That helps flush salts off the
shaft. Yes, it is nice to have a perfectly dry bilge. But that isn't always
possible on older boats due to wear and tear.
30)
Have a cool beer.
Welcome to the club. Hopefully you didn't drown, and your boat is still
floating on its waterline.
regards,
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I just did mine for the first time. I had a
hell of a time finding the right tool to do it. A good spiral pick as
recommended by Nigel Calder wouldn't fit in the 1/4" space on my V-42 and
West Marine, Boat US & Boater's World no longer sell the cheap picks.
However, I found an excellent set of 3 picks at Home Depot that worked very
well. They look kind of like dental picks but they are built much stronger and
my regular dental picks wouldn't work. Once I got the right picks the job went
pretty well. I was on the hard and for my first time I think that was a lot
safer.
Harry & Melinda Schell Sea
Schell April
2005
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Great job on how to repack a stuffing
box. I love all the detail. You
need to write a book, Harvey! The ones on sale now always say something simple
like, "Remove old stuffing." As you pointed out, there are 25 steps
to doing this including tools, lighting, and body positioning. That's why it
takes 2 hours to do a 15-minute job on a boat!
Sea story about stuffing boxes: when
I got my V-42 long ago, I had it "professionally" commissioned by a
Tayana dealer. They hauled my new boat with the sling on the prop vice the
keel. As the boat cleared the water, the sling came off the prop and caught on
the prop nut with a jerk that bent the shaft like a pretzel. Luckily, the boat
stayed put until they got it back in the water.
After replacing the shaft, it was "professionally" repacked. I
thought the stuffing was too tight. I had heard that it should drip a little
when first launched and should only be adjusted to stop the drip after motoring
for an hour. Then it should drip twice a minute underway but not at all when
docked. I argued with the "professionals" but gave in to their
expertise. My first
day underway, I put my new boat aground in a marina and momentarily went to
full power to get the boat moving. After a short while, I heard the
loudest, most agonizing "squeal" from my engine room. After the smoke
cleared, you could see a cherry red stuffing box in the dark engine room. The stuffing box overheating and subsequent
friction had taken my new Perkins from a full power condition and shut it down
completely!
I finally went to a Lasdrop shaft seal 15 years ago. When it was only 5 years
old, the plastic collar around the shaft was found cracked during an annual
inspection and required replacement. The problem was that the screw that held
the collar together may have been too tight. After 10 more years, I replaced
the whole thing with a new Lasdrop since the rubber bellows was getting weak
and the sealing face sometimes leaked when underway. The new models don't use
screws anymore but hose clamps instead. On a couple of occasions while still in
the water, I have had to slide the shaft back over a foot to change the
transmission. There is a little bit of leakage while moving the shaft but then
the bellows can be tensioned and there is no leakage while the shaft remains
backed out. Otherwise, the Lasdrop seems to be a satisfactory seal and I never
worry about a hot stuffing box.
Wayne V-42 C/C RESTLESS April
2005
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I prefer to pack repack the shaft on the
hard, and also like to pull the shaft out for visual inspection. Remove the
coupling, depending on clearance when the rudder is full to one side - drop the
prop, slide the shaft out to where you can inspect where its
riding in the stuffing box. If heavily scored or galled, take to a machine shop
and 'dress' and polish the journal surface. Tayana’s don’t seem to have very
good quality metal on their propshafts - about $600 for a new shaft.
Haven't checked the shaft on Sojourn yet
but it's on the list for next time in the yard. I have had good luck in the
past with repairing a galled and pitted shaft with a machine shop process of
metal spraying. They turn down the damaged area just a little bit to remove the
damage and get a smooth surface, then it's sprayed with stainless steel until
it's built up larger then the shaft and then machined down to the required
size. I had this done to the transmission shaft on a tractor where the reverse
gear had ceased on the bearing surface, it still
looked like new 8 or 9 years of hard use when I had to replace a seal in the
trans... I was also thinking of having the packing area on the shaft polished
next time it's out... Just had the same thing done to save a 400.00 dollar pump
motor on a spa, I took it apart and the cost to repair it was 60 bucks with new
bearings...
Ventura Bill April
2005
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Everything Harvey wrote sounded reasonable,
but it is really not necessary to use the wax ring. The flow of water will not
be more than your bilge pump can handle.
BTW, I once had a PSS shaft seal on
the prop shaft and I removed it and went back to the Gore-Tex packing while the
boat was in the water. In this case I did use a wax ring to seal the shaft and
the vent holes in the stern tube from the outside and it worked perfectly.
A couple of extra suggestions:
1.
Cut the lengths of packing (before removing the old) by wrapping the packing
around the exposed prop shaft and slicing it with a razor blade. This way you
will get exact lengths. If you use the little
corkscrew-like tool, remember to get one that is small enough to fit between
the shaft and the stuffing box.
2.
I've found that a hemostat or needle holder is helpful in pulling the old
packing out. Cheap needle holders can be purchased in fishing supply stores.
3.
Rather than a stick to push (tamp) the new packing into place, I use a 6"
piece of 1" or 1.25" diameter thin wall PVC pipe cut in half
length-wise. It fits around the shaft easily and insures that the new packing
slides evenly into place around the shaft in the stuffing box.
Jim Smiley (SMILES) April
2005
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We bought a set of picks at Home Depot,
too, and they ended up being junk. The
picks came out of the handles on two of them. I ended up returning them and
going to the local NAPA store and getting their heavier-duty set for about $7,
IIRC.
Mark Kaynor "Rachel" April
2005
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Harry,
Harry, Melinda, Bill, Jim, Mark, Bruce and others:
With all your help, advice and counsel, I
replaced the packing in my stuffing box and all went exactly according to your
descriptions. And, I will never again worry about performing this maintenance
chore.
To be on the safe side, I bought 3
widths of packing material, and ended up using 1/4". There was enough room
to put 7 rings in, so I did, but I suspect that 3 or 4 would have done the
trick. The 7 rings used most of 2 packages of stuffing. The toilet base wax
ring worked well, but a fair amount of water entered anyway; I wonder how much
more would have flowed in w/o the ring??
The whole process took about 45
minutes, not including the dive time. 35 minutes to remove the old packing
(I'll be more aggressive next time) and 10 to install the new stuffing and
tighten down the flange. Bilge pump cycled about every 2 minutes for 30 seconds
after the last old stuffing ring was removed.
After I got done, I wondered if there
is a similar stuffing box for the rudder post? Does
anyone know how the rudderpost is sealed from the water and is there a
maintenance procedure for it?
Thanks again for all the help.
Michael Quirk s/v Vacilando T37,
Hull 242 April
2005
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Subject: Rudder Stuffing Box
Is this connection like adjusting the nuts
for the packing gland? Yes?
Is there a packing gland of some sort in
the rudderpost connection on the inside of the hull? Yes, identical to a
regular stuffing box.
Anyone with experience
with this? I tighten mine
periodically when needed. If you want to know if doing this affects your
steering, you can try using a fish scale on the spokes of your wheel. After the
wheel is turning, just read the pounds of force required to keep the wheel in
motion. Make sure to attach it as far
out on the spokes as possible and do it before and after the job. I just
overhauled my steering pedestal, had previously replaced the pull-pull cables
with Morse cables, and have gone over the entire steering system. It takes 3
1/2 pounds at 29 inches from the center to keep my wheel moving.
I can answer this question for the
V-42. Unlike the hose setup on the T-37,
it has a fiberglass "pyramid" or "cone (a foot tall) with a
standard stuffing box flange on top. The bronze stuffing box flanges are clear of
the water at rest but are underwater when moving. Checking for leaks can only
be done underway. The same stuffing used for the shaft can be used for the
rudder. The rudder shaft is a larger diameter than the prop shaft.
Wayne
V-42 C/C RESTLESS April 2005
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Harvey's description of how to replace the
packing was just fabulous. I had all the
right tools, parts and pieces and since I had the water heater out I even had a
place to sit.
First off I couldn't imagine doing it
in the water with water flowing by, I'd be an absolute
nervous wreck. My biggest challenge and lesson learned was trying to remove the
old waxy stuffing material after the boat has sat through a cold Minnesota
winter made for some tough pickin. A couple of the
rings came out pretty much intact but several were just a waxy/hairy blob. A
chunk got stuck on the
underside of the shaft and wouldn't budge. I eventually resorted to my trusty
heat gun and gently warmed the contents, which really made a difference.
I'm still not 100% sure I got all the
old stuff out, probably one of the advantages to the in water
replacement method, I'm guessing you know for sure when that last piece comes
out. Anyway I got 6 or 7 rings of new GFO in place with a steady drip and a
1/4" to 3/16" to go to reach the point where the retainer ring was
previously. This weekend I'm planning on doing the break in process and
hopefully
declaring success.
I want to say a special thanks to
Harvey and everyone else who contributed suggestion and advise.
J. Ware s/v Tortuga 1979 #175 T37 May
2005
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