My turn with Stuffing box Q.

[chris20636]

Got V2933 Renee back in the water. Good news is that all new thru-
hulls don't leak. Even better news, the engine started 15 seconds
after cranking. The distressing news is the major stuffing box leak
I found after arriving at my new slip. I'm pretty sure it wasn't
there on haulout last year. I will probably have to pump her out
tomorrow morning and gauge how bad it is. I have looked at past
messages and looked at the AVA and VAGB material.

Did all variations of the Vega have the same stuffing box design? I
think mine is one of those late series II's. It is MD6B and has fuel
tank in port locker. The reason I ask, is that, first, I could not
find that grease bolt anywhere. And second, after looking at the
exploded view of the prop assembly, my stuffing box does not look
like the picture. The stuffing box appears to be mostly one piece in
the picture I'm looking at. Mine looks like two large hex nuts
screwed together. The leak is ocurring around the shaft as it enters
the stuffing box. Moving aft to forward, I have a large rubber hose
with clamps on each end. The rubber hose is clamped on a threaded
metal pipe. A very large hex nut appears to be either threaded on
the pipe or is part of the pipe. This whole mess is very green so it
was hard to see exact details. Maybe tomorrow in better light I can
get a better description. I think I remember there was something
that looked like a second hex nut as well. Then the shaft comes out
of the stuffing box and enters the combi.

I will try to move the engine control in reverse to see if that slows
or stops the leak to check for worn shaft. Most of the messages
about stuffing box here, talk about greasing. One message talked
about flax packing. I'm wondering if some models had the flax
packing arrangement? Or maybe someone switched the original stuffing
box on V2933 for something different?

Ideas? Suggestions?

First thing in the morning I'm going to get a sump pump and hook to
shore power as was suggested in one of the messages here.

Thanks.
Chris
V2933 Renee

 

[tlochhaas]

Chris,
I'm certainly no expert on stuffing boxes, and I'm clueless what the original
Vega ones look like, but what you describe here sounds similar to my stuffing
box (my Vega was repowered in the mid 1980s with a newer diesel)--and what
sounds like a classic stuffing box with internal packing rings. If so, one hex
nut (the outer one) is the lock nut and the other the adjusting nut. (The
"pipe" part should also have a hex shape at its end so it can be held in place
with a wrench while tightening the other.) If this is what you have, you simply
loosen the locknut to allow the adjusting nut to turn freely, then tighten the
adjusting nut a little, which compresses the flax packing rings inside tighter
against the shaft, slowing the leak. If tightening it doesn't slow the leak,
that may mean new packing is needed--not something you can do in the water. (You
can tighten it in the water, but only if you're careful--if you opened the
packing nut by accident to the point where it slipped off the end of the "pipe,"
theoretically water pressure could push out the flax rings around the shaft and
make it difficult to stop the ingress of water into your boat!) It would be good
to find someone around the boatyard who could show you how to do this the first
time--you may want to ask around even before trying to tighten it on your own.

But note that a flax stuffing box is supposed to leak a little--the water must
saturate and coat the packing rings for lubrication. So don't tighten it so
tight that there's no drip at all. (The shaft can overheat and become scored.)
The ideal is that it drips a few drops per minute with the shaft turning but
stops leaking (or slows to maybe a drop or less per minute) with the engine off.
It's hard to get it that perfect--I always have a little water in the bilge
whenever I've been away from the boat a couple weeks.

I found all this intimidating myself when I first confronted it, but after a
couple minutes with an experienced mechanics (and a look at a cutaway view of
what's inside the stuffing box--check books at your local bookstore or West
Marine), I lost any fear of this simple device.
Good luck,
Tom
Vega 1240 Allegro

chris20636 wrote:

 

[chris20636]

Hello Chris:

I agree with Tom@greennet as to the function of your packing gland.

I've had that system on two boats; my first Vega, #321 as well as my present
Vega, #1868. I make it a point to adjust it every time I prepare to get
underway. At this time I back-off the "jam nut," the aft one, and loosen the
forward one, the "compression nut," as Tom said, the one that actually compresses
the packing. It should be loosened to the point where a very small drip is felt.
Then - - and this is quite important - - bring the jam nut back to the
packing nut and twist them so they lock together in-place. The purpose of this is so
that the rotation of the shaft (counter-clockwise, viewed from aft) does not
cause the packing nut to tighten. This action has been known to actually twist
the shaft to the point of breaking. Bad situation.

When the day's sailing is finished, I reverse this by: backing off with the
jam nut a couple turns, then hand-tightening the compression nut to stop the
drip.

I hope this helps.

Regards............Ed Davis....aka saylered@...

 

[mocap1]

This is the common type of marine shaft seal.There are some face-type seals used that have zero leakage, but they are not favored by many boatyards because they are subject to catastrophic failure if something is forced between the faces.

I don't mean to sound criitical, or even suggest that you change your procedure, but in almost fifty years of sailing, and ownership of numerous boats, I have never adjusted a packing gland each time it was used, nor have I known anyone who has. I suppose it's like many other things in life, probably a good idea, but more trouble than it's worth for most people.

I don't think a shaft could seize because of self-tightening of the packing nut. This would requre that the packing spin with the shaft and somehow grip the end of the packing nut with considerable force. I have heard of shafts being damaged by packing that was adjusted too tight, with resulting high friction, heat generation, and lack of cooling, but that is another matter.

I believe it is good practice to touch the stuffing box the first time it is used after adjustment to make sure it hasn't been adjusted too tight and is overheating, and to observe the leakage then, and regularly thereafter.Mort

 

[chris20636]

Thanks, Mort/Ed/Tom for the info. I've got the sump pump installed
which has taken care of some of the panic. Adjusting the throttle to
move the shaft did not slow the drip. This seems to indicate that
the shaft is ok, but stuffing box needs servicing. I guess my
message was intended to get confirmation that my stuffing box is not
Vega standard and what it might actually be. Now that I'm out of the
yard and in my slip on the Navy Base, I don't have ready access to a
mechanic. Consensus seems to be "standard" stuffing box with
packing. If the weather cooperates, I'm going to try and get a wire
brush and some penetrating/cleaning oil to clean the "green" off the
stuffing box. If I can get it clean and can get the various parts
unstuck, then I'll try adjusting to slow/stop the leak. I have the
notes from members here and Calder's book to help me adjust it. If I
get it clean and it doesn't look "standard", I'll attempt to draw a
picture and post it to see if anyone recognized it.

Chris
V2933 Renee

 

[chris20636]

I got an off group reply with an email link,

Loading…

www.mooremarine.com

All doubt is gone, this is exactly what have.

I was able to get the stuffing box clean enough to back the lock nut
off a few turns. A 1/8 turn on the packing nut stopped the leak. I
ran the engine for 5 minutes, in gear, and no heat was generated.

Problem solved for now. I will repack the box next haulout.

Thanks all,
Chris
V2933 Renee