[C320-list] Dry bilge?

[Allan S Field]

Scott - Following are notes in my files regarding the stuffing box.  There
are at least 3 options for dealing with the packing gland/stuffing box.  One
is to go with the cloth-like packing material; this probably is what the
boat came with.  Another is to go with a GoreTex material; I have no
experience with this but have heard of good reviews.  The third option, and
the one we have on Sea Shadow, is to invest in a dripless packing gland from
PSS.  Notes that I have in the file for the PSS also follow.  When our boat
was originally commissioned, we invested at that time in the PSS as I didn't
want to deal with the traditional packing gland.  At the time, the PSS
required occasional "burping", especially when launched in the spring, which
brought a small amount of water into the boat.  But it never leaked.  This
summer, after 13 years with the original PSS, we prophylactically changed it
out for an upgraded PSS that never requires burping.   Following is a link
to the PSS - http://www.shaftseal.com/en/categories  

Hope this helps!

Allan S. Field
Sea Shadow - #808
Columbia, MD
***
Traditional Stuffing Box / Packing gland:

If you have a more traditional stuffing box / packing gland, you'll see two
very large brass nuts around the shaft. The packing material resembles
clothe with a waxy feel to it.  It's packed around the shaft.  As the
collar/nut is tightened, it compresses the packing material more snugly to
prevent leaking.  But a packing gland *does* need to leak.  The leaking
serves to cool it and also proves that it isn't TOO tight.  If it's too
tight, it will overheat, and not get any water to help cool it.  This will
cause premature failure of the packing gland which will then need to be
replaced (and constant tightening).

The 2nd collar/nut is really just to lock against the first so that, once
set to the appropriate amount of compression on the gland, it won't move.

Adjust the gland so that you're seeing 1 drip of water every 15 seconds
while the shaft is NOT engaged / turning.  Use the lock-nut to lock it in
position once you've found that rate and re-verify that you're still getting
1 drip about every 15 seconds (as it tends to turn the packing gland
adjustment when you try to tighten the lock nut).

***
PSS Dripless system:

The PSS is very simple.  There is a black rubber "bellows" which is attached
via hose-clamps to the shaft log (the hole made into the boat through which
the actual prop shaft goes).  The bellows doesn't turn.  At the end of the
bellows is a black graphite seal.  On the shaft itself, is a stainless steel
collar.  It has rubber o-ring seals on the inside.  It is fixed to the shaft
and spins.  The graphite seal on the end of the rubber bellows rests on this
stainless collar (which is spinning when the shaft is engaged).  The seal is
perfect, creates very low friction so it really doesn't heat up and wear
out, and yet it's just a good fit that water cannot get through.

The inside of the bellows needs to be flooded with water for cooling
purposes.  To do this the bellows are "burped" my merely pushing the rubber
bellows away from the stainless collar.  This allows the air to escape and
the be replaced with water - which will spray over the place if you hold it
too long. So hold a hand over the gap you're about to create to deflect the
water and keep it from spraying your mattresses and you.  Just release it,
you're done.

Occasionally a bit of debris will get into the seal.  It's basically
"pinched" between the graphite and the collar and it causes a small leak.
When this happens, all you need to do is re-burp the seal.  As soon as you
compress the bellows, the flood of water will flush out whatever was caught
in the seal.

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Scott Westwood
Sent: Thursday, November 20, 2014 7:10 AM
To: C320-List at Catalina320.com
Subject: [C320-list] Dry bilge?

I have seen several notes on how to re-pack stuffing boxes etc...

I also have heard different takes on dripping and "drip less" vs.
"dripless".  My wife "hates" water in the bilge with a passion.

Is there a truly safe way to get a dry bilge?  Cost/benefit analysis?  You
can but it would cost as muchas the boat etc???

Our box drips 3-5 drips/minute even at the dock.  Is this normal?  I hear it
is for cooling underway etc...


What thoughts are out there?

One concern we both have is the odd chance that we have a bilge pump failure
(or battery failure) at the dock.  We have shore power but we often can't
get to the boat for a month or so.  Worst fear is bilge pump failure and
boat sinks.  I know it should not happen within a month or so but there is
also the fear of wood deck damage if bilge water rises etc...


Thoughts out there?


Scott Westwood scottwestwood at bellsouth.netH (919)-362-8538C (919)-618-7185