Correct packing size for stuffing box is now 1/4" x 1/4"?

[Breakin Away]

The manual for my 2001 MkII (7th edition dated 12/14/99) has a hand-drawn sketch of the packing gland by Gerry Douglas that says to use 3 wraps of 3/16" x 3/16" packing.

The MkII manual on this site (also 7th edition, but dated April 22, 2002) has a computer drawing by Kent Nelson that says to use 2 wraps of 1/4" x 1/4" packing.

The stuffing box does not appear to have changed, based on comments from Lowell at Catalina Direct and based on comparing my factory original stuffing box with the replacement that was installed in 2019 (which CD said had 1/4" packing). When viewing the stuffing box on the CD website, their "May we recommend" shows both 3/16" and 1/4" items.

Changes like this do not happen accidentally. Does anyone know why Catalina made this change? Have any of you tried both and can provide comments on whether the 1/4" packing was more difficult to install and/or too tight leading to heat and difficulty establishing a drip?

[Jim Hardesty]

Changes like this do not happen accidentally. Does anyone know why Catalina made this change? Have any of you tried both and can provide comments on whether the 1/4" packing was more difficult to install and/or too tight leading to heat and difficulty establishing a drip?

Breaking,
I don't think Catalina purchasing concerns itself with the internal parts of suppliers.  Shamrocks' hull number and year is close to your boat.  Takes 1/4 inch packing, 2 rings, tried 3ed but didn't have enough threads for my liking.  I used GTU brand packing and had no issues.  Has been giving good service for 10+ seasons and guessing 1500 engine hours with only a small adjustment after the spring launch.
Much has been posted here on shaft packing, suggest you search and review.
Jim

[Stu Jackson]

The manual for my 2001 MkII (7th edition dated 12/14/99) has a hand-drawn sketch of the packing gland by Gerry Douglas that says to use 3 wraps of 3/16" x 3/16" packing.

The MkII manual on this site (also 7th edition, but dated April 22, 2002) has a computer drawing by Kent Nelson that says to use 2 wraps of 1/4" x 1/4" packing.

The stuffing box does not appear to have changed, based on comments from Lowell at Catalina Direct and based on comparing my factory original stuffing box with the replacement that was installed in 2019 (which CD said had 1/4" packing). When viewing the stuffing box on the CD website, their "May we recommend" shows both 3/16" and 1/4" items.

>>>>>>>>>>>>>>>>>>>>>

Changes like this do not happen accidentally. Does anyone know why Catalina made this change? Have any of you tried both and can provide comments on whether the 1/4" packing was more difficult to install and/or too tight leading to heat and difficulty establishing a drip?

Given your opening paragraphs, I can understand the confusion it initiates.  As you may be aware I have been with this website since shortly after it formed and before this forum even was begun.  Accordingly, I have followed or at least been aware of changes to production runs, hull details and equipment mods/changes/enhancements.

After a few years, especially with the introduction of the Mark II boats, folks started asking about packing size.  My personal understanding was that the new boats with the larger M35 engines came with 1/4" while the older boats with M25 and M25XP engines had 3/16" (even though the shaft diameters remained the same).  Perhaps that was a simplistic "understanding" because your post here is the first one that challenges that assumption especially with your quotes of the two very different manuals for the same Mark II boat.  I had always recommended that folks check the manual that came with their boat.  With the advent of the internet and our ability to store and preserve complete boat manuals, complicated with the fact of boats with now-multiple owners who may not have retained the original manuals that actually came with that particular boat, referencing "a manual" is not a specific as it once could be.

What changed?  The only thing that changed was the specific stuffing box installed on any given boat.  So, most likely, as is often the case with other items on our Catalina 34s, the builder started buying different stuffing boxes.

In times past, I have also recommended that owners who are unsure physically measure the box on their boats to find out.  It's not that hard to do and made easier with inexpensive calipers available thee days.

[Noah]

I use 1/4 in. GTU

[Breakin Away]

I just re-installed my stuffing box onto the shaft hose, and re-packed the stuffing box with two rings of 1/4"x1/4" DuraMax Ultra-X. I am very pleased with it, but I was unable to get it into the nut when it was on the shaft. There wasn't quite enough clearance between the shaft and the threads in the nut, and I didn't want to risk damaging it by forcing it in. Instead, I removed the nut from the shaft (easy, since I already had the coupler off), pre-packed it (using the tapered end of my old, bent, bronze shaft as a mandrel to push the stuffing out into the threads), then popped the pre-packed nut onto the end of the shaft.

If I ever had to re-pack the stuffing box with the nut on the shaft (especially if the boat was in the water), I would think twice before doing it with 1/4"x1/4" packing. The clearance between the threads and the shaft is very tight, and risks twisting or fraying the packing when inserting it (even if using MaineSail's PVC insertion tool). If I were doing it in the water, I would probably go with 3 rings of 3/16" stuffing, which would insert into the nut more easily. The Ultra-X is deformable, so after tightening the rings would compress axially and expand radially into the threads. But the 1/4" material works fine as long as you have a tapered mandrel to expand the ring into the threads.

[Noah]

Hmmm? Could be the difference in brand/design of stuffing boxes, but I did mine in the water with 1/4 in. and it has worked quite well. I followed Mainesail's instructions on his "How to". Website. However, I used GTU packing on my Aquamet 22 shaft. No leaking and no corrosion evident after several years.

[Ron Hill]

Guys : Years ago (1990s) I wrote a Mainsheet tech note article on "How to replace the stuffing box packing with the boat in the water" (with pictures).  Not that difficult!!

A thought