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Flax packing size for 3207

Posted: March 25th, 2024, 6:45 am
by Dad Joke
I'm replacing the packing on the rudder seals on my 3207. The shafts and stuffing boxes are the same size as the prop shafts. What size packing do I need? I thought it was 1/4", but that seems to be too thick.

Thanks,

Re: Flax packing size for 3207

Posted: March 25th, 2024, 11:21 am
by km1125
Not sure what size shafts you have, but here was a post from VIPER a couple years ago that might help:

Viper wrote:Source of the post Here are the standard sizes by shaft diameter

1" shaft = 1/4" packing
1 1/8" shaft = 3/16" packing
1 1/4" shaft = 1/4" packing
1 3/8" shaft = 5/16" packing
1 1/2" shaft = 1/4" packing
1 3/4" shaft = 1/2" packing
2" shaft = 3/8" packing
2 1/4" shaft = 7/16" packing
2 1/2" shaft = 5/16" packing
3" shaft = 9/16" packing

You can do this in the water, just cut your 3 pieces per shaft prior to removing the packing nut. To do this, cut one end of your new packing at a 45 degree angle, wrap the packing around an exposed area of shaft, and cut the packing at 45 degrees ensuring it butts up tight against the first end you cut. Make three of these per shaft. Make sure you use a new blade and let it do the work or you'll fray the ends, try to make as clean a cut as possible.

Have pick with little hook hook on the end, remove the nut and pick out all the old packing inside. You will get some water coming in but it'll be manageable. I like wrapping a rag around the shaft at the tube. Take each piece you cut and install them with the cuts offset from the previous one. I like putting them at 12, 4 and 8 o'clock then thread the nut back on.

Tighten the nut just enough until you get a steady drip, not stream. DO NOT over tighten. I like walking away for a day and allow the packing to get wet and expand. Then tighten the packing until you get a drip every couple of minutes. Then you need to revisit after a good run on the water. Dripping while running is normal.

Having a drip is normal with this type of system, it's what lubricates the contact area between the shaft and packing. If you tighten too much, this area will heat up and damage the shaft.

Wax impregnated flax packing has been around for ever and still a standard when this type of system is used. There are other newer tech packing such as GFO that have become popular over the years as they offer better heat dissipation allowing for a tighter fit and less lubrication which reduces the drip but I'd still be careful. The best way to go of course is to retrofit with a dripless shaft seal system.

Re: Flax packing size for 3207

Posted: March 25th, 2024, 1:16 pm
by Dad Joke
Thanks. I think my mistake is that I didn't cut the flax on an angle, so the ends couldn't overlap and allow the flax to compress between the packing nut and the rudder port.

The boat is on the hard and has been since 2008. So, replacing the packing is essential. I was unable to separate the packing nuts from the jam nuts, so I ended up having to cut the rudder ports and replace them. I wouldn't wish that job on anyone.

Thanks again.