This is a due diligence question for NS 33 owners.
I am in the process of repacking the flax in the stuffing box packing gland on my 33.
I have a 1 1/4" shaft on a Hurth V drive transmission which makes access interesting. At least I get to lie down on the cabin floor while doing the job.
The Hinterhoeller NS 33 owners manual advises that for the NS 33 with a 1 1/4" shaft, the correct flax size is 1/4".
Has any NS 33 owner who has repacked the gland with a 1 1/4" shaft found differently in terms of flax size?
Thank you Mark
I was already aware of the marine- how-to website and several others, and put their recommendations into practice. But I expected and found the task more challenging given the V drive transmission compared to the generalities of these sites. At the outset of the task, I did not know whether the previous owner of the boat had changed the stuffing box prior to my ownership meaning that the 1/4 inch flax size identified in the NS 33 manual for a 1 1/4 shaft might not be relevant, hence my question. After removing the very old flax which was compressed to about 1/8 thick in the gland nut and attempting 1/4 installation without success, I chose to err to the conservative side by using 3/16 flax size. It was recommended to me to hammer the flax flat before cutting and installation which I tried but even with that, I did not like the amount of force it would have taken to install 1/4 flax into the gland nut. I still had to hammer the 3/16 a bit to get 3 good bedded layers in the nut. I'd rather have a bit more water in the bilge and an undamaged shaft, and gland nut with 3/16. The sailing season is short here and I can always try again next fall after haulout after assessing the drip rate and gland nut temperature under operation with 3/16.
Ken Dakin
NS 33 # 7
Sashay
Collins Bay Marina
Kingston ON
Is it possible that two layers of 1/4 would fit? My 22 manual calls for that, in spite of having seen other tutorials that state there should be three layers.
Hello Ron
The NS 33 manual advises the use of 2 layers of 1/4 teflon impregnated flax on 33’s equipped with a 1 1/4 shaft which is the shaft size I have on a V drive transmission.In reply to an email from Paul Miller, I noted that I attempted to use this guidance without success and chose to err to the conservative side, and avoid use of force by completing the task using 3 layers of 3/16 flax. The issue was not a question of fitting one, two or three 1/4 layers but rather, getting the first 1/4 layer to seat in the bottom of the nut. The space between the shaft OD and the gland nut ID is about 1/8. Even with hammering the 1/4 flax flat which I was told was necessary and found to be true, I could not get the first layer in beyond the first threads of the gland nut. With a V drive, access is difficult, everything must be done with a light and mirror. My reading tells me that 2 layers of flax is good and 3 layers is optimal. We shall see whether 3 layers of 3/16 does the job without too much drip.
Ken this sounds fishy. If you have 1/8 inch between the shaft and the gland nut ID that would make the tube the nut is threaded on very close on the shaft. There usually is some clearance between this tube and the shaft so it isn’t touching.
I know with the V drive you can’t easily see what’s in there.
There is definitely clearance between the gland nut ID and the OD of the threaded tube onto which the nut is threaded. My 1/8 dimension comes from measuring the thickness of the innermost compressed edge of the old flax I removed. I tried measuring the diameter of the nut and the nut wall thickness but could not get a caliber in the small space between the shaft and engine mount. Suffice to say 1/4 is tough to pack.
Ken Dakin
