I am still in search of info on the prop shaft seal for the NS33.
Owners Manual don't have this info in Sect, 55.1 which is not
provided. Since it is a 1-1/4 inch shaft, is there info available
on the flax packing size for a typical 1 1-1/4 shaft stuffing box?
Any one know how to get Sect. 55.1 from the manual?
Thanks very much,
Ken Bitting
Cosmos NS33 #60
Mystic, CT
I think you don’t have it because some 33’s were supplied with a dripless stuffing box, and some not. Sounds like you have the standard bronze stuffing box, and not the dripless shaft seal; thus #55.1 is blank.
Mark Fagelman
Ken: My belief is that you should have 3 pieces of packing set with the split at 120 decrees from each other. The size would depend on the depth of the packing area. Assuming the assembly is the same manufacturer as that of the 30s, I will try and get down to my boat and look in my manual for the specs. BTW, I’m using the Teflon style now as it can be adjusted much tighter for a near dripless application.
Joe Valinoti
S/V IL Gatto NS30U #221 (1984)
Sea Harbour Yacht Club
Oriental, NC
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Joe,
My boat came with the remains of flax packing but the package is printed for 6 different packing sizes but none of the boxes is checked so I can’t tell what size to buy.
Ken
Ken: The manual for my 30 says two pieces of 1/4" packing.
Joe
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Joe,
What is your shaft diameter?
Ken
Ken:
Measure the outside diameter of the threaded tube that the shaft goes into.
Measure the diameter of the shaft.
Subtract the shaft’s diameter from the tube’s diameter, and divide by two. That is the packing size.
Draw two concentric circles and it will make sense. The packing occupies the space between the shaft and the outside of the tube; it is held in place in the packing nut when you tighten it down. You know the inside diameter of the packing nut is the same as the outside diameter of the tube, because your are going to screw the packing nut onto the tube…right?
Typically, you install three circumferences of packing on the shaft. Wrap the packing around the shaft three separate times and cut it each time with a razor blade for the best (closest) fit. Do not install the packing rings with the breaks you cut in each ring next to each other.
If you don’t have a vernier caliper to take the measurements, buy one. You can get a cheap, plastic (rustproof) one for less than $10 US. Keep it on the boat to check bolt sizes, etc.; most of them will measure inside diameters as well as outside, inches as well as metric. Very useful. You don’t really need to know how to read the vernier scale; very few of our measurements need that level of accuracy.
The shaft on my NS33 is 1.25". I don’t know the packing size because it has been 5 years since the teflon packing was installed by Brewer’s Dauntless in Essex, CT.
Joe Tierney Allegro NS33 #64 Annapolis, MD
1 inch.
Joe
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