The Stuffing Box (click any image to see a larger version) While digging around in some old boat parts boxes I found a stuffing box from an older sailboat. I though it would be a good time to rig it up
I am going to suggest you try the 1/4” first. But as Stu says have both on hand. It is cheap and you do not want to have it all open then have to go back to the store.
Ditto for the GFO packing. Works great and BTW my shaft is also 1'' and takes the 3/16. The idea of buying both is good. FYI I have attached some pics: one of the packing gland type on my boat so you can compare and the other ones are how I have simplified measuring the 3 pieces by measuring the stern railing (1.01''), then wrapping 3 turns around it and cutting with a sharp exacto knife. The 3-pieces are then installed at 120 degrees intervals inside the packing gland. You'll see that the packing looks bigger then 3/16 and you'll be right. I made the pictures some time ago when I had to do it in the water and the store where I was only had 1/4. I could only put 2 wraps inside instead of 3 and had a little drip. I redid the job when I could get my hands on 3/16 and it has been working almost dripless since. Good luck.