Monday, July 15, 2013

Before picture

Repacking a stuffing box (packing gland)

Vessel: 1979 Newport 30MKII
Engine: Universal Diesel 18hp (5216?)
Gearbox: 2:1 ration
Propeller shaft: 7/8"


This is just to share some interesting lessons learned that might apply to similar set ups or sister boats. For general instructions on how to do this please see.

Disclosure: what follow is for information purpose only. What you do with your boat is your responsibility. Some have reported significant amount of water flowing in once the stuffing nut is removed so it is your responsibility to make the right decisions before attempting any project.

Tips and tricks

After picture (wet due to cleaning)
  • In my case the stuffing box body was tight enough around the shaft that the leak was minimal after I removed the packing nut.  So I did my job with the boat in the water. The water flow increased over several minutes but it was still well within what a bilge pump or manual pump can handle.
  • I used narrow pipe wrenches. In my case the two nuts measured 45mm and 50mm. Big, crude plumber wrenches might not work well. Look for something sturdy but narrow that can properly grab the nuts.. I used RIDGID E-110 Hex Wrench. Just FYI.
  • The packing material for my stuffing box was 1/4" Flex. 
  • The packing gland in my case is so close to the gearbox that you can barely unscrew the stuffing nut and move it away from the rest of the packing gland so you can work on it. Be prepared and check yours before you start
  • to remove the old packing, that is hard as a rock initially, I used a long wood screw. I carefully thread it into the stuffing for about 5 full rotations and then gently wiggled it back out. Do make sure to stay away from the shaft, you do not want to scratch it! Same for the stuffing nut albeit it is less critical. It worked like a charm and cut my time in half once I realized I could do that. I pulled the first of three stuffing sections using a picker and it took for ever since the only way to really get it out is to carefully find the splicing point and use that as leverage. Using the screw method above it is straightforward and considerably faster, just align the screw with the shaft so not to touch it and go.
  • Once I put it all back together with new packing, I hand tight it and left it soaking overnight. There were no leaks already. The next day I unscrewed it until I saw water dripping, then slowing tighten it until the leak stopped. Secured the counter nut, started the engine and tested that it drips every 30 sec or so. Ditto, done.