How many rings of packing for the stuffing box?

[bostonhatteras]

What about the theory that when the boat is cruising forward the water flow into the shaft packing is actually under a vacuum ??

This is an interesting observation. It would imply that all stuffing boxes run dry at planing speeds and I would then figure that the critical and overriding factor is the tightness or friction due to compression of the packing. It would be interesting to also know how shapes, speed and depth (pressure) work together to affect the waters ability to remain in contact with the stuffing boxes. Maybe on actual experience has anyone viewed a leaky stuffing box at speed and seen it actually stop leaking because of this potential vacuum? Lip and face seals having water injection seem to corroborate the fact that the water does literally move away from the shaft log. Air conditioners have scoop strainers to ensure adequate water at speed yet generators do not. The fear is that generators may be overwhelmed by the scoop strainer and flood a cylinder or two but even without a scoop strainer I have never seen my genset run hot or pump less water at speed. Obviously these intakes are in different positions relative to the water flow but water can behave in odd ways around obstacles. I think I will try an experiment this spring. At speed, I will clamp the raw water line to my pss shaft seal and pull back on the boot and see what happens. Should be interesting.

[SeaWhisper]

Ang,

I used 4 rings of that packing on our 53. One thing I discovered when I installed it the first time - if you over tighten, it won't matter how much you loosen the fitting, the packing will not loosen and it will not start dripping. I had to remove the packing and do it again, paying much more attention to the tightening process. If you follow the manufacturer instructions to the letter, it works perfectly. If you don't, it wont. Installing it based on experience with different types of packing will not work - you have to follow the instructions.

The packing can provide totally dripless operation but it takes careful attention - again - to the instructions. Ours are dripless at all times but it takes a few runs to get them that way, with SLIGHT adjustments (tightening) as you go along. Our boxes will run just noticeably warm to the touch running at WOT from Rock Hall to the Marina - about an hour - and they do not drip at all.

Mike, my 53' has 2 inch shafts. Was your packing the 1/2" ?

Thanks

[TROUBLE]

What is an acceptable temp at the stuffing box when under way?

Art

[MikeP]

"Mike, my 53' has 2 inch shafts. Was your packing the 1/2" "

Ang, I have the 2" shafts; I'm pretty sure it was 1/2" packing but it was several years ago so I wouldn't trust my memory on that! I have a spare package of it on the boat but since I'm not there, I can't check it. Sorry!

[SeaWhisper]

Thanks!