My last boat had a single grease fitting. I never adjusted the packing
nut except the first time. If yours is leaking more than a drop every
6 to 10 seconds then it needs to be tightened. THEN squirt it with a
grease gun (one shot) at the end of the days run and there will be NO
leaking.

Terry K wrote:
You don't say what type boat, etc.

Not all shaft logs use piped water cooling. Some use a slow drip leak
to cool the shaft, packing, etc. Do you have two grease nipples on your
shaft tube? Don't know about that, but you might want to pump in some
heavy grease.

My packing tube uses a woven packing, comressed between the shaft and
packing tube / nut. The second nut is purely to lock the first. The
tightness of the packing nut is adjusted to allow about one drip every
minute while under power. Mine does not drip when stopped.

Terry K