View Full Version : Shaft log question
08-10-2006, 05:00 PM
Hamilton Marine sell this shaft log assembly. It seems that the flange is not rigidly attached to the gland assembly, which means that it would likely forgive a bit of movement or small changes in alignment between the engine and the shaft log. Am I understanding this correctly? - Norm
08-10-2006, 05:26 PM
I got something like it.
The rubber tube does let it move a little.
The rubber tube needs to be the thick walled reinforced stuff. I have heard of tubes twisting off which then perhaps sinks the boat.
08-10-2006, 06:07 PM
We have a similar one on Lorelei which was there when we got the boat some 7 or so years back. Which was a good thing as the motor was hella out of alignment when we bought her. We've never had a problem. Replaced the hose part a few years in when I replaced the prop shaft and repacked the stuffing box. I think as long as you don't over tighten the stuffing box an insane amount that this works fine.
S/V Laura Ellen
08-10-2006, 06:14 PM
IMHO The flex hose is meant to take the movement associated with the flexible engine mounts, they should not be counted on to take care of poor alignment issues.
08-10-2006, 06:23 PM
The rubber could twist off if the gland nut is over tightened.
You would probably smell the rubber getting hot first.
That is really extreme though.
Install a grease fitting and fill the log with polypropolene red wheel bearing grease (saltwater proof) and it will never leak a drop even if the gland nut is loose.
i know it works from experience on two boats.
08-11-2006, 07:34 AM
Thanks everyone. I wasn't thinking of this as a cure for serious misalignment, just for the little bit that seems to occur during the season as the moisture content in the hull changes. My practice has always been to leave the gland a bit loose and live with the drip, and fortunately, it's easy to see and get at for maintenance.
The first year I had the boat (1982) the shaft became misaligned after a hard sail (the engine moved!), and when I next ran the engine, the friction of the misaligned shaft melted the bearing material in the stuffing box. It ran okay that time, but next time I started up, the shaft and the box were basically welded together by cooled bearing material. That taught me something about proper vigilance.
Great suggestion about fiilling it with grease, Don. It eliminates another worry about being able to get the water out for winter storage. By renewing the grease at haul out, it would displace any water.
08-11-2006, 08:17 AM
this is good stuff to use
GFO Fiber Packing
Virtually Dripless marine shaft packing
Pack it and forget it
08-11-2006, 09:15 AM
GFO Fiber Packing
These are called "self aligning stuffing boxes", that is they will accept a small amount of offset from the shaft centerline, usually between the gear box output bearing and the strut bearing (cutless?), not mis-alignment and /or wobbley/bent shafts. These are tried and true, in use many years before the packless came on the scene. Why anyone would honk down on the packing till the gland twisted out of the hose is hard to believe. The hose part is a shelf item, and should be changed when deteriorated from saturation with engine room oils, or otherwise about 20 years.
Also I would second, or third, the GFO suggestion, another solution to a problem that wasn't a problem until there was a solution. Great Stuff. Just a little wetness and no temperature rise, whatsoever. The grease idea - seems like the grease would just escape out the stern tube, and/or stop water from reaching the stuffing box part, for cooling purposes. Grease has been used on ships as a temporary get home measure, when oil lubricated metal strut bearings have wiped. cbob
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