shaft log

[Thad]

Is there a recommended/standard space around the shaft?

[mmd]

Hi, Thad;

In my experience the diameter of the bored hole is dictated by the diameter of the inner boss ("hose ring", "nipple", etc.) that is usually part of the casting of the stuffing box and tail bearing/shaft log units. Sometimes the shaft bore is left "naked" (no liner, just slathered with red lead and bottom paint) to the free ingress of water (this is OK in our cold, mostly critter free waters when the life expectancy of wooden commercial boats is about fifyeen or twenty years, but not for fancy boats in warm waters), sometimes a bronze liner tube is inserted, and sometimes a hose is fitted to keep the water away from the inside of the deadwoods and keel. Personally, I prefer the last option because it keeps the water away from the inner surfaces of the shaft bore and when it's day is done, it can be reamed out easily with a boring bar, which ain't the case with a bronze tube (them buggers are in there for ever!!). If one of the latter two methods are selected, the bore diameter is dictated by the O.D. of the shaft log liner tube.

Edit to add: A quick skim of my Buck-Alqonquin catalogue indicates that up to shaft diameters of 2" the inner boss O.D. is about 1" larger than the shaft size, leaving 1/2" clearance all 'round the shaft. The boss O.D. gets progressively larger as the shaft diameter increases, with a 3-1/2" dia. shaft having an inner boss O.D. of 5-5/16", resulting in a shaft clearance of 29/32".

[ 08-14-2004, 12:22 AM: Message edited by: mmd ]

[Thad]

Thank you.