Monday, November 8, 2010

Propeller is off

Jose showed up 10 minutes early and got to work while I finished the varnishing.  He used a hookah supplied by an electric compressor.  The job took more time and effort than I had anticipated, principally to force the propeller off the tapered shaft using pulling equipment.

He had been confident that he would be able to find markings identifying the propeller diameter and pitch.  I showed him "Australia" and "17LRX" stamped on the hub.  The 17 represents the diameter, the "R" must indicate that it is a right handed propeller.  He thought that the position of the letter L in the alphabet might indicate its pitch, which would suggest a 12 inch pitch which we both agreed was too low.  On the other hand, the letter X would suggest a 24 inch pitch, which seems much too high.  Tantalizingly, the letter R would suggest an 18" pitch.  The rule of thumb is that to gain the required 600 rpm we should drop the existing pitch by 6 inches, which if we accept the 18" pitch would suggest a requirement for a 12 inch pitch which as pretty close to what has been proposed.

Jose showed me nicks in the propeller due to electrolysis.  I asked him if the propeller was still OK and worth re pitching so he passed a rope through the hub, tied a knot, held the propeller up by the rope, and hit each blade which rang like a bell.  He pronounced the propeller as good.  A dead sound would have indicated a problem.

He told me that the two anodes on the propeller shaft need replacement.  WHAT??? I asked - the anodes are only a couple of months old.  The good old La Paz Bay gumbo has struck again.

That's Ib looking at the propeller, then a happy Jose.
The last photo shows the companion way landing with its second coat of varnish.

1 comment:

  1. Jose sure does look happy. Hope all is solved.

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