Thursday, January 24, 2013

Mast Rake

When I installed the furling foil, Blackheart was on the hard so I was not able accuarately determine the mast rake. I guestimated it by assuming the saloon sole was level with the waterline.  It turns out I was off by about 1 degree which actually gave the mast forward rake rather than aft racke.  As a result I was always steering with about 3 degrees of lee helm.

Once I got around to measuring while on the water, I determined that I had 0.10 degrees of foreward mast rack with this "Mini Digital Protractor"


I also calculated the angle by dropping a line from the main halyard sheave which was about  5" before adjustment.


It's difficult to determine the exact angle the line makes without climbing the mast, but taking a picture from shore showed the line was a distance of about 1 1/4" at the top of the mast and the tape measure shows a distance at the goose neck is 6 1/4".  The net distance at the goose neck is about  5". The mast height is taken from P which is 42.0' or 504".
The angle can be found by the formula:
atan (5/504) = .57 degrees which is pretty close to the measured angle which does not take into account the masts pre-bend.


That's about as much rake that I can get as the forestay can not be lengthened any more due to the limited adjustment available on the foil and also the back side of the mast is pretty much up against the partners.
Should be better than it was at any rate.

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