Measurement Day

March 5, 2013 posted by admin

Today was boat measurement day for five of us.  There is a new offshore rule that requires Minis to increase their stability index measurement.  Now the boats must be able to handle a fifty kilogram weight on the mast head and maintain positive stability.

So today’s measurements included several tests.  The first was passing the boat through a jig that was floating in the water at a very specific mark.  As we passed the boat through the jig, we had to make sure that the keel passed through without hitting the lower bar in the water.  This measured the draft of the boat. You can see the jig just behind us.

Next we had to establish the black band measurements.  These determine the upper and lower limits of your sail area…or “air draft”.  The measurer uses the same jig as before, but this time with a cross arm and a marker strapped to it to mark the distance from the bottom of the keel to a fixed point on the mast.  We litterally drag the jig back and forth a little so that the marker draws a line on the mast, and then take the average of it.  Then we hoist the spinnaker halyard to the top of the mast with a tape measure on it and measure.

Once all that is sorted, it’s time to pull the boat over to measure the boat’s stability.  We attached a very very long tackle to the top of the mast at the spinnaker halyard, and started pulling and pushing the boat out from the dock.  Once the mast head was all the way down to the dock, and the traveler was at 90 degrees tro life, we attached a scale and put all the load between the scale and the mast head.






We measured in at 56 kilos!  Perfect!  We have 6 extra kilos of stability!  Last measurement of the day was for and aft angle and mast rake angle.  The cockpit has 2 degrees of slope, and the mast rake is 3 degrees.  All is right in the world 🙂

One Response to “Measurement Day”

  1. Dave Hamburger Says:

    Cool…very cool. Thanks for getting pix of this.

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