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    Re: Magnetic variation changing faster than anticipated
    From: Mark Coady
    Date: 2019 Feb 27, 18:03 -0800

    David,

    Most correct, I missed that one, I just often tend to think of collsion avoidence more on my radar tracking, spoiled as I am.  A pelorus does the job perfectly on visible targets. Risk of Collision:  Constant bearing, decreasing range as per COLREGS Rule 7.

    The other one I did a poor job noting is the use of the steering compass for a maintaining directional stability on a small boat in a heavy sea, especially one that slaps you around on the quarter and skews your course constantly.  GPS's take time to stabilize heading, vs a steering compass that gives you an instant visual and reaction feedback on your countersteer.

    You actually use the compass to learn and anticipate the magntude of the swing.  You can often tell an experienced helmsmen in a rough sea by his smoother track, vs an inexperienced one who doesn't anticipate and correct for motions well.  Often overcorrection is the enemy so the vessel is constantly yawing about the base track. Its the time delay between the motion and response to helm command that creates the problems, with good compass work a way to solve them. 

       
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