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    Traverse boards
    From: Rick Emerson
    Date: 1998 Oct 29, 10:25 PM

    While visiting the Dove in St. Mary's City, I wondered about the idea
    of using a traverse board for taking quick notes for DR work.  For
    those who don't know what it is, there are two parts: a compass rose
    and a rectangular array of holes.  The rose is used to record heading
    and the array records speed.
    
    The speed section contains two sets of four rows of holes, like so:
    
    0  1  2  3  4  5  6  7    0  1  2  3  4  5  6  7
    o  o  o  o  o  o  o  o    o  o  o  o  o  o  o  o
    o  o  o  o  o  o  o  o    o  o  o  o  o  o  o  o
    o  o  o  o  o  o  o  o    o  o  o  o  o  o  o  o
    o  o  o  o  o  o  o  o    o  o  o  o  o  o  o  o
    
    Every half hour, at the turning of the 30 minute glass, a peg is put
    in a hole to record the boat's speed.  Each row represents one half
    hour's reading of the log and each column is the boat's speed.  The
    total of eight rows makes up fours in a watch.  Here's a filled out
    board:
    
    0  1  2  3  4  5  6  7    0  1  2  3  4  5  6  7
    o  o  *  o  o  o  o  o    o  o  o  *  o  o  o  o
    o  o  *  o  o  o  o  o    o  o  *  o  o  o  o  o
    o  o  o  *  o  o  o  o    o  o  *  o  o  o  o  o
    o  o  o  *  o  o  o  o    o  o  o  o  *  o  o  o
    
    At the start of the watch, the boat was doing 2 knots, speed increased
    to 3 knots, fell back to 2 knots before hitting 4 knots at the end of
    the watch.
    
    The compass rose follows this concept albeit with a different layout.
    Here the arrows of a 16 or 32 point compass are carved into the
    board.  On each arrow, a row of 8 holes is drilled in a line (forget a
    drawing of that here!) so as to make 8 concentric rings of 16 or 32
    holes each.  To make a record of the boat's heading, the
    whole board is turned so that the arrow for due north matches the
    north arrow on the boat's compass and a peg is set into a hole on the
    arrow closest to the boat's heading.  For example, if the boat is
    sailing due west, looking down on the compass, north is at the 3
    o'clock position and the row of holes for west lies at 12 o'clock.
    The first peg goes into the innermost hole, the second peg goes into
    the next ring out from the center and so on.  Even if the boat's
    heading changes, each subsquent peg goes in the next ring out from the
    last one.
    
    At the end of the watch, there is a record of speed and heading
    without having to write anything.  The navigator then copies the
    information onto paper and removes all pegs (the board I saw had the
    pegs on a long string so they wouldn't get lost).
    
    Anyway, comments on the idea of using something like this today?
    
    Rick
    S/V One With The Wind, Baba 35
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