DAVIS Charting Kit - Manual (Page 4)

#075 / 076 DIVIDERS
TO MEASURE DISTANCE BETWEEN TWO POINTS:
1) Separate the arms of the divider, placing the tips of the arms on the two points.
2) Without changing the setting of the arms, carry the divider to the latitude scale
mid-point of your course on either side of the chart. Placing the tips of one arm on
a whole minute mark, count the number of minutes or tenths of minutes to the tip
of the second arm.
3) Note that one minute of latitude equals one nautical mile.
TO MEASURE DISTANCE GREATER THAN WIDTH OF DIVIDER:
1) Draw a line on chart connecting the two points.
2) Using the latitude scale mid-point of your course on either side of the chart, set
the arms of the divider to a convenient distance, say 5 minutes (5 nautical miles).
3) Without changing the setting of the arms, carry the dividers to the line drawn on
the chart. Set the tip of one arm on one point and “walk” the divider down the line,
counting 5 nautical miles for each width of the divider.
4) When the distance to the second point is less than the width of the arms, change
the setting of the divider so that the tip of second arm touches the point.
5) Without changing the setting of the arms, carry the divider to the latitude scale on
either side of the chart and read the number of minutes (nautical miles) as above.
Add this distance to the number of nautical miles found in Step #3 above.
TO DRAW A LINE BETWEEN TWO POINTS OR TO EXTEND A LINE:
1) Separate the arms of the divider, placing the tips of the arms on the two points or
along the line.
2) Placing a straight edge against the divider, draw the line.
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083_Inst.pdf June 2008
Replacement Parts
#061 Parallel Rules may be purchased separately.