DAVIS Charting Kit - Manual

#061 PARALLEL RULES
TO MEASURE COURSE BEARING:
1) Place outer edge of one rule on the course line. Holding that rule down firmly
against the chart, swing the second rule out away from the first.
2) Hold the second rule firmly against the chart and swing the first rule up to meet it.
3) Alternately holding and swinging each rule, “walk” he rules across the chart to the
nearest compass rose.
4) With the outer edge of one rule at the center point of the rose, read the bearing at
the rose.
TO DRAW A COURSE OR BEARING FROM A GIVEN POINT:
1) Place the parallel rules on the chart so that the outer edge of one of the rules
passes through both the center point of the compass rose and the desired bear-
ing.
2) “Walk” the rules across the chart as above until the outer edge of one of the rules
passes through the given point. Draw the line against the edge of the rule.
#062 PROTRACTOR TRIANGLE
TO MEASURE COURSE BEARING:
1) Extend the course line so that it intersects either a meridian of longitude or a par-
allel of latitude.
2) If course line intersects a meridian, place the 180° line of the triangle along the
course line. Slide the 180° line along the course line until the center point of the
triangle is at the intersection of the meridian and course lines. Read the angle at
the meridian. Use the outer scale if you are traveling in an easterly direction, and
the inner scale if you are traveling in a westerly direction.
3) If course line intersects a parallel, place the 90° line of the triangle along the
course line. Slide the 90° line along the course line until the center point of the tri-
angle is at the intersection of the parallel and course lines. Read the angle at the
parallel. Use the outer scale if you are traveling in a southerly direction, and the
inner scale if you are traveling in a northerly direction.
4) To find magnetic course, add or subtract the local variation given for your area in
the center of the compass rose on your chart.
OTHER USES OF PROTRACTOR TRIANGLE:
1) Extend a line by sliding one triangle against another or against other plotting tools.
2) Lay off bow or beam bearings.
3) Measure distance using handy inch and centimeter scales on base edge.
#083
Kit includes:
• Parallel Rules
• Protractor Triangle
• One-Arm Protractor
• Course Plotter
• Professional Dividers
• Pencil
These precision plotting tools are everything you need
for chart work in one handy kit. A choice selection of
navigational tools for cruisers and racers as well. All
are conveniently organized in a 5-3/4" x 16-1/4" (15 x
42 cm) heavy gauge plastic carrying case. Instructions
included (and reproduced here).
Highest quality printing: Davis plotting tools feature
sharp printing process, high gloss finish on front and
back, and overlamination for durability.