Owner manual

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#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.

Summary of content (4 pages)

PAGE 1
#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).
PAGE 2
#063 ONE-ARM PROTRACTOR TO MEASURE COURSE ANGLE: 1) Place the one-arm protractor on the chart so that the compass rose points true north. The grid on the base plate should be parallel to a meridian of longitude or a parallel of latitude. 2) Keeping the compass rose pointing north and the grid parallel, rotate the arm and slide the protractor along the chart until the “true index” edge of the arm is along the course line.
PAGE 3
#064 COURSE PLOTTER TO MEASURE COURSE ANGLE: 1) Place either long edge or any of the parallel lines of the plotter along the course line. 2) Slide the plotter along the course line until the center point is at a meridian of longitude or a parallel of latitude. 3) If the center point is at a meridian, read the bearing at the meridian using the large outer scale.
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.