5" Douglas Square Protractor

Handy sizes 5" Douglas square protractor. Printed black with red reciprocal numerals and centre pen hole.







• Place the protractor on the chart: Lay the navigational chart flat on a stable surface, and place the protractor over the chart,
aligning it with the lines of longitude and latitude or the desired course.

• Align with the chart's meridian or vertical grid lines: The protractor's vertical edge should be parallel to the meridian or
vertical grid lines on the chart. This ensures accurate angle measurements.

• Determine the bearing: Identify the two points you wish to measure the angle between, such as your current location and
destination. Place the center of the protractor on the first point and align one of the vertical edges with the second point. Read
the angle where the aligned edge intersects the protractor scale. This is the bearing from the first point to the second point.

• Plot a course: To plot a course, align the protractor with the desired bearing and draw a line connecting the two points.
This line represents your intended path.

• Measure distance: Using the chart's scale, measure the distance between the two points along the course line.
This information is essential for calculating time and fuel requirements.

• Transfer bearings: The Douglas Square Protractor can also be used to transfer bearings between charts by aligning the
protractor's edges with the corresponding bearings on different charts.

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