Section 11 EO C390.06 – DETERMINE DIRECTION USING THE SUN

In a survival situation, one may not have a map of the area, a compass or the use of a watch. On this occasion, it may be necessary to use natural guides, such as the sun to determine direction. The sun can be used to find north using a branch or stick to cast a shadow on the ground.

A shadow stick works because the sun always travels east to west, even though it may not rise at exactly 90 degrees or set at exactly 270 degrees. The tip of the shadow stick’s shadow moves in the opposite direction, so the first shadow tip is always west of the second, anywhere on earth. Improvised methods are only general indicators of direction. The shadow stick is more accurate and easier to read when the stick is narrow.

National Association of Search and Rescue, Fundamentals of Search and Rescue, Jones and Bartlett Publishers, Inc. (p. 76)

Figure 1  Shadow Stick

The objective of this activity is to have the cadets construct a shadow stick and determine direction using the sun.

Stick.

N/A.

1.Divide the cadets into groups of three or four.

2.Have the cadets find a 45–60 cm straight stick.

3.Find a level vegetation-free spot. Push the 45–60 cm straight stick into the ground about 10 cm so it will remain upright, inclining it by 5–10 degrees to create a longer, bigger shadow.

4.Mark the tip of the shadow with a stone. Wait until the shadow tip moves several centimetres (10–15 minutes with a 45 cm stick).

Use the time interval required for Step 4. to instruct TP 2.

5.Mark the position of the new shadow tip.

6.Draw a straight line from the first mark through the second mark and continue about 30 cm past it (as illustrated in Figure 18-11-1).

7.Have the instructor or a supervisor verify the bearings with a compass.

The line drawn indicates the east–west line. The first mark made is west and the last mark made is east. A line perpendicular to the east–west line is a north–south line.

N/A.

An analog watch can help establish direction using either standard or daylight savings time. The analog watch method is based on the principle that at noon (or 1 pm for daylight savings time) the sun is approximately due south in the northern hemisphere and approximately due north in the southern hemisphere. Using this principle, an analog watch’s (with the correct time) hour hand, at noon, pointed at the sun, also points approximately due south/north. At times other than noon, bisecting the angle between the hour hand (pointing at the sun) and the 12 (or the 1 for daylight savings time) on the watch face, creates an imaginary line that points approximately due south/north.

This method becomes less accurate the closer a person is to the equator.

National Association of Search and Rescue, Fundamentals of Search and Rescue, Jones and Bartlett Publishers, Inc. (p. 76)

Figure 2  Analog Watch

The objective of this activity is to have the cadets determine direction using an analog watch.

Analog watch (with the correct time).

N/A.

1.Point the hour hand towards the sun.

2.Determine the halfway point between the hour hand and noon (or 1 pm for daylight savings time).

3.Create an imaginary line between the centre of the watch face and the halfway point (as illustrated in Figure 18-11-2).

The imaginary line is a north–south line (points to the south in the northern hemisphere and to the north in the southern hemisphere).

N/A.