Monday, 6 August 2012

How to use a Compass

How to use a compass
A compass is a simple and brilliant navigation tool.  At the very least it will have a needle that points north which will allow you to orientate your map and give you a rough indication of which way to walk.  If you have one designed for hill walking, mountaineering and orienteering then you will have "the full monty" and be able to use it for accurate map reading and navigation.  The compass used to illustrate this blog is a Silva type 4 Expedition (not the military version) and is a great all round compass. In this short feature I can't teach you all of the techniques involved in navigation but will show you how to use a compass to navigate across a short stretch of open moorland from a known point (where you are) to another point (where you want to go).

Step 1:
I want to navigate from the Trig Point 590m to Madwoman's Stones.

Step 2:
Lay the edge of the compass across the Trig Point 590m and Madwoman's Stones.
It is important to have the "direction of travel" arrow pointing in the direction you want to travel.

Step 3:

Rotate the dial of the compass (the compass housing) so that the lines inside it become parallel to the grid lines that run up and down the map (not the ones running across the map).

It is important that the "N" on the compass housing points to the top of the map.

Step 4:
Pick the compass up off the map.  There is a line inside the dial of the compass that enables you to read the number of degrees of the "bearing" you have just worked out.  In the example illustrated this is 72 degrees.

Step 5:

Because there is a variation between Magnetic North (where the compass needle points) and Grid North (the grid that the map is drawn to), we have to add 2 degrees to the bearing we have.  On the
example illustrated we adjust the bearing from 72 to 74 degrees.

Step 6:
To walk from the Trig Point to Madwoman's Stones following the compass, we rotate the compass until the north needle (red on the compass shown) lines up with the arrow inside the compass housing.  The direction of travel arrow now points the way to walk.

If you want to learn this and other navigation techniques safely in the company of experts, go the the Peak Navigation Courses website and book your course