Aiming off is a useful navigation technique that involves intentionally aiming away from your final destination.
If you’re walking off-track or in low-visibility conditions, you can walk on a bearing to reach your destination. But if you aim precisely for the feature and miss it, you will not be sure which direction to go to reach it. That’s where aiming off comes in handy.
If there is a good catching feature like a river, it is better to aim to miss your destination slightly so once you reach your catching feature, you will know which way to go.
In our example, we want to go from the bend in the creek (A) to the bridge (B). To walk on a bearing to a precise point requires knowledge of exactly where you start from. It is hard to identify the exact point on a bend so it would be easy to miss the bridge if we walked directly to it on a bearing. If we could not see the bridge once we arrived at the river, we would not know whether to go upstream or downstream.
The solution is to aim upriver of the bridge (C). Here’s how to do it:
1. To find a bearing, use the compass baseplate edge to make a line from your location to the catching feature you wish to walk to – in this case upstream of the bridge where we’ve marked C on the map.
2. Keep your compass still, but rotate the dial to line up orienting lines to match the north/south northings (gridlines) on the map.
3. The dial will indicate the degree bearing; take away the map, and spin yourself so the red magnetic arrow points to the variation (24 degrees for Topo50 map BP33).
4. The direction of travel arrow will indicate the direction to walk. Continue on that bearing until reaching the designated catching feature. A leapfrogging technique may be useful, especially in low visibility.
5. Once you reach your catching feature – in this example the river – walk in the predetermined direction, downstream, until you hit your destination, the bridge.