Timing
It is important for us to know how far we have walked in poor visibility, and also to know how long a walk should take us. For these reasons it is important for us to be able to look at the map and have some idea of how long a certain leg of a walk will take. It will also allow us to vary the route if we are going slower than expected. The speed of walking will vary with conditions both above and under foot, and this needs to be allowed for.eeds to be allowed for.
When calculating timings it is usual to use Naismiths Rule. This allows 5 km per hour with 10 min for every 100 m climbed. This applies to a fit adult. When walking with a mixed group it is usual to allow 4 km per hour. If going down hill, you should add an extra 10 min for 100 m descent if the ground is very steep. If it is a gentle slope you may subtract 10 min for 100 m descended. Generally I do not subtract time for down hill and find it works out reasonably well (but I do add times for steep sections).
Calculating from the above we are allowing 12 min to walk 1 km and 1 min added for every 10 m climbed. This is a good estimate, and can be used along with the map to plan a route. Rest is usually added at 10 min rest for every hour of walking. This does not generally allow for prolonged photo stops or lunch.
You should now be able to measure a distance on the map, calculate the height gain, and work out how long the section of walk should take. This will, as with everything else, improve in accuracy with practice. In poor weather the timing can be used to calculate how far you have walked. Using this in conjunction with the compass will allow accurate navigation.
To be even more accurate over short distances pacing can be used. You need to know how many double paces (one double pace occurs each time the same foot touches the ground) you take for 100m. I am fairly tall and usually take approx 65 on flat ground. Pacing should be tested on several types of ground, such as rough ground and going up hill so that you are aware of the differences from walking on flat ground.
Knowing that one grid square (40 mm on the 1:25,000) is 1 km we can state that 4 mm is equivalent to 100 m (65 double paces) and therefore 1 mm is equivalent to 25 m (16 double paces). This can now be used to measure distances on the map and accurately convert them to distances walked on the ground. It may be useful to keep beads on the compass string, to mark off the number of 100m walked, since it is all to easy to forget when pacing for real.
Last updated: 22/04/01