Expeditions, Navigation, Guided Walks and Trekking
I have been playing with building a Walking Time table, using this when teaching Navigation. Here’s a copy of the table, if anybody wants a copy in a handy size to keep with your compass, drop me a note and I will post on when back from printers.
Anyway, after battling through some complex Excel formula and formatting, I came across a nifty website that will do the calculations, including Trantors corrections. These adjustments where new to me, and make sense.
Here are brief explanations;
Scottish climber W W Naismith put his rule together in 1892. It’s simple, effective and easy to remember on the mountain. In Imperial measures it uses an average walking peed of 3 miles per hour and an additional allowance of half an hour per 1,000 feet of ascent. Its much easier In metric, based on 4 km per hour and an additional minute per 10m gained.
For distances of around 10 km, it works well, as long as you have good conditions on good paths. To be more accurate the calculation needs to take into account the slowing effect of steep descents and the speeding up on gentle descents. Most times these offset each other, but when out trekking could be important.
If you have a big pack; have had a hard day or week; covering more difficult ground or weather, then it is necessary to make more adjustments. These are taken into account in Tranter’s corrections. They were designed to take fatigue and fitness into account, and consist of a table of adjustments for different fitness levels and different lengths of walk.
So, fitness level; time an ascent of 300m in 800m. If you are fit then the corrections reduce the time for shorter walks by up to half! Corrections then progressively increase the time estimates for both increasing walk lengths and reducing fitness levels. By adjusting fitness levels, Tranter’s corrections can also be used to take into account bad weather or the conditions underfoot. So if you have a big pack then drop down one fitness level. Similarly if the weather is bad and conditions under foot are poor, drop a further level. So a fit walker, with a big pack over rough ground should expect to take around twice (x1.83) times as long.
“…time an ascent of 300m in 800m.”
That sounds so easy. However I can’t find any trails that meets those parameters. By my reckoning, that’s a 20 degree slope. There are lots of steep trails near me, but none of them are sufficient. A tall building’s staircase seems like the only candidate.
No one seems to have offered any equivalent with more common slope angles either. It makes me wonder if anyone has actually used this correction as designed.
Good point. I expect that much of the research for these adjustments was undertaken in Scotland, where there are many such slopes. The tourist track up to Ben Nevis has a number of stretches at that slope level. Also in the Peak District, Jacobs Ladder is about the right angle.
I do know of Fell Runners who have used the tall building method as well. A run up the BT Tower in London is a good test of the fitness level!
However, unless you are seriously into Micronavigation, this adjustment is just a guide. Checking it out is just for fun.
Thanks for your prompt and thoughtful reply.
Jacobs Ladder seems to only climb about 135m over 372m. Steep, but not long or high enough overall. The steepest portions of Ben Nevis also appear to fall short.
I am beginning to doubt that even Tranter could have conducted the test he requires of the rest of us. His table may be correct for other reasons, but since it is premised on something that appears to be either impossible or impractical, his exact conclusions might not be trustworthy.
Langmuir’s ‘Mountaincraft and Leadership’ is possibly the most popular source for Tranter’s Correction. He cites three works:
‘Navigation; Routefinding with Maps and Compass’, The DofE Awards, 1989.
‘Mountain Navigation’, Cliff, 1991.
‘Orienteering: The Skill of the Game’, McNeil 1989.
Here in California, I don’t have access to any of those. I wonder if any of those are the original source. Perhaps there was a transcription error.
I help teach navigation to would-be mountaineers. We use Naismiths Rule, so that’s why I’m interested in making Tranter’s Corrections usable. It should be possible to create a more practical test that would result in the same or similar fitness levels.
You have been doing your research. I’m busy out on the hills this week, so will dig out my other textbooks and have a look.
Doing the research again that led me to this blog, I have just realised that Trantor based his rule on Naismiths original formula adding 1/2hour to every 1000ft climbed. I have also found that these rules were developed in the Crianlarich hills, taking in Cruach Ardrain, Ben More and Stob Binnein. Ben More has the right slope for 1,000feet in 1/2 mile. Also the original walking was done by a Willie May who must have ran up Ben More many times.
In practical terms, I have taught Naismiths Rule many times and along with the pacing and timing techniques, I have found that along with the adjusments this works in all practical purposes. I have used the concept of adjusments to bring in all the other factors that effect our navigation, ie fitness, terrain, weather, our our equipment and choice of strategy.
So rather than actually work out how long it takes to climb 300m in 800m (or 1,000ft in 1/2 mile in old language) I would use an assessment along the lines of;
Fit Average Walker;
Good questions and thanks for the comments again.