Plotting “time traveled” in dead reckoning landnav

Before I was a paracord junky, I was (and still am) an outdoorsman with a love of off-trail exploration. It was my efforts to make myself a better set of pacing beads for land- nav that jumpstarted the knotting frenzy I find myself in today. Land navigation with traditional skills that include “dead reckoning”. Recording distance travelled through pace count or distanct/time relationship along with direction allows you to find your way back, even if you don’t have a map. With a map, you can plot your courses AND use terrain recognition and baselines to re-calibrate your location as you go. I will never rely on the GPS, only use it to supplement a traditional approach that has guided explorers, sailors and aviators in the past.

Pace count is important, and a way to keep track like ranger beads helps. Also, experience and calibration will give you a good pace number for certain distances under a variety of terrain conditions. When exploring off trail for fun I enjoy honing my skills by creating my own map, plotting (to-scale) the courses of my travel (bearing and distance) on paper using my simple $10 silva baseplate compass. If I reach a point where I want to wander a bit, I tie up a piece of bright survey flagging, or my orange handkerchief at the location of the end of my last course so I can come back (keep it in sight) and resume.

Draw a north arrow on your sheet (I keep a little rite in the rain notebook with grids); use the lines on the paper for n/s reference or draw your own to aid in proper compass placement on the paper to transfer a real world bearing onto paper. if you stick with magnetic north and are plotting your own map, you need not worry about declination. I think this skill allows you to safely hit the woods for some exploration when you may have otherwise not if you didn’t have a pre-printed map. Also, with this method, your course can change as field conditions warrant and you'll always have a map back to the start. When you reach an obstacle like a swamp or lake, you don’t need to use the oversimplified techniques of doing a couple of uniform 90 degree or 45 degree turns and expect to be around your obstacle and on the right course. You have the freedom to adjust your direction as real conditions require, and always know your current position relative to where you started – and can set a bearing for home!

What many people don’t realize is that because what you are plotting for distance is all relative (in similar terrain); you can even plot "paces", or “time traveled” rather than "distance"! This works as long as you determine a scale and stick to it (ie. so many inches = so many paces, or so many minutes).

Here are the field notes from a little jaunt I took 4 years ago; note that since I was in similar type terrain the whole time so there was no major adjustments required for terrain changes. I didn't plot distance OR pace count, instead I plotted TIME - again this works because its all relative! You can see I chose one block to represent 2 minutes, then I kept a log of bearing/start/stop travel time. I love this stuff!



When plotting time, you must adjust if you have a very easy segment, then some really tough terrain you must realize that you'll cover more ground in the same amount of time on the easy segment and adjust accordingly. this is similar in concept to adjustments you make to pace count in varying terrain.

Great post, kevingg. I'm a total nav dummy, so bear with me. I assume from your sketch that you were able to make a big loop and hit your embarkation point using your "time spent" system that day? That's cool.

yes, so the 212 degree heading, and approximate time to get there were actually measured on the map when I decided to head back to the car (P for parking, near the star symbol)! I was travelling "clockwise" on the picture.

My primary means of navigating (on land) is a topo map and terrain feature recognition. On those times when I have counted paces, I have been agreeably surprised at how accurate the technique has been.

I seem to remember that there were procedures for dropping paces or adding paces when going uphill or downhill. Do you know anything about that?

Inquiring minds want to know - why do they call it "dead reckoning?" Sounds kind of ominous......

Don't know if there's any accurate universal formula for adjusting your pace count.

One simple way to check the effect for particular gradients is to make two marks (with a known distance between). Start from one mark and walk uphill to the other, counting paces, then rotate 180 and starting from zero, count paces back to the point. Try a few times for average, and compare both counts to your average on similar but level terrain.

EDIT: And dead reckoning means determining your position from your previous known position + average speed and duration to direction travelled.

Dead reckoning is pretty accurate when on a sailboat in fog, trying to include currents and wind to your calculations. Not fun.

-jh

Hikermore,

They call it "Dead" reckoning from the old days of sail. You assume no currents or wind drift, as though the water was DEAD (ie., not moving). Of course, they began to use it knowing current and/or wind drift and correcting that in, but the idea is that the water is dead or not moving. It works even better on land where wind and currents don't move you off course.

Kevingg,

Your explainations are almost as good as your knots -- which is to say VERY good. Thanks!

Respectfully,

Jerry

thanks Jerry, years of teaching (unrelated subject) may be the reason..

there are no hard and fast rules about adjusting pace count although I've found rules of thumb. Don't trust any formulas or typical percentage adustments either. don't use any charts! you need to calibrate your own paces. I chose to do 1/10 mile increments because I could use a handheld GPS to track 1/10 mile while I counted paces a bunch of times to get an average. The reason I chose 1/10 is that i use 1:24000 scale maps and my compass base has a scale for 1:24000 maps in 1/10 mile increments. When I'm doing shorter walks, I just assume 1/2 my normal paces for 1/20 (0.05 miles) and use the same compass baseplate scale to plot on the map. you follow me? your pace count on the street with no backpack is your optimum pace, your numbers will increase depending on trails, conditions, pack weight. its easy to adjust/check in the field by pace counting from say a trail head to a river where you can measure the distance on the map. knowing how far you travelled, and how many paces it took you will allow you to calc your pace count under those conditions. over time making adjustments becomes second nature.

Every once in a while when I'm off trail and I know I'm going to hit a trail or a river, I'll pace to calibrate. Lets say the map indicates I'll hit the trail in 0.35 miles. I'm pace counting and I hit the trail when I'd only tabulated -.25 miles. This means I was actually travelling further with each pace than I anticipated, so going foreward that day I should adjust accordingly, counting fewer steps per 1/10th (or 1/20). Conversely, if I did not hit the trail until I'd counted 0.45 miles in beads, that means I was travelling a shorter distance with each pace than I thought. I should adjust by counting more paces per 1/10 (or 1/20) from there on.

one other option to practice in different terrain, trail conditions, steep ups, steep downs, bushwhacks etc. is to watch the trip counter on your GPS while pace counting - whatch it tic 1/10th of a mile and see how many paces you took. Do it a couple times and average. take notes for future reference about that sort of terrain (and whether or not you were carrying a heavy load or not).

its may sound complicated, but in reality its just plain fun!

Impressive nav skills, Kevingg.

To be pedantic: I was taught that it was "ded reckoning" which stands for "deduced reckoning". If you know where you started from and how far and which direction you've traveled, you can deduce your current position.

Good post. It reminds me of old school D&D games from 35 years ago when we used paper to 'map as we go' through a dungeon.
I wonder if there is a flat field nearby I could use on a dark cloudy night for dead reckoning exercises... I think I can plot my way back to the beginning after a couple of random headings and distances, but it would be fun to try.

Before the advent of GPS, the only way to navigate was by map, compass, pace count and terrain association. I learned from Uncle how to go from point A to point B with reasonable accuracy.

Using a pace count was a must. We almost never (at least I never used) time as a measurement of distance traveled.

I also learned to get an accurate pace count using a known distance, and walking with what I would be carrying.

Frankly, once the batteries die, a lot of GIs today are lost. Land nav is a dying art.

If you pay attention to the map features, and can match terrain to the map, and have kept a pretty accurate pace count, you do ok. Oh yeah, one big rule. If you think you should be there, but aren't - you almost never have overshot. Keep going a bit farther.