Navigating With Only A Compass

Antique compass sold through BADA. Click here for more information.

I remember reading how Merriweather Lewis created maps of the upper Missouri River for the Corps of Discovery using Dead Reckoning, a technique where he recorded a known distance  with the compass bearing to recreate the rough contours of the riverbank. Having a compass can be an item essential for a trekker's survival.

Just for fun, I've included an excerpt from a Gudgear.com posting on mapless compass navigation. You can view the entire article here.

Navigating a Walk With Only a Compass

"...This is often known as “mapless dead reckoning” and is what Christopher Columbus did when he set out on an exploration.

The basic idea is that you keep track of the direction that you have gone in, and how long or how far you have gone, and then when you wish to return, you plot your journey back by piecing together your journey and determine the direction and the distance to return to where you started.

You can choose to use timing or pacing, or both when setting out. I personally prefer pacing rather than time especially if you are in uneven terrain, for the simple reason that you are going to go at different paces depending on the terrain and so the timing may vary considerably.

However, if it is even terrain timing can be easier and requires less concentration on your part (for example if you’re with a group and chatting as you go).

How Pacing Works

For example, if you go 312˚ for 1200 paces (or in meters if you work out how long your paces are), then 215˚ for 600 paces, and you want to work out what direction you take to get back to your start point, you can easily map this out on the ground in front of you to work out the distance and direction.

If you use your foot length to represent 100 paces, place some twigs out in the direction of 312˚ for 12-foot lengths.

Once you have done this, then measure out twigs for six-foot lengths at 115˚. Then, using your compass, determine the direction you must head to get back to the starting point and measure out the distance in paces using your foot lengths.

Once you have clarified direction and distance, it is worth using a slightly different direction and then walking back to your starting point so that at least you know the direction your starting point should be in case our calculations are slightly out.

For example, if I have left my car on a dirt track as a starting point, and determine that I must walk at 28˚ 850 paces to return to my car, I might choose to walk at 18˚ for 850 paces and then when I reach the road I know that I have to turn right to navigate back to my car.

If I were to walk at 28˚ and then came out on the road and could not see my car, I would have no idea which way to head to find it. Purposefully navigating your return slightly incorrectly can mitigate this risk.

If you are wanting to try this and learn to orient yourself in this way, I would suggest you start with easy terrain and having back up technology. Do this a few times and only once you feel confident with the technique should you try something a bit more challenging.

Once you have mastered this skill, you will find it incredibly rewarding, and surprisingly useful in many different circumstances! You can be sure that your friends will also be very impressed..."

Those wishing to purchase a period-correct compass need look no further than Crazy Crow and Townsends. They both sell a compass that features a sundial for those frontier people with places to go AND people to see. Compasses are available from Crazy Crow (left) and Townsends (right).  

Get yours here.

Based on offerings from a variety of vendors, the Lewis and Clark Corps of Discovery used compasses that were securely housed in wooden cases. Crazy Crow gives you an opportunity to outfit yourself with a compass that appears to have more provenance that the compact brass-bodied compasses shown above. Whichever version you choose, read the "Navigating A Walk With Only A Compass" section. Take the time to understand what is required. It's helpful to have a pencil and paper handy to help you visualize what the author is saying. You will have an "Ah HAH" moment, and once you do, it's yours forever.

If I were outfitting a team for the Trek, I'd keep all of this in mind, and think about buying a compass.

Just sayin'.

Update June 11, 2022: Crazy Crow posted an article on the Lewis and Clark compass. Read it by clicking here.