We were deep inside Lake Superior State Forest, seven miles from the nearest paved road. I was explaining the nuts and bolts of compass navigation. One of my survival students looked pensive, like he had something to say but wasn’t sure if he should say it. When I asked him what was on his mind, he said, “I just thought it would be more complicated than that.”

Far from being offended, I took that as a compliment. An irony in the 21st century is that many outdoors lovers will study a manual about using an inherently unreliable GPS and reading maps scaled to UTM coordinates, yet consider the original navigation tool to be too complex to understand.

All Compasses Point North

Allow me to dispel the mystery. Regardless of make, model or design, a magnetic compass does only one thing—it points toward the magnetic north pole. It does that all of the time, and unless it’s broken so that it’s indicator can’t move, it’ll point toward north forever. And that’s all a compass can do by itself. The user must perform the numerous other functions of orienteering.

That’s usually enough. A normal adult can walk at least 10 miles in a single day. People have been making roads and trails on this planet for a very long time, and chances are better than good that you won’t cover even 5 miles before encountering one. If you can walk in a relatively straight line over that distance, that’s all you’ll need to get out of almost any woods. Never believe that you can walk a straight line through wooded terrain without a stable point of reference; in more than 40 years, I’ve never seen anyone do it.

Compass Basics

You’ll probably want your compass to do more than just keep you from becoming lost. First, let’s examine the bezel, which is the ring surrounding the indicator that’s marked in increments of 5 to 360 degrees on most compasses. You might recall from high school geometry class that there are always 360 degrees in a circle. That 360 degrees is divided into four quadrants of 90 degrees. Facing north (0/360 degrees), if you hold your right arm straight out at 90 degrees, your fingers point due east. Add another 90 degrees and south is directly behind you, at 180 degrees. Hold your left arm straight out from your shoulder at 270 degrees and it points due west.

Precise navigation demands a map. A map can give you a preview of surrounding terrain, and tell you in which direction rivers

and other landmarks lie relative to your own location. But be aware that most maps are oriented to true north, which may be as much as 10 percent in error from the magnetic north indicated by your compass. Magnetic lines of latitude aren’t straight, and there are few places where map north and compass north will be in agreement.

The difference between the norths is called “declination,” and is usually measured in degrees. In North America, the zero-declination line extends from Ishpeming, in Michigan’s Upper Peninsula, south to Baton Rouge, Louisiana. Most maps are referenced to true north and don’t take declination into account. The difference is often minor enough to be ignored, but in places like Anchorage, Alaska, the difference between map north and compass north can be in excess of 30 degrees.

Declination Error

Accounting for declination error is as simple as adding the difference to your compass heading if you’re east (right) of the zero line of longitude, and subtracting it from the compass bearing if you’re west of zero. If the declination value for your location is +10 degrees, and the direction you want to travel is 115 degrees, the correct compass bearing to follow is 125 degrees. On some compasses the bezel is adjustable to compensate for differences so that coordinates can be read directly from a map.

Any compass can be used to plot a course, but precision navigation demands precision instruments like on-board sights, accurately marked bezels and a see-through base that complement a map. Sights may be prismatic (mirrored), lensatic (magnifying lens) or like rifle sights. All of them enable a user to get an accurate bearing on a distant landmark—a mountain peak, a point of land or even a cell tower—then walk toward that landmark without using the compass again until it’s reached.

Direction Indicators

Direction indicators may be needle or dial type; either works as well as the other. Indicator capsules may be magnetically induction-dampened or liquid filled to make indicators settle rapidly, without swinging back and forth excessively. Beware bubbles of air trapped inside the capsule of liquid-filled compasses; a large bubble can prevent an indicator from rotating, resulting in false readings (this is usually obvious to a user).

Whichever brand or model of compass you choose, it does no good if you don’t have it with you. Avoid designs meant to pin to your jacket, as these have a long history of being gone when you need them. A button-down pocket is acceptable, but the most field-proven method of carry is around the neck on a lanyard and tucked safely inside your shirt.

Compass navigation

Always take a bearing before you enter the woods. It’s tough to find your way back when you don’t know from which direction you came. This may sound like common sense, but failure to take note of where you parked is as common among day hikers as among mall shoppers.

With a compass and map, a knife and a fire starter you have the basic-three survival kit, and there are few situations that you can’t live through. The most fundamental secret of surviving a crisis is to prevent it from becoming a crisis in the first place, and the best defense against getting lost is to have at least a rough idea of your location, and of the way out. A good compass, area map and the savvy to use them can make all other survival tools unnecessary in most instances.

This article was originally published in the AMERICAN FRONTIERSMAN™ issue #205. Subscriptions are available here

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