You’ve got somewhere to be. You know where it is, but not how to get there exactly. No GPS. No clear road route. Just a compass, and if you’re lucky a map. How can you use the compass to most reliably navigate to where you’re going?
This is just the situation my hiking partner and I faced last summer. We were miles from anything more developed than a foot path when even that trail disappeared. That proved to me both that having that compass and map was truly valuable; and that I needed to up my skills. I’m writing this series of posts on navigation as I study up. Could your navigation skills use an upgrade too?
This is the third installment. The first describes what magnetic declination is and how to find it. The second describes how to set declination on your compass so the thing actually Will indicate true north. A future post is planned to help you find yourself if you’re lost.
Navigation of the compass itself
A quick review, so we’re all talking the same language. Here’s a picture of the compass I most often use. Mine is a Brunton TruArc3, but works the same as most of the other decent compasses.
A midrange compass, with adjustable declination.
The baseplate is the acrylic almost-rectangle with scales along the sides. The direction of travel arrow is the black arrow along the midline of the baseplate. The index point is where the direction of travel arrow meets the bezel.
The bezel is the black ring with degree markings on it. It turns on the baseplate. The magnetic needle swings in its fluid chamber; right now it’s hovering over an outline on the bottom of its chamber. That outline is called the orienting arrow.
That ought to be enough for us to talk about how to use this thing. What follows assumes you’ve already set the declination on your compass. If you don’t get that set and you live on the east or west coast of the U.S. where the declination is about +/-15 degrees, the error adds up quickly. If it’s ten miles from where you start to your target, you’d end up about 2.7 miles east or west of your target.
How to find your navigation bearing using a map
Suppose you know where you are now and have a map that shows your destination. But, you can’t follow a nice little road for whatever reason. You’ll need to get the bearing, then follow the compass. Like this:
- Each side of the compass is a straightedge. Put one end of a straightedge on your start point. Specifically, use the end of the compass that doesn’t have the Direction of Travel arrow.
- Now put the other end of the straightedge on your destination. This leaves the Direction of Travel arrow pointing the way you want to go.
- The bezel has some parallel lines on it, called orienting lines. Rotate the bezel until those lines are parallel with the north/south lines on the map. Every decent map is also printed so the side of the map is one of those straight north/south lines. The direction arrow somewhere on the map will confirm this.
- Make sure the 0 degrees on the bezel is on the map’s north side. If it’s not, rotate the bezel another half turn. Now it does!
- The index line (point where the orienting arrow meets the bezel) now reads your correct bearing.
An example of finding a navigation bearing
Suppose you’re in Independence, Missouri and your bug-out location is in the happening burg of Regal, MO. You’ve got one of those laminated flip-fold road maps — Just like mine! You can see in the photo below that the tail end of the straightedge is on Independence (arrow marked S) and Regal (marked F) lies at the other end of the straightedge.
Once the straightedge runs from origin to destination with the bezel oriented north, the bearing is read off the index point.
The Direction of Travel arrow points from Independence to Regal. The 0 for North is now aligned with north on the map by turning the bezel until the orientation lines are parallel to the north/south dividers on the map. That puts the 38 degree marker at the index point.
To get to Regal from Independence, you’d head to 38 degrees. That’s roughly northeast; but just heading ‘roughly northeast’ would leave you in the middle of a cornfield.
What if your destination is farther away on the map than your compass is long?
If your compass’s straightedge won’t reach all the way from origin to destination, just find any suitably long, straight thing. Lay it from start to finish points on the map. Align the compass edge with the edge of your ruler. Align the bezel to point north and read the heading as before.
The photo below shows using that method to discover that the navigation heading from Independence to New Boston, MO is 52 degrees.
If the compass isn’t long enough, any straightedge can serve as an extender.
Navigation using a bearing
Maybe you’ve just used a map to get a bearing, or maybe you just know “I need to go east”. Either way, the process now is pretty simple.
- Assure the bearing you want is lined up with the index point on the Travel of Direction arrow.
- Hold the compass in front of you with Direction of Travel arrow pointing away from you.
- Rotate your body until the north (red) end of needle is in the Orienting Arrow. Remember the Orienting Arrow is the outline of an arrow you can see underneath the magnetic needle. When Orienting Arrow has two sides, the red side is the one the north end of the needle should lie within. Compass users call this lining up of the magnetic needle within the Orienting Arrow putting “Red in the Shed”. Red in the Shed is way easier to not mess up when you’re tired than numbers and mental math.
- You’re now facing your destination.
Navigate to a landmark, not just watch the compass and move
Once you know which way you’re going, pick a visible landmark as far in that direction as you can reliably see. Head to that landmark.
Picking a distant landmark more accurate than just watching the needle and moving. It also makes it easy to navigate around terrain and end up still going the right way. Moreover, you’re paying more attention to your surroundings, instead of fixating on a compass.
Once you get to a landmark, reorient by making sure the index point is still on the right number, putting Red in the Shed, and picking a new landmark further along the route.
Important compass navigation tips
Always hold the compass level when orienting. If it isn’t level, the magnetic needle won’t move freely and Bad Things happen. Cheap compasses are worse than this than better ones. Rocking the compass a bit and assuring the needle stays oriented in one direction when you rotate it a bit are ways to check for free movement.
Magnetic compasses are more disturbed by metal than you might guess. Don’t hold a compass near metal when getting the magnetic needle orientation. Even a staple in a map might mess it up. In some places magnetic compasses won’t be reliable because of rock ores. Not much you can do about that but pay attention to other cues (like sun direction) and engage common sense.
Electrical current flows also cause magnetic fields that distract the magnetic needle. When working a compass, keep it away from electronics and batteries. Also, get out from under (or over) power and phone lines before taking readings. Oh, and if it’s an EMP that caused the need to beat feet … if the event is still in progress, compasses won’t be reliable.
Practice navigation
I’ll admit, this compass stuff didn’t come easily to me. My first attempts weren’t great. (In my defense, my first attempts were under water. Scuba compass use adds a level of difficulty.)
My point is, working with it a little made me much more comfortable, and reliable. If you need these skills, you don’t need the stress of wondering if you’re doing it right. And you need to be doing it right. Practice.
If you prefer to get your learning through videos, I liked this one: https://www.google.com/search?q=compass+use&oq=compass+use&aqs=chrome..69i57j0l5.1896j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=1