COMPASSES

COMPASSES

Hi guys,
The impulse to write this post came with the recent discovery that we live in the midst of a generation so dependent on gadgets (and adept at using them) that they lose, or never discover, the simpler way of doing things.

I conducted an “antler hunt” in the April spring woods with a group of Boy Scouts of my son’s troop. The plan was to scout the woods during the day and using flashlights at night, employing compasses to coordinate the excursion.
The group consisted of several boys aged 13 to 16 years, bringing with them a large assortment of electronic equipment. I have to say that they were very excellent at using them, especially the iPods, cell phones, two-way radios, and GPS’s, but they failed miserably in their understanding of the low -tech compass.

THIS PICTURE SHOWS A VARIETY OF COMPASSES AND TWO GPS’S, THE GARMIN XL12 LT
AND THE GARMIN E-TREX SUMMIT, AS WELL AS A SUREFIRE AVIATOR FLASHLIGHT.

[IMG]http://img.photobucket.com/albums/v111/blackbear11784/severalcompass.jpg[/IMG]

I have nothing against GPS’s; as a matter of fact, I use them myself and have a couple that I use often to complement the compass I use.

After all, the GPS can give you your position (and you can plot this in a map) in any weather and even at night, making it easy to walk cross-country in the woods. However, I am not one of those guys glued to the GPS. After I get my position and course to follow, I put the gadget away and use the compass to get the direction for my trek.

This is going to be sort of a very short (space limitation) refresher course on how to use the basic base plate compass. Of all the types available, I am going to stick to the Silva system for now, as it is the easiest to understand. They come in several flavors; from the inexpensive less- than-$10, to the more elaborate of $50 or so, but they all do the basic job of guiding you well.

That I stick to the Silva system doesn’t mean that you have to buy a Silva Compass. The market is full of others brands that use the same base plate system such as Brunton, Suunto, Kasper & Ritcher, etc.

The mechanics of taking bearings and following directions are very easy. I will try to make them short and understandable, as the scope of this article is only to produce the basics, and should not be considered a treatise in navigation.

The compass’ needle points to the Magnetic North, not the geographic North, but we only have to compensate for it when we use the compass together with a map.

For navigation in the woods without a map, this is what you have to do. With the compass in front of you, point the direction-of-travel arrow in the direction you want to go, then rotate the capsule until the magnetic arrow North part (usually red) lies pointing to the letter N (for North) in the capsule. Read the bearing (in degrees) at the junction of the line-of-travel arrow and the capsule. In this case, it is showing 270 degrees, which means that the direction you want to travel in is 270 degrees, or exactly West.

Now, move your feet and rotate your body (not the compass) until the magnetic needle points to the N. Pick a landmark lying in your direction (West) and walk to it without looking at the compass. When you reach that landmark, reorient your body again, pick another landmark (a tall tree?) and keep walking until you get to your destination.

When you want to return, don’t change anything on the compass! Move your body, putting the South part of the needle over the “N,” or alternatively, just invert the base plate with the direction-of-travel arrow pointing towards you. Or, if you want to change the setting, just put East as your returning direction in the line-of-travel; that will be 90 degrees in your numbered capsule.

And to make this explanation as simple as possible, I will explain compass and map together in the next posting.
Best wishes

Juancho

COMPASS AND MAP TOGETHER

The compass needle points to geographic North only at the agonic line (line of no declination because it is the same as the geographical North line). This line passes now through the west part of Florida and the Great Lakes. My friends in Wisconsin never have to adjust for magnetic declination. I hike and hunt in New York, where I have to adjust for 17 degrees West, and in Maine as much as 22 degrees West. The people on the West coast have to adjust for declination East.

If you are located over that line, the needle will point geographic North. All other times the magnetic needle points to the magnetic North that is located some 1300 miles from the geographic North.

Your topographic map will tell you in a diagram found in the left corner how much is the declination in your area. If the map is old, you may have to find the present declination to be more accurate in your traveling if it involves a long trek, where one degree could make a difference.

Once you found how many degrees of declination you have to adjust for, you can do it on the compass or on the map.

PICTURE OF A COMPASS WITH INSIDE DECLINATION SCALE

[IMG]http://img.photobucket.com/albums/v111/blackbear11784/insidescale.jpg[/IMG]

PICTURE OF A COMPASS WITH AN ADJUSTABLE SCALE, IT MOVES THE LOWER INSIDE DIAL
BY A GEARED SCREW.

[IMG]http://img.photobucket.com/albums/v111/blackbear11784/M5SK.jpg[/IMG]

PICTURE OF A COMPASS WITHOUT A SCALE, IN THIS CASE YOU HAVE TO FIGURE YOUR DECLINATION BY ADDING OR SUBSTRACTING FROM THE 360 DEGREES, IN THIS CASE THE DECLINATION IS 18 WEST, SO THE NEEDLE IS PLACED OVER THE 342 MARKINGS.
EACH OF THE MARKINGS IS EQUIVALENT AT 2 DEGREES, THERE ARE 180 OF THEM AROUND THE COMPASS.

[IMG]http://img.photobucket.com/albums/v111/blackbear11784/noscale.jpg[/IMG]

ADJUSTING THE MAP
To make the map speak compass language (magnetic North), extend the line of declination all across the map from the little diagram in the corner, using a long ruler and spacing the lines about two inches. Or use your compass as a protractor (measuring angles) to trace the start of the line from anywhere on the map.
After doing this, both the compass and the map will “speak” magnetic readings and you will not have to adjust the compass for magnetic declination.

ADJUSTING THE COMPASS
If you would rather adjust for declination on the compass (and save yourself from tracing lines on the map), every time you are going to follow a bearing in the field, you have to move the needle to the proper declination. So instead of pointing to North, it will point 22 degrees West of North (in the case of Maine), or 338 degrees.

Or, if you are West of the agonic line, then your declination will be East and you will have to move the needle East of the North marking on the compass.
Some compasses have a scale printed in the capsule, and some of them adjust by means of a internal rotating bezel that adjusts with a screwdriver stored in the lanyard. I like the latter type because there is nothing to do after you set it; you just place the needle in the “gate” that is already adjusted to the proper declination after you do it the first time.

To use the compass and map together, find where you are in the map and where you want to go, connect the two places with a line that extends from the side of your compass, and without moving it, rotate the “capsule” of the compass so that the lines inscribed on the bottom of the capsule combine with your drawn magnetic lines on the map OR the North line(s) or margin on the map if you are adjusting for declination on the compass.

Just follow the bearing that you have just set at the back end of the “line of travel arrow” and you will arrive at your destination.

IN THIS PICTURE, A SUUNTOO S5SK IS USED TO CONNECT THE START AND FINISH, ONLY THING TO DO NOW IS ROTATE THE CAPSULE UNTIL THE LINES INSCRIBED IN IT, PARALLEL THE NORTH LINES ON THE MAP, AND READ THE DEGREES AT THE JUNCTION OF THE LINE OF TRAVEL ARROW AND THE BEZEL WITH THE NUMBERS. (DISREGARD THE MAGNETIC NEEDLE WHEN THE COMPASS IS ON THE MAP)

[IMG]http://img.photobucket.com/albums/v111/blackbear11784/firekiller.jpg[/IMG]

All this is very basic, but it will take you to the proper destination. If you would like to study map and compass a little more and learn how to navigate using more elaborate techniques, such as using handles, taking triangulation, or navigating in open terrain without the use of landmarks, I recommend you buy one of the books that are available on the subject.

I started many years ago with the classic “Be Expert with Map & Compass” by Bjorn Kjellstrom, which I recommend, but there are many other books that you can get from places like REI.
Using Map and Compass by Don Geary
The Outward Bound Map and Compass handbook by Glenn Randall
Wilderness Navigation by Bob and Mike Burns

I hope this little post can help someone interested in navigating the woods by map and compass. I feel that is a great need to go back to the basics to supplement and complement navigation with GPS, that after all, being electronic and depending on batteries can fail us when most needed.

Cheers
Juancho

I have been a scoutmaster for several years, and have always emphasized compass+Map use on (almost) every campout or hike we go on, for exactly the same reasons you mention. Plus, a compass never needs batteries, and will work anywhere in the world (except the magnetic poles, I guess). In southern Utah's slot canyons, I always come across people wandering around trying to get some sort of signal onthe GPS- doesn't work in deep, narrow canyons where the signal bounces around. I have often had competitions with boys who thought they could do better with a GPS than I could with a compass at finding my location. I always bet that if I win, they they cannot use a GPS again until they have mastered the compass. I've not lost yet. On one occasion, on an extended bacpacking trip, we found a group that was disoriented (lost) because they had a GPS, but the batteries were dead and had not brought a compass. Some people should not venture past the trailhead... really.
Thanks for the refresher post.

I never leave home without my Silva Ranger. If you buy one, take the time to learn to use it correctly and you will likely never have a problem with getting lost.

juancho -
first comment - leave off the IMG tag in these forums - Trailspace does not have image posting capability at present for regular posts. Just put the URL, and people will be able to click to see the image you are referencing. Like this (your first link) - http://img.photobucket.com/albums/v111/blackbear11784/severalcompass.jpg
[Good grief! That's an ancient Boy Scout Silva next to the Ranger 15! It didn't even have liquid damping, just relying on eddy currents in the aluminum bezel!)

Second, there are a number of excellent books out there that cover map and compass basics both at the simple introductory level and in depth. You could add your own favorite list to help people. You mention Boy Scouts - Bjorn Kjellstrom's excellent classic book (which I mention below) is sold in most Boy Scout Shops. Several outdoor organizations (Seattle Mountaineers, Appalachian Mountain Club, NOLS, etc) also publish excellent books on the subject.

A couple of historical points - The Silva system was invented by the Kjellstrom brothers in Sweden in the 1930s. The family started and still has majority control in Silva. The company uses that name for their compasses and other survey and navigation instruments (and orienteering gear) in the whole world outside North America. When Bjorn (author of the still best book on map and compass, even though he passed on several years ago) came to the US, he was looking for a North American representative. The company he chose and was a spokesperson for eventually became Johnson Worldwide Associates (started by the founder of the Johnson Wax company). To this day, JWA retains the marketing rights to the name Silva as far as compasses are concerned in North America. In the 1990s, Silva (Sweden) bought Brunton, an old line surveying instrument company that also manufactured compasses and various types of optical and outdoor gear. When they asked for the return of the North American rights to the Silva name, JWA refused (there was a major court battle, decided in 1997, if I recall correctly). So Silva severed relations with JWA (which means that "Silva" compasses sold in North America are not made by Silva Sweden). Silva first used a name they had used for years for marine instrumentation, Nexus, for their compasses in North America. But there was so little name recognition that they have recently (few years ago) started using the Brunton name for all Silva (Sweden) gear sold in North America. JWA meanwhile contracted Suunto (Finland) to manufacture compasses for them, while Suunto continues to import compasses and other gear to North America under their own name. Compare, for example, the Brunton (Silva of Sweden), JWA Silva, and Suunto model 15 mirror compasses - you will immediately see the strong resemblance of the Suunto and JWA versions, and some interesting differences with the Brunton (Silva Sweden) version - then compare to a JWA Silva (made by Silva Sweden) from the 1960s through 1980s. There are differences in the way the similar models are designated, with Brunton/Silva and JWA Silva using the "15" - Brunton 15TDCL, Silva Ranger 515CL, and Suunto MC-2.

I mentioned the "professional" mirror compasses because it is easy to see the strong resemblances and minor differences. I do NOT recomment these for most people. A simple baseplate compass is more than enough for the vast majority of people in the outdoors (I even carry one of the little $10 ones as a spare backup myself, despite having a plethora of compasses up to and including a venerable Brunton Pocket Transit). The other styles of inexpensive compass (the little ball-shaped ones, the kind found on the top of hiking poles, the key-chain ones, etc) are next to useless for even simple navigation - they are barely able to point out magnetic north. The expensive ones, including the mirror ones, have their uses, but only for someone thoroughly trained in their use (oh, ok, you can use the mirror for shaving or coming your hair, or even maybe making sure your sunblock is evenly applied).

And, yes, I teach land nav to scouts and scout leaders, and for various outdoor organizations, from the basics of map and compass through use of the various electronic widgets.

Jeez...and I was never even a damned Boyscout...(but I grew up near Bjorn Kjellstrom's house in New York, and he got a great grant from Silva in 1980s for an extraordinary orienteering map of local park).

GPS seems to falsely imply that you don't need to know where you are in order to navigate. It's the map or chart that is the key to navigation and continually monitoring position is the thing. I can't speak from experience with GPS, and am not particularly curious.

I was boyscout and learned, and have since forgotten, but good information. I have been practicing the past couple of weeks as I prepare for my summer trip.