In an emergency situation, a good compass is an essential tool. Even if you have lived in the area for your entire life, the effects of a disaster will often change the appearance of the terrain, sometimes radically. Street signs, business signage and the appearance of buildings can look completely different, and trees, foliage, and landmarks can literally disappear. In addition to this, during a natural disaster or manmade problem such as social unrest, you may be forced to find a new route to your destination. In either of these scenarios, even those who have a good sense of direction will need a compass to help them get to their destination safely.
A good compass can tell you more than which direction is north. Combined with a map, it can help you pick the shortest, safest route to your destination. Then it can help you get there quickly.
Unfortunately, compass use, map reading, and land navigation are lost skills. Many of us have become so dependent on electronics for finding our way that we are debilitated when they fail. And, they will. Even if we know how to use paper maps and a compass, most of us don’t carry them in our vehicles or GO-Bags, anyway.
Even if you have a compass and know how to use it, do your family and friends have these items and skills? Those who want to be self-reliant must regain these tools and skills, and we need to help others prepare, too.
Fortunately, this isn’t difficult. And thankfully, a quality compass needn’t be expensive, either. Cheap or expensive, a suitable compass will have features which make it useful for finding magnetic north and an assortment of other critical land-navigation uses. (A compass should be tested for accuracy before putting it to use in the field.)
What to Look for in a Compass
Adjustable for ‘Declination’. If you want to use a compass for navigation, it should be adjustable for declination. This capability lets the user calibrate the compass for the difference between ‘true north’ and ‘magnetic north.’ If this is new to you, watch the below video, “Introduction – How to Use a Compass.”
Other Features to Look for in a Compass. In addition to being adjustable for declination, find a compass that has a rotating bezel that moves easily but stays in position when not being turned. It should have N, S, E, and W, clearly marked, and degree tick-marks at 5-degree increments or less. (High-contrast directional and degree markings will provide a distinct advantage for land navigation.)
A feature often overlooked is a compass needle that is set for the Northern Hemisphere (or Southern, if you live south of the equator), or a universal needle. The chamber (dial) should be ‘Liquid Filled’ to stabilize the needle, and the needle itself must be balanced on a pivot which allows it to find north unencumbered, even when the compass is not entirely level. (Quality compasses have a jewel bearing.)
Also needed are a bearing index line (route direction indicator), grid lines to allign the compass to the map, and a straight edge to set the direction of travel or triangulate your location. A ruler edge in inches with the opposite side in centemeters, or rulers designed for the the scale of map you will be using, is also an important feature. Lastly, though not required, a magnifying lense can be helpful for studying fine map details.
Optional Features: A sighting-tool which lets you view the compass dial while pinpointing a waypoint is helpful for navigation. A sighting lens (Lensatic) or a sighting mirror add precision to navigating a route. Grid alignment lines for the scale of maps you will be using. Tritium microlights for night use (battery-free), or at least luminescent markings which are easily seen in low light. If your compass has an attachment hole, a string can be added and marked to measure distances on a map, or used as a lanyard so that the compass can be worn around the neck. Whichever brand and model you select, make sure it is durable.
You probably won’t find all of these optional features on the same compass, so identify those which are important to you before you shop. Sporting goods stores which specialize in backpacking usually offer better products than big-box discount stores.
Pros and Cons of Various Compass Types
Military compass vs. a plastic-plate “orienteering” compass. More accurately referred to as a Lensatic Compass, a genuine military compass is exceptionally durable yet a precise instrument, designed to be used outdoors in any weather with a topographic map. As the term suggests, this type of compass has a lens which is used to read the compass dial and set a direction of travel.
Armed with a quality topographic map and a Lensatic-style Compass, even a minimally trained person can establish a route (bearing) to a destination. No roads or signposts, no problem. A Lensatic-style compass can also be used to find the user’s location on the map.
Most military Lensatic compass use metric measurements and are designed for use with military maps which are also metric, but some non-military Lensatic-style compasses use inches/miles, or both. Either way, it is not difficult to convert metric readings to the American/British (Imperial) system if necessary.
Unfortunately, the market is currently flooded with knock-off military-looking Lensatic Compass replicas which are of poor quality and provide inaccurate readings, so buyers must be discerning.
Specific Brand/Model Compass Recommendations
The Best Military Compass
Cammenga 3H Tritium is the Lensatic Compass used by the U.S. Military, NATO, and many military forces worldwide. It has seven battery-free microlights powered by tiny radioactive Tritium cells which will illuminate the dial and needle on dark nights for about 12-years. More to the point, this means the compass can be used at night without a flashlight.
The body of the 3H is cast aluminum and waterproof, and so durable that a truck can drive over it without damaging the compass dial. But not only is it rugged, it is also a precision instrument, and has a dial that provides for precise adjustments, and has graduations in both degrees and mils.
A legitimate military-grade compass will have the procurement number NSN 6605-01-196-6971 cast into the body of the compass. This indicates that it has met the U.S. Army’s rigorous testing standard, MIL-PRF-10436N.
Cammenga 27CS Lensatic Compass. This is the exact same compass as the 3N but without the expensive Tritium microlights. For those who want to save $20, the 27CS is an almost-as-good option. It is equal to its counterpart in accuracy and durability. It only lacks the expensive-to-produce Tritium microlights. But since this model uses phosphorescent glow-in-the-dark paint rather than Tritium, it does not qualify for sales to the military. Therefore, the NSN validation is not cast into the case.
Night Travel Consideration. During an evacuation, it may become necessary to travel at night, and it is difficult to illuminate a compass with a flashlight. Besides, unless your flashlight has a night-vision-saving red or green light, the white light from your flashlight can also reduce your ability to see at night for 5-30 minutes.
Phosphorescence vs. Tritium: A compass which uses phosphorescent paint requires sustained exposure to light to glow for a few minutes, whereas Tritium inserts shine continuously and do not need a battery for power. Both the Cammenga 3N and 27CS can withstand generations of use, but the Tritium used in the microlights has a half-life of 9-years. When the microlights cease to glow it essentially becomes a 27CS.
The Best Lensatic-style Compass – Non-Military Model
The purchase price of the ‘best’ Lensatic-style compass is astronomical, so we have selected the two best reasonably-priced non-military Lensatic compasses for this category. Both the Navigator and the Ranger S sturdy, versatile, easy to learn and use, and they represent a good value. The Navigator is more feature-rich than the Ranger S, but both are precision instruments.
Nevertheless, neither are as durable as a military compass, nor are they as easy to use at night because they do not have the Tritium microlights of the 3N military compass. But, an advantage they do offer is that they are designed specifically for the needs of civilian orienteers. Since these compasses do not utilize a lens for sighting, they are technically not Lensatic (lens) compasses, but they do perform the same function using a mirror and a sighting aperture. For many, this style of a compass is the best choice because they incorporate additional features designed for USGS topo maps.
The Best Orienteering Compass (Basic Land Navigation)
Brunton Eclipse Compass is compact and lightweight, yet full-featured and fast to use in the field. Though it will work with any map, it was explicitly designed for the 1:24,000 scale USGS “Quadrangle” maps, and other maps which use UTM. This is a great compass which is also popular with trail runners.
The Best Modest-Price Feature-Rich Compass
The Suunto M-3 series of compasses are baseplate compasses which boast many of the features only found in compasses which are twice the price of a model such as the Suunto M-3 G or M-3 D Leader compasses. For example, not only is it a precise instrument, it has nighttime luminessence which is better than some compasses which sell for twice the price.
The Best Compact Hiking Compass
Suunto M-3/360 Compass is a minimalist design for simplicity in use. A built-in magnifying glass makes this compass particularly useful for reading small details on large-scale maps. This is a workhorse compass favored by many backpackers.
The Best Budget Compass
Brunton TruArc 3 Compass is a small pocket-size compass that is reliable, reasonably accurate, and suitable for basic orienteering and land navigation. This is our top pick for a low-cost ‘budget’ compass. With both metric and American/British (Imperial) measurement scales, and a global-needle which makes it suitable for use in both northern and southern hemispheres, this is a multipurpose travel compass. It is a prudent choice if you are looking for an entry-level hiking compass, and its small-size qualifies it as the best EDC / Kop Kit (Keep on Person) compass choice. It is small enough to carry in a pocket, purse, or attached to a lanyard and worn around the neck under clothing. And, it is also worth considering as a spare backup compass to include in a GO-Bag. In an emergency situation, having a second compass that is small and lightweight, is an insurance policy against the loss or damage to your main compass.
The Best Watchband Compass
In our tests, the $2 Type-3 compass functioned equally well to the $16 Suunto Clipper compass for finding North. Frankly, that is the only use for a watchband compass–but this simple little task is still an important one. It is easy to get turned around while traveling through difficult urban or wilderness terrain, so these little gems can be worth their weight in gold if you become disoriented.
Note: The reading of a little compass such as this can be adversely affected by both the watch itself and the buckle on the strap, so test it, and reposition the compass to correct the problem.
Wristwatch with Built-in Electronic Compass
Suunto and Casio are known for their multifunction watches which have a built-in electronic compass. The Casio Pathfinder PRW3500 not only has a compass, but also provides altitude, barometric pressure, and thermometer readings. It is water resistant to 200-meters and is solar powered. No batteries to replace. Our test watch has been in use for 8-years of field use without a power problem. Nevertheless, all electronics can fail, so adding a small compass to the band is only prudent. The Suunto Ambit3 Peak is another highly rated watch. It has similar sensors but is not solar powered, but it does have a built-in GPS.
As with all electronics, they should be used in an emergency situation if they work. But these tools do not take the place of a magnetic compass and paper maps.
Declination: The often forgotten but very important factor.
What is ‘Declination‘? There is a difference between “True North,” the axis for the rotation of the earth which is the North indicated on maps, and “Magnetic North” which is used by a compass.
The magnetic needle on a compass is drawn to the earth’s geomagnetic field, or ‘Magnetic North,’ and this location periodically changes a few degrees. Since this field is not constant, a compass needs to be calibrated so that North on your compass matches the North on your map. A good compass can be adjusted to automatically adjust for declination.
Most low-cost compasses cannot be calibrated, so this adjustment must be calculated manually each time the compass is used. Though this is simple math, it is worth the modest extra cost to purchase a compass that is adjustable.
Click Here to Calculate Declination for your location. This link will take you to a free online tool which you can use to calculate the declination for the place where you will be using your compass. Though the declination change is usually only 1-degree every 9-years, this can adversely affect the plotting of your route since most maps are made from old data. This is a common problem.
The data used to create many of our modern maps is more than 50-years old. To solve this problem, use the USGS calculator found through the above link, and then plug this information into your compass. Once your compass is updated with the current declination, then it can be used for navigation in the entire region, not just the city or zip code you used for the calculation. Note: The method used for adjusting the declination of a compass may be different from one compass model to another. Check your adjustment results closely, to see if you should make a clockwise or counterclockwise adjustment.
All compasses do not provide the same precision. In addition to the earth’s magnetic pole, a compass’s direction-finding needle is also influenced by nearby metal objects and magnets. A quality compass will have a needle which is not as easily influenced by nearby metal objects. However, all compasses are affected by metal objects such as cars, so readings should be taken with this potential problem in mind. This photo of two compasses illustrates this point.
Take Two. Due to the close proximity, the military compass (right) has adversely affected where the needle points on the other compass. (The red lines were added to make it easy to see the needle’s direction on each compass.) In this example, the strong needle of the military compass is providing an accurate reading, but the other compass is not. If a user isn’t aware of this potential problem, it can result in heading off in the wrong direction. Therefore, a compass reading should be taken twice, with the second reading a short walk away, just to make sure that the first reading was accurate and not influenced by something in the environment.
False Readings. In addition to metal objects such as cars and iron ore mineral deposits creating false readings, simple objects such as a screw or nail in the table under the compass, or the proximity of a mobile phone, television, radio speaker, or other electronics, can skew the compass reading. A compass is designed to be used outdoors.
New Compass. A new compass should be checked against the reading taken from another compass, to verify that the new one is giving an accurate reading. Don’t assume. Even an expensive compass can be defective.
Short Video Tutorials and Recommended Books
Video: Introduction – How to Use a Compass (7-minutes) REI
Video: How to Use a Military Lensatic Compass (30-minutes) U.S. Army
This video is an old U.S. Army training film which teaches direction finding and navigation using the military-issue compass and military grid map (MGRS). Despite the age of this video, the content is excellent. Note: There are various map grid methods in addition to the one used by the military. For more on this topic, refer to Part-1 in this series, “Maps – Navigating an Emergency Situation.”
Video – Using a Compass to Set Your Direction of Travel [Bearing] (3-1/2 minutes) MapTools.com
Book: “Be Expert With Map and Compass: The Complete Orienteering Handbook,” by Bjorn Kjellstrom (founder or the Silva Compass Company), and his daughter, Carina Kjellstrom Elgin. This book contains simple and straightforward instructions for the novice. Don’t be misled by the chapter titles as they don’t adequately describe the content of that portion of the book.
Book: “Map Reading and Land Navigation, FM 3-25.26,” U.S. Army Training Manual
Practice is Necessary.
Just as owning a football doesn’t make you a football player, owning a compass does not prepare you to navigate in an emergency situation. A compass looks deceivingly simple to use. And it is, as long as you only need to use it to find North. Every other use requires instruction and practice. The above video tutorials are an excellent place to start, followed by either reading an instruction manual or book, or taking a navigation class from REI or an orienteering club (Orienteering USA, Orienteering Canada, British Orienteering Federation, or International Orienteering Federation).
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