Choosing a compass

Posted: 12/16/2014 in Land Navigation

I’ve been asked by several readers which compass I use and why I chose it. My primary compass is the Suunto MC-2, my alternate compass is a Suunto A-10 and the compass in my survival kit is a little Brunton Globe. While in the Army we were trained to use the standard military lensatic compass but, during the deployments during GWOT, some SF teams were issued a version of the Suunto MC-2 with special tritium illuminated parts that most of us found to be superior to the lensatic.

Like weapons, not all compasses are of the same caliber and no one compass excels for all uses. Some are toys, some are junk and some are overkill, so depending on the terrain you are operating in and what you are doing at the time, they can get you lost and embarrassed or worse, lost and dead. If I had to bet my life on a compass, it would be either a Suunto,  Cammenga or a Brunton.  My primary, the MC-2 is considered an advanced nav. compass and it is pretty rugged. My secondary (backup) is an orienteering compass that is quite a bit lighter, and while it won’t take the licks the MC-2 will, it will allow me to continue the mission. The little Brunton Globe is my go-to-hell compass, it will get me home and that’s about all I can ask of it. Avoid very expensive professional compasses designed for surveyors, loggers and geologists. They are usually a little bulky, heavy and you’ll cry like a baby when you lose it or break it. Also avoid the Chi-com made Silva compasses like the plague. Yes, Silvas sold in North America are made in China. The true Silva compasses are still made in Sweden but are not imported here.  I still have a Chi-com Silva Ranger someone gave to me that has the direction-of-travel arrow pointing in the wrong direction. The Suunto is made in Finland, the patron nation of orienteering, the Cammenga in Michigan and the Brunton in Wyoming. My only hands-on experience with the Bruntons, beside the little Globe, is the Army M-2 that was used by Army mortar and artillery crews and I remember it being a well-built compass. If you’ve used the virtually indestructible M-1950 military lensatic compass, you’ve probably used a Commenga. The civilian version of the M-1950 is the Commenga 3H. As far as I know, it is the only civilian compass with a tritium illumination. The use of tritium allows the compass to self-illuminate without the aid of a light that is required to charge the phosphorous in other compasses. The life of the tritium is about 10 years (true half-life of 12 years). If you feel that the lensatic compass is for you, a word of warning; there are tons of cheap Chinese knock-offs floating around. I see one or two at each land-nav class I teach. Usually, they are made of plastic, don’t have a dampened floating needle, (the needle never seems to settle down) and the parts that are supposed to be phosphorus are just green paint. Also of note; if you find a military surplus lensatic, it’s probably past the half-life of the tritium and will not illuminate properly. Check for the manufacture date on the back of the compass.

What to look for in a good compass:

The compass should have a liquid filled housing with no bubbles under the lens and a jeweled needle bearing.

The base plate should be transparent in order to view a map through, and have embossed scales relevant to the maps you will use.

The needle, orienting arrow, rotating bezel ring and orienting marks should be luminous for night use.

The bezel should have detents (or “clicks”) to hold it in place when set.

Declination scale.

There should be an attaching point for a lanyard. This is pretty important. I usually keep my compass lanyard (a piece of gutted 550 cord) tied through the button-hole in either my top left shirt pocket or lapel, or if no button-hole when wearing a combat shirt, attach it to the suspenders on the battle belt or a plate carrier attachment point.  My point is attach it to your person.  Do not tie it around your neck, that’s a no-no that might come back to haunt you during a ground combatives engagement.  Do not make the lanyard so long that it can reach the ground when you go down on one knee. Old war story; I had a buddy going through SF Selection with me, taking the land nav. exam when he fell onto a knee at night while moving through the woods. His lanyard was so long that when he fell, his knee fell onto his open compass, breaking out the lens and crushing the needle. He had no backup compass and failed the exam. Close your compass cover and stow it away when you’re not looking at it.

Additional items I look for:

A hinged cover with integral mirror.  The cover protects the compass face, base plate and mirror from damage and, of course, keeps the mirror from flashing inadvertently. The mirror is used for the more precise land nav. functions such as section/re-section. It can also be used for applying camo, signalling, shaving, and checking for ticks in those places you can’t normally check by yourself and your Ranger Buddy probably won’t help you with. When the mirror is folded out flat, it gives the user a longer straight edge for drawing lines on the map.

Multiple map scales and rules. Something  very important to consider before purchasing a compass.

Determine the scale(s) of the maps you intend to use since the scales on the compass need to match them. With the Suunto, the embossed compass scales will either be in inches (standard) with map scales of 1:24,000 and 1:62,500 for use with USGS maps printed for the United States, or for maps of virtually all other areas of the world, the compass scales required will be in centimeters and the map scales of 1:25,000 and 1:50,000. Military Grid Reference System (MGRS) maps, including those of the USA, use metric scales. I keep compasses for both type of maps.

Magnifying glass. Comes in handy for reading the fine map print, especially when you are long-in-the-tooth, like me, and the eyes start to go bad. It can also be used to start a survival fire, providing the big heat-tab-in-the-sky is shining.

An adjustable declination setting. Determine the declination for your AO, set it into the compass once, and forget it. Big time saver and one less mistake to make.

Sighting apertures and wires between the base and hinged lid.

Most compasses are hemisphere specific. A compass made for the northern hemisphere will not work in the southern hemisphere and vice-versa. You can, however, buy a special compass that will work in both.

For example: The Suunto MC-2 360/D/L/CM/IN/NH  has/built-n Declination adjustment/Luminous dial/inClinometer/INch scale/works in the Northern Hemisphere. The Suunto version for both north and south hemisphere will have the letters NH/SH or G for Global. Each uses a different method of needle stabilization.

If you have any interest in land navigation and are planning a compass purchase, visit your local sporting goods/backpacking store and puts your hands on one first. Usually someone behind the counter will have some experience with one. Another good source of information is a local orienteering/hiking club.

I have updated this post to include this Youtube video that I think will help. It is very well done.

http://www.youtube.com/watch?v=SI-dTsi5nhQ

 

 

 

 

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Comments
  1. Ant says:

    I have been working on my Nav skills recently and currently using the Cammenga US issue compass. while attending a NAV course I saw the need for a secondary better compass for map work & planning. while doing research I came up with 2 choices the Silva Ranger and the Suunto MC-2. both were in the same price range. I wound up picking the Silva…WTF? one of these days I will choose wisely. yes, it’s made in China…

  2. Ant says:

    There are many MC-2 models. which exact model do you recommend?

    • danmorgan76 says:

      I would recommend the model that I broke down the codes for in the article, however, if you’ve had no issues with your Silva Ranger, you might want to stick with it and pick up a Suunto A-10 as a backup. Again, you have to determine what scales to the maps you will primarily use. I am working up an article on map choices next.

      • Ant says:

        Thank you for the reply. I broke down the codes and went to Suunto’s website to find the right model. My Silva Ranger just arrived yesterday, so I have not had time to work with it yet. I did compare the readings to my USGI compass and they were the same. one of the main reasons I chose this compass was that it had 3 scales; 1:24000, 1:25000, and 1:50000. From what I initially read the Silva’s were Swiss made, and as you were correct my unit was made in Indonesia China. go figure. Not sure if I should re-sell it or work with it for a while…

      • chris says:

        Great compass info. I use USGS maps@ 1:24,000-and using the UTM system. I live Montana.
        Which Suunto MC-2 (letter designation) would you recommend. Also have/use a 1:24,000 UTM
        grid scale.I just want to order the correct Suunto w/ correct relevant scales. The previous comment
        about the ‘inch’ letter designation seems it.?

      • danmorgan76 says:

        You’re correct, the IN designates the inch or standard compass with 1/24,000 and 1/62,500 scales. I will do an article soon showing folks how to set up a the UTM grid system on their USGS maps. You might already know how.

  3. Thanks for the run down. I’m going to check out the MC-2 360/D/L/CM/IN/NH. If it’s easier than the Cammenga USGI, it might become my primary.

  4. JudgementComes says:

    Sorry for being off topic, but I would appreciate some advice. I have finally noticed the transceiver you are squatting in front of on your blog page. It looks fairly large. I own a unit of similar size. When I bought it I had in mind the need to pack it. Would you hump a unit and peripherals of the size that I see on your blog page? If so, how did you protect it? Thanks for your advice.

    • danmorgan76 says:

      You have just opened Pandora’s Box. Ask an old SF Commo guy about radios (Am I right Sparks?) and you had better have a few hours of spare time. No short answer here. The photo was taken in Bavaria, FRG during REFORGER sometime in the ’80s. My wife found it and insisted I use it. The radio shown is the AN/PRC-74. It was one of the HF/SSB radios issued to Army Special Forces in the late 70s through the mid 80s. It was replaced by the AN/PRC-70 which was replaced by the AN/PRC-104. At the time we thought THE 74 was great because at about 28 lbs it was one box replacing the older AN/GRC-109 with it’s minimum 4 seperate boxes which, depending on which power supply and wet cell batteries you had could weigh in at up to 74 lbs. And it would only transmit CW on very specific frequencies using installed crystals. The batteries on all except the 104 were recharged via a heavy hand cranked generator that was jumped-in and packed also. So was it a good radio, yes, during that era. I never broke one but they were all a bear to hump in your ruck along with everything else. Ask any SF guy from that time and they will verify what I am about to say; Most 18Es (SF Commo guys) have jumped out (or waddled to the door and fell out) of aircraft in flight with rucksacks that weighed more than they did. Would I hump one now with all my other light weight field gear? Not on your life, there are too many better alternatives. Unless that was the only radio I could get my hands on. As to protection of the radio in the picture; you could not immerse it, other than that, it was waterproof. The old 103 was designed to be buried underground in a cache if necessary and I remember digging up a PRC-70 wrapped in a Army waterproof bag during an emergency resupply once. So they needed very little, if any protection.

      I now have an Elecraft KX-3 that will do everything each of those older radios would do and more (voice, cw and data, HF,SSB,UHF,FM) and it weighs in at 1.5 lbs. I charge the internal batteries with a small flexible solar panel that weights about 12 oz. Or plug it in with a tiny radio shack power supply. Or run it off of a car battery. And it has a built in tuner. And CW keyer. And it will decode CW or PSK with a memory playback. And it puts out about the same power, 12 watts as those others but, if that’s not enough, you can get an upgrade for it to 100 watts output power to use as a base station. I will say that the KX-3 is not waterprooof or even water resistant, but I keep it in a special heavy zip-lock type bag that is kept in a dry bag in my ruck when I’m not using it. I also upgraded the radio with the ruggedized side panels and cover from gemproducts.com. I would have given my left nut (the smaller of the two) for this radio when I was in SF.

      Now I gotta ask; Is the radio you want to carry an HF radio or a VHF/UHF radio? And what make/model is it?

      • JudgementComes says:

        Its a Yeasu FT897D. 20 Watt portable with 100 watts when attached to 13.5 v DC adapter. 160-10 meter bands plus the 6 m, 2 m, and 70 cm bands, includes SSB, CW, AM, FM, and Digital modes. I am a noob. But I do have my technicians license. Because of my age, I am looking to help support FREEFOR through auxillary activities like comms/intel. I think I would be a liability on small unit ops.

      • JudgementComes says:

        And thank you very much for your reply. By a liability, I mean that I would be a liability in a firefight. But am still fit enough to wander around in the woods with a pack on my back. My longest all-day hump was 20 miles in North Georgia mountains with a loaded day pack.

      • danmorgan76 says:

        Acually, in my experience, it’s the fellow that can shoot well, can manipulate his weapons systems (plural – long gun, side arm, edged weapon and fists) without much thought, because the manipulation is second nature due time spent in correct practice, can keep a cool head when everyone around him has long since pissed their pants, has a normal degree of physical fitness (you don’t need to be a superman and if you can hump 20 miles in those foothills, sounds like you are in pretty good shape), quickly understands the tactical situation unfolding around him and reacts correctly, he will usually win the day. The most important trait: If you can help those on your team pull their heads out of their fourth-point-of-contact and get back in the fight. I saw Georgia Force-on-Force is offering some training in your area in February. You might want to check that out.

  5. gamegetterII says:

    Reblogged this on Starvin Larry and commented:
    I have an old Silva compass,made before they were made in China,along with a newer Silva starter made in Indonesia that I carry in my hunting pack when I’m hunting in Ohio-it works fine for that,as anywhere we hunt is not all that large of a tract of land.
    Out west I use a Suunto A-30.
    These get me where I need to go for hunting purposes.
    Never learned to us lensatic,as never had a reason to-the starter compasses are fine for what I’m doing.
    I am going to take a land nav class to learn the lensatic type in the near future.
    Looking at the Suunto site-I’ll probably go with one of the MC 2 360’s.

  6. Brian from Georgia says:

    Thanks for the compass advice. Your last four posts were excellent.

  7. Lost Dog says:

    I’ve used Brunton Pocket Transits (one of the very expensive professional compasses designed for surveyors, loggers and geologists as you described) for over 30 years. And I completely agree with your advice not to get one for orienteering. They’re great for what they’re made for; but mine cost about $300 in the mid 1980’s (more than the total cost of the orienteering compass and GPS I currently use), is bulky/heavy, and I do believe I would cry if I lost it. 🙂

  8. Anne Walker says:

    Thanks for the advice. I have been looking at upgrading the little compass I had, so I went with the Suunto mc-2 360 D/L/IN/NH. Thanks for the great posts. I always learn so much.

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