Tru Nord Backpacker/Survival Compass

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If you travel far afield the value of an accurate, reliable compass cannot be underestimated.  Yet, all too often cost becomes an overly influential part of the decision-making process.  After all, how much better can an expensive compass be over a cheap one?  Not surprisingly there is a big difference.   When your life can depend on an instrument is this really a time to opt for that budget model?   The Tru Nord Model 100C Backpacker Compass just might be one of the best backup compasses you can own.

I’ve been fortunate to rely on many models and types of compasses through the years.  The U.S. Army issued me an M-1950 Lensatic Compass, but it was my liquid-filled Silva wrist compass that best helped me dead-reckon from Saudi Arabia to Iraq to Kuwait.   GPS technology was pretty unreliable in those days, so a compass, wrist watch and my Humvee’s odometer worked pretty well as I traversed the Central Arabian Desert.

Eventually, my trusty wrist compass succumbed to the dreaded bubble, but only years later.  Over time liquid-filled compasses can form air bubbles that can hold the dial or needle up or down preventing it from zeroing in on north.  This creates accuracy issues as large as tens of degrees. Manufacturers of precision liquid-filled compasses are supposed to expel the air suspended in the liquid before filling the capsule.  If this is not done well, bubbles may form as a result of repeated trips to higher elevations and back down again.  Sometimes these bubbles form up high and get reabsorbed into the liquid after descending.  Unfortunately, sometimes they never go away.  This problem is characteristic of cheaper brands, but given enough time, even quality brands can have this issue.

I ultimately replaced my Silva wrist compass with a Suunto M-9, another well-regarded liquid-filled wrist compass.  It’s accurate but I’ve found it very sensitive to level.  Just slight variations prevent the dial from moving, which can mislead you into believing you’re on course.  Careful observation must be used to ensure you’re seeing a true bearing and that the dial is free-floating

My primary compass is a Silva Ranger Type 15 Sighting/Baseplate liquid-filled compass, which is almost 20 years old now.  The sighting mirror and adjustable bezel permit precise bearings to be taken and coordinates plotted with the Romer scales imprinted on the baseplate.   It has been a fantastic compass and to date has never had an issue with bubbles.

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Tru Nord Model 100C shown in my own personal survival kit

I purchased the Model 100C specifically as a more robust and reliable alternative to the many 20mm liquid-filled button compasses that I have used in my survival kits.   I’ve not had very good luck with them.  I’ve tossed several after bubbles have formed.   It seems that for a while every time I inspected the contents of my survival kit, I found a compass with a bubble.  I spent quite some time looking for alternatives.  I purchased essentially the same type of button compass from several sources on the internet with varying levels of quality.  I have three now that seem to be quite good, but I kept waiting for the dreaded bubble to form.  Finally, I decided that I needed a quality dry compass, but where do I find such a thing.    There just aren’t that many sources available, but I found two.

The only two in consideration were the Francis Barker FB1605 NATO Survival Compass by Pyser-SGI Limited and the Tru Nord Model 100C Backpacker Compass.   Both have excellent reputations, are brass cased, dry compasses utilizing jeweled bearings.   Both can also be found for $45 at retail.    The FB1605 is a tactical compass.  It has a black outer case, glass lens, black compass dial with three luminous dots.   At 15mm in diameter it is quite small and easily concealable.   Since my tactical days are long over, this wasn’t much of a concern.  The Tru Nord has what appears to be a thicker case, knurling on the outer edges for grip, an unbreakable Lexan® lens and a 20mm glow-in-the-dark luminous dial marked with degrees.  The major increments are every 30 degrees and the minor increments at every 10 degrees.   Although larger and heavier, the Model 100C is more usable for serious navigation, not just SERE (Survival Evasion Resistance and Escape) activities the SAS surely intended for the FB1605.  I need a compass with dial I can see and take bearings from that I won’t lose if dropped.  I’m confident the FB1605 would be hell to find if dropped in the brush, especially in the dark.

For those of you not familiar with Tru Nord, the company was founded by Vern Budlong more than 69 years ago. Their products are made in Brainerd, Minnesota, right here in the good old U.S. of A.   These precision compasses are short on bells and whistles but long on quality and accuracy.

The Model 100C case is CNC machined from Alloy 360 Half Hard Brass and contains a seal making it water and dust resistant. The Model 100C is a dry compass, meaning it contains no dampening liquid.  As discussed earlier, the advantage of this is that no air bubbles can form diminishing its accuracy. However, it does take time to settle on north.  The dial is very sensitive to movement, so a steady hand is required.

The Tru Nord Model 100C comes in a synthetic velvet pouch with an instruction sheet. What you do get is a well-built brass compass with a jeweled bearing, a Lexan® lens and weather resistant seal.  The knurled edges allow for a secure grip even when wet.   The compass dial swings quickly and takes several seconds to settle.   There is no doubt of your direction once the dial stops.   Some liquid-filled compasses damp so quickly, you’re not 100% sure it’s homed in.  There is no concern of that here.  The compass also includes a lifetime warranty.

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Tru Nord Model 100C various views

The case is 27mm x 12mm and weighs 18 grams. The lens is 20mm, which is more than enough to view the sizable dial containing a cobalt magnet that can be custom calibrated for whatever magnetic declination you choose.   I travel quite a bit and I prefer my compass to be calibrated to magnetic north only.  It’s a lot easier for me to add or subtract the full declination of my current location without having to worry about how it was originally calibrated, adding that number back in and then calculating for the new declination. The dial is large enough for me to read without reading glasses, which may be an important consideration if you’re forty-plus like me.   It feels solid and you won’t worry about it if dropped.  The lens gives only enough clearance for the dial to rotate freely but not so much that the dial itself could be stuck or damaged if handled roughly.  It’s appears built to withstand the bumps and bruises that accompany wilderness travel. That said, all precision compasses should be handled as if your life may depend on them, because it just might.

Time will tell how the Model 100C will hold up, but so far I’m extremely pleased with it.  The fit, finish, function and attention to detail shown in the instrument seem to pay tribute to the 69 year history of Tru Nord. I think I’m going to be very pleased with it. In fact, I’m betting my life on it.

 

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About Author

Chris Morrison

Chris is an avid amateur astronomer, birder, photographer and general nature and science nut. He was a Vice President at a major telescope manufacturer, where he was directly involved in product development and testing for much of his 15 year tenure. His passion for all things science and nature is what led him to found localmeridian.com, an online outlet for his desire to share his love of the natural world.

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