Compass questions...

Classified00

Classified00

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Jul 14, 2000
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210
Hello all,

I posted this on another forum and thought I post here too to get more feedback.

I'm looking for compass to use to brush up my land nav skills and keep in a survival kit. I'm after a lensatic / map compatable compass that's durable, accurate and easy to use.

Silva, Suunto, and Brunton seem to be the three most popular makers. How do they stack up against each other or is there no noticable difference?

I'm looking seriously at these three:

http://www.campmor.com/webapp/commerce/command/ProductDisplay?prmenbr=226&prrfnbr=1980353

http://www.campmor.com/webapp/commerce/command/ProductDisplay?prmenbr=226&prrfnbr=13869

http://www.campmor.com/webapp/commerce/command/ProductDisplay?prmenbr=226&prrfnbr=13870

Any thoughts?

Thanks,
Brent...
 
None of the above. Look at Stockard and Yale, you can find them at Cabelas. They have no fluid to freeze in the cold, and it's what the military uses. When you close them, they lock up the internals, preventing damage. They are also very easy to sight an azimuth off of. Of course, I was in the Army for 6 yrs, so I am very biased.

I find the ones that you mentioned very hard to use. I bought a Silva, but find the S & Y much better and more accurate. The only good thing that I can say about the Silva is that it has a mirror for emergency signalling.

Your mileage may vary, but them's my thoughts.
 
All of those appear to be mirrored orienteering compasses, not lensatics. But that's okay. I prefer the orienteering compasses anyways. The Silva Ranger is pretty much the king of the hill as far as mid range compasses go, IMHO. It’s the tried and true mirror compass that’s been around for a long, long time. The only compass I’ve use that comes close in the same price range is the Brunton Eclipse 8099. It’s a real Cadillac.

I will admit that I absolutely love green tinted base plates though. They make it much easier to read maps.

Of the three you mentioned, I believe the Ranger is the only one that has a real declination adjustment. That’s worth a million extra dollars as far as I’m concerned.

Oh yah. Take a look at your most often used maps, and notice what the scale is. Then try to find a compass with that same scale on the base plate. Having the same scale makes life a lot easier.

I hope all of this rambling helps. :rolleyes:
 
If you want a mirrored compass, I recommend the Brunton, not for the price, but for the sighting hole. I can get at 2 deg reading when I look over the bezel and through the hole, viewing the bezel in the mirror. I have never had good luck trying to sight over the mirror or worse, trying to hold it at waist level, sighting through the mirror. Bugs attacking me, sweat dripping from my brow - forget it. I need something fast and easy to allign.

I have used many compasses hiking, for engineering, and geologic field work. For general cross-country navigation and rough map making, I use the real military compass that swede79 describes; fast, accurate to 1 deg, tough as nails. They are also much less affected by transient magnetic fields like from your rifle - go figure. This is my favorite compass. I only leave it home when weight is critical.

When I am taking really careful measurements, I use a Suunto optical compass, just as fast and accurate to 1/6 deg. I think Brunton or Suunto makes a yellow one light enough to float with similar accuracy, ~$40.

The lightweight compass alluded to above is a $12 silva with a mirror that allegedly floats and is accurate to 5 deg, adequate for trails. I chose one with a mirror so I don't have to carry my (heavier) real signal mirror.

And then there is the cold problem with liquid filled models. You have to keep them warm on really cold nights. If they don't freeze and break, they will get a bubble which can push the needle off north.

All that said, you should just buy the one you like. If you use any good compass for serious navigating, it quicky becomes a trusted friend. If there is one that you are particularly fond of, just buy that one. Becomming a skillful navigator is far more important.

Scott
 
Obvoiusly I'm new to compasses and thank you for all of the advice. I'm going to keep weighing my options.

Brent...
:p
 
What about the U.S. Army issue compass by Cammenga?

I've been considering a compass as well and I'm considering this model.

Has anyone ever had any experience with this compass?
 
"What about the U.S. Army issue compass by Cammenga?"

I can't imagine it would be any different performance-wise. It is mil-spec; that's the important part. The construction should be identical.

I only wish someone would make one of these out of polycarbonate or similar. I love the design, but it is a little heavy in aluminum.

Scott
 
Brothers & Sisters of Navigation,

Would anyone have a web site for Stockard & Yale?

Regards,
Lance Gothic
Shibumi
 
I highly recommend the KONUSTAR 4074/4075 compass used for mountaineering and geological/surveying work. It is quite heavy but comprehensive. It has an clinometer, sighting eyepiece, tripod ready, spirit level, oil-filled, map measurement scale, etc. It is one of the most comprehensive lensatic compasses I have yet seen I own several and this one is part of my survival/emergency kit. Konus is an Italian company that produces various instruments including telescopes etc. The Konustar is manufactured in Taiwan under the auspices of Konus Spa.

You can find it here: http://www.konus1.com/pagbuss.htm


Good luck.
 
I have to agree with Buzzbait....the addition of a declination adjustment is a must have.

So, buy yourself a Silva Ranger 515CL Compass. I have the identical model. Since some folks have mentioned freezing of the liquid - I have to comment that my compass has been exposed to -40C temperatures without any problems....go figure?

I like this compass because it is light, has a rotating bezel, has a declination adjustment and is easy to use....did I mention it is light?

Several folks have commented that the mirror is a "signal" mirror. Might explain why they didn't like the compass - the mirror is designed to be used for sighting a bearing.....it's secondary use is helping me put my contacts in. :D

Enjoy your new compass

D
 
I think different manufacturers use different fluids in their compasses. I have seen a lot of Bruntons with bubbles (had to retire my old search-and-rescue compass for this), but only a few Silvas. Theoretically, the "antifreeze" molecules break down with exposure to heat and light, resulting in elevated freezing temperatures. I have known people who have had compasses of unknown brand freeze, but to be honest, I have no first-hand experience with it.

I didn't mean to imply that the mirrors are actually signal mirrors. They will work in a pinch, but are much more difficult to aim than real signal mirrors.

In general, my experience is that Silva mirrored compasses have a slightly better fit and finish than Bruntons. For example, Brunton's "push & twist" declination adjustment is a little sloppy feeling. Still, it is no less accurate than Silva's gear mechanism.

In any case, I think it is worth stating that I have never seen a lensatic compass that is worth its salt and not mil-spec. A military lensatic compass is an entirely different animal than the little round kind that you find for $15. I don't think you'd be sorry for going with phosphorous ($50) instead of tritium illumination ($90), but there is a very impressive difference between the real thing and a cheap immitation.

Here are some weights and performances for those interested. The times are from picking up the closed compass to reading an azimuth aloud. I didn't hurry and am used to using all compasses shown. My old Brunton Sportsman was not included. It was about 4 oz, good to 2 deg, and took around 15 sec to read well.

Stocker & Yale military lensatic:
5.1 oz, 1 deg, 7 sec

Suunto KB-14 optical:
4.2 oz, 1/4-1/8 deg, 7 sec

Silva Landmark:
0.8 oz, 5 deg, 15 sec

Brunton 1.75 in dia "zipper pull":
0.5 oz, 10 deg, 5 sec

Eddie Bauer "$15" lensatic:
~5 oz, 1 deg*, 7 sec

Brunton M-2 Pocket Transit:
8.4 oz in case, 0.25 deg, 3-5 min**

* You can read the compass to 1 deg, but I am skeptical of its reliability.

** Includes initial setup - requires staff or tripod. This is why I got my Suunto :-)

When you are triangulating a position on a map in a field office, the full accuracy of your compass an be used. Roughly, this is the sine of the accuracy "a" of your compass times the distance "d" or

error ~ d*Sin[a].

So, if you sight at 3 miles (~16,000 ft), you can locate to within a box with the following side lengths:

0.25 deg -> 70 ft
0.5 deg -> 140 ft
1 deg -> 280 ft
2 deg -> 550 ft (most common)
5 deg -> 1400 ft

Adding real-world conditions like drawing on a folded map on your knee with cold fingers significantly magnifies these errors.

Scott
 
Lance,

I couldn't find a website for S & Y. I think it's worth noting that mil-spec lensatics such as S & Y have declination adjustments also, and they are very well designed for sighting. I have never been able to sight accurately with a mirror, others might have different experiences.

That KONUSTAR sounds like a winner also!
 
I don't know much about the mineralogy of magnetism, but it stands to reason that if a compass was stored near a magnet or electrical source, its needle's magnetization could have been altered or destroyed.

Here are some things to look for which can be easily diagnosed at the gun show table, etc.

1) Jewel repeatability. Open the compass and take a reading on some fixed object. Close the compass or turn it upside down and repeat several times. This lifts the needle off the jewel between readings. If the compass has a damaged jewel or was poorly designed, it will sit differently and give different readings each time. Ambient fields (like being in a steel building) will cause a wrong azimuth reading, but you should still get the same wrong reading every time if you stand in the same place.

2) Jewel friction. The needle (or disk) should rotate freely. Take several readings as above, but keep the compass level. Start with the compass pointing to the left, then slowly turn to your target and read the azimuth. Repeat several times, alternatly turning to the target from the right and left.

Other than this, stay away from anything that has been (internally) opened, repaired or is loose as in slop. Loose as in easy is ok.

If you are thinking of a military lensatic, it may look beat to heck, but still perfectly worthy. When their lids are closed, the needle/disk are off the jewel, which prevents damage.

The only thing I can think of that can't be tested on site is a bubble that has been "forced" out. When my Brunton got a bubble, I accidentally removed it with moderate heat (left it next to my heater vent). The bubble was only gone for a few months, and came back each time after I repeated the "treatment." It worked fine as long as the bubble was gone, but you never knew when or how fast it would return. If someone who knows the trick does this to sell you a compass, you could get took.

You can compensate for a compass that points off north, but not for one that is inconsistent.

Scott
 
According to the Cammenga site, http://www.cammenga.com/ they have been the "real deal" since 1992. I got my Stockard & Yale in ~91, which was allegedly official issue then.

I searched for S & Y , but I don't think they make them any more. The Cabela's compass is probably a Cammenga - I think the designs are identical, just like all M-16s are the same but aren't all made by Colt.

Scott
 
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