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#81585 - 12/31/06 08:05 PM Re: I need a compass
TimLarson Offline
Stranger

Registered: 10/19/03
Posts: 16
If you are in North America, all "Silva" brand compasses are marketed by Johnson Worldwide, who owns both the Silva and 'Ranger' brand names in North America. JW appears to source their better compasses, such as the Ranger models, from Suunto in Finland (check for 'made in Finland' on the box). Elsewhere in the world, 'Silva' still means Silva of Sweden, the original manufacturer of the Ranger.

Original Silva of Sweden compasses, including the Ranger 15 and 25 are sold in North America as Brunton Nexus 15, elsewhere in the world as the Silva Ranger 15 or 25. The top of the line Swedish Silva Ranger is the 25TDCLE with built-in illumination, which Brunton doesn't seem to carry anymore.

I like most of the Silva Ranger-style compasses, including the Suunto MC-2G, one of the best. Along with the other Ranger-type features such as adjustable declination, the MC-2G is of very high quality, has a FAST-settling needle, a FULLY luminous and clearly-marked dial with raised degree markings, and two sighting ports (high notch and eye-level)for different-height landmarks.

I really don't like the Brunton Eclipse compasses at all. Both the 8099 and 8096 I own get frequent bubbles with rapid temperature changes. The 8099 is just plain too bulky and clumsy, requiring removal of the rubber boot and cards to use with a map or to take a bearing at chest-level. The mirror is small, and the twin plastic cover pieces have quite a bit of slop or play on my example. The numbering system inexplicably uses hard-to-see green ink for the forward bearings, yet black ink for reverse bearings. The Eclipse declination system uses only friction to hold its position and frequently slips (unlike the geared screw systems used on most Silva and Suunto adjustable compasses). The circle-on circle magnetic indicator on the Eclipse models is actually slower to settle and more inclined to bob than most ordinary needles and is NOT luminous (nor is the dial or the direction-of-travel indicator). This compass is completely unusable in low light without constant flashlight illumination. Finally, the dial markings are printed on cardboard instead of engraved on the dial, the baseplate roamer & scale markings come off easily as they are just printed on and not engraved, and the meridian adjustment lines are limited to two tiny red lines on the outside of the dial (which is not transparent) instead of the bottom of the clear capsule, making it hard to align them with a map meridian when taking a bearing from the map.

The Brunton (in North America) or Silva of Sweden (elsewhere) 54LU prismatic compass is basically a Silva Type 4 NATO baseplate compass with a compass card instead of a needle, and a built-in prismatic sight. It is considered a military model compass and is used by Australian military forces, among others. It can be used at waist-level or with a map like an ordinary baseplate compass, but the 54's prismatic sight also allows 0.5 degree accuracy with eye-level sighting in ideal conditions (one must be careful not to tilt the compass as the compass capsule is quite shallow and it is easy to 'ground' the compass card, and the prism is also not that visible in poor light). Because of the special prismatic sight design, the 54 is not available with adjustable declination. Its luminous sights work well. Outside North America, the Model 54 is also available in a tritium-illuminated version.

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#81586 - 12/31/06 11:51 PM Re: I need a compass
KenK Offline
"Be Prepared"
Pooh-Bah

Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
(Sorry about the long post - I just kept writting and lost track of time/space. I'm sitting here enjoying watching old Outter Limits episodes on the SciFi channel!)

Yeah, I've heard similar comments in other reviews. That is part of the reason I tend to compare my 8099 to my 15TDCL almost in hopes convincing myself that I like the 15TDCL better.

I did get a bubble in my first 8099, but they fixed it for free and since then neither of my two 8099's have gotten bubbles.

People say the 8099 is bulky. The whole 8099 package at 3.80 oz. is about 1 oz. heaver than the 15TDCL at 2.85 oz. The 8099's boot weights about 1.10 oz and the reference cards weight about 0.40 oz (both weighed with lanyard on, so these are approximate). Ironically the 8099 compass itself weights only 2.35 oz. which is actually less than the 15TDCL.

Ironically the older 8099 weighs in at 3.90 oz, but the newer one weighs in at 3.80 oz. They cut a bit of weight somewhere.

The 8099 is a bit larger.
The 8099's dimensions with the boot are 2.50"x4.00"x3.85". The 15TDCL's dimensions are 2.375"x3.875"x0.50".
So, the 8099 is 5% wider, 3% longer, and 25% thicker than the 15TDCL.

The boot & cards do need to be slid up the lanyard in order to use the compass on top of a map (though not to orient the map), but it can easily be used to take bearings at belt (or chest) level with the boot on. Since I tend to mostly use the compass for orienting the map and taking bearings the boot isn't an issue for me.

The mirror on the 8099 (1.25"x2") is indeed smaller than that of the 15TDCL (2.38"x2.56") - which might account for the heavier weight of the 15TDCL compass itself. Still, I find sighting bearings with the mirror on the 8099 much easier than with the 15TDCL - possibly because or the circle-in-circle method. The larger mirror on the 15TDCL would certainly be better for signalling, but I carry a separate signal mirror in my kit.

There is bit of wiggle in the cover joints on my older 8099, though I hadn't noticed it before. They must have changed tolerances, because on the newer 8099 the main cover is rock solid. The smaller mirror cover still has a bit of wiggle at 90 & 45 degrees, but is rock solid when fully open at 180 degrees and when nearly closed. Like I said, I've never noticed the wiggle before and it has never bothered me.

As mentioned, the 8099 dial shows two numbers - green numbers for forward bearings and black numbers for backbearings. On my first 8099 the green numbers are toward the center and have lower contrast, but on the newer one the green numbers are on the ouside of the dial and are much higher contrast due to a bolder font. I like the numbers on the newer one much better - very easy to read, at least for me. I also like that the 8099 displays one tick for each degree - the 15TDCL only displays one tick for every other degree - this is probably made possible by the 8099's magnified reading area which works well.

I like that the 8099's declination can be adjusted without a screwdriver. That is how all the Brunton-designed compasses work, and I haven't had any probllems with any of them that I've used (8099, 8096, 8010G, 9020G). On the 15TDCL (and the Suunto M3) I worry that I might strip the adjustment screw, but have assumed (hoped) that the supplied aluminum tool is not as hard as the screw head.

The settling time on each seems pretty similar. Because of the nature of the 8099's disk there isn't any "wiggling" that I see on the 15TDCL, but the wiggling never bothered me. I've always figured that settling time is a balance between convenience and accuracy, and a compass that settles too fast might not settle off the true bearing a bit.

I can't tell what the dial markings are printed on - could be cardboard. I can't tell since it is embedded under plastic so nothing can touch them or wear them out and I don't care to rip mine apart to find out. The markings are printed on white, but on the newer 8099 it is actually brighter white than on the older one. I suppose this is part of the better contrast mentioned earlier. The white numbers on the 15TDCL's dial is printed on the outside and under magnification doesn't appear to be engraved. It definitely is touched by the operator. I see some of the edges of numbers chipped and missing, but there isn't enough wear to make it unusable.

By the way, the reference cards are printed on durable plastic. They include:

1. A quick clinometer scale that is displayed under the compass capsule when the boot is on.
2. First aid instructions for choking, fractures, heatstroke, hypothermia, abdominal wounds, frostbite, snake bite, clearing airway & mouth-to-mouth breathing, cardiac message (supposed to be massage?), shock, bleeding, and burns.
3. Instructions for sighting a field bearing, traveling a bearing, and orienting a map to true north, getting a map bearing, and triangulation.
4. Survival hints: if lost, signals, water, water purification, food, shelter, common knots,
5. Instructions for clinometer measurement: 1 degree resolution using dial
6. Tangent conversion table for calculating heights, common metric conversions
7. Instructions for UTM grid determination
8. Instructions for height measurement
9. UTM corner tools for 1:24k, 1:25k, 1:62.5k, 1:50k, 1:250k, and scales for 1:63.36k, 1:62.5k, 1:100k, 1:50k, 1:250k, and 1:25k

The survival hints say to move as little as possible to maintain strength, make shelter & signals, inventory supplies & ration food/water, travel only if you know where you're going, and don't panic. Keep at least one fire going, use three of anything to signal. Water is important - conserve and try to find more, but don't ration in hot weather. Drink what you need and conserve fluids by seeking shade, and moving only as needed. Water purification methods listed are boiling water for 20 mins, bleach, and iodone. Keep shelter as small as possible so body heat keeps it warm. Choose a location to protect from wind, rain, snow. Knots shown are the taughtline hitch and the square knot.

There markings on the bottom of the 8099 are only printed on - with no engraving. Those on the 15TDCL are engraved and printed. I've read others have a problem with the markings on the 8099 coming off. Since I mostly use the compass with the boot on that hasn't been an issue at all for me. I've wondered if the ink removal on the 8099's are related to DEET. I've rubbed and rubbed on mine - even scraped it for a while using my fingernail and don't see any wear. Hmmm.

I haven't used the meridian lines on a compass since I was a kid using a compass that didn't have adjustable declination. To make up for that we'd draw magnetic N/S lines on the map and use those lines to set the bearing (without having to orient the map to north). These days I just orient the map and "box the needle" since UTM grid lines aren't truely N/S and I prefer not to draw true N/S lines.

I do wish the 8099 had a UTM corner tool right on the baseplate instead of on the reference card, but I tend to use a UTM grid from maptools.com instead anyway.

One other thing to note is that the 15TDCL has glow-in-the-dark points while the 8099 doesn't. That hasn't been a problem for me since I don't navigate with a compass in the dark.

Like I said, I just find the 8099 to perform better for my uses (orienting the map and sighting bearings). While I have too many compasses, I prefer to use the 8099.

I find the Silva 54LU very intriquing, but lack of adjustable declination makes it unacceptable for my needs.

Ken

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#81587 - 01/01/07 12:58 AM Re: I need a compass
TimLarson Offline
Stranger

Registered: 10/19/03
Posts: 16
"I did get a bubble in my first 8099, but they fixed it for free and since then neither of my two 8099's have gotten bubbles."

The bubble issue with Eclipse compasses has been mentioned many times by many people who bought Eclipse model compasses. Sometimes the bubbles disappear when the compass is warmed, sometimes not. I can't quantify the exact number of complaints or what Brunton may or may not have done to address the problem (they don't mention it), but I do know that since its introduction, I have seen many more complaints with the Eclipse capsule than with other liquid-filled compasses of similar price and class (including other Brunton models).

"So, the 8099 is 5% wider, 3% longer, and 25% thicker than the 15TDCL."

Measurements aside, the 8099 is just plain bulky for what it does - even the lanyard is oversized. I can fit most Ranger compasses into a shirt pocket, but not the 8099.

"I also like that the 8099 displays one tick for each degree - the 15TDCL only displays one tick for every other degree - this is probably made possible by the 8099's magnified reading area which works well."

Well, the eye splits 2-degree increments easily, so actually the 8099 isn't any more theoretically accurate than the Ranger designs - both are readable to one degree. Someone who demands higher accuracy would probably switch to a Brunton Transit or a Suunto KB sighting compass, but you certainly won't get more accuracy out of an 8099 than say a MC-2G or a Silva 25 Ranger, especially in dim light.

"I've always figured that settling time is a balance between convenience and accuracy, and a compass that settles too fast might not settle off the true bearing a bit."

Actually, that's not true. Fast-settling handheld compasses with 0.25 degree accuracy are available now, but they are expensive, do not possess a separate baseplate, and usually need to be rested or tripod-mounted to achieve their inherent accuracy. Another method is to use two magnetized needle ends, which gives a very fast and accurate needle. Orienteering compasses such as the Silva Jet or Suunto Arrow have them, though such compasses do not normally feature sighting mechanisms due to the specialized nature of that sport. The global needle used by Suunto is a twin-pivot design that settles very fast. Suunto and Recta (owned by Suunto now) have since combined that design with a prismatic sight that is also very accurate. In contrast, I think the Brunton card-type needle ('circle-on-circle') design offers nothing in the way of an improvement. At the very least, it needs a heavier dampening fluid.

"The white numbers on the 15TDCL's dial is printed on the outside and under magnification doesn't appear to be engraved. It definitely is touched by the operator. I see some of the edges of numbers chipped and missing, but there isn't enough wear to make it unusable."

The 15TDCL is one of the lower price-point Ranger compass models. At some point, something has to give. Try the 25TDCL or 25TDCLE, or Suunto's MC-2G, all of which have either raised or engraved dial markings, as well as engraved scales and markings on the baseplate. They also feature a raised transparent gripping section, so the fingers never touch the printed portion of the dial.

"I've wondered if the ink removal on the 8099's are related to DEET. I've rubbed and rubbed on mine - even scraped it for a while using my fingernail and don't see any wear."

No, it's because the numbers are only printed on. If you have an 8099 and always keep the rubber boot on, (and never use the compass as protractor or measuring tool on the map), yours might last longer. It's almost standard practice for 8097 and 8096 compass users these days to place clear packing tape on the baseplate bottom to preserve what's left of the roamer scales and markings.

"I like that the 8099's declination can be adjusted without a screwdriver. That is how all the Brunton-designed compasses work..On the 15TDCL (and the Suunto M3) I worry that I might strip the adjustment screw, but have assumed (hoped) that the supplied aluminum tool is not as hard as the screw head"

It's a matter of personal preference. I have never had any stripped adjustment screws on Silva or Suunto compasses (of course, one rarely needs to make that adjustment more than once prior to a trip), but I HAVE had too many Bruntons slip their declination setting. The Brunton adjustment system necessarily changes the relation of the dial to the capsule bottom, forcing the designers to place the orienting lines on the outside of the non-transparent dial (if they put the lines on the bottom of the capsule, one would have to remember to readjust declination to zero and back again each time you took a map bearing). To me, the Brunton declination system takes a definite second, as the whole point of a baseplate compass with adjustable declination is to rapidly coordinate with map, including ease of use as a protractor to measure one's true bearing along a planned course.

"To make up for that we'd draw magnetic N/S lines on the map and use those lines to set the bearing (without having to orient the map to north).

I have never been a fan of drawing magnetic lines all over a map myself. As you imply, few people do it anymore. You sometimes see adventure racers still employing the practice, always done in advance, usually with drafting boards and one-arm protractors to accurately reproduce angles on special large-scale racing maps. Otherwise, it is rarely accomplished with complete accuracy (using the declination diagram as a angle indicator is a common mistake) and the pencil lines often obscure important detail. Also, having bought a compass with adjustable declination, it seems pointless, now that the compass can be easily adjusted to give true bearings and make compass and map 'talk the same language'.

"These days I just orient the map and "box the needle" since UTM grid lines aren't truely N/S and I prefer not to draw true N/S lines."

You never take a map bearing along a planned course on the map, point to point? I find it indispensable, especially when the initial landmarks on my course aren't readily distinguishable from each other. To use a compass as a protractor with a USGS topo map, you can orient the compass' meridian lines with the map margin or the intermediate lines/crosses of longitude, which on US maps corresponds to true north. That's one of the major benefits of a baseplate compass.

"One other thing to note is that the 15TDCL has glow-in-the-dark points while the 8099 doesn't. That hasn't been a problem for me since I don't navigate with a compass in the dark."

Most people don't navigate with a compass in the dark, but occasionally an emergency or other circumstances (hunting, etc.) require its use in the dark or - in low light. The 8099's small mirror and complete lack of luminosity or built-in illumination genuinely handicap it in that respect.

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#81588 - 01/01/07 01:20 AM Re: I need a compass
KenK Offline
"Be Prepared"
Pooh-Bah

Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
That's good to hear that the declination screw is robust. I've wondered aobut that.

"You never measure your map bearing along a planned course on the map, point to point? "

I usually set up routes on my PC first and then download the routes to my GPS. I then take bearings from the GPS. Even if plans change I'll usually try to add the new waypoint to the GPS and then get the bearing.

If someone is using the meridian lines a lot then the Brunton-designed compasses simply aren't the best choice.

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#81589 - 01/01/07 02:40 AM Re: I need a compass
haertig Offline
Pooh-Bah

Registered: 03/13/05
Posts: 2322
Loc: Colorado
A few more thoughts on the 8099...

I find some of the clinometers unuseable with my nearsightedness and bifocals (the 8099 has multiple different clinometers). The hinge clinometer is fine. The 1 degree accuracy one that uses the "clinometer marking" on the backside of the baseplate is OK, about 90% perfect. The other ones that require you to read the hanging green arrow pointing at the green scale are impossible for me. This is an bifocal thing. Younger eyes or people that aren't so nearsighted possibly wouldn't have these problems. But how often do you use the clinometer, and how many different versions of the thing do you need on one compass?

The size of the mirror on the 8099 vs the size on the 15tdcl ... who cares? As long as the mirror is large enough to accurately align things. And it is on the 8099. No problem seeing the entire compass dial in the mirror. Bigger might be better for preening yourself, but it's not needed for compass functions. I also think the skinnier mirror on the 8099 might be easier to adjust the angle using a one-hand hold and your thumb. The full width mirror of the 15tdcl seems like it might be more awkward to hold and adjust one-handed (this is just speculation on my part). Using a compass mirror for signalling would be marginal at best. I always carry a seperate real signallying mirror anyway.

I'm not sure why the 8099 has two flip up covers. That does seem overly complex on first look. One guess is that this makes it easy to hold the compass and use your thumb to line up the marks to take a bearing. Only one hand is needed. The second cover isolates the turnable dial from the baseplate. Is this easy one-handed operation the same for the 15tdcl? I don't have a 15tdcl to test and comment on this.

As far a declination adjustment (screw vs friction), I'd just as soon have no adjustments at all. I really don't have a problem doing a little simple math in my head. I'd probably be more worried wondering if I'd remembered to pre-adjust declination or not.

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#81590 - 01/01/07 04:44 AM Re: I need a compass
KenK Offline
"Be Prepared"
Pooh-Bah

Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
I"ve read several comments that the magnified area of the dial is a big hit with us older bifocaled crowd. I finally was forced to get them in August. I really struggle to read the small red print on the body of the 15TDCL and the UTM scales on the 8099's UTM card.

The 15TDCL would work just fine one-handed but on mine the dial isn't nearly as smooth-turning as the 8099, so it is kind of hard to rotate one-handed with a thumb. It can be done though. There is no way I can flip the 15TDCL open one-handed without using toes too. The 8099 can be flipped open one-handed, but it is awkward.

I'll assume you have a newer verson of the 8099 - with the green forward bearing numbers on the outside of the dial. Consider yourself lucky. For some reason I only use the old one thinking that I'm saving the new one for my son or something. The reality is that having the green numbers on the inside of the dial does make them hard to read.

In the older one they also had the black backbearing numbers backward under the philosophy that you'd use them when using the compass & mirror backwards - what they call "reverse mirror sighting" (kind of like the old press cameras where you look down on the mirror) - when backwards the black numbers would be the facing up - it kind of made sense. I think the reality is that users didn't use the compass that way and more often used the black numbers as back bearings while holding the compass at eye-level. So now the newer version has both green & black numbers facing the same way.

I should start using the new one and let my son (with better eyesight) use the older one.

I finally got around to doing more repeated measures (in the house - its been raining all day today) and I continue to get +/- 1 degree (a 2 degree range) for both the 8099 and the 15TDCL, but do find boxing the 15DTCL needle harder. Hmmm, I just realized that the problem might be related to the colors involved. On my 15DTCL both the north end of the needle and the north end of the box are red and I find it hard to see the red line of the box next to the red part of the needle. The south ends use a white needle and a black box so that is easier to see.

Ken

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#81591 - 01/01/07 05:09 AM Re: I need a compass
aardvark Offline
Member

Registered: 03/11/06
Posts: 109
Loc: So. California
I've owned and used both silvas and suuntos, the old silva type 3, 7 and 17 and the suunto m3-g with global needle. These were used for coarse surveying for radio work and casual hiking. Two silvas eventually developed bubbles, one from a crack in the capsule, the suunto (so far) has been bubble free. The main advantage of the global needle is that it will work in the southern hemisphere, though a regular one will eventually point north-ish if you tap it.

One possible advantage of the global needle apart from using it in the south is that the capsule is deeper and the needle itself is further down in the liquid. If a bubble does develop, it may have less effect on this design than on a regular capsule where the needle is closer to the top.

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#81592 - 01/01/07 02:54 PM Re: I need a compass
Old_Scout Offline
journeyman

Registered: 11/03/06
Posts: 95
Loc: Delaware
I've used Silvas, Suuntos and Bruntons for 45 years for rough surveys, wilderness routefinding and backpacking. Like a lot of technological gizmos compasses increase in cost as precision and durability increase. There are trade-offs. For me compasses are like firemaking - carry redundancy. So here's my take - for map orientation and cruising from a map the Ranger type is best. My old Silva has served well for 40 years - don't know what's up with those today. When marching the handbearing compasses are best - I now carry a fairly new Suunto combo compass and clinometer - accuracy is high order (est. to 0.25 deg.) - but you'll blow your $100 on the compass alone. It is not best for baseplate/map work. Finally, the top of the heap is the Brunton Pocket Transit. I have one nearly 45 years old and it's a gem. Heavy as lead, faultless accuracy (you could, if careful, survey with it), tough as nails. The real thing will set you back more than $200. Knock-offs for under $100 - but I wouldn't trust them. I usually carry two of these plus a Marbles Arms pin on. I don't usually <img src="/images/graemlins/crazy.gif" alt="" /> get lost!
_________________________
See 'Ya Down the Trail,
Mike McGrath

"Be Prepared" "For what?" "Why, any old thing!" B-P

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#81593 - 01/02/07 03:57 PM Re: I need a compass
MarshAviator Offline
Marsh Aviator
Journeyman

Registered: 11/18/05
Posts: 70
Loc: Baton Rouge, LA, USA
You can't go wrong with either the 8099 or the 15TDCL.
I have both along with a couple of Suunto Globals (Matchbox and mirror).
These are both great for experienced user and novice.

All this being said, for most land navigation as well as ruggedness I prefer the SIRS G-150 or P-G M-73. Both are tritium prismatic s.
If you want the cheaper version the standard MIL-SPEC lensatic is a good compromise for 1/4 the cost.
Durability of any of these is excellent.
A lightweight version of the P-G is the M-88 which is about 1/2 as heavy as the M-73.
While many observers will question the need for night navigation capability, there are some conditions that warrant self illumination, not all military either, all the same I would rather have it and not need it than the converse. Cave exploring being just one example; even with a headlight (most cavers would carry at least three light sources), but try doing this;hold a flashlight in one hand, compass in the other (you need two hands for the compass if it's indirect reading).

These compare with my professional hand compasses for accuracy; Brunton GEO pocket transit and swiss merridian engineering/geological compass. These will set you back about $400-$500 plus accessories. Professional compasses like these or the Suunto Tandem, are good for engineering work, but lack features for land navigation. Also the GEO with it's rare earth magnet will have to be separated from any other compass by three or more feet. The magnet is so strong it will defect any other compass by a couple of degrees.

The biggest thing in favor of the baseplate/mirror compasses is magnetic variation adjustment (declination for the non-aviator).
While this is a nice feature, all mariners and aviators get by with protractors that do the same.
In the Army most of us learned the LARS technique.
Both work, along with whiz wheels and the like.
It just isn't that hard.

Plastic protractor baseplate compasses have to be protected in rough use, if you fall on one it's toast.
Another reason for having a backup (or two).
Personally I would rather have two medium compasses in the bush than only one "High" end compass, but three is even better.
They weigh nothing.

I can't say which is my favorite, the 8099 has a lot of goodies with it. The 15TDCL is a trusted standard, everybody seems to have one. the Model 54 is nice, has both prismatic and baseplate features, but no clinometer. Then again you can buy a clinometer from Suunto or Brunton as well.
The Global needle is only needed for the zones South of the equator with a couple of exceptions. But I find the Global needle does make vertical alignment easier, This helps if you are not on even (level) ground. It also seems to make for a steadier needle.
Both forms of the Global (Matchbox,MG-1) have clinometers.

All the same, you most likely will end up with a couple or three.
You really can't have too many.


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#81594 - 01/02/07 06:23 PM Re: I need a compass
TimLarson Offline
Stranger

Registered: 10/19/03
Posts: 16
"All this being said, for most land navigation as well as ruggedness I prefer the SIRS G-150 or P-G M-73. Both are tritium prismatics."

They are very fine compasses. Personally, I'm of the opinion that there is no perfect compass with 100% durability or suitability to conditions. All have certain applications and certain disadvantages; it's a question of choosing the right type with the durability you need and the amount of hassle you're willing to endure. My W.F. Stanley/Francis Barker/M-73/Mk III/SIRS "oil bottles" are not map-friendly, and ALL have all developed bubbles with sharp temperature drops, despite the built-in diaphragm. They all use iso alcohol as a dampening agent, which in my experience is more subject to bubbles than those using light viscosity oils. I know one guy that filled his with marine compass oil to effect a fix and provide more dampening of the card. They're also heavy for what they do.

"These compare with my professional hand compasses for accuracy; Brunton GEO pocket transit and swiss merridian engineering/geological compass. These will set you back about $400-$500 plus accessories."

In my experience the 'oil bottle' prismatic compasses are accurate to about one degree or 20 mils, hand-held, when used in good light (the prismatic sight dates from the 1930s and is a bit dim) This is quite good, but I have a $5.00 Taiwanese liquid-filled lensatic compass that also provides this level of accuracy with no bubbles, either (though I wonder how many lemons I'd have to sort through to achieve similar results with a replacement). The Silva Model 54 can also be read to this level of accuracy in ideal conditions. Most individual compasses that purport to offer even finer readings and greater inherent accuracy usually need to be mounted on a tripod to provide consistent, repeatable results. That's just as well, since such accuracy is really unnecessary for general wilderness navigation. Even resection and triangulation position-finding techniques can be accomplished well enough with an ordinary baseplate compass to landmarks within normal distances, especially since there are nearly always ready alternatives for most of us with the availability of detailed large-scale topo maps and of course, GPS.

"The biggest thing in favor of the baseplate/mirror compasses is magnetic variation adjustment (declination for the non-aviator). While this is a nice feature, all mariners and aviators get by with protractors that do the same."

Right, but the point is it's one less thing to have to carry along, plus the declination adjustment feature eliminates the possibility of forgetting to make the necessary compensation (or doing so in reverse order) when cold, tired, or otherwise out of sorts. It must have value, as the popularity of these compasses has long since extended from recreational users to countless military, rescue, and mountaineering organizations all over the world.

"Plastic protractor baseplate compasses have to be protected in rough use, if you fall on one it's toast."

I'd have to disagree with that. Hit any compass just right and you can break it (especially the older oil bottle designs with multiple small parts and a glass dial face), but modern baseplate compasses are very durable and stand up well to most impacts - usually better than the U.S. army lensatic, which often bends the pivot with impacts onto hard surfaces. I've seen Silva 4's that survived being run over by truck wheels. Furthermore, I would expect many more reports of baseplate compass damage due simply to their huge popularity, not to mention the fact that a $25 lightweight baseplate compass might be in hand and in use a lot more, and not be carried or protected so carefully as a $150-$300 instrument. If you want an advance demonstration of ruggedness, Suunto used to test samples of their KB line by dropping them onto hard concrete from 1 meter height, not sure if they still do that (I'm not testing my $150 KB-77 that way, that's for sure). A lot of military forces have formally adopted the lightweight protractor compass and issue them (Silva, Suunto, or Recta) for active field service (U.K., France, Canada, Germany, Sweden, Norway, Finland, Denmark, Australia, etc., etc.). So far, the Eclipse design compasses have not found popularity either with the military or with the forestry/surveying market. At one point Brunton was marketing the 8096 GPS compass to adventure racers who liked the roamer scales, but recurring problems with worn-off markings and bubbles seem to have soured its appeal a bit, judging from comments by some owners.



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