Compasses. The good, the bad and the ugly.

thejungleisneutral

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I thought it might be useful to post an all-in-one thread about compasses and other navigation gear so we can see which bits and pieces people use or have used and what they thought of them.

British Aircrew Escape Compass - Currently made by Physer-SGI - NSN 6605-99-522-0223

brass_button_compass.jpg
Image from Bestglide in the US - the cheapest source for these, even with shipping. I picked mine up from Fusion Gear.

A 1/2 inch format compass, it actually feels a lot smaller than it appears in the photo. First thing I did with mine was to zip a little yellow cable tie around it and thread through a metre of 550 cord inner strand to use as a lanyard. Really easy to lose, which I guess is the whole point. It was designed by MI9 in the UK in WW2 and its lilliputian dimensions facilitate easy concealment. They also reckon you could swallow the compass and retrieve it later.

I've been carrying mine in my survival tin, which is part of my PSK system.

Pros -

Does point north.
Tiny and lightweight
Painted brass - and I like brass things

Cons -

Too Expensive
Too tiny
Not waterproof

The last one is a biggie and the dealbreaker for me. You'd expect a piece of rugged, military "special forces kit" to be waterproof, but it's not. During a recent trip, it became sodden during a waist-deep river crossing and when I next went to use it, the compass card (needle/pointer/whatever) was stuck. The tolerances are so fine that a single droplet of water under the card can jam it. To get it working again I had to heat up the compass (which, as we know is bad for accuracy) to evaporate the offending droplets. It now works, and still points north accurately when tested against a prismatic compass, but I will be replacing it with something suitable for serious use.

I wouldn't buy another one.

right-size.jpg
Mine, with zip tie and paracord strand, prior to its swim.



Sorry Mods, I just realised I posted this in the wrong spot :( It's probably more suitable for the "member reviews" forum.
 
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Aussie123

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Hi TJIN,

It seems odd to have a compass which is not properly sealed, is it possible that you got a dud ?
Could you add some silicon to waterproof it ?

Personally I think that a larger compass is far more practical for navigation. I've seen a few button compasses and they can only really give general directions, and usually I know were I am well enough to know the general direction I want to head in.

Having said that I do have a button compass on my keyring and I noticed a while back that it doesn't point North anymore !
(Not sure what brand it is, just a small plastic compass).

I think an important reminder is to always check your compass before you head off. From time to time compasses do "fail" and it would be better to discover that before you depart.
 

thejungleisneutral

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It's possible that its a dud, and I've since heard whisperings about quality control issues on some of these.

The case construction is just brass with a glass top crimped on. There's no seal or o-ring, and it seems to me they are relying upon the black lacquering to provide some water proofing, which isn't good enough.

It's interesting to note that unlike the current ones, the original WWII compasses were issued in a plastic holder which was waterproof as seen below.

comp RAF.jpg

I won't be messing around with the compass to try and fix it. I'll on-sell it and let someone else enjoy it.

The purpose of a button compass is just to give general direction for unfamiliar country. They were used with cloth charts (maps) which weren't gridded and just had a north line. For anything more precise you need an indexed compass, preferably full size and preferably used in conjunction with a proper map.

I discovered the issue with the button compass when I was cleaning my gear when I returned home from the trip in question, but that's a great reminder about checking your nav gear. When I was younger I had a Silva-brand baseplate compass completely reverse polarity on me, but I caught it before I took it into the field.
 

Adrian

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I really enjoy analog navigation, Ive used silva baseplate compasses in conjunction with a mil spec roma ( a protractor divided into 3200 mils not 180 degrees ) and string.

Being driven out into the never never dropped off and told to make your own way home was great fun.

First the resection to find where you are then the route home, caring all your kit..... GOOD TIMES
 

Aussie123

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The previous post got me thinking .... I went away and pulled apart my button compass.

Top view. The compass card on the left and the open case on the right (there is a pin in the centre to suspend the card):
IMAG1163 (Mobile).jpg

The underside of the compass card reveals the needle. You can see that its a strip of magnetic material with the circular card on top:
IMAG1164 (Mobile).jpg
 

Thrud

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I carry the Silva global sighting compass. I've got a few of the button compasses, the best I got from Kitbag, the cheaper variety I got from Fusion gear.
 

Wentworth

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I use a suunto global baseplate compass.
My watch has a GPS built in, which is handy. Every now and again I fire up the GPS to get a grid reference to check that I'm in the right spot on the topo. By using it this way, the battery lasts well.
I wouldn't know how to use the button compasses when navigating with a map. How do you take an accurate bearing?
 

DavoAnth

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I have been using both a Silva Ranger and a Suunto that was given to me (no idea what model but a baseplate version) for years, both in bushwalking and orienteering, and IMO I have seen little difference - they both get me to specifically where I want to go. I also recently bought a Brunton adventure racing model that was designed to function in both Northern and Southern hemispheres (yes there is apparently a degree in error and the major manufacturers make hemisphere specific models - so beware of ebay purchases from the Northern Hemisphere, although careful tilting of the baseplate will usually get you back on track with an incorrect hemisphere model) for my journeys North of there equator and have been very impressed with it. I have a silva button compass in my first aid kit as a back up, but the button compasses - no matter what the model - are designed only for emergency generic bearing / direction navigation - i.e to a town, road, coast etc, whereas the baseplate models are designed for accurate navigation, such as a specific landmark, track junction, creek crossing etc (naturally dependant on the map reading skills of the operator). I view navigation (without GPS) as a critical bush crafting skill, and it is one of the areas that I will not compromise on equipment quality or cost. Learning solar or celestial navigation is easy and IMO more important than reliance on a button compass - although as a Northerner I will admit that with overcast skies being the norm for a reasonable periods of the year a button compass is better than no compass...
 

Wentworth

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thanks Aussie and Davoanth, I figured they must be a backup. But if I was going to carry a backup compass, it would make sense to me to carry the smallest baseplate compass I could find, at least it could still be used. The silva 1-2-3 is tiny and low profile and still does what it's meant to do: take a bearing from a topo. I know Corin carries 2 baseplates as do some others.
 

Aussie123

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thanks Aussie and Davoanth, I figured they must be a backup. But if I was going to carry a backup compass, it would make sense to me to carry the smallest baseplate compass I could find, at least it could still be used. The silva 1-2-3 is tiny and low profile and still does what it's meant to do: take a bearing from a topo. I know Corin carries 2 baseplates as do some others.
The button compasses are about e&e (escape and evasion) rather than "navigation". East to conceal and sneak past the guards at Stalag 13 ! Its also something which you could have on your key ring as survi*** tool !

I've read that one reason people get lost is because they lose faith in their compass; they think its pointing in the wrong direction because they "know" which way they should head, but the compass says otherwise. A (functioning) button compass should be sufficient to confirm that your main compass is infact pointing in the right/wrong direction; of course a base plate compass would be even better in that situation.
 

Bloffy13

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I had to rely on a button compass on my watch once when I somehow lost the compass from the centre of my base plate (Still no idea how it happened.)
Basically it was a little slower because I had to let it settle properly but with a good estimation of the mils and a good map (Yep, I use them instead of degrees. More accurate) I was able to navigate, with a couple of mates, through some pretty rugged and unfamiliar terrain back to our base camp. But it's not an experience I would like to repeat readily.
I've also used it when scuba diving. Accurate enough for my purposes. It's amazing how you can become orientationally misaligned in a strange environment.
BTW I now sport a Silva button compass on my watch. Been on there for at least six months now and still accurate.
When I go bush, I carry a Silva base plate compass (yes this one has a compass rose...).
Have used military-style prismatics but prefer the base plates.
Cheers
Bloffy
 

barefoot dave

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I wear a Casio Protrek 5 sensor (incl compass) which is pretty accurate.
Have done a bit of off track work work in my time.
Started with Engineers prismatic. Bombproof, but big lump of brass to carry around, especially around the neck.
When the Silva Prismatic baseplates were issued, we almost creamed. Still my favorite to this day.
With a little practice (no, not 20yrs, a couple of well tutored hours) celestial nav can be very accurate on a clear night. particularly in Savannah country.
i haven't bought any really expensive button compasses (>$20) and haven't had much luck. usually get bubbles after about 1 month on a watch band.
This can be fixed fairly easily by hand drilling a hypodermic needle size hole to refill it with alcohol and re-seal

I caution against storing any compasses in a metal container. The 'Altoids' kit with a cheap button compass is a waste of time. OK if it is brass or other non-magnetic material, but good luck finding one. Consider a polycarb Pelican or lifecase for your kit. Not trad, I know, and you cant boil water directly, but if you insist on keeping a compass in there....

A small rare-earth magnet will make a compass out of any needle or small scrap of metal. It will also help you collect meteoric iron from the topsoil with which to forge a blade ;) hmmm, there's a challenge..

You will have a watch on more than a can in your pocket. This also allows you to check its function daily.

Daves Credo "The best survival gear to have, is the stuff you have when you need to survive";)
BDave.
 

thejungleisneutral

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I caution against storing any compasses in a metal container. The 'Altoids' kit with a cheap button compass is a waste of time. OK if it is brass or other non-magnetic material, but good luck finding one. Consider a polycarb Pelican or lifecase for your kit. Not trad, I know, and you cant boil water directly, but if you insist on keeping a compass in there....
Thanks for the tip. I'll just jot that down "don't store your compass in a metal tin"...

I'll check out that Silva 123 mini-baseplate compass Wentworth, but I have lately been questioning the need for a compass in the "survival tin" at all.

Because I like shiny brass compasses best of all, especially if they are big and heavy "engineer types", here's my thoughts on some of the older ones -

All are graduated in degrees since back in the day mils were only used by artillery types. Infantry and even engineers used degrees.


1918-manufactured Cruchon & Emons Verner's Pattern Mk.VIII prismatic.

This is a WWI compass with no oil or induction damping. It's very, very accurate, and as you can see, it's pretty, but how does it work in the field? I've taken it out bush a few times since I restored it and although it was designed as a marching compass, I found it very frustrating to use on the move. The compass card swings freely and although there's a little brass button brake which you can press to arrest the movement and get the thing to stop moving and give you your bearing it's a bit clunky and counterintuitive to me. I'll be selling this one, since a compass is no good to me if it's just gonna sit on a shelf.


1918-manufactured Cruchon & Emons mirror sighting compass.

This one has the same drawback as the Verner's pattern above, but it seems easier to use to follow a bearing. It's as easy to use with a map as the WWI prismatic, but the more open sighting system seems to be quicker. You still have to use the brake to damp the movement of the card, but it's not as much of an issue. This one is staying put as my "period" compass. Although I like it, its on-dial accuracy is only down to about 5 degrees on the dial. You can guesstimate your bearing pretty easily, but it's just not as precise as the one above or the one below.


1943-manufactured MKIII prismatic marching compass.

Apologies for the cropped photo. This is the old-timey one I use most often. In fact I used it again on the swag trip this weekend just gone. It's chunky and it's a bit heavier than the others above, this is because its oil-damped. The capsule is filled with purified kerosene (clear, unscented lamp oil) which stops any jitters or sudden movement of the card. It's the same damping system they use on aircraft and maritime compasses, and when it works, it works great. Unfortunately, any large change in altitude or temperature can cause these to bubble, which affects the accuracy. Before I restored it, this one had a huge bubble. The compass is very accurate and is carried in either the left shirt pocket or in a belt pouch. Both types of carriage are best performed with a lanyard. Unlike a baseplate compass, you really do need to use a protractor with this compass and any of the old-style marching compasses, including the US military M1955 lensatic compass. I use the protractor in the picture which is the same vintage as the compass itself. I have also used a degrees-graduated US military pattern protractor with it with good results. See this youtube vid for a description of the US military one - http://www.youtube.com/watch?v=rD0d29CuTjQ

So what's the advantage of using the old-style compasses instead of the baseplate types? None. I like the nostalgia of using the old gear, but for serious land nav in remote areas, I use a Silva baseplate compass since that's what I learned on in scouts and that's what I'm most comfortable with using under pressure.
 

Mickldo

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Another tip is not to carry your compass next to your UHF hand held radio. The radio has a magnet in the speaker and it will wreck the compass. How do I know? While doing a geocaching day for the scouts I went to show the group of scouts the compass I always carry as backup to my GPS and I grabbed it out of my CamelBak and noticed that the north arrow was pointing south. Lucky I knew the area and knew where north was and picked it up before I really needed it out in the field. Now I carry my compass separately to the rest of my electrical stuff (phone, GPS, UHF, PLB and even my torches). I just carry it in my shirt pocket at the moment but I am looking for a compass pouch for my belt.

Just for the record it was a Silva baseplate that was wrecked. I also have an ex-army prismatic but I don't use it much except as a demo compass for scout navigation lessons. As a replacement compass I bought a Silva Ranger which I find to be a great compass.
 

thejungleisneutral

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Another tip is not to carry your compass next to your UHF hand held radio. The radio has a magnet in the speaker and it will wreck the compass. How do I know? While doing a geocaching day for the scouts I went to show the group of scouts the compass I always carry as backup to my GPS and I grabbed it out of my CamelBak and noticed that the north arrow was pointing south. Lucky I knew the area and knew where north was and picked it up before I really needed it out in the field. Now I carry my compass separately to the rest of my electrical stuff (phone, GPS, UHF, PLB and even my torches). I just carry it in my shirt pocket at the moment but I am looking for a compass pouch for my belt.

Just for the record it was a Silva baseplate that was wrecked. I also have an ex-army prismatic but I don't use it much except as a demo compass for scout navigation lessons. As a replacement compass I bought a Silva Ranger which I find to be a great compass.
Great point about carrying your compass separately from your electronics. I had a similar problem with this one -

IMG_20140421_224846[1].jpg
Silva 4/54B Military baseplate graduated in mils and degrees.

I went to use it at one stage and found it had reversed polarity on me. I "fixed" it by running a strong magnet over the underside of the dial until the red bit pointed to magnetic north again. I have checked it against a couple of working compasses, but since I don't know how it swapped polarity I don't really trust it anymore. Since it was a great compass, I'm thinking of sending it off to Silva for a checkup and/or repair. Has anyone done that?

Thinking about it, it may have happened since I usually carry my compass in my left shirt pocket on a lanyard, and occasionally I'll carry my phone in there while I'm out bush as well. Doh.

Like Mickldo, I have a basic Silva as a baseplate compass I trust. Here's a bit of a tutorial on modding an army surplus nylon Alice pouch for a baseplate compass - http://thejungleisneutral.wordpress...uch-hack-accommodating-the-baseplate-compass/
 

Bloffy13

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I reckon you would be right on the mark by re-magnetising the needle. Once you had it showing true again, there's no reason why it shouldn't stay so unless it gets "corrupted" again.
I've heard dropping them can cause problems too but I am not sure.
Cheers
Bloffy
 

Mickldo

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While we are discussing compass problems......

Do bubbles in the damping fluid affect the accuracy of the compass? I reckon that the needle is the bit that does the work and the fluid just stops the wild swinging. As long as the bubble isn't touching the needle it shouldn't affect it. Last year on a Scout camp (Operation Nighthawk) the patrols had to have compasses for some night navigation. Before the hike the compasses were checked and if they had bubbles they weren't allowed to use them and they had to find replacements. I checked ours before the camp but in the cold of the camp (night time mid-winter) there was a small bubble. Maybe the temp caused the bubble to appear as the bubble isn't there anymore. Are they just being fussy or is it really an issue. If it is an issue how do stop them getting bubbles?
 

Blake

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While we are discussing compass problems......

Do bubbles in the damping fluid affect the accuracy of the compass? I reckon that the needle is the bit that does the work and the fluid just stops the wild swinging. As long as the bubble isn't touching the needle it shouldn't affect it. Last year on a Scout camp (Operation Nighthawk) the patrols had to have compasses for some night navigation. Before the hike the compasses were checked and if they had bubbles they weren't allowed to use them and they had to find replacements. I checked ours before the camp but in the cold of the camp (night time mid-winter) there was a small bubble. Maybe the temp caused the bubble to appear as the bubble isn't there anymore. Are they just being fussy or is it really an issue. If it is an issue how do stop them getting bubbles?

Hi mate. A small bubble wont affect the accuracy of the compass. It may become an issue with larger bubbles where the needle could, perhaps, possibly become deflected slightly by the surface tension of the bubble but I wouldn't consider it a catastrophic problem unless the bubble becomes very large. Some manufacturers I beleve will replace a compass that has a bubble but ive never had to do this as its never been a problem for me as I dont have a dampened compass. I use a Silva Ranger base plate compass and a Cammenga lensatic compass, depending on what Im doing. As you say the liquid is really only there to dampen erratic needle movement so I cant see it being an issue unless your doing some high speed orienteering competition. A bubble can appear depending on altitude and temperature and can become larger as the water contracts. If you are worried you could leave it in the sun for a bit to warm before taking a bearing.

A compass is only accurate to a certain level when used with a map and on foot travel in my humble opinion. Ive never needed to hit a mark so specific that a bubble would worry me as I usually shoot for some kind of terrain feature that I can identify by eye and go from there. Then again, I play 99% of the time in country with terrain so it might be a bigger concern for our flat country members. I think you called it right Mick.

As for how to avoid it. Im not really sure how they form, if its a temp /altitude issue or a manufacturing issue. I imagine that if the bubble is going away and coming back then its just an environmental influence. If the bubble is growing overtime I would suspect there is a leak and most quality makers would likely replace it within warranty. The only other thing I can think of is purchasing an oil filled compass, perhaps these are more stable and less likely to develop bubbles? I would need someone to comment on this as Ive never owned one either.

In summing up.. A small bubble I wouldn't worry about, a large growing bubble might be another matter.
 
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