Always trust your compass? Right? Wrong!

A magnetic compass will be affected by close proximity to alkaline batteries such as Duracells. Storage in a backpack next to a flashlight and GPS will be enough to permanently affect the polarity of the compass needle/pointer.

To see if your electronic gizmos are affecting your compass, try the simple experiment of moving your flashlight, GPS, etc. close to the compass. If the needle moves, you've found the culprit.

If you're trying to find your way in low light or the dark, holding the light close to the map or compass will be enough to distort the compass reading by a large amount. That deviation will not always be the same, so it isn't possible to compensate for that "interference" alone.

In compass navigation it's useful to remember the nemonic for accuracy, "True Virgins Make Dull Companions": True, Variation, (from the compass rose on the map) Deviation, (from nearby metal or other interference) and Compass (reading).
 
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Looking at your scenic view of New Zealand a second time. If caught off guard while in the bush with a broken compass. You could look for a tree and check and see if the moss is growing on its North side? ~~or is it the South Side down there? Now that I think about it. I'm not sure if you folks have a tree?_:rolleyes:
One good thing about your conundrum though. New Zealand is indeed a island so you got to come out someplace on it with or without a compass. That's a +1._:D

Here in MN we have open pit Iron Ore Mining and tailing dumps to deal with that often emit magnetism to where at times the needle on my compass resembles the wife's kitchen blender. Were taught early on to watch where the Sun is located over our shoulders for direction. And walk a straight line. That's Old School teachings.
New way the Military way. Dependance on a compass is assured. If you don't get lost your at least going to be confused. i.e. Calculate distance, bearing between two latitude/longitude points. Topographical maps. Oh that was so much fun._:eek:_:confused:_:o
 
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I'm a cheap SOB, and I hunted with a Silva compass that's polarity was reversed for years. As long as I knew it was reversed and it was consistent, it made little difference that it was the white end of the pointer showing North instead of the red. It wasn't until I cracked it somehow and the fluid leaked out that I broke down and bought another. I always checked it and every other compass I have owned in the last 40 years before I lose sight of the vehicle. Most times more than once. This tells me I can trust them before I NEED to trust them. I take a bearing on which way I'm headed when I leave and know that I need to be doin' the opposite to get back. The sun and the watch trick was taught to us in the Boy Scouts almost 50 years ago. Unfortunately, it only works when you can see the sun. But then, generally, if you can see the sun, you don't really need a compass, unlike when it's snowing, raining or just plain overcast.
 
Consider a SPOT. They can be viewed at REI dot com. They are handy if you get lost as long as you have satellite access.
 
As Kraigwy said, you can find South with an analog watch or you can make a rough sundial if you have a digital. Point the hour hand at the sun and halfway between the hour hand and 12 is relative South.
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I often use this method, but it has limitations. The major limitation is that within the tropics, where I used to spend a good deal of time, you have to know were you are in relation to the equator and the relative position of your general latitude to that of the celestial latitude of the sun. Of course is you are in the extratropical latitudes of the Southern Hemisphere, the method renders North.

Having been a professional navigator for several years, you pick up all kinds of tricks. For gross reference at night, I tend to use Orion, if the Pole Star is not visible. In the Southern Hemisphere, Crux is valuable the same way.
 
I don't know if this explains what happened, but there are a number of magnetic anomalies in this wonderful country, and a well known one in the top of the South, by Nelson. I had a geologist explain to me once why this was, and he used big words so my eyes glazed over.
 
I live on the Minnesota Iron range and worked in that industry for 35 years.
SSMagee is right to say there is magnetic influence from the ore but it is a very minor influence unless there is Lodestone(natural magnet) nearby.
The early explorers carried large "Dipping Needle" compass to map out the boundary of an iron ore formation. There is Hematite (Non-magnetic) ore and Magnetite (Magnetic ore) here and the magnetite is very low grade and the most abundant.
We have a State Wide Program that started in the County I live in that provides compasses to all Firearms Safety Students; Here
Tennison Memorial

After their son's disappearance, Jim and Mary Tennison worked with the DNR to set up the Jamie Tennison Memorial Compass Fund. The fund buys compasses and provides survival training for Minnesotans completing DNR's firearms safety training.

Questions or donations may be addressed to:

Jamie Tennison Memorial
Compass Fund
Grand Rapids Area Community Foundation
201 NW Fourth Street
Grand Rapids, MN 55744
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This program provided training and compasses for all Itasca County FAS participants but is now a State Wide program. In the early years the compasses were low quality but today the compasses are top line A-10 SUUNTO although I would prefer a simple Fisheye.
My favorite method is the cloudy day one.
Using a very small twig or stem of grass, or a knife as in this illistration The shadow cast on my thumbnail will tell in which direction the sun is. I work with this with my Grand Children all the time, and here in the Northwoods we can use the fallen tree method.
All our BIG storms come straight out of the west, therefore if we see snapped off trees (as in numerous) they will point East.
 
I have a great deal of experience with GPS. Mostly for being a heavy equipment operator. Most of our heavy iron had GPS grade controls. I don't trust it. It go's out to much. When we hit Iraq after 9-11 our GPS was out for months. Every time there's a solar storm we'd loose signal and have to calibrated.

Any of you recalibrate your GPS? Probably not.

I use it in my car and hunting but always carry a compass for backup( on the hunt, not in the car).

Boomer
 
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Boomer, my GPS always seems to get me to where I am going and back again. I plot home in it. I plot way points, and it always gets me within a few yards of where I am supposed to be. I don't really need it walking, but I am terrible out on the water. My sense of direction sucks when I am in a boat.
 
That said, I always used 2 compasses, AND a topo map, in conjunction with each other. In teaching students to use a compass, I included the precaution to be aware of magnetic influences, such as the presence of iron objects (rifle, pistol, trucks, railroad tracks, overhead power lines, hand grenades hanging off your web gear, etc.) The army even specified exact "standoff distances" for each object, and included several questions in the end of course test to be sure the students understood/learned that a compass needle is sensitive to magnetic distractions, some of which are not obvious.
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The kevlar helmet was a great invention in land navigation.
 
Boomer58cal said:
Any of you recalibrate your GPS? Probably not.
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"Recalibrate GPS"?

GPS is based on the time delay between the device and the satellites. The satellites are in geosynchronous orbit. There is no way of "recalibrating" and no way for them to lose calibration.

I have used a large number of GPS products over the years, from $100 units bought at WalMart to cell phones and units built into aircraft communication equipment that cost $15,000+.

I have never seen a single unit that was wrong, beyond reasonable accuracy errors of a few tens of meters.

The only calibration that needs to be made is the receiving units internal clock. It does that automatically by adjusting time until the signals that it's getting from at least 4 satellites create 4 spheres that overlap at a single point. It's pretty much impossible for that calibration to be wrong.

MAYBE there's something about military units that require that time calibration to be done manually, I don't know, but I do know that no civilian units I've ever seen have any such thing.
 
Ewwww. Did you ever reset the field on it? Be a good way to fix compasses if you can not go buy one.

I hope that doesn't happen to my compass. Sucker was $50. I highly recommend it though.

thecompassstore_2257_10201420

[url]http://ep.yimg.com/ca/I/thecompassstore_2257_10004403[/URL]

edamned - I never understand why fellow soldiers fail during land navigation, but I always manage to find the coordinates no problem. Then again it was funny watching how some would read their compasses.

Then again I did forestry judging for 6+ years. So pace count was already muscle memory.
 
I am enjoying reading the various comments even if we have wandered slightly off the original topic of reversed polarity in a compass.

Whether you actually use the compass depends a lot on the terrain you are in. Here in the South Island of New Zealand it is quite difficult to be "lost" in the high country as you should know which valley you are in and you would surely have noticed if you had climbed out over an 1800m ridge! The bush runs out around 1000m so you have a clear view when on the "tops". The problem is more likely to be finding a safe route back to your base around bluffs, gorges, glaciers etc. especially in fog. I make a habit of building a small cairn when I reach a ridge or other prominent feature so that if returning in fog I know where to descend or can get my bearings - it is reassuring even if you were 99% sure of where you were. A topo map is essential in this country - I am continually surprised at how a route traced off a topo map is feasible in practice. Conversely I can only think of a couple of instances when I have actually used the compass in such terrain.

In the North Island or in the flat front country of the South Island it is easier to get lost as the hills are lower and the bush covers them so that you can cross from one watershed to another without noticing. And it is easy to lose your sense of direction in bush in flat terrain. Here a compass is essential. There are many times when I have been "temporarily confused" and taken the advice of an old bushman "Stop. Sit down. Have a cup of tea or roll a smoke and THINK!"

As for GPS their main problem is batteries. The typical 2xAA barely last a day if the unit is left on to record your track even with the backlight turned off. And GPS accuracy is markedly reduced in thick bush, or the bottom of a valley. Their topo maps are pretty limited too because of the small display.

Beautiful country you live in David.
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I agree, 2damnold4this. If you want to see some pictures of a 6 day chamois hunt we did in March I have posted some on this forum.

http://www.sakocollectors.com/forum/showthread.php?8106-M995-in-6.5x55-strikes-again

We can hunt deer, chamois and pigs here all year round though it gets a mite chilly in winter.

David
 
GPS ? Ha, Ha, Ha. Nobody can find my house with a GPS and it has been sitting here before the Civil War. It is unbelievable trying to get something delivered. You tell people not to follow the GPS and they will not listen to you.
 
buck460XVR brought up a good point. If you know which way the compass is actually pointing towards. Lets say (EAST) By lining up its compass face with its pointer (East) You should still be able to figure out which way you want to walk. Just use it knowing its pointer will always point East or whatever instead of true North as it should but doesn't. Kind of like a GPS behaves like on low battery's_:p.

S/S
 
Gunplummer said:
GPS ? Ha, Ha, Ha. Nobody can find my house with a GPS and it has been sitting here before the Civil War. It is unbelievable trying to get something delivered. You tell people not to follow the GPS and they will not listen to you.
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Not being able to find your house is a mapping problem, not a GPS accuracy problem. Give someone the coordinates instead of a street address and they'll find your house just fine.
 
During last year's Elk hunt, I found myself in unfamiliar territory while hiking in to retrieve the last load of meat. After arguing with one of my brothers for 15 minutes, about our location, I pulled out my compass (while he continued to insist that we were short of our objective).

The reading was about 90 degrees off from my natural sense of direction and neither the compass nor my own sense of direction matched the visible landmarks in the area. Being well aware of the affect certain natural deposits can have on a compass, I kept my eye on it, while hiking another 100 yards or so. As we moved away from a collection of large rock formations, the compass came into agreement with local landmarks (not so much with my own sense of direction).

My brother's response to the compass: "It's wrong. That thing is broken. Let's keep going." .....:rolleyes:

I was much more familiar with the area (as a whole), and simply laid it out for him: "I have the gun. You have a knife and a pack that smells like dead elk. If you want to keep hiking that way, where we know there are several bears, you go right ahead. I'm turning around, because I think we overshot the top of the ridge and walked right around the meat about half a mile back. Neither of us knows where we are, but the compass agrees with the peaks I can see. I'm turning around."

He went about 50 yards, before hearing a twig snap and returning to the guy with the compass and the gun. ;)



Later that night, one of the two members of our hunting party that were using the latest and greatest Garmin Rino GPS units showed up in camp about 4 hours after dark. As he dropped his pack, he lobbed the Rino across camp, into the back of a truck, stating "That damned thing sent me 2 miles that way [motioning over a really nasty mountain], and then reset and told me camp was behind me."

Later, he freely admitted that his gut was telling him the Rino was wrong (he had studied my topo maps), but he followed it because he hadn't had one let him down before. :rolleyes:
 
We used a compass when I would go coonhunting with my friends down in the bootheel of Missouri, fellas there are a bunch of big long deep hollows, in that Mark Twain National Forest. We would generally head out out about 9:00 pm and hunt til about 5:00 am. My friend would hand the compass to me and say dont let us get lost, and we never did, and this is why: When we got ready to leave truck I would take a reading, and coordinate our travel direction from the truck, for instance the truck set in a parking lot at 30 degrees south and we knew that to find this truck at 2:00 am or whenever we would have to use this first reading and triangulate off large topo features and record direction. Large topo features can be anything you can see from a distance like highline poles, lookout towers, cellphone towers, bluffs,,, etc. we called our coonhunting party "lost in the dark"...:rolleyes:
 
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