How
to use a compass
Finding the directions without a compass
You are lost. I mean
really lost. Standing in the middle of
nowhere, and you have no idea where to go. If you are really in trouble,
remember two things first of all: stay calm, think rationally, and you
can survive a long time without food. What you need is to drink.
Further thoughts about extreme survival skills is beyond the scope of
this page, seek advice elsewhere beyond this introduction. This page
deals with the situation of finding your way, without the aid of a
compass. What you have, is the sun, the stars, and the nature around
you.
This page is mainly about the northern hemisphere of the earth.
For a start, it may be a good idea to climb a hill, and get a good
look around. Try to see traces of human activity. If you see nothing,
you should try to figure out in what direction would be the best to
travel. If you haven't got a map, try to draw one if you can of the
terrain in front of you, and try to mark off where north is, using the
methods below. If you have got a map, try to determine where you are.
Remember, you don't want to climb more hills than you have to. Also you
should carefully consider not to climb if you are very tired. In that
case you should consider staying where you are. Consult other sources
for information on how to make it easy for rescuers.
Let us start with the most
accurate method. This method requires that you have a pretty clear sky,
though, and takes a lot of time. One of the advantages is that you don't
need any equipment. You would need a straight pole about 1 meter (or a
yard) long, two small sticks or rocks, another stick (or rock) that
needs to be a little sharp, and something that can act as a string.
In the morning, at least before noon, the trick starts. Stick the
long pole in the ground, upright. The ground around the pole needs to be
horizontal. Now, you can place one of the little sticks in the ground
exactly where the shadow of the pole ends, like on the figure.
Then tie the string to the base of the pole, and tie the little, sharp
stick, to the other end, so that when the string is stretched it reaches
exactly the little stick standing there in the soil. Then, scratch half
a circle in the soil with your sharp little stick, and wait... Wait.
Wait until the evening. During the day, the shadow will get shorter and
shorter, until noon, when it gets longer again. At noon, when the shadow
is at its shortest, you may want to mark the point. The shadow is now
pointing north (if you are north of 23.5 ° north). It is however not
very easy to see exactly when this is, but it is useful anyway. Finally,
the shadow reaches your circle again, and when it does, place your other
little stick at the spot where the shadow ends. If you haven't got a
string, you could use a pole that has the right length, or try to come
up with some other improvised solution. Just make sure what you draw is
a circle.
Now,
the line from the first stick to the second is west-east, like on the
figure. Actually, you may want to mark points regurlarly, because any
two points that have exactly the same distance from the base of the pole
will give the West-East line. If it is partly cloudy, this may be a good
idea.
There is a short, fast version
of this one as well. This is only approximate, though, and the further
away from the equator you get, the more inaccurate is it. You don't need
the sharp stick and the string. Just wait 20 minutes between placing
each of the sticks, and the line between the two sticks will be
approximately west-east, like on the figure. Often, you wouldn't need
anything more accurate.
At night, you can navigate after
the stars. You should, however, be careful with walking, it is easy to
stumble and fall and get injured, and also easy to lose sight of the
stars as you go, and you might start going around in circles. Often it
will also be more physically and mentally demanding.
In
the northern hemisphere, there is a star that is almost exactly in the
north at all times, the Polaris. It is pretty easy to find, if
you know the "Big Dipper". Take the two stars at the end of the
"Big Dipper", and make an imaginary line "upwards", and extend it five
times the distance between the two stars. There you have it - Polaris.
That way is always north.
If
you have an analog wrist watch, you can use the time to find north. Hold
your watch up in front of you, and let the short hand, red on the
figure, that indicates hours point at the sun. While holding it like
this, cut the angle between the red arrow and 12 o'clock in two, (noonwards
if the time is before 6am or after 6pm), that way is south. (The reason
you need to cut it in two, is because the clock takes two rotations
while the sun takes one around the earth, it is of course the other way
around, but never mind.)
Many people wear digital watches these days. If you do, draw an
analog watch face on a piece of paper, and then mark the hour hand on
using the digital watch. The rest of the method is identical.
This method can be used even when it is pretty foggy. Although you
may not be able to see the sun, it may still cast a shadow. If you take
up a straw or a tiny stick, and you may see a shadow. You just have to
remember that the shadow points the opposite way from the sun, but the
rest of it is quite similar as above.
Want to make your own compass?
Sure. You need a needle and a glass of water. A needle can in fact float
on the water, or that is, on the surface tension forces if put carefully
on the surface. Just put it carefully down on the surface of the water.
This demands a lot of patience though. There are three tricks that makes
it go easier. One: Put the needle on a piece of paper. If the paper
floats too, there is no problem, and if the paper sinks, it'll probably
leave the needle. If you put some grease on the needle that isn't
water-based, it'll go easier, or if you put it carefully down with a
fork or something. Once it has got there, it stays there pretty good.
If the needle is magnetic, it will act as a normal compass and be
very accurate. A problem is though, that you don't know north from
south. All you know is that it lays north-south. You would have to use
one of the other techniques to find out, or make a good guess.
The greatest problem with this is: Not many needles are made of
magnetic materials these days.... You can't just use any needle. You may
just have to look around to see what you can find, if you want to make a
yourself a compass.
What if there is no shadow?
Then, there are a few methods based on natural signs.
It is very much about trees. First of all, there will be fewer branches
to the north. This is usually easiest to see if you look up along the
trunk of the tree. The north face of the tree would be more humid than
the south face, which is something most species of lichen (or moss)
likes, and consequently, there will be more of it on the north face. On
the image above, you can also see that ants likes to build their nests
on the south side of the tree.
It is also worthwhile to look at how snow melts. In the spring in the
mountains, snow will melt faster on the south face of rocks, or in south
faced slopes. Also, vegetation and undergrowth will typically be thicker
on the South facing slopes, and also fruits ripen earlier on the South
facing slopes.
These methods are not very reliable, I am afraid. Winds may alter the
average conditions significantly, and cause deviations. If you use
natural signs, you should use as many signs as you can before you draw a
conclusion.