The most important component of any orienteering compass is its needle. Its job is to point towards magnetic north, wherever you are in the world. If your compass needle is not straight and floating free (not dampened by fluid), then it will not work properly.
Compasses for orienteering need to be lightweight, because their users often carry them for hours over rough terrain. Suunto’s M-3G Global contains an accessory red pointer with a luminous tip which you can use to take bearings. It’s not really necessary but many orienteers like it – it gives them something else to play with while they’re waiting for the next control.
Some orienteering compasses contain an “orienteering base plate”, or miniature map printed on plastic, which allows you to draw your route on the map after you’ve taken your bearing. Orienteering compasses with this feature usually include a digital electronic readout of your bearing, which displays both degrees and compass points – something that few field compasses have.
Compasses for orienteering are often fitted with covers to keep sand and grit out of their mechanisms, but even if they don’t come with covers they’re usually fitted with rubber or neoprene boots that seal them up nicely.
Orienteering compasses allow you to measure bearings to features on the map (trees, boulders, hills) and take them off again later when you’re running. The most common bearing used is “back azimuth” or “back bearing”. You can easily take a back bearing with most orienteering compasses.
For that matter, you can use any magnetic compass to do it. Just point the needle at your feature and turn your body until the ‘red end’ of the needle is under the fixed black arrow marked N on your compass housing. Then read off the bearing, in degrees. If you turn your compass over, you can measure a back bearing instead – by turning until the red end is under the fixed black arrow marked S on your housing.
You might need to take bearings for control sites too. A lot of orienteering compasses have scales that let you work out distances between two bearing lines on a map. You can even do this with a simple protractor compass, but the scales on orienteering compasses are usually accurate to 1:10,000 or 1:15,000 – better than you need for orienteering.
If you don’t want to take bearings from your map, some compasses have optional sighting mirrors that clip on to the side of your compass housing. They’re a bit old fashioned, but they work very well if you’re standing in open country.
An orienteering compass needs to be reliable, easy to use in difficult terrain, and accurate. There are a lot of compasses which have these qualities in varying degrees. Your choice will depend on your budget, the features you want in your compass, and how serious you are about orienteering.
Competition level orienteers tend to choose Suunto or Silva compasses – they’re light, rugged and reliable. Recreational orienteers often choose a Brunton or a Suunto Quest instead – they have all the same features as an orienteering compass, but include optional extras like sighting mirrors which help make them more versatile too.
What Do All Good Orienteering Pocket Compasses Have?
It’s also worth mentioning that ‘pocket’ or ‘baseplate’ compasses are very useful for taking bearings on control features. They’re small enough to carry in your pocket, and they have a base plate rather than having the map printed on the housing. That makes them easier to use on uneven terrain – you don’t need to keep turning the map over to check that you’re pointing at the right feature.
Pocket compasses aren’t as accurate as orienteering compasses because they don’t have magnifying lenses. They’re also much less robust – it’s easy to break a lens or damage an orienteering compass if you drop it on hard ground, but pocket compasses are more delicate.
Pocket compasses are just as easy to use as orienteering compasses, though – all you have to do is point the direction of travel arrow at a feature and read off your bearing from the compass housing.
As far as reliability goes, both ‘orienteering’ and ‘pocket’ compasses can be equally reliable or equally unreliable. Some orienteers use a baseplate compass as their main compass, and carry an orienteering compass as a backup. Other people prefer to use an orienteering compass as their main navigation tool, and keep a reliable baseplate compass for emergencies.
Whichever type of compass you choose, make sure it’s a good one! Don’t be tempted to buy a cheapo from a discount store. Make sure that any compass you use is accurate, and water resistant too if you’re using it in the rain or wet conditions.
What Do All Good Compass Have?
Take a back bearing with most orienteering compasses. For that matter, you can use any magnetic compass to do it. Just point the needle at your feature and turn your body until the ‘red end’ of the needle is under the fixed black arrow marked N on your compass housing. Then read off your bearing.
This is really useful because it lets you take bearings on features that are behind or to one side of your line of travel – something that can’t be done with sighting compasses.
But professional orienteers tend to choose an orienteering compass ‘cos they’re more accurate (the scales are accurate to 1:10,000) and easier to use in difficult terrain.
Of course, if you’re really serious about orienteering, you should make sure your compass is accurate – but even an inaccurate orienteering compass will get you to the controls if you take enough bearings! You can check that your compass is accurate by taking a bearing on a prominent feature while standing at the start of a leg. If your bearing is different from the one printed on the map, you should change the adjustment before starting a race!
Your choice of compass won’t make any difference if you don’t know how to use it. Eventually, you’ll learn what works best for you personally – but in the meantime, do some practice with your orienteering compass and work out which way of using it is easiest and most convenient for you.
There are a lot of different ways to use a compass, and the technique you choose is up to you. Try out different methods and see which works best for you.