Discussion: Compass problems

Our club started the season with two "Come and Try it" events. One of the very keen newcomers went out and purchased herself a new base plate compass. The next event I was acting as sweeper out on the course and found her totally bamboozled. When I started to explain map orientation I found myself bamboozled as well. This picture explains the problem.

That is not uncommon, happens if you store your compass near a strong magnet. Not a quality control problem.

Easy enough to fix: Google something like "Fixing a compass with reversed polarity"

OK. Its a store problem probably then.

storage problem - don't store compasses near magnets - it may have happened in the store or in transit but it is also possible it happened after purchase.

I had one do that spontaneously once, not stored near a magnet as far as I know. I still have it somewhere as a curiosity. It's not common, but it does happen. I've heard that a common cause is a bunch of compasses stored together, tilted on edge so that the needles can't rotate freely. One or two end up pointing the opposite way as the rest, and over time eventually succumb to peer pressure. That could happen in a shipment of new compasses to a store, resulting in one that's bad right out of the box.

Not unheard of. We had a Boy Scout show up at an event once with a compass like that. While giving instruction I noticed the boy's compass issue and warned them their compass was backwards.

Just turn the compass around and it should fix the problem.

Turn map 180 degrees and walk backward to complete course.

Move to Australia

Move to Australia

By that logic Neil has it all backwards - his newcomer's compass is correct (for Australia) - all the other compasses in Australia that point north are wrong.

In theory, my northern hemisphere compass that reversed might work properly in Australia as long as I remember that the red end points south. It's definitely no good here in the USA because it's unbalanced now.

I still have it somewhere as a curiosity.

That's weird - you can fix it in a matter of seconds. And you can reverse the polarity of any of your compasses in a matter of seconds if you ever feel you are in the need of a 'curiosity' . I just did it now to an old compass using a fridge magnet - easy - then reversed it back again.

It would be a good way of sabotaging a rival - reverse their compass while they are not looking just before a race.

The most likely big magnet to do this is in the speaker of a cell phone. Keeping phone and compass anywhere near each other will do it.

My reversal happened long before I had a cell phone. (Although, I have to say that the magnet in a cell phone speaker seems like it would be pretty tiny.) It may have been in the glove compartment of my car for a while before the reversal, which doesn't especially seem like a place where there would be strong magnetic fields.

No need for me to flip it back, I don't use that style of compass any more.

I'm now worried that Neil (TIL) has just completed the map for the long distance event for our Australian Championships carnival and that he may have been using one of those malfunctioning compasses that all the Aussies use down here whilst he was drawing. The mapped boulders are all probably rotated 180 degrees.

Try a look at this;

https://www.mountaineering.scot/safety-and-skills/...

Most climbers are aware how metal, such as an ice axe, can deflect the compass needle if held too close

I remember going on a mapping weekend with some friends - one guy was proudly showing off his new sighting compass. After the first day he was very frustrated that nothing he did seemed to line up properly. Turned out his metal framed glasses were affecting the compass.

I have learnt to be careful with mechanical pencils - the metal in them can affect the compass on my mapping board.

I don't use a compass in my mapping.

That explains why the boulders are facing the wrong way.

How much trouble is it for the course setter to bring a crowbar and turn the boulders around, really?

Using Moscow Compass (models 3 and 9) for many years.
Very reliable and durable, no complaints.

That's what I've used for about 30 years. They do develop bubbles, but so do other brands.

yurets: "no complaints"

I've seen quite a few cases of reversed polarity in the past, but this is quite remarkable.

I have a compass story which happened in Australia but has nothing to do with polarity but does fit in the 'you don't always need a working compass' category so I think it fits.
Scene: Some woods in the extreme SW corner of Queensland. I am running with a brand new thumb compass balanced to the Australian magnetic field. Cost some $150 AUS.
The event: Leaving the fifth control I trip on a rock and fall forward putting out my hands to break my fall. I break my fall and also my brand new $150 compass. I decided to try to continue. The woods and the day were too beautiful to do otherwise.
At one point I had to explain to someone that I had broken my compass and ask could he show me on the map where we were.
About ten minutes later he asked if I was the one with the broken compass.
"Yes"
"The sun is in the north west," he exclaimed.
After that the navigation was a 'piece of cake'. I just 'moved' the meridian lines 45 degrees.

I didn't realise they had orienteering in SW Qld. Qld has two SW corners but they're pretty remote from anywhere civilised.

Just don't stay out on the course too long...

At one point I had to explain to someone that I had broken my compass and ask could he show me on the map where we were.
About ten minutes later he asked if I was the one with the broken compass.

These Aussies don't sound too bright if it took him ten minutes to figure out something you'd already told him. Were you on course at the time patiently waiting for him to respond? Mind you, you did say it was Queeeeeeensland. They take a bit more time up there.

There are no 'woods' in the extreme SW of QLD - just desert. My guess would be Gordon is describing granite country - (Stanthorpe?) which is 3 hours drive south west of Brisbane but not in the SW of QLD. But we should forgive Gordon this geographical exaggeration - he is from Ontario where Sudbury is considered to be 'north Ontario'.

Easter 1987 in QLD granite - day 1 - I broke 2 compasses within 500m (always carry a spare). I still won.

I once saw an installation in Stanthorpe erected on behalf of the South West Queensland Electricity Board, so maybe that's where he got the idea (I think of western Queensland as starting somewhere around Roma but am well aware that many Queenslanders think of it as starting somewhere around Ipswich).

Clive Palmer would have you think western Qld starts on a line running between Kununurra and Eucla.

Just cut your thumb compass in half, or almost in half, with a saw. Glue it back together and secured it with a strong tape. Next time you fall the clue will crack, but the compass will more likely stay perfectly usable, just slighlty flexible for just the tape keeping it together. Afterwards just glue and tape it back together and carry on.

Some nice sand dunes in the bit of SW Queensland I've been in - but with a hundred or more metres of nothing between each one, not really the kind of sand dune terrain to get orienteers excited. And as for some of the country to cross to get there, good luck finding anything other than a compass to aid navigation....

If it wasn't so long a drive I would go exploring.

There's definitely some interesting country on the NSW side of Camerons Corner, both of the sand-dune variety and some seriously complex (probably unmappably so) granite around Tibooburra.

Neil accepts your challenge to map the unmappable!

Yes, I have known about Tibooburra granite, but it looks patchy and tough.