I think there are two sorts of navigational compasses, a magnetic one and a mental one. Both are liable to fail.
Set off with Danny early one morning to hunt from our tent south from Waihora toward the Mangatu. Dropped off the track into the heads of the Mangatu and hunted the steeply creek cut spurs. Big mobs of nothing. Bit of sign but nothing to get excited about. Heading up one particularly gnarly creek when Danny stopped and got his compass out. He said “h’m that’s funny”. I had a look at his compass and I thought that’s hard case, Danny must have bought a northern hemisphere compass because the red part of the needle was pointing south. Who would be mug enough to get a crook compass. Took me some time to think compasses never point south. My mental compass was 180 degrees out as was Danny’s which was why he’d got the compass out in the first place. Figured we’d travelled south so camp must be north. No matter how wrong it felt we marched north till we saw the edge of the escarpment which was right where the compass said it should be. Climbed up the escarpment when the lay of the land went haywire again. Danny got his compass out again and sure enough the red needle pointed south. Started looking more carefully at the terrain and realised that we were on a spur rather than the main escarpment. Got to the edge of the escarpment and were faced with a choice of difficult or terrible possible routes back to camp. The land directly between us and camp was flat terrace which had been logged years before and had thick second growth vegetation.
Bugger this I thought and pulled out my GPS. I’d waypointed our camp last night so found a bearing and a distance to camp. Crashed through the heavy veg and in a surprisingly short time were back at the tent. Bloody crooked compasses.
Years ago Clive and I left my VW at the Te Rimu skid site and set off to get to our campsite above the falls on the Tauranga Taupo. We’d done this trip a couple of times before and had been very successful on the easy terraces along the river. This morning there was a heavy fog down but, no worries, we had previously put a bit of a dazzle marking between the first and the fifth creeks. We’ll be right, March on. Lost the dazzle at some stage but my mental compass had us firmly on track. Several hours later the fog lifted. I saw something very shiny a little way in front of us. I couldn’t think what could be making that much shine, maybe water flowing over a rock. Went to investigate and saw it was the windscreen of my vehicle. Bloody mental compasses.
I’ve done the same at Chew Tobacco bay on Stewart Island. Heading back to camp from a hunt south to Pikaroro. Got back to the flat land west of the camp and decided to try a different way back. Some time later saw the same tree where I had decided to plunge off into the thick scrubbery. That’s funny I left here half an hour ago. Took a bit of concentration to reorient myself and make a correct decision to get back to camp.
Both mental and magnetic compasses can fail but I would trust the magnetic one before the mental one every time.