Page 1 of 1

Reverse polarity in compasses

Posted: Wed Aug 08, 2018 12:55 pm
by Mr Ed
Great article on UKC. ... users-5385

Worth thinking about? especially with compasses often held close to VHF on a BA or the new front day hatches where GPS, Phones, Compasses often all get parked together...

Anyone got any horror stories?

Mr Ed

Re: Reverse polarity in compasses

Posted: Wed Aug 08, 2018 1:25 pm
by seawolf856
Oh blimey! I keep a conventional Silva walking compass in my PFD pocket in case I need it (I haven't got a deck compass). I also keep my PLB in a dry bag in the same pocket. I'd better check my compass to see if it is OK.

Re: Reverse polarity in compasses

Posted: Thu Aug 09, 2018 9:27 am
by Ken_T
I have seen this happen to a Silva hand compass. I always like to have at least 3 compasses in a group & if I think we may need to navigate by compass do a comparison of compasses before launching. The compass that I had reverse polarity appeared to have happened when it was in the boot of the car at the bottom of a pile of clothing.

Re: Reverse polarity in compasses

Posted: Fri Aug 10, 2018 11:51 am
by PeterG
Seen this several times, it doesn't seem to take much, just another compass or speaker VHF or phone. It is frightening how easy it is to reverse them back with a magnet. We always check each others and think about wind direction if in the mountains or waves on the sea.

Re: Reverse polarity in compasses

Posted: Fri Aug 10, 2018 12:04 pm
by Mr Ed

One of my pet hates sea kayaking is the compass recess kayak manufacturers put in place for the Silva 70p. I just find it far too forward to be of much use as I struggle to read it so much (wear glasses but i'm not that blind). However being that far away from hopefully mobiles, GPS, VHF etc could well be a very good thing. I might have to re-consider.

My preference is a clip on compass on the deck ahead of me and a handheld expedition 4 Silva on my person. Definitely worth checking both.

Speaking of magnets a friend ran into some problems off Muck a few years back due to the magnetic anomaly marked on the chart there. He was relying on OS maps- sometimes charts really do come into their own....