My compass has died (again!)

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daved

Forager
Aug 1, 2005
126
0
London
Toddy,

Although you have had some bad luck with Silva compasses, I would still think they are a really good choice - good quality, functional and not too expensive. Wouldn't rely on the "novelty" keyring/button types though (that goes for all makers).

I would back up Doc's suggestion of a couple of models, the 15TDCL and the 54. I have had a 15 for about 16 years (former Geology student). It has seen a great deal of (ab)use and has never given me any trouble. My father has had one of 54 models (or similar) for about 25 years, again with no trouble. I have used both types and several other more basic models and my favourite is still the 15 (and that is not just nostalgia for my student days.)

Some features to look out for:
A large base plate. This makes it much easier when you are trying to pin down your location from bearings on distant features. It helps if the plate is marked with a good ruler/scale to help with measurements and grid references. Check that they aren't so numerous though that they clutter the plate and obscure the map below. A Magnifier can be useful if your eyesight needs a bit of help with the details on maps.

Liquid filled. Not everyone will agree but the damping effect on the needle makes it far less frustrating to use.

Sighting compass - worth the extra for the increased accuracy of the bearings you can achieve. The mirror really helps with cutting down parallax errors.

As I said, I favour the 15 over the 54 but both are good. The 15 wins for me because I find the sighting mechanism easier and more natural to use and find the mirror quite useful (suncream). The mirror/lid can also be fully opened to increase the length of the baseplate. Its real winning feature is the "declination adjuster". This allows you to adjust the dial of the compass to take account of the magnetic declination rather than having to remember to add on or take of the adjustment each time (and remember the figure in the first place). This doesn't sound much but it is a real boost if you have to take a lot of readings - particularly at the end of the day when you get tired and lazy. I haven't seen this feature on any other compasses. Unless you are a geologist, the clinometer is not much use but I've not seen this model without one.

If you don't plan to use the compass too much, you might be better going with a basic model and saving the pennies.

Good website by the way. Can't comment on the prices but a nice selection there.

Dave
ps PM me if you want to ask anything else about those compasses.
 
...both my silva ones got a bubble and the last one no longer points North.
My kit usually last me forever, I'm not careless or harsh on it, but I have*no*luck with compasses. Now I'm wondering, is there anything in my bag that I really ought not to keep my compass next to? Is there anything that might de-magnetise it?

I saw a compass go wonky once when the backpack containing it had traveled in a Jeep very near the generator (magneto).
 

ddokkum

Forager
Feb 16, 2007
161
0
48
The Netherlands
Just take a magnet and move it in one direction to the otherside for a couple of times. and you will see it will point to the magnetic north. you can check it with an other compass. i saved a few compasses this way.
 

Toddy

Mod
Mod
Jan 21, 2005
38,992
4,645
S. Lanarkshire
My bother bought me a Suunto one for Christmas that year, and, so far, touch wood, it's rock solid reliable :D
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Bet we've jinxed it now :rolleyes: :eek:

atb,
Toddy
 

Wayland

Hárbarðr
I'm always getting bubbles in mine.

I think it's the altitude and temperature changes.

I'm fed up with buying new ones..
7983.gif
 

crazydave

Settler
Aug 25, 2006
858
1
54
Gloucester
mobile phones I'm told can effect compasses as can a mixture of things. I found that when I stuck my hand into a certain machine at work the polarity of the one on my watch strap would be reversed so I change it every year.

I did have a casio watch with a built in compass that you had to tune in. never worked properly.

lots of things effect compass needles though, have you been standing on laylines or dancing in stone circles again :)
 

woodstock

Bushcrafter (boy, I've got a lot to say!)
Apr 7, 2007
3,568
68
67
off grid somewhere else
I have used my silva 15t since my recce days it has never let me down GPS systems have come and gone but I keep my silva, essential bit of kit in my opinion everyone who goes into the wilds should have one
 

malcolmc

Forager
Jun 10, 2006
245
4
73
Wiltshire
www.webwessex.co.uk
Ferrous metal will affect compasses but the amount of mass required is significant. For the sort of amounts in kit being carried, whether magnetised or not, it would have to be quite close to the compass, within about 6” (15cm), to be detectable. It is possible to alter magnetic properties mechanically but it is rather difficult, a severe shock may do it but normal use shouldn’t. (When my compass is out of its pouch it’s secured to my webbing by a lanyard. I do tuck it into my kit belt to stop it swinging about but that’s more for my comfort rather than anything else.)

What will demagnetise things are high heat or a strong varying magnetic field. Leaving a compass behind glass in strong sunlight is not advisable. The sort of domestic things that produce strong varying magnetic fields are loudspeakers, old style phones with a real bell, mobile/cordless phones and colour cathode ray tubes (used in TVs and monitors which have demagnetising coils, activated every time they are switched on). Even then, close proximity would be needed.

Since I’ve had my Cammenga model 3H compass I’ve become a convert to inductive damping, which will work with the same efficiently over a wide range of temperatures and at any altitude. You can also lock the indicator card after taking a bearing, which I find a useful feature :) . I would recommend this compass (no connection other than a satisfied user). Although the case has a straight edge with a scale it does not have a base plate but then I’ve always employed a separate romer specific to the map scale I’m using at the time.

Hope that helps Toddy.
 

ol smokey

Full Member
Oct 16, 2006
433
2
Scotland
Have used Compasses for years, and only had trouble with a couple getting bubbles.
The latest was a Silva the one with the rubber casing and all the roamer cards and clinometer instruction cards incorporated with it. I took it back to the shop and it was sent bak to Silva. I got it replaced free of charge. It was one of their more expensive models.
I did have a friend who found that the polarity of his compass had reversed after being left in the clove compartment of his car for some time. So we concluded that it was the windscreen wiper motor that had caused the problem.
If the compass is only slightly out from Magnetic North , It can be that the caseing has
become magnatised from some source, and holding it under a running tap or other water source will wash this away , and it will be O.K. again. This was advice given with a Suunto compass I had years ago. Hope this helps.
 
Dec 3, 2008
5
0
France
It's pretty difficult to de-gauss a compass needle but some of the equipment on shop counters for de-gaussing shop-lifting tell tales might do it. In my experience, needle problems are usually caused by bubbles and these may have an avoidable source ...

Squeezing the capsule between finger and thumb will temporarily break the seal between the capsule base and the walls. This lets oil out and air in.

The main offenders are, in my experience, Silva compasses of the universal (Voyager) type, where one has to grip the capsule and turn the bezel against friction to set declination values. Grip it too hard and there's a slight noise and the smell of turps. That's another compass ruined.

I used to have a tiny Silva compass with which it was easier to hold the capsule between finger and thumb rather than turn it by the bezel. That went the same way. Eventually, the air from the bubbles caused the needle to rust badly. Some compasses, however, just have bubbles that come and go, probably with pressure variations.
 

Wayland

Hárbarðr
Snip>

Squeezing the capsule between finger and thumb will temporarily break the seal between the capsule base and the walls. This lets oil out and air in.

The main offenders are, in my experience, Silva compasses of the universal (Voyager) type, where one has to grip the capsule and turn the bezel against friction to set declination values. Grip it too hard and there's a slight noise and the smell of turps. That's another compass ruined.

<Snip

That would explain a lot. :bluThinki
 

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