Lensatic/Prismatic/Sighting Compasses

[Britboy]

Hey everyone,

Currently using a Silva lightweight compass (Type 4 NATO, seen it advertised as 'Expedition' one for civvies) as issued, and all is well.

Wondering if there is any more accurate compass for taking bearings though.

Googling around, I came across various other compasses, some ones with mirrors and sights on them. There was the US issue one described as 'lensatic' and an older GB issue one described as 'prismatic' too...

I understand you need a separate protractor to use them alone (which'd be a bit of a ballache) but am wondering:

A) Are they much more accurate than Silva-type protractor-compasses?

B) Worth getting one to augment the Silva, for making resections/fixes more accurate? Wouldn't need a separate protractor then, could just set the reading on the Silva...

C) What are the various types available, do they work around the world (would hate to buy e.g. a US one and find out the needle is weighted for a different part of the world)?

and

D) Whats your opinion in using them for land nav? Worthwhile tools or better off sticking with a Silva?

Cheers!
BB

[Alpheus]

I have a Suunto MC-2D. Very useful and easy to use.

http://www.travelizmo.com/archives/000759.html

[Crewdog]

Any western military compass you find will be built to nato specs. That being said I have used the US lensetic and find it very good at what it is designed to do. It has a straight edge on one side which is graduated to measure distance on military maps. the wire site on top and the small magnifing glass, which is the lensetic part I believe, alow you to shoot a bearing with ease.

I can not speak for the other compass' you mentioned.


As for being accurate, I would guess that a compass is as accurate as the operator. So long as you have your deflection accounted for in the region you are working in you should be fine.

[Britboy]

Yes I agree its down to the individual. Its just that with some compasses (the thin ones that you just point at the object you are taking a bearing of) there is no sighting system on it like the Suunto/US ones you both mention. Its good for the great majority of the time, and when you do get a 'cocked hat' or triangle on a resection you can normally figure out where in it you are by local features and its not really that big anyhow, but part of me wonders if it wouldn't be worth getting a proper sighting compass as well, just for those times when you wish it was a bit more accurate.

And yep you're right on GMA, in the UK it is not such a large GMA so some people say you can get away with not worrying about it...

Anyone know the accuracy of some of these sighting compasses? ~50 mills?

[Royal]

Anyone know the accuracy of some of these sighting compasses? ~50 mills?

Have you never used the issued G10 prismatic?

Accuracy is down to user experince/skill, maint and the compass itself.

The prismatic can be accurate to 10 mils with a really good user. It's old and heavy (and needs a protractor) but it's bombproof.

I have a WWII dated one that I picked up in a junk shop in Glasgow in the 90s. I had one of the REME techs give it the once over and its still spot on. I still stick it in the top of my rucksack when I head out in winter, partly for old times sake, but also because its more accurate than anything else that I own.

[digrar]

I used a prismatic Silva while i was in, did the job, bonus of having the inbuilt protractor.

[Britboy]

Never used a prismatic/lensatic/sighting compass.

In fact never used anything but the issue lightweight compass, Silva one with the protractor built in as the baseplate.

If you can shoot a bearing down to 10 mils, thats got to help a lot with fixing posn off faraway objects, and other things of that ilk (I bet FOOs and MFCs get them then..?).

To be honest I'm quite tempted to seek one out now...
Keeping the Silva as well for the majority of stuff and to use the protractor part of it...

[Royal]

Never used a prismatic/lensatic/sighting compass.

Jeez - what is the world coming to?


If you can shoot a bearing down to 10 mils, thats got to help a lot with fixing posn off faraway objects, and other things of that ilk (I bet FOOs and MFCs get them then..?).

They were issued down to section commander level in my day - mind you that was back when we also got the 58 pattern webbing pouch to put them in :D

[oldsoak]

Trying to get a lensatic out of the Q is like asking for the crown jewels. I always get issued the the Silva type 24 - but as I've got my own....
Is it for mil or civvy use ?
Try getting a recta globemaster -its balanced for worldwide use and its a good sighting compass. In fact, the whole recta range is worth looking at.

[Britboy]

Mil and civvy - I'm a territorial (inf), but also like getting out in the hills when I can, that and the odd bike ride/long jog in the country where I usually get lost, so I take a map to be sure :p

You can get a compass that is alright for worldwide use? Interesting, thought they had to be balanced from region to region, or at least hemisphere to hemisphere...

[oldsoak]

Yep - I needed one I could use downunder as well as Europe - hence the Recta globmaster. Rather than use a magnetic needle balanced in the middle on a bearing like traditional compasess, they use a small magnetic ring. The ring can pivot up and down around the bearing, so automatically compensates for balance.

www.mapworld.co.nz/global.html says it better.


Have a look at these - www.alloutdoor.co.uk/recta-compasses-142-c.asp

good gear.