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Author Topic: Thumb compasses
Mike
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Post Thumb compasses
on: March 15, 2017, 16:16
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Dear All
Some juniors have been asking me to recommend a thumb compass.
I use a Silva Spectra 6 Jet which I think is fairly common.
Unfortunately this is now out of production.
Any advice?
Thanks
Mike

Angus
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Posts: 219
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Post Re: Thumb compasses
on: March 15, 2017, 16:29
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I have been through a few different makes and have settled on Suunto arrow 6 which I really like and I get on well with it. It's different for different users as the angle between thumb loop and the long side varies between the makes. I suggest that different ones are tried before committing to a purchase. I have a spare Suunto and previous compass that I replaced with the Suunto that I am willing to lend to juniors if they want to try them out.

hugh
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Post Re: Thumb compasses
on: March 15, 2017, 20:25
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I use a moscow compass they have quite a few different models. I use a model 3 stable.
They have more info on their website
http://www.moscompass.ru/mc/index-en.html

johnmccull-
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Post Re: Thumb compasses
on: March 15, 2017, 22:37
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You also need to decide which hand you are most comfortable holding your map in and to get a thumb compass for that hand. Another feature is that some thumb compasses have a rotating bezel like a conventional baseplate /protractor compass so you can take fairly accurate bearings with it; others don't have a rotating bezel so you can't take bearings. The stability of the needle and the speed the needle settles vary between models: there can be a trade-off between speed and stability.
I'd agree with Angus: try a few before deciding. Borrow one from another orienteer and try it.
Ultrasport and CompassPoint both have a range of compasses on their websites. Another option is to get a thumb compass with a built-in SI card from Sportident.
JMcC

psmythirl
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Post Re: Thumb compasses
on: March 16, 2017, 01:58
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I use a Moscow Model 3 (Stable). I find this to be an excellent compass, not just for orienteering but also for NAV and MM events. It has a rotating bezel which is ideal for long legs on mountain navigation type events. I also use this feature on certain types of legs in ordinary orienteering.

SportIdent are doing a World O-Day special offer at the moment (at least it still appears to be available) where you can buy a "school" SI Compass consisting of a Moscow thumb compass with built in SI card (20 punches only) for EUR22. This is a less specialised compass than the model 2 or 3 type but should still be a good general all-round compass. I have one but have only used it once so I can't really give a review of it at the moment. Details at https://www.sportident.com/wod.

With regard to John's points I think most orienteers hold their map in their off hand and use their dominant hand for punching with their SI-card. The greater dexterity in the dominant hand generally makes punching much more fluid with that hand while the other hand is free to keep track of the position on the map, and the map and compass don't get in the way of punching.

This raises the interesting question of what happens when using an SI compass. I don't have an answer to that question and I only know one person who is using an SI compass regularly in Leinster, so I don't have much data to go on. I'd be interested to hear other people's experiences with the SI compass.

You could of course just use the SI compass as a compass and continue to use an SI card. My current thinking is that there isn't an advantage to having the SI card and compass combined and in fact it is a disadvantage for the following reasons:

- The card, compass and map will all be in the one hand and the whole shebang has to be used to punch whereas with the usual arrangement, with practice, one can punch and continue essentially unterrupted to read the map.

- The compass has to be positioned in just the right way to punch which again breaks attention from the map during punching. With a regular SI card, again with practice, if you position your hand in the right way then the card is pretty much guided into the hole for punching and this becomes almost a reflex which takes no conscious effort and therefore doesn't break concentration while punching.

I think that our system of positioning controls in this country is part of the problem with this. There is little doubt in my mind that it is more more akward to position the compass correctly for punching when the control is vertical rather than horizontal. Never mind that the intended positioning of the control boxes is horizontal. Every international event I have attended has had the controls positioned horizontally and SI themselves have started selling specially designed control stakes which also position the control horizontally. These are thin and lightweight fibreglass stakes that take a standard SI control baseplate. I hope to get Ajax to get some of these to try. While much more expensive than electric fencing posts I think they potentially have a lot of advantages.

It would be interesting to have a survey of the compasses used in Leinster by regular orienteers. I had assumed that the Moscow compasses were currently the dominant model but I haven't looked that closely to see what people were using. Certainly, up until 2000 or so the Silva compass was dominant. Anyone want to set up an online survey?

Looking at the current Silva product pages I notice that their thumb compasses don't have any scale along the direction of travel edge. That's a pity as I find that indispensible in the Moscow compass. Some of the Silva thumb compasses also feature what is known as the Spectra System which divides the bezel into twelve regions identified by colours and black dots. Essentially you have yellow (no dots) yellow (one dot), yellow (two dots) etc. There is a video here https://www.youtube.com/watch?v=h1w1mqVF-2c, that shows how it's intended to work (bizzarrely, the Silva web-page doesn't seem to have any information on it!). My reading of it is that it's intended to be a kind of idiot-proofing of the task of taking and following a bearing. Unfortunately there are a lot or problems with this, not least of which, is the idea presented in the video, that you take a bearing, then take your compass of the map to follow it. That is just wrong! It's also too inaccurate an approach for bearings in orienteering in my opinion. I'd be interested to know if anyone is actually using this system and what their experiences are. I would personally dissuade novice or junior orienteers from adopting it in favour of the standard approach to the use of a thumb compass. I'm happy to be convined otherwise if I'm wrong that this is actually a great approach to compass use in O, but I doubt it!

psmythirl
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Post Re: Thumb compasses
on: March 16, 2017, 02:05
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Sorry, all that diatribe and I forgot to say that I agree with previous posters who recommend experimenting with different set-ups. The only way to be sure of what works best for you is to try out all the different options. For the juniors I'd recommend setting aside some time at a junior training session where they can experiment over a section of a course with different models, arrangements etc.

Angus
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Posts: 219
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Post Re: Thumb compasses
on: March 16, 2017, 08:59
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One issue I've found with the fibreglass stakes is they are not rigid and blow about in the wind making one handed punching difficult in windy conditions. Of course for organiser they are great as they're lightweight. AJAX already have lightweight stakes that hold the boxes horizontally so I don't see why you need more unless it's to replace broken/lost stakes.

Back to compasses I'd say it was an innocent enough question that started this, without thinking there'd be so many pints to consider. My original silva thumb compass had a fixed housing. Any compass I've got since has had rotating bezel. I failed with the spectra system becasue I would immediately forget which colour and dots I needed for the particular bearing 🙂

psmythirl
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Post Re: Thumb compasses
on: March 16, 2017, 09:33
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We have reasonably light stakes which hold the box horizontally but most clubs have their boxes mounted vertically which makes punching more awkward with the compass. Our stakes are still quite bulky and toting 10 or 12 of them around when putting out or collecting controls is still a bit of a pain. Your comments on the fibreglass stakes are interesting - were they SI stakes or some other brand? Does Setanta have some of these stakes? I'd be interested in having a look at them if so.

I'm digressing too far though from the topic at hand so I'll close with this:

The Spectra system is completely unnecessary if you use a thumb compass as it's designed to be used, i.e. constantly on the map.

johnmccull-
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Post Re: Thumb compasses
on: March 16, 2017, 16:41
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The Sportident World O-Day combined compass and SI card offer is an attractive price but the SI card only holds 20 controls.

psmythirl
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Post Re: Thumb compasses
on: March 16, 2017, 18:41
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20 punches is adequate for almost all junior use and even with that limitation EUR22 is an excellent price for a thumb compass alone.

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