A Walk In The Bush (Part 2)

Anyway, once we’d gotten back to the upper part of Mt Donna Buang it was time for a quick brew. Normally, of course, I’d be taking great care with selection of a campsite, but that wasn’t the purpose of today. I only really wanted to take some photos of the DD Hammocks multicammo tarp that I’d recently received. I found a nice little sunspot amongst the trees and got a brew on. Very welcome it was, too.

Image

The tarp, by and of itself, was perfectly fine. I like the 3x3m dimensions, but not enough to replace my smaller bashas (sorry, “hoochies” – I have been ordered to say “Damper” instead of “Bannock” as well). The pattern itself is a good demonstration of the difference between genuine multicam and its lesser imitators. Now I am a massive fan of the DD hammock, I am unable to find fault with it and could rave about its positive features for hours on end, but I was less impressed with the tarp. Don’t get me wrong – it’s perfectly functional and comes with lines, pegs and nice bags to keep it all organised: great value for money. I just feel that the pattern is too fine, leading to ‘blobbing out’ rather than blending in, it seems to reflect light very brightly rather than absorbing it, and due to the size of the tarp compared with the small grid of the pattern, it leads to a rather obvious repeat pattern in the darker shades that run in a visible line which makes it look artificial. I reckon if they had enlarged the pattern it may have worked better. However, its square shape makes it good for setting in a diamond configuration over a hammock, so I may yet use it and re-appraise it.

Rough setup to demo the pattern

 Donna Buang is the source of the Yarra river which hits the ocean at Melbourne. There are multiple run-off streams cascading down the mountain, and so clean, fresh water is abundant for longer term stays.

 

I’ve been trying to adapt to international map reading standards since coming out here. It makes me appreciate fully how awesome the Ordnance Survey is – to have the entire country mapped in 1:25000 is a luxury I sorely miss. Victoria is covered by a 1:25000 grid, but this is about 25 years old, apparently. For topography it’s fine, of course. The newer maps are all 1:50000 and use Universal Transverse Mercator Datum, specifically GDA94. On a GPS receiver (I use the Garmin Fortrex 401) it gives you two seven figure grids for eastings and northings. A standard six figure reference is made up of the 3rd, 4th and 5th digits of each set. For compass work, you need an Australian compass. This is because the planet has several compass zones (five or six, I can’t remember – most of them divide up SE Asia), the entire northern hemisphere being one and the others spread across the south to allow for the interference of the magnetic south pole. The deviation here seems to be about 100-200mils and gives the compass needle/plate an annoying skew which can further affect a reading. It occurred to me that I don’t have the first clue how a calibrated compass affects GMA when translating between magnetic and grid. Things were so much easier in the UK…

 

The day was a simple success, and gave a glimpse of the possibilities that Australian free camping has to offer. Since arriving I have seen at least three news stories of locals getting lost in the bush and being rescued by helicopters and large search parties. It’s a big old place, and I can only smile when I look at a 1:50000 sheet map that only has about 20cm of sealed road on it amidst an endless sea of contour lines and rivers. Can’t wait for my first nights out in the bush and have a few locations in mind to take full advantage of this stunning landscape.

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4 Comments

  1. ukbushcrafters said,

    May 11, 2012 at 9:47 am

    What is GMA? I’m assuming something like magnetic declination? Great article Stu. That last paragraph really gives a sense of the scale of the place and the possibilities of actually being ‘in the wilds’ which are sadly lacking outside of Scotland back here in the UK.

    • Stuart said,

      May 11, 2012 at 10:31 am

      Grid Magnetic Angle – the variance between grid north on a map and magnetic north on a compass. Magnetic declination is the difference between true north and magnetic north. When going from a compass reading to a map you remove the GMA and to go from a map reading to a compass bearing you add it. The army taught it like “Mag to Grid, Get Rid – Grid to Mag, Add”. The problem is that GMA varies over time and location. In my day, in the UK, it was 100mils near as dammit. I doubt that’s the most accurate measurement the world has ever seen…

      • Stuart said,

        May 12, 2012 at 1:43 pm

        So, if you want to know the GMA, look at the small print on the map…bleedin’ obvious really. GMA 11.1.0 degrees east in 2010 with +1 degree annually. That’s 233 mils in 2012 which is more than twice what I thought it was. Without that adjustment, if you stuck exactly to a bearing from the map for 1km, by the end of it you’d be 233m east of where you thought you were on the map. 1/5th of a grid square – not inconsequential…

  2. Stuart said,

    June 26, 2012 at 11:41 am

    Just as a quick correction, the map says +1 minute annually, so GMA in Oz is 200mils in 2012. Don’t know what it is in the UK at the moment…


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