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119 lines
5.2 KiB
HTML
119 lines
5.2 KiB
HTML
<!DOCTYPE html>
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<html>
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<meta http-equiv="Content-Type" content="text/html; charset=utf8" />
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<title>Stone bridge bivi rigging guide</title>
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<link rel="stylesheet" type="text/css" href="../css/main2.css" />
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</head>
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<body>
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<h1>Bivi Rigging Guide</h1>
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<p>Every year some poor bugger who has probably never done it before it
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gets to rig the tarps and be responsible for any soggy miserable
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nights that might result if it's not done well enough. Starting from
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the bare space it's really quite hard to know where to start if you've
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not done it before, so this doc attempts to provide some advice.</p>
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<p>Note that this was written after Wookey+Joe's rigging effort in
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2014. It is not necessarily optimum, but did seem to more-or-less
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work. Feel free to improve it over time.</p>
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<p>There are two essentially-separate jobs:
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<ol>
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<li>the
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<a href="water">water-collecting tarp</a>, and </li>
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<li>the <a href="#main">main tarp</a></li>
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</ol></p>
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<p>If there is any chance of it raining soon, <strong>start with the <a href="water">water
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tarp</a></strong>, as you <strong>really</strong> don't want to miss collectingt all that water, and
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setting up in the rain is rubbish.</p>
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<h2>Terminology</h2>
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<p>I will describe things as if standing at the bottom entrance looking
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up, because that works for all three sections. So the
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<strong>left</strong> wall is the
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gear/stove/animal-hole wall. The 'back' is the top end of the bridge.
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The 'front' is the main entrance.</p>
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<h2 id="main">Main roof tarp</h2>
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<p>How not to do it</p>
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<img src="i/bivirignm.jpg" alt="Bivi Rigging Nightmare" width=800>
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<p>Since 2015 we have one really big (15x10m, white) tarp (rather than
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the smaller 10x10 green one, shown in the diagram). This covers the whole
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sleeping area from front to back and is a lot drier. It is set up so
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that essentially the whole bivvy is covered. The tarp is just about
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wide enough to span the width of the bivvy. The instructions below are
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a good guide as to how to set up any tarp, and the large white tarp
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actually has a few instructions written on it. You can largely ignore
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the 'fold' notes, and use your own judgement.</p>
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<img src="i/bivirig.jpg" alt="Drawing of pre-2015 tarp layout" width=800>
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<p>Start with the big white tarp. The long edge goes from front to
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back of the bivi. The basic position is that it goes all the way to
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the right wall, partly 'underneath', and the left hand edge crosses
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the steps up the middle. The back edge reaches the floor behind the
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top 3-person flat area at the back entrance.</p>
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<p>So start by opening it out to full width on the wide central
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bed-shelf. and pulling the RH edge close to the wall. Sequencing the
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ropes is a bit tricky, you need the tarp vaguely in place, then
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install the two main ropes to lift it up. Finalise the tarp position
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and tension it.</p>
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<p>Once the tarp is somewhat spread out, rigging the ends of the two
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main ropes - one across the front and one across the middle (passing
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under the tarp). These are the two that take high loads. The rear
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major rope has no real load - it just keeps things neat. Now tension
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them to lift the tarp up and ensure it is neatly spread. The middle
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rope attaches to the roof bolt just at the LH edge of the tarp. This
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needs someone very tall, or sitting on shoulders, or something devious
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with bivi string to pull it tight.</p>
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<p>P.S. At the rear entrance, you can rig up some extra tarps to make
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it more comfortable.</p>
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<p>This is one large tarp covering most of the internal
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roof. There are two main cross-ropes to hold it up, ties at the back
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edge and 'knitting' to reduce sagging in the almost-flat central area.
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The objective is to get it taut enough and square enough that almost
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all the water runs down the top and out the front not collecting in
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'buckets', which then drip. That means that it has to be fitted quite
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'flat'. </p>
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<p>Ideally the lines that run down from back to front should be so tight that
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no cross-lines are needed. Thene there can be no dripping pockets at all. This requires
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threading lines through maillons in the roof, rather than tying them off,
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then pulling down on the line with all your weight (jammer and a friend useful)
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before tying off at another bolt at about waist level.
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You should not need to put in new bolts, they should all be in place already.
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<h3>Rear entrance tarps</h3>
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<p>to be written</p>
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<h3>Front entrance tarps</h3>
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<p>to be written</p>
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<h2 id="water">Water tarp</h2>
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<p>Use a long/thin (2x5m) waterproof 'logpile' tarp. It is hung
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between two side longitudinal ropes, with lots of bits of string
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attaching the eyelets to the side ropes. Aim to hang it under the hole
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in the roof, and far enough forward that water off the front falls
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onto the 'water platform' (not into the food boxes).</p>
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<p>It's easiest to approximately tie the tarp to the side ropes with
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adjustable knots, then put the ropes in place, adjusting as you
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go. The outer line ends up too high to adjust once properly in
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place. Adjust it to catch as much of the water falling through the
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hole as possible, and slope gently, but consistently downwards.</p>
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<p>In past years we have hung the funnel in the hole. This is a faff
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and misses a lot of water. Just hang it below the end of the tarp where
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it will get nearly all the water and is much easier to hang/adjust/unclog.</p></body>
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</html>
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