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<h1>Bivi Rigging Guide</h1>

<p>Every year some poor bugger who has probably never done it before it
gets to rig the tarps and be responsible for any soggy miserable
nights that might result if it's not done well enough. Starting from
the bare space it's really quite hard to know where to start if you've
not done it before, so this doc attempts to provide some advice.</p>

<p>The diagram comes from Wookey+Joe's rigging effort in
2014 when the tarp wrapped up around the rock and a separate one covered the rear. In 2015 we bought a much longer big white tarp which covers the whole rear area down to the ground. So the description no longer really matches the diagram. An updated diagram would be good one day.</p>

<p>There are two essentially-separate jobs:
<ol>
<li>the
<a href="water">water-collecting tarp</a>, and </li>
<li>the <a href="#main">main tarp</a></li>
</ol></p>

<p>If there is any chance of it raining soon, <strong>start with the <a href="water">water
tarp</a></strong>, as you <strong>really</strong> don't want to miss collectingt all that water, and
setting up in the rain is rubbish.</p>

<h2>Terminology</h2>

<p>I will describe things as if standing at the bottom entrance looking
up, because that works for all three sections. So the
<strong>left</strong> wall is the
gear/stove/animal-hole wall. The 'back' is the top end of the bridge.
The 'front' is the main entrance.</p>




<h2 id="main">Main roof tarp</h2>


<p>Since 2015 we have one really big (15x10m, white) tarp (rather than
the smaller 10x10 green one, shown in the diagram). This covers the whole
sleeping area from front to back and is a lot drier. It is set up so
that essentially the whole bivvy is covered. The tarp is just about
wide enough to span the width of the bivvy. The instructions below are
a good guide as to how to set up any tarp, and the large white tarp
actually has a few instructions written on it. You can largely ignore
the 'fold' notes, and use your own judgement.</p>
<img src="i/bivirig.jpg" alt="Drawing of pre-2015 tarp layout" width=800>

<p>Start with the big white tarp. The long edge goes from front to
back of the bivi. The basic position is that it goes all the way to
the right wall, partly 'underneath', and the left hand edge crosses
the steps up the middle. The back edge reaches the floor behind the
top 3-person flat area at the back entrance.</p>

<p>So start by opening it out to full width on the wide central
bed-shelf. and pulling the RH edge close to the wall. Sequencing the
ropes is a bit tricky, you need the tarp vaguely in place, then
install the two main ropes to lift it up. Finalise the tarp position
and tension it.</p>

<p>Once the tarp is somewhat spread out, rigging the ends of the two
main ropes - one across the front and one across the middle (passing
under the tarp). These are the two that take high loads. The rear
major rope has no real load - it just keeps things neat. Now tension
them to lift the tarp up and ensure it is neatly spread. The middle
rope attaches to the roof bolt just at the LH edge of the tarp. This
needs someone very tall, or sitting on shoulders, or something devious
with bivi string to pull it tight.</p>

<p>P.S. At the rear entrance, you can rig up some extra tarps to make
it more comfortable.</p>

<p>This is one large tarp covering most of the internal
roof and coming out both the front and the back to the ground. There are two main cross-ropes, one at either entrance to hold it up, another central cross-rope, and 'knitting' to reduce sagging in the almost-flat central area.
The objective is to get it taut enough and square enough that almost
all the water runs down the top and out the front, rather than collecting in
'buckets', which then drip. That means that it has to be fitted quite
'flat'. </p>

<p>Ideally the lines that run down from back to front should be so tight that 
no cross-lines are needed. Thene there can be no dripping pockets at all. This requires 
threading lines through maillons in the roof, rather than tying them off, 
then pulling down on the line with all your weight (jammer and a friend useful)
before tying off at another bolt at about waist level. 
You should not need to put in new bolts, they should all be in place already.

<h3>Rear entrance tarps</h3>
<p>to be written</p>

<h3>Front entrance tarps</h3>
<p>to be written</p>

<h2 id="water">Water tarp</h2>

<p>Use a long/thin (2x5m) waterproof 'logpile' tarp. It is hung
between two side longitudinal ropes, with lots of bits of string
attaching the eyelets to the side ropes. Aim to hang it under the hole
in the roof, and far enough forward that water off the front falls
onto the 'water platform' (not into the food boxes).</p>

<p>It's easiest to approximately tie the tarp to the side ropes with
adjustable knots, then put the ropes in place, adjusting as you
go. The outer line ends up too high to adjust once properly in
place. Adjust it to catch as much of the water falling through the
hole as possible, and slope gently, but consistently downwards.</p>

<p>The funnel/filter is hung below the end of the tarp where
it will get nearly all the water and is much easier to hang/adjust/unclog. (Prior to about 2010 we hung it directly below the hole, but that missed a lot of water and was very difficult to adjust or unclog.)</p></body>
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