Update tarp diagram and description for 2015 and 2024 layouts/tarps.

2025-12-08 23:04:35 +00:00 · 2025-06-30 00:56:39 +01:00
parent 85cb9c1efd
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3 changed files with 364 additions and 257 deletions
--- a/handbook/bivirig.html
+++ b/handbook/bivirig.html
@@ -2,11 +2,11 @@
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-<title>Stone bridge bivi rigging guide</title>
+<title>Stone bridge bivvy rigging guide</title>
 <link rel="stylesheet" type="text/css" href=/css/main2.css />
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-<h1>Bivi Rigging Guide</h1>
+<h1>Bivvy 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
@@ -14,8 +14,7 @@ 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>Until 2014 we had a shortish green tarp (10mx6m) wrapped up the back edge at upper entrance and a separate tarp for that upper area. It wasn't very good. In 2015 we bought a much longer big white tarp (15x6m) which covers the whole rear area down to the ground. In 2024 we bought a replacement but due to a documentation error that one is 15x10m which is really too wide. This description has been updated for the 2024-on version.</p>

 <p>There are two essentially-separate jobs:
 <ol>
@@ -31,70 +30,75 @@ 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
+up, because that works for both 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>

-
+<p>Tie bungee-balls (not rocks!) into the tarp to hold it in place
+when you do not have eyelets to hand. Rocks are pointy and damage the
+tarp. We have plenty of bungee-balls - find them.</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>Since 2015 we have had one really big tarp. This covers the whole
+sleeping area from front to back. It is set up so that essentially the
+whole bivvy apart from the water-tarp area is covered. The 2015 tarp
+was just about wide enough to span the width of the bivvy (i.e. the
+right size (15x6m)). The 2024 tarp is 3-4m wider than the bivvy, so
+has to be folded along the long axis to work. It is 15mx10m. </p>
+<img src="i/bivirig.jpg" alt="Drawing of post-2024 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>
+top 3-person flat area at the back entrance. The front edge comes down
+to ground level.</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>So start by opening it out to full length over the sleeping areas
+to the right of the steps, and folding 3.5m of the right hand edge
+back over on top. This needs to be reasonably neat and square, as you
+can't get to it later. Then pull the folded RH edge close to the
+wall. Sequencing the ropes is a bit tricky: you need the tarp vaguely
+in place, then install the four main ropes to lift it up. Then
+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>Once the tarp is somewhat spread out, get the 4 main ropes in place
+underneath it.  Use the anchors shown on the diagram. The secret to
+the middle rope is _not_ to use the obvious ceiling bolt which is hard
+to reach; instead tie the rope to a tension rope (5) above the
+steps. This allows the tarp edge to come further left and run square
+to avoid sagging. Tension rope 2 first, then 1,3,4 to lift the tarp up
+and ensure it is neatly spread. You will need bungee-balls to hold the LH
+edge of the (folded) tarp in place.  To get good tension on the main
+lines thread them through a maillon, and tie off on another bolt. You
+don't need to add any new ones - there are more than enough bolts
+now.</p>

-<p>P.S. At the rear entrance, you can rig up some extra tarps to make
-it more comfortable.</p>
+<p>At the left-hand end of rope 4 the tarp gets scrunched round the
+anchor. This is fiddly to get it all to hang nicely. The objective is
+to get the whole tarp 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'. To make this theory actually work, add extra lines in a
+zig-zag pattern between the main ropes so no buckets can form. Don't
+tension them too hard as they distort the main ropes - it's a
+balancing act to get the tension everywhere right.</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>To keep the electrics dry the edge of the tarp is held taut with string to concrete screws in this area</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.
+<p>At the front edge the tarp lays over rocks. Put some padding
+(karrimat/old tarps) over the rocks to avoid damage to the new
+one. Lay rocks on the edge on the RHS. On the LHS use string to tie
+the front edge down. </p>

 <h3>Rear entrance tarps</h3>
-<p>to be written</p>
+<p>This is the hardest part to get right. A couple of judicious
+bungees tied up high at the back wall will stop 'buckets'. [More detail should be added here]</p>

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

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

@@ -102,7 +106,8 @@ You should not need to put in new bolts, they should all be in place already.
 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>
+onto the 'water platform' (not into the food boxes). We now put two of
+these up to avoid drips and add water-collecting redundancy.</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
@@ -110,6 +115,7 @@ 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>
+<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.</p></body>
 </html>
--- a/handbook/i/bivirig.jpg
+++ b/handbook/i/bivirig.jpg
--- a/handbook/i/bivirig.svg
+++ b/handbook/i/bivirig.svg