Instructions for creating a fast water proof bivouac
This is how we construct a bivouac. It does not use natural materials for the covering because :
we want something that is quick to put up, and a couple of skilled Scouts can put this up in 5 minutes;
the location where we often undertake this activity just could not sustain the loss of the materials such as branches and leaves (the only materials available in quantity are ferns and it not advisable to use them for a bivouac);
and if necessary, you could probably find the materials needed as scrap on a farm.
For building a standard bivouac we use cheap plastic sheets available in B&Q. These only cost a few pounds and come in small and large sizes. The large size (5m x 4m) produces a comfortable bivouac for at least 4 scouts. Two small size sheets could be used by 2 scouts.
Select two trees, ideally as far apart as the width of the sheet. Tie a rope at head height between the trees. (Use a harvester's knot to tighten the rope: the tighter the better.)
Place the sheet over the rope in the shape shown. A 6th over-lapping the front, a half making the rear wall, and the rest making the groundsheet. Peg the sheet down at each corner. Add two guys for the front of the sheet. (Bailer twine is fine for this.)
And that's it. The advantage of an open side shelter is that you can light a fire a few feet away from the shelter. Sit in comfort whilst you cook your meal, or keep warm at night.
The best design of fire to use is a reflector fire. It will radiate heat into the shelter.
See attachment for how it should look.
Placing you bivouac under trees is a good idea in the colder months of the year, as you will find the trees protect you from frost and cold air. This is particularly true of Scotch's Pine. However, be careful where you place your fire. Do not use a position which might damage the tree.
Alternative designs of bivouac.
There are a number of other designs you can use :
If the weather is very wet, then rather than an open sided shelter, tie the rope at a lower height and make a tent shape.
If you don't have two conveniently spaced trees, use a pole instead of a tree, with guys to hold the pole upright.
You can use a long pole instead of the rope, lashing it to the trees.
If you don't have any poles, tie the rope from the tree to a peg in the ground.
The sheets you get from B&Q can be heavy to take on a hike, an alternative can be made from lightweight tent material. It's much more expensive though !.