Edited by Rachel Duncan 4th Edition ISBN 0-907649-91-2 London ...

Campcraft, Equipment and Clothing 25
versatile and allow faster travel, but their efficient use does require practice. Snow shoes
are better than skis in deep-soft snow and in woodlands and need virtually no initial skills.
3.5 Clothing
There are numerous articles on clothing for expeditions and the three-layer principle, not
least in the technical brochures of the manufacturers. Here is an overview:
3.5.1 Base layer (or vapour transmission layer)
Moisture should be carried (‘wicked’) away from the skin through the base layer, instead
of remaining and evaporating with consequent heat loss. Garments are generally close
fitting and designed to stretch. To be effective, the material should absorb little or no
moisture and be quick drying. The layer usually has some insulation value. Synthetic thin
fleeces have a high warmth to weight ratio, absorb very little moisture and dry very
quickly. Don’t be tempted to wear your favourite cotton T-shirt.
3.5.2 Mid layer (or insulation layer)
Warm air is retained within the bulk of the material whilst still allowing moisture to pass
through. This layer may also at times be the outer one and garment design should allow for
adjustment of ventilation – zip, sleeves able to roll up, etc. Modern fleece garments may
have pockets and be of a more generous cut, particularly under the arms. For the upper
body, two thinner layers may be more effective than one thick one, thereby allowing one
layer to be removed if too much heat is being produced. It should therefore be easy to take
off. Mid-layer trousers will only be needed in severe conditions. An outer fleece with a
windproof shell can prove very practical. In addition, down clothing cannot be beaten for
its insulating properties.
3.5.3 Top layer (or protection layer)
The outer layer should be ‘breathable’ as far as possible, windproof, and except in dry
polar conditions, waterproof. Most fabrics may have to trade ‘breathability’ for
waterproofness and vice-versa. Draw-cords at the waist and lower hem and certainly
around the hood, are useful features for helping to retain warm air and reduce its
circulation. Salopettes will avoid cold around the midrift but make sure that they have zips
so that you can go to the loo without removing the rest of your top layers first. They should
also have long leg zips so the legs can then be tied up at the waist when not in use and you
do not have to remove boots to take them on and off.
The traditional outer layer used particularly in Antarctica where rain is not a problem, is
windproofs of Oxford cotton Ventile. The advantage of Ventile over Gore-tex is that it will
release moisture more effectively, is more flexible/softer in the cold and more durable.
This has been overtaken by the system described below but Ventile still has its followers.
3.5.4 Alternative layering system
The challenge with polar clothing is how to provide enough insulation to keep warm over a
range of efforts from producing a lot of body heat whilst moving to cooling down at rest
and how to minimise moisture in the clothing. The traditional shell or outer layer is very
wind and waterproof but not particularly breathable.