The Technology Centre had been approached in 1952 by the British Everest Expedition and tasked with designing so-called ‘assault’ boots for the final push to the top of the mountain. The specification seemed to be straightforward, and called for footwear that was warm, strong, a comfortable fit, able to take crampons and easy to put on and take off. Nevertheless, it was obvious that radical ideas were needed to enable the climbers to cope with altitudes never before reached.
Until the British Everest expedition, climbing boots had been traditionally made from thigh-length deerskin cocoons which were bulky and rather cumbersome to move in – hardly ideal for the ultimate climbing challenge. Responsibility for conceiving a revolutionary design was given to SATRA Director of Research, Harry Bradley, who created a very warm, low and lightweight boot which set the style for many commercial productions during subsequent years. A small team of experienced SATRA experts started work on four trial pairs of boots. Leather with a lightweight rubberised fabric backing was selected for the insoles, and the linings were also made from rubberised fabric, all seams being sealed with latex. A light and flexible leather with reasonable water repellence was required for the uppers, glacé kid being chosen for this component of the boot, being sprayed with latex for added protection. These uppers were deliberately made considerably larger than the linings in order to allow for the inclusion of ample amounts of Tropal insulation material (figure 1), described as ‘an uneven web of kapok fibres’. A vapour barrier was formed by cement-lasting the rubberised fabric linings to the backed insole, thus creating a completely moisture-proof inner ‘skin’. This prevented the insulation from becoming wet, which would have reduced the effectiveness of the insulation. Allowing the climber’s sock to become wet was judged as acceptable, so long as his foot remained warm…‘ full article http://www.satra.co.uk/bulletin/article_view.php?id=529