1948/01/01 by M. F. Perutz · 1 voice · 1 citation
Engineering · Medicine · #Forest Biomass Utilization and Management #Winter Sports Injuries and Performance
paper · pdf · doi:10.3189/s0022143000007796
openalex publication_date 1948/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
I NTRODUCTIONIn the autumn of 1942, when the German army had advanced almost to the gates of Alexandria and the U-boat war had reached one of its most critical phases, it was evident that some of the Allies' difficulties were due to their lack of air power in the distant battlefields.There was not only a scarcity of aircraft, but such machines as they possessed had a limited range and could not be brought into operation where they were most needed.It had been a common experience that the carrier-based aircraft of the Allies were inferior in armament and speed to the land-based planes of the enemy.It was feared, therefore, that in an invasion of a distant shore the allied armies would be handicapped by lack of air support until they had actually succeeded in establishing their own airfields there.It was only natural, therefore , that a proposal for the apparently cheap construction of gigantic aircraft carriers, capable of operating land-based aircraft thousands of miles from their base, was seriously considered.In October 1942 Mr. Geoffrey Pyke, the originator of the plan, submitted a memorandum to the Chief of Combined Operations in which he proposed that an iceberg, either natural or artificial, should be hollowed out to shelter aircraft and levelled to provide an adequate runway.It must have a mobility of at least a few knots and be guaranteed against melting, if not indefinitely at least until it had fulfilled its strategic purpose.Mr. Pyke pointed out that all strategic materials such as metals, wood and concrete were already being used to the full for the war effort and that ice , requiring for its manufacture only I per cent. of the energy needed for an equivalent weight of steel, would be ideal as a basic material for the construction of large carriers.Ice, he considered, possessed many advantages; it was difficult to break up with explosives, as shown by the tenacious resistance of icebergs to shellfire, and it melted very slowly when insulated.Moreover, the greatest attraction of a floating air-base made of ice was the fact that it could not be sunk.In December 1942 Mr. Churchill issued a directive that research on the project should be pressed forward at the highest priority, but expressed the opinion that it would be essential "to let Nature do the job" of making the bergship, as otherwise the technical difficulties would prove insuperable.He also suggested that ice floes might be towed into the Atlantic from the Arctic Seas and used as airfields until they were broken up by melting.It soon became apparent, however, that neither natural icebergs nor ice floes were suitable as air-bases, the former because their surface above the water was too small and the latter because they were too thin to withstand the waves of the Atlantic.The Russian North Pole Expedition under Papanin, for instance, had shown that the thickness of the pack ice even at the North Pole was less than 3~ m.Moreover the experts of the Fleet Air Arm considered a free board of at least 15 m.essential for the continuous operation of aircraft from the deck of a carrier.The minimum length of runway required for bombers at that time was 600 m., and 60 m. was considered the most desirable width.Thus the engineers and physicists were given the task of building a raft or vessel of these gigantic dimensions, made basically of ice and satisfying a number of essential requirements.The vessel must be sufficiently seaworthy to withstand the waves of the Atlantic and Pacific oceans; it must be self-propelled; it must have a speed at least sufficient to prevent its drifting in the wind; and it must be difficult to sink.