MARCHWOOD MILITARY PORT AND CONSTRUCTION OF THE MULBERRY HARBOUR скачать в хорошем качестве

MARCHWOOD MILITARY PORT AND CONSTRUCTION OF THE MULBERRY HARBOUR

Churchill had conceived of creating rudimentary harbours by sinking sand-filled barges during World War I. Although the concept was not used at that time, Churchill remained a strong advocate of the potential of artificial harbours. In 1941 the War Office established a department to evaluate and refine artificial harbour designs, under Major General D J McMullen, Brigadier Bruce White and Major Cornick R E. The final decision to proceed with the artificial harbours was, however, not taken until the Quebec Conference in late August 1943, with designs only begun in October and construction in December. This allowed only a very short, six month, construction period. The artificial harbours were made up of three structures: outer breakwaters, pier heads and floating roadways that connected to the shoreline. Each component was given a codeword to maintain secrecy for the operation. The breakwater comprised three elements: a floating outer line of connected hollow steel breakwaters (Bombardons); the Phoenix caissons, which were very large rectangular concrete structures that were airtight enabling them to be sunk and re-floated; and an assembly of 60 obsolete vessels that would be scuttled to form a protective line of block ships (Gooseberries). The pier heads were made up of floating pontoons (Spuds), which were attached to legs that permitted the pier head to move up and down with the tide. A total of 10 miles of floating roadways or bridges (Whales), supported on floating pontoons (Beetles), connected the pier heads to the shore. The Whales were designed by Colonel Steer Webster. Orders were placed for the construction of the whales in June 1943 and components were farmed out to about 200 companies throughout Britain. For reasons of secrecy the Whales were only assembled at two Royal Engineer depots, principally at Marchwood, Hampshire. The Whales were specially designed to allow structural flexibility, both on installation and as they were towed across the English Channel in 500ft sections, when 40% were lost. Each bridge span consisted of two 80ft (24m) long steel box trusses with a 10ft (3m) wide steel plate roadway bolted to cross girders. Each section weighed 30 tons. One in six of the bridge spans had sliding telescopic joints at the centre to allow for adjustments in length.