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Mulberry Harbour pierhead fendering
former Russia Dock, Rotherhithe, London SE16, and other sites
associated engineer
Sir Ove Arup
Ronald Jenkins
date  1943 - 1944
era  Modern  |  category  Harbour  |  reference  TQ360797
Ove Arup was one many engineers called upon during World War II to contribute to the design of two huge demountable harbours, known as Mulberry Harbours, required for the pivotal Normandy landings. Arup was experienced in pierhead construction and was given the task of providing concrete fenders designed to absorb the shock of large vessels hitting the harbour piers at reasonable speed in choppy seas.
All the components of the two Mulberry Harbours Harbour A for the American-led forces landing at "Omaha Beach" and Harbour B for the British-led forces landing at Arromanches were designed and built from scratch in just one year at sites all over the country. The Ministry of Defence instructed some 550 engineering contractors in October 1943. At the planning stages of the project, Winston Churchill famously said, "Bring me the best solutions, do not waste time with the problems, they will take care of themselves".
The harbours consisted of an outer protective assembly of 146 huge concrete caissons. Inside these were a series of floating quays and pontooned roadways running to shore. All the elements were constructed between October 1943 and June 1944, when they were towed across the English Channel for assembly during the landings.
Although all design work was carried out in strict secrecy, Arup quickly discovered that many of his contemporaries were also involved consulting engineers Oscar Faber, Ralph Freeman and Alan Harris, and contractors Malcolm McAlpine and Norman Wates to name a few.
Arup, working with his trusted structural analyst Ronald Jenkins, was responsible for the design and construction of a new type of Baker fender, which is named after A.L.L. Baker, then Scientific Advisor to the Ministry of Works. The concrete fenders were required to absorb the shock of 20,000 tonne displacement LSTs (landing ship tanks) hitting the piers at a speed of four knots, while at the same time guiding them into position.
The concrete work was carried out in a series of Thameside docks and slipways, in particular, Russia Dock, which had been devastated in the bombing raids of September 1940 and is now filled in to make Russia Dock Woodland. Here, aggregate created from the rubble of bombed-out local buildings was combined with cement, which possibly came up-river from West Thurrock.
Arup's solution consisted of a series of 600mm long moulded hammer-shaped blocks, each weighing two tonnes, strung together into 45.7m lengths weighing 150 tonnes. The kinetic energy of an impact between vessel and fender was absorbed by rotation of the blocks, which pivoted about the heads of the hammer shapes. The loosely hinged and interconnected blocks dissipated the energy of any impact to neighbouring blocks by shear force or by couple, with the horizontal beam action of the row preventing all but minor displacement.
Other requirements were that the impact of incoming vessels would not result in downward deflection of the fender assembly and that minor displacement from the rotation action would not expose sharp corners that might damage the vessels.
Arup's analytical attention to the problem at hand brought praise from the commissioning authorities. The only unsatisfactory outcome was the squealing that resulted from the friction between blocks.
Research: ND
bibliography
"The Mulberry Harbours" by Alan Harris
Royal Engineers Journal, Vol 108, April 1994
"The Building of Mulberry Harbour" by Michael F Kennard
The War Illustrated, April 1947, pp 771-2, consulted at www.thewarillustrated.info
Location

Mulberry Harbour pierhead fendering