The Maritime Archaeology of Duplex Drive Tanks in the United Kingdom
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The Maritime Archaeology of Duplex Drive Tanks in the United Kingdom Thomas Cousins Bournemouth University, UK [email protected] Thomas Harrison MSDS Marine, UK [email protected] Dave Parham Bournemouth University, UK [email protected] Abstract The catastrophe at Dieppe in 1942, where unsupported infantry attempted to capture a fortified beachhead, showed the allied forces how difficult such a venture was. As part of the invasion plan for what became Operation NEPTUNE or the Normandy landings, the allied staff saw the need for armoured support for the first waves of troops ashore. This need evolved into the concept of ‘swimming tanks’ that would land a few minutes ahead of the first infantry waves. The development of such a weapon was undertaken in conditions of absolute secrecy in the UK from late 1942 onwards. This secrecy led to the destruction of much of the historical records that relate to these armoured vehicles, leaving a confused and largely unknown record of what was an important aspect of WWII. This project sets out to record the known examples of such vehicles on the coast of the UK including a group lost as part of ‘Exercise SMASH’, the largest live ammunition exercise of the war, a full scale beach assault training exercise with all supporting arms including amphibious tanks. Though six tanks were lost during the exercise in conditions, which are not fully understood, the loss led to the changing of the operational plans for D-Day. Using archaeological and historic data, this project offers an alternative interpretation for these loses and provides a better understanding of their subsequent impact on Operation NEPTUNE. Keywords World War II, D-Day, Duplex Drive Tanks, Exercise SMASH Introduction short distance across the Channel, the allied forces also needed to pre-empt an invasion of mainland Europe In late 1941, following the Japanese attacks on Pearl to meet the now advancing Soviet army to the east of Harbour, Hitler and Mussolini declared war on the Germany. Furthermore, Stalin was keen for the allied United States (Belcham 1981: 10: Doherty 2011); in forces to create a western front, relieving some of the response, under Prime Minister Churchill and President pressure Germany was putting on the Soviet armies. Roosevelt, the American and British forces formed an alliance. Although differences arose in their ideas, their In response, Churchill and Roosevelt devised the defining decision was the large scaled assault of Europe largest and most complex invasion ever to take place, to defeat Germany, launched from the British coast Operation OVERLORD. The plan was to land forces on when the time was right (Belcham 1981: 10; Doherty the northern French coasts, liberate France, then push 2011). The British Combined Services Committee towards Germany. The invasion, which was to take (BCSC) was formed to study methods of gaining access place on the Normandy beaches, was named Operation to Europe, as by 1942 Nazi Germany had control over NEPTUNE and was described by Churchill as ‘the most much of Europe. During the Nazi occupancy of France, difficult and complicated operation that has ever taken Hitler had also ordered the construction of the ‘Atlantic place’ (Winter 2014: 2). Wall’. This series of coastal defences running along the Channel coastline were constructed between 1942 During the planning of the landings on what became and 1945, for the purpose of preventing amphibious known as ‘D-Day’, the vast scale of the task at hand invasions (Anderson 2010: 61–63). With France being a meant that invaluable cooperation was needed from IKUWA6: 649–656 Thomas Cousins, Thomas Harrison and Dave Parham all of the armed forces including resources and amphibious tanks had been studied by several nations specialist equipment. Armoured units were needed to prior to the war (Fletcher 2006: 3). Many concepts were eliminate the German defences along the Normandy devised but Straussler eventually broached the idea of beaches, otherwise high casualties among the infantry Duplex Drive swimming tank. The Duplex Drive tank would prove unacceptable. During the earlier landing works by having a transfer box within the gears that at Dieppe in August 1942, a force of c. 6000 British, switch power from the tracks to a single three-blade Canadian and US infantry was landed suffering heavy propeller (two propellers on the later Sherman tanks) casualties (Thompson 2011: 38). There, the infantry (Anderson 2010: 23). Flotation being provided by a was supposed to be supported by the Canadian 14th canvas screen erected using compressed air filled tubes, Army Tank Regiment with their new Churchill tanks; given shape by a series of tubular supports running these were late arriving, leaving some of the infantry around the circumference of the tank (Doherty 2011: unsupported and exposed to German machine gun fire 51; WO185/66). Once the tank has ‘swum’ ashore after (Poolton 1998: 38). Driving the landing craft loaded leaving its transport the Landing Craft Tank (LCT) at sea, with tanks up to the beach resulted in the Churchill the drive reverts to the tracks and the screen is lowered tanks getting stuck in the shingle beach, with two and propeller(s) raised (Fletcher 2006; WO185/66). landing craft reported to have sunk as a consequence of this. Those tanks that made it over the sea wall were The British took on the idea of Duplex Drive (DD) tanks prevented from progressing further due to a mass of and Straussler was provided with an 8-ton Tetrarch Mk anti-tank obstacles. The losses were very high, with 60% VII from the 1st Armoured Division in July 1940 to begin of infantry being either killed or captured (Thompson work on his prototype (WO185/66; AVIA22/1522). The 2011). Tetrarch prototype was fitted with an outboard motor for propulsion, technically making it not a DD tank. The failed raid at Dieppe in 1942 led to the formation of The resulting prototype was trialled around the Brent the 79th Armoured Division, later known as the ‘Hobart Reservoir in June 1941, and in September the Tank Funnies,’ in October 1942 under the command of Major- Board agreed Straussler’s design would be applied to the General P.C.S. Hobart. At this time the Duplex Drive Vickers-Armstrong Valentine and later the Sherman (DD) units consisted of the 27th armoured brigade, tank (Fletcher 2006: 6–7; WO185/66; AVIA22/1522). which itself consisted of the 13th/18th Hussars, 4th/7th Dragoon Guards and the East Riding Yeomanry, and On 6 July 1942, the first order for 450 sets of DD the infantry of 285th brigade. In April 1943, Hobart’s equipment was made prior to the seaworthiness trials division was reformed as the only division in the British due to the equipment being a ‘matter of great urgency’ army made up of just specialised armoured units (Anon (WO185/66). The DD tanks were all placed under the 1945: 9). A series of vehicles designed for specific command of Hobart’s division (Anon 1945: 9). Hobart roles during the invasion, including Bridge laying, began his career in 1904, a Royal Engineer throughout minesweeping, flamethrowers and swimming tanks the First World War, his career continued through to were all developed and extensively tested (Anderson the end of the Second World War. He was described 2010: 223; Anon 1945: 31). A key feature was the Duplex as a determined leader who the war office received Drive system (DD) i.e. having a transfer box within the countless comments about as being ‘impossible to work gears that switch power from the tracks to a single three with’ (Macksey 1967: 12). Nonetheless he was a devoted blade propeller. The novel idea of these inventions was patriot with high expectations and a sense of urgency, that they were armoured engineering machines, able an inspiration and irritation (Duncan 1972: 1). After to assist troops and other vehicles across and off the transferring to the Royal Tank Corps in 1923 he was beaches as quickly as possible. To ensure their success responsible for the training of some of the best known the special vehicles had to be kept under extreme and most successful armoured divisions of the Second secrecy, for example the DD tank does not appear in the World War including the 7th Armoured Division, better normal A.F.V. schedules (AVIA22/456). Additionally, the known as the Desert Rats, the 11th Armoured Division, destruction of records was ordered in some cases, ‘All acknowledged as the best British armoured unit in papers concerning Exercise SMASH will be destroyed Europe and the creation of one of the most important after the final conference’ (WO199/2320). This high aspects of success on D-Day, the 79th Armoured Division level of secrecy was maintained throughout the build- (Macksey 1967). up to D-Day (Anon 1945). While the DD tanks would not directly operate under the Development 79th Armoured Division, Hobart would be responsible for the training (Doherty 2011: 51). Most training in Nicholas Straussler was a boat builder specialising Britain took place using Valentine tanks and Hobart in floatation devices. He began working for Vickers- eventually trained ten regiments from Britain, Canada Armstrong designing tank accessories. The idea of and the United States (Anon 1945: 9; Fletcher 1984: 23). 650 Thomas Cousins, Thomas Harrison and Dave Parham The Maritime Archaeology of Duplex Drive Tanks By the time D-Day was approaching the light Valentine Wight, as well as further landing sites at Hayling Island, tank had become out-dated compared to other allied Bracklesham Bay and Littlehampton during Operation and German tanks, both in terms of firepower and FABIUS. FABIUS was the final and largest rehearsal for armour (Fletcher 1984: 23).