DD tank
The DD tank ( English duplex drive tank "tank with two types of drive ") was a type of floating tank developed during the Second World War for amphibious operations . The name is mainly used in connection with the converted medium-weight American M4 Sherman used in Operation Overlord , among others .
The floating tank was needed to support infantry operations on the landing beaches. The tanks, which had been made buoyant, were to be launched from landing ships and reached the beach under their own power. The Allies wanted to gain an advantage in this way, as the German defenders were not prepared for tank attacks from the seaside. The tanks were used successfully at Juno Beach , but failed almost all along the line at Omaha .
The floating tanks belonged to the so-called Hobart's Funnies , which were specially developed for invasion and use on the beaches. Most of these devices were used on their beaches by the British and Canadians , only the swimming tanks were adopted by the Americans. However, it is speculative whether a more extensive use of the other developments or a prudent use of the swimming tanks, especially on Omaha Beach, would have led to fewer losses.
development
Amphibious tanks were tested as early as the First World War ; but since none of these vehicles worked reliably, they were not used. Development in this area continued in the interwar period . Basically, two types of amphibious tanks were distinguished:
- Armored vehicles with natural buoyancy - but these were either too small or, on the other hand, of so bizarre size that their use was out of the question.
- Armored vehicles with attached floats - but their size did not fit into any landing craft.
In 1941 Nicholas Straussler solved the problem by assembling water-repellent canvas into a foldable umbrella that gave the tanks buoyancy without increasing their width significantly. However, this procedure could only be used in calm waters. The British Major General Percy Hobart successfully tested Straussler's folding umbrella on Valentine and Tetrarch tanks. The Valentine tanks went into production and were subsequently used by the Allied tank crews for landing training. There were always fatal accidents.
In 1944 it turned out that the American Sherman tank was much better suited to being converted to buoyancy. A big advantage of the Sherman was its direction of travel with the cannon ahead. He was ready to fire immediately after landing. In addition, the Valentine tank was significantly older and inferior to the Sherman in terms of combat power.
For the use of the DD tank , the Shermans armored hull was sealed and two additional drive propellers were attached at the rear , which could be switched on via the gearbox of the tank. Then there was the Straussler floating cover.
The floating tanks were driven by the two propellers in the water about 7 km / h . The steering was done by turning the propeller and a rudder . The floating cover consisted of a linen umbrella that could be set up using 36 rubber hoses. They were filled with air and gave the canvas umbrella the necessary rigidity. The floating cover was attached to the outer skin of the tank with a metal frame above the chain covers. Inflation took about 15 minutes. Folding it was much faster to make the tank operational on the beach.
The British tried to equip the Cromwell and Churchill tanks accordingly. However, these could no longer be completed. The British post-war tank Centurion was also tested with a floating hull and a duplex drive. By the late 1950s, development of the DD tanks ceased as the newer tanks had become too heavy to be buoyant. However, light floating tanks were produced in China ; amphibious vehicles have also been developed in some other states, but not tanks.
The German Reich also developed tanks for an amphibious landing for use during Operation Sea Lion . The result was no floating tank , but the Tauchpanzer III , a modified version of the Panzerkampfwagen III . Like the DD Tank, this could be launched from a landing craft about one and a half kilometers from the beach. In contrast to the floating tanks, the Tauchpanzer III drove on the sea floor ( underwater driving ). A rubber hose supplied the engine and the crew with air. With this he reached a maximum diving depth of about 15 meters.
commitment
The main use of the DD tanks took place during Operation Neptune on D-Day . A small number were also used in Operation Plunder , the Rhine crossing at Rees and Wesel in March 1945.
Ten tank battalions of the Americans, Canadians and British were equipped with Sherman floating tanks before the Normandy landing. Special landing craft ( LCTs ), each loaded with four tanks, were supposed to bring their load up to about three kilometers to the coast and let the tanks into the water there. These should then swim to the bank and surprise the German defense, which was not prepared for a tank attack. During the fight, the use of the swimming tanks was partly successful, but partly failed - the latter mainly on Omaha Beach.
On British Sword Beach , at the eastern end of the invasion zone, the swimming tanks worked very well, as the sea was relatively calm there. The DDs were released around four kilometers from the beach. 32 of 34 floating tanks reached the bank, where they were able to support the landing forces as planned. In doing so, they made a major contribution to the relatively low number of victims there.
The sea at Gold Beach was much more turbulent, so it was decided to bring the DDs ashore directly with the boats and not to release them to sea beforehand. Therefore, they were not the first units on the beach, but arrived together with the invasion troops. In some sections, the Germans succeeded in putting several DDs out of action with anti-tank bullets . The mission was successful on the whole.
The Canadians were only able to launch and land a few of their swimming tanks on Juno Beach . The launched DDs swam to the shore from a distance of about 700 meters. Because of this, they arrived after the first wave of soldiers who suffered heavy losses. However, the tanks managed to successfully fight the defensive positions of the Germans, so that the Canadians could quickly advance a few kilometers inland. At the east end of Juno Beach the sea was even rougher; the Canadians who landed there stood on the bank without tanks, which cost them many victims. Nevertheless, they made the breakthrough.
Four swimming tanks were lost on Utah Beach when their landing craft hit a mine, exploded and sank. The remaining 28 reached the bank unscathed, but about a quarter of an hour after the faster infantry landing craft. Here, too, their use contributed to the low losses on this American landing section.
The floating tanks suffered the highest rate of loss when they were deployed on Omaha Beach , as 27 of 29 vehicles left at sea were lost during the approach. This is generally attributed to the underrated and very troubled seas. The wave height for which the protective cover was built should normally not be more than 0.3 meters. On that day, however, the wave height off Omaha was almost two meters. The crews had never trained under these conditions and the protective cover quickly filled with overflowing water. In addition, the tanks were launched too early, almost five kilometers from the shore. Some of the crews warned the following forces by radio, which meant that they did not launch their floating tanks at sea, but brought them directly to the beach, which, however, meant a delay. Thanks to the breathing apparatus and inflatable lifeboats at their disposal, most of the crew members of the sunk tanks were rescued.
Recent studies assume that the Omaha DDs aimed at a church spire on the horizon behind the Omaha cliffs, but were driven off to the side by a current. As they tried to maintain their target, they aligned themselves more and more parallel to the waves, making them even more prone to flooding. The crews of the only 2 tanks that did not sink had not done so, but instead navigated straight onto the beach.
DD tanks today
In the Bovington Tank Museum in England there are still intact Sherman and Valentine swimming tanks with a functioning floating cover.
Three of the tanks sunk on D-Day were lifted in the 1970s. One is on display at the Musée des Épaves Sous-Marine du Débarquement (Museum of Underwater Wrecks of the Invasion), a private museum near Port-en-Bessin in Normandy. Another is in the Juno Beach Center , a D-Day museum near Courseulles-sur-Mer dedicated to Canadians .
In 2000 the US Navy tried to lift a sunken DD tank near Salerno in Sicily , but failed.
Amphibious battle tanks today
The tanks and battle tanks used today can be divided into several categories:
- Tanks that can cross streams and rivers of shallow depths by means of an attached snorkel tube
- Tanks, which for the river crossing on ferries or bridges the pioneers are dependent
- Light tanks, due to their specific weight without buoyancy aids buoyant are
- Tanks that need additional buoyancy, for example through attached floats, for example K21 NIFV
- Tank based on the DD principle, such as the Swedish S tank
literature
- Antony Beevor : D-Day. The battle for Normandy , Penguin, London 2009, ISBN 978-0-670-91809-6 , pp. 90f, 127-137
- Patrick Delaforce: Churchill's Secret Weapons. The Story of Hobart's Funnies , Pen & Sword, Barnsley 2006, ISBN 1-84415-344-4
- Kenneth Macksey: Armored Crusader: The Biography of Major-General Sir Percy 'Hobo' Hobart, One of the Most Influential Military Commanders of the Second World War , Grub Street, 2004, ISBN 1904010644
- Cornelius Ryan : The longest day , Bertelsmann, Gütersloh 1962, p. 209f
Web links
Individual evidence
- ↑ Vaughan, Don. Neptune's Treasures ( Memento from June 1, 2008 in the Internet Archive )
- ^ The tanks that didn't land on D-Day . BBC News. May 30, 2002.