WWII Notes 7: Allied Preparations for D-Day Modern US History Unit 3 WWII

Planning and Training

SHAEF  The Invasion of Normandy was put under the command of SHAEF (Supreme Headquarters, Allied Expeditionary Force) which was led by General Dwight. D. Eisenhower  All Allied troops were put under this single command Ike speaking to the 101st Airborne on June 5, 1944

Location Selection  The best choices of landing sites on the continent were: the Pas de Calais and Normandy.  Because the Pas de Calais is the shortest distance from England, closer to Germany, and has the most accessible beaches, it was the most heavily fortified by Germany and the site Germany suspected.  The Allies chose Normandy for their invasion because Germany expected them to go to Pas de Calais Normandy Pas de Calais

Plans for the Final Attack  The final plan for the landings had five groups by sea and three by air – the air divisions were the paratroopers landing the night before  In total, 47 divisions would be committed to the Battle of Normandy: 19 British, five Canadian and one Polish divisions under overall British command, and 21 American divisions with one Free French division, totaling 140,000 troops.  About 6,900 vessels would be involved.  A total of 12,000 aircraft would support the landings including 1000 transport planes to carry the parachute divisions

Plans for the Final Attack

Espionage

Double Cross  During the war, the British operated a system known as Double Cross.  Through Double Cross, the British turned German spies and used them as double agents. Many of the spies were captured and some even turned themselves in to the British.  Initially Double Cross was used to determine what the Germans were looking for, but later it was used to pass along misinformation, such as before the landing at Normandy. XX Double Cross was run by the Twenty Committee

Operation Fortitude  Then, in the weeks leading up to the invasion, in order to persuade the Germans that the main invasion would really be coming to the Pas de Calais, as well as to lead them to expect an invasion of Norway, the Allies prepared a massive deception plan, called Operation Fortitude.

FUSAG – Fake Army to Convince Germans that Allies had enough troops to go to Calais  An entirely fictitious First U.S. Army Group (“FUSAG”), supposedly located in southeastern England was created in German minds by the use of double agents and fake radio traffic “confirming” the existence and location of FUSAG and the Pas de Calais as the likely main attack point.  General Patton was placed in command of FUSAG. This placement of such a famous general strengthened Germany’s belief in the existence of FUSAG.  Dummy tanks, trucks, and landing craft, as well as troop camp facades (constructed from scaffolding and canvas) were placed in ports on the southeastern coasts of Britain to look like the army.

Operation Skye – fake groups in Northern Scotland to convince Germany that Allies would attack Norway  Operation Skye was mounted from Scotland using radio traffic designed to convince Germany that an invasion would also be mounted into Norway.  Two dozen aging British officers were sent to Northern Scotland where they carried on constant radio conversations for their fake armies.

Dummy Paratroopers on the Night of June 5, 1944  The last part of the deception occurred on the night before the invasion: a small group of SAS operators deployed dummy paratroopers over Le Havre and Isigny.  These dummies led the Germans to believe that an additional airborne assault had occurred; this tied up reinforcing troops and kept the true situation unclear.

Benefits of Spreading Misinformation  One benefit was that the Germans kept many divisions in Norway (to protect their U-Boat fleet)  Another benefit of all of these deceptive measures was that they convinced the Germans that the Allies had 3 times as many troops and landing gear than they actually did.  Therefore the Germans believed that a fake attack (a feint) would come before the real attack - when the D- Day attack came they thought the Normandy invasion was just a diversion to pull their divisions away from Calais.  This worked so well that the Germans kept 18 reserve divisions near Calais even after the invasion of Normandy began.

Technology for the Invasion

Mulberry Harbors  A complete Mulberry harbor was constructed out of 600,000 tons of concrete between 33 jetties, and had 10 miles (15 km) of floating roadways to land men and vehicles on the beach. By June 9, just 3 days after D-Day, two harbors that were built in England and floated across the Channel, codenamed Mulberry 'A' and 'B', were constructed at Omaha Beach and Arromanches, respectively.

Mulberry Harbors  A large storm on June 19 destroyed the American harbor at Omaha, leaving only the British harbor which came to be known as Port Winston.  In the 100 days after D-Day, it was used to land over 2.5 million men, 500,000 vehicles, and 4 million tons of supplies providing much needed reinforcements in France. Omaha Harbor after the storm of June 19, 1944

Operation Pluto  Operation Pluto built oil pipelines from England to the French coast to transport much needed fuel in a faster and safer way to the continent.  By VE Day, over 781 million liters of oil had been pumped to the continent.

Higgins Boats (LCVP’s)  Higgins Boat – LCVP: Boat with a wide ramp on the front and a shallow draw allowed the Allies to land their troops at Normandy.  Troops climbed down rope nets from their ships onto the Higgins Boats to go to shore. They could also carry small vehicles. LCVP at Omaha Beach

Higgins Boats (LCVP’s)  "Andrew Higgins... is the man who won the war for us.... If Higgins had not designed and built those LCVPs, we never could have landed over an open beach. The whole strategy of the war would have been different." — General Dwight Eisenhower

LST’s  Many other landing craft were also used to land people and equipment  The LST - Landing Ship Tank – could carry tanks for an amphibious landing – used at Sicily and Normandy Canadian LST at Sicily, 1943

Hobart’s Funnies  Hobart’s Funnies were specially designed British tanks used to accomplish specific tasks: Churchill AVRE with bobbin – had a 10 foot wide canvas cloth that was reinforced with steel poles to roll in front of it so itself and following vehicles would not sink into the soft sand on the beaches

Hobart’s Funnies  ARK – armored ramp carrier – Would lay down ramps for other tanks to climb over obstacles  Armored bulldozer – used to clear obstacles on the D-Day beaches

Hobart’s Funnies  Crab- Modified Sherman Tank with a mine flail (rotating chains) in front to clear land mines  AVRE with fascine – carried a large bundle of sticks and pipes to throw into a ditch to use as steps for following tanks.

Hobart’s Funnies  The DD had a flotation device that went around them and could be deflated at shore. This allowed tanks to land at Normandy without using landing crafts for them, they were deployed 2 miles from the beach and swam to shore.  Worked fairly well except at Omaha where 27 of the 29 were lost in high swells. DD Tanks – Duplex Drive medium tanks (Shermans) that used propellers in the water and treads on land.

Allied Invasion Routes