As the number of Allied troops in Normandy increased, the need for a constant flow of supplies became critical. Although divisions landed with full gas tanks and a week's rations, a growing army could consume an immense amount of stores even if it sat on the beach and did nothing. Once troops engaged the Germans, gasoline, ammunition, and supplies were used up at a prodigious rate--the Allied armies demanded 26,000 tons of stores a day to sustain them in action. The battle to build up supplies was one of the underestimated parts of the Normandy campaign.
The Allies had planned for the delivery of masses of supplies and reinforcements across the English Channel--but harbors were needed to unload and stockpile supplies. The Germans anticipated the need for the Allies to capture a harbor and heavily defended the ports of Cherbourg and Calais. The Germans did not expect the Allies to bring their harbors with them.
Two innovative artificial harbors, called "Mulberries" served a crucial role in the early days of the invasion. These engineering marvels, partially built in England and towed across the Channel, were constructed out of deliberately sunken ships, steel floats tied to sunken concrete tanks, and vast rubber floats covered by prefabricated roadways. Docks were attached to deliberately sunken ships; other ships were sunk as breakwaters to protect the docking area from harsh currents and channel swells. Finally, road sections placed over floating pontoons ran from the docks to the beaches to convey the supplies.
On 19 June 1944, at the very time when a record number of ships were ferrying across the British Channel, the worst storm in years began to blow and continued for three days. Many barges were lost during the storm. Worse, the artificial ports themselves suffered severe damage. Afterward General Omar Bradley surveyed the damage to an Allied Mulberry and remarked, "I was appalled by the desolation for it vastly exceeded that on D-Day." (1) The storm severely affected the Allied supply build-up, leaving General Bradley with only three days of ammunition.
The Allies had targeted the port city of Cherbourg, on the northern tip of the Cotentin peninsula, as a vital link in the supply chain. But Hitler and Rommel had planned an all-out defense of Cherbourg. Hitler said to Karl-Wilhelm von Schlieben, commander of the Cherbourg forces, "Even if the worst comes to the worst, it is your duty to defend the last bunker and leave to the enemy not a harbor but a field of ruins." (2)
The Allies concentrated on capturing Cherbourg and fought their way across the peninsula, eventually surrounding the city and its German defenders on 21 June. When Schlieben refused to surrender, the Allies answered with massive air strikes, unloading hundreds of tons of bombs on the twenty square miles of German defenses. Soon after, Allied units began taking the city in fierce house-to-house combat. Block by block, the Germans lost ground, but they inflicted high casualties on the Allies and slowed the Allied advance. Finally, on 26 June Schlieben surrendered. Even so, isolated units of Germans stubbornly fought on until 29 June.
When the Allies had finally taken Cherbourg, they were shocked at what they found. The Germans had followed Hitler's orders to destroy the port in what one United States engineering officer called "the most complete, intensive, and best-planned demolition in history." (3) Although the Allies had expected some sabotage, and their engineers had trained by defusing mines in the muddy waters of the Thames, the damage at Cherbourg was worse than anyone had foreseen.
The Germans had left basins and docks blocked by more than fifty-five scuttled ships, barges and smaller craft, and by overturned cranes and dynamited bridges. They had also wrecked docking and unloading facilities, including piers, wharves, warehouses, railways, and utilities. Sunken ships and mines were used to block ninety-five percent of the crucial deep-water channel area that was needed by the Allied supply ships. Hundreds of mines hampered clearing operations. Rather than simply wrecking a railway bridge, the Germans had mined the sections of it that remained above water. To confuse the Allies, they had marked minefields where there were none--then attached booby traps to the signs.
Eventually, the Allied engineers were able to repair the port facilities, but only after a costly delay that slowed tank and infantry advances across France. While ships were able to begin to unload supplies at Cherbourg by 16 July, the port facilities were far below the planned capacity. It was late September when Cherbourg reached full operational capacity. By this time almost every harbor in France and Belgium was in the hands of the Allies.
Despite the setbacks at Cherbourg and the marginal success of the Mulberries, the Allies were able to deliver a steady stream of supplies over the Normandy beaches until other harbors were captured. But shortages of gasoline, ammunition, and other supplies continued to hamper the Allies throughout their eastward spread across Europe.
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1. Warren Tute, "D-Day," (New York: MacMillan Publishing Company, 1974), p. 244.
