the disastrous 1942 Dieppe Raid. It was decided that a direct attack on a port from the sea was not an option. The Germans, realizing this, began building fortifications around these ports earlier in the war through their Organization Todt, as part of the Atlantic Wall concept. Some of these ports were major U-boat bases as well, and had bomb-proof concrete submarine pens built. These fortifications had been surviving Allied air strikes for some time. Local resistance groups operating in Brittany especially near Brest sent spies to observe and report German naval activity such as arrival and departure of U-boats and other Kriegsmarine naval ships. If these ports, where the U-Boat bases were located, were to fall into the hands of the Allies, the submarines out at sea would have to fight their way around England, pass Allied destroyers and aircraft to ports in Belgium, The Netherlands, Denmark, Norway, or Germany still under German control, while docked U-Boats would be captured or put out of commission. Prelude Soon after Normandy was invaded, the Mulberries were towed from England and deployed on the French coast. Unfortunately for the Allies, one of them was destroyed after less than two weeks by a storm. Supplies were then mainly landed directly via the beaches, but this process was not as efficient. Cherbourg, at the tip of the Cotentin Peninsula in Normandy, was captured by the Americans who landed on Utah Beach, but the German garrison destroyed its harbour facilities before surrendering. Cherbourg was the only major port in the Allied invasion area. Soon after, the Germans in the Brittany peninsula were isolated by a north–south breakthrough accomplished by George S. Patton's Third United States Army, exploiting the success of Operation Cobra. The US VIII Corps was diverted into Brittany to capture Brest and secure the northern flank of the breakthrough and to prevent German reinforcements to Army Group B and threatening the Falaise pocket as well as fortifying the defenses of the French capital of Paris. Wehrmacht troops trapped in Brittany retreated to the fortified ports in the peninsula, as US Third Army troops moved in and surrounded them. The Brest garrison, Festung Brest, meaning "Fortress Brest", as German propaganda referred to surrounded cities, was put under the command of General der Fallschirmtruppe Hermann-Bernhard Ramcke, a paratroop veteran of the Afrika Korps. His forces consisted of the German 2nd Parachute Division, 266th Infantry Division,