Short History of World War II - James L. Stokesbury [167]
As troublesome as the problem of providing the material were the questions of what actually should be done with it. An amphibious operation is an immensely complicated affair, when conflicting requirements have to be juggled to a successful resolution. Most difficult of all is the fact that several items of the equation are outside human control: the state of wind and tide, the phase of the moon, visibility, weather. Sailors want a moonless night for their approach to a hostile shore, airmen want moonlight so they can see to drop their paratroops. If a landing is made at low water the enemy’s underwater obstacles can be seen and avoided, but the ships are constrained to beach farther out, and the troops must move over greater exposed distances.
The biggest question, though, was whether or not the Allies needed a port, and how soon. Contradictory though it may seem, getting ashore in an amphibious landing is not as hard as staying there. The real supply-and-support problem comes not with the initial landing, but with the follow-up material, the men and supplies necessary to turn a landing into an invasion. The planners did not doubt their ability to put five divisions ashore in Normandy—they had already put more than that on the beaches of Sicily—but their problem was how to build up and supply the hundred divisions they wanted to get ashore all told.
The shortest crossing of the Channel would take the Allies over to the Pas de Calais, around Boulogne, Calais, and Dunkirk, where the British had been driven off four years ago. While doing everything possible to make the Germans think this was where the assault was coming, the Allies actually decided to land farther down the coast, on the Normandy peninsula. The beaches were not bad, though they could have been better; they could hope to take Cherbourg, a major seaport, and supply through that. To solve their immediate problem, however, they decided to take their ports with them. Several great floating caissons, as well as many old ships, were to be floated across and then anchored in position and sunk off the beaches, creating artificial harbors—the “Mulberries” as they were code-named. The remains of these can still be seen off the Normandy coast, and though they were eventually badly damaged by storms, they served their purpose admirably, and relieved the Allies of the immediate problem of getting a port. In giving the invaders more options for landing, they compounded the problems of the defenders.
For the Germans faced the same kinds of questions as did the Allies; they too knew the invasion had to come, and for them also it was a problem of where, when, and how to meet it. The Germans had officially sixty divisions in France and the Low Countries, but more than half of them were second-line formations, either training divisions or coastal defense formations with reduced establishments and mobility. One of their major problems, especially concerning mobility, was that they had now definitively lost command of the air, and this aggravated their disagreements over how to react to the expected invasion.
In the air the bomber offensive was still gaining momentum, but the attacks, moving ever farther into Germany, were forcing the Germans to concentrate, albeit unwillingly, on home defense. As the Allies waxed stronger in the air over Germany, they gained increasing tactical mastery of the air over France. By the spring of 1944 the air forces were able to promise a massive interdiction campaign that they hoped would seal off Normandy and prevent the arrival of German reserves. Anything that moved by day, and much that moved by night, would do so at its own peril. And to the efforts of the tactical air forces could be added the disruptive campaign of the French underground as well.
Some of the German commanders were aware