The general plan of Operation Overlord was realized during many months of planning in which the different forces and specialties combined and coordinated their needs and capabilities. For the success of the plan it was necessary that the navy, air force and army of different nationalities cooperated profitably and without any accident.
The landing had to occur on 5 different shores: Sword, Juno, Gold, Omaha on the coast of Calvados and Utah on the peninsula of Cotentin. This last shore was inserted in the plan just a few months before the operation because it was able to place the invading army near to Cherbourg, the most important short-term objective.
The primary objective of Overlord was to establish, within the first day of the invasion in the immediate interior, a force capable of resisting a counterattack for the amount of time necessary for the arrival of reinforcements in the following days. The landing forces then had to overcome the obstacles, make the landing zone secure for the following reinforcements and to head for the interior, connecting themselves with the contingents that had landed on the other shores. It was fundamental that the beaches Omaha, Gold, Juno and Sword were united in one front as soon as possible to oppose major resistance.
An isolated landing force, exhausted by clashes and with limited resources of means and ammunition could not easily resist a rapid German counterattack conducted by armored and mechanized forces. A united front instead would permit the concentration of effort and the prolongation of the defense.
Everything depended on the success or failure of the first wave of invasion.
All of the beaches are of compact sand and present natural passages between the dunes, necessary conditions for allowing the rapid sorting of the reinforcements toward the interior. Like good part of the northern coast of France, the shores were defended with anti-landing obstacles, mines, bunkers armed with machine guns and cannons of various caliber, antitank moats, barbed wire.
Forces and short and long-term objectives were assigned for every beach.
At UTAH the 4th Division of the US infantry had to land, with the objective of reaching as soon as possible the principal road artery and then heading toward Cherbourg to the north. UTAH was isolated from the other landing zones and its flanks would be protected by airborne forces.
According to the original plans, the 101st Division of US paratroopers should have landed between UTAH and Ste Mere Eglise, behind the lines of German defense on the beach and the 82nd Division of US paratroopers would have landed at St Saveur, blocking the influx of German reinforcements through the eastern part of the peninsula of Cotentin.
The plan was modified a few days before D-Day. The 82nd would land at the threshold of Ste Mere Eglise with the objective of conquering the town, whle the 101st would land further south to protect the southern flank of the landing zone.
The zone of OMAHA was among the vastest and best defended. Here would land the 29th and 1st Divisions of the US infantry. Two battalions of US Rangers had the objective of landing at Point Du Hoc and to scale the cliffs to reach the cannons of great caliber that were located at the top.
The forces landed at OMAHA had to conquer the towns along the coast, Colleville, St. Laurent and Vierville, extend themselves east to link up with the British and reach the principal road.
With GOLD the sector of the theater of operations under the responsibility of the British and Canadian forces began. At GOLD the 50th Division of UK infantry would land with the task of conquering the Arromanches.
At JUNO the 3rd Division of CA infantry would arrive near Courseulles with the objective of reaching the road that goes from Caen to Bayeux and blocking German reinforcements.
SWORD was the beach furthest east and here was assigned the 3rd Division of UK infantry and the 79th Armored Division UK. The primary objective was to reach Caen and the airport of Carpiquet. The flank of this zone would be protected by air transport forces. The 6th Division of UK paratroopers had to land on the western side of the Orne River and conquer the bridge on the canal of Caen and the nearby bridge on the Orne from which the Germans could launch an attack. Moreover, it had to deactivate the battery of cannons at Merville, before the beginning of the landings.
The air transport troops had to land during the night to surprise the enemy, even if it would make the launch, the grouping together and the reorganization of the units extremely complicated. The darkness would also protect the air transport forces from an immediate German counterattack.
At dawn the invading fleet reached near the coasts and the landing vehicles placed themselves according to the order of proximity.
While the landing vehicles brought the infantry and the armored means toward the shore, all the major naval units began a cannonade against the fortified German positions. A little bit later began the air bombardment on the landing zone.
The air bombardment had the same scope as the naval bombing, it had take the German defensive bunkers out of the game and liberate partially the beaches from obstacles but, while the ships were stationed within firing range of their targets and reached the zone together with the landing forces, the waves of bombardiers carried out a long journey from the aviation fields in England to reach the coast. Organizing a prolonged bombardment on the zone during the night, considered necessary by the commanders of the land forces, would eliminate any doubt by the German Command regarding the zone of invasion. On the other hand not too much hope could be placed on the effect of a time limited bombardment.
Moreover, the type of aircraft used affected notably the precision and efficacy of the bombardment. The B-17 “Flying Fortress” were strategic bombardiers conceived for flying in formation against strategic objectives but unfit for striking objectives precisely within a limited distance from the Allied troops. The B-26 “Marauder” and other medium bombardiers instead could strike with precision flying at a low altitude and they succeeded in giving their contribution in the zones where they operated.
The bombardments had to be suspended a little bit before the landing means reached near the beaches and could then turn around toward inland objectives. From this point on all the weight of Operation Overlord moved onto the first waves of infantry and limited armored forces. Under intense enemy fire they had to win the shoreline and to cross uncovered a stretch of beach in order to reach the base of the fortifications and dunes where they could take refuge and from which they could launch attacks toward the enemy positions and trenches.
The landing on a beach is composed of numerous waves, spaced out at in intervals of a few minutes, of soldiers, equipment and means with specific tasks. Organization was very important and possible landing errors would be paid at a high price. For example, if the units of one wave landed in a sector different from the one assigned, the following waves would not find them in the pre-established sector. If the tasks of the numerous waves are interdependent, the delay or failure in reaching an objective has repercussions for the following arrivals.
The continuous flow of waves of soldiers after the first phases of the landing was tied to the success of the operation. If in one beach sector the troops were not capable of penetrating the enemy’s defenses, they would suffer considerable losses and they would not be able to guarantee the necessary security for the landing of the reinforcements.