In June 2, I was ordered to England with instructions to begin preparation for United States participation in a cross-Channel attack against Fortress Europe which had been agreed upon by the American and British governments in April of that year as the Allied principal effort in the defeat of Germany. Some planning, in cooperation with Admiral Sir Bertram H. Ramsay, General Sir Bernard C T Paget, and Air Chief Marshal Sir Sholto Douglas, all of the British forces, was undertaken immediately following my arrival, but this had not proceeded beyond the informal, conversational stage when I received orders to take command of the Allied attack in Northwest Africa, decided upon on 26 July. As a result of these conversations it seemed clear that the Normandy region offered the greatest chance of success in an invasion of Europe, although some individuals favored a more direct attack against the Calais area.
The successful conclusion of the campaign in North Africa was necessary before the attention of the Allies could be devoted to a full-scale attack upon Europe, but at the Casablanca Conference, in January 1943, the Combined Chiefs of Staff felt that the time had come at least to evolve the outline tactical plans for cross-Channel operations. They directed that preparations be undertaken for an emergency return to the Continent in the event that Germany suddenly should weaken sufficiently to permit our landing in the face of light or negligible resistance. While preparations for such a hoped-for contingency were necessary, the chief problem was the planning for the full-scale assault to be launched against the Continent as early as possible in 1944. Some consideration was given to the possibility that a return to the Continent in force might take place late in 1943, but a review of the build-up figures of United States forces in the United Kingdom indicated that this would be impossible and that no large- scale attack could be undertaken until 1944.
Accordingly, in preparation for the day when a Supreme Commander should be appointed to command the Allied forces, the Combined Chiefs of Staff named Lieut Gen Sir F E Morgan to the post of Chief of Staff to the Supreme Allied Commander (designate). Using the initials of this title, the organization was called COSSAC, and, with a staff composed of both United States and British personnel, work began upon the creation of the assault plan against Fortress Europe. By July 1943 the Outline Plan for OVERLORD, as the operation was called, was ready for presentation to the Combined Chiefs of Staff. In August of the same year the Combined Chiefs, with the concurrence of President Roosevelt and Prime Minister Churchill, approved the plan at the Quebec Conference and ordered the completion of its details insofar as this was possible prior to the arrival of a Supreme Commander.
In the creation of the plan, COSSAC had been instructed on 25 May, through a supplementary directive from the Combined Chiefs of Staff, that the target date for the operation was to be 1 May 1944, and that simultaneous landing-craft lift for the assault forces would be limited to craft sufficient to load five divisions. A total of 29 divisions in all was to be available for the assault and immediate build-up. Of these, five infantry divisions were to he simultaneously loaded in the landing craft, three to assault initially with two in the immediate follow-up. In addition, two airborne divisions were to be employed and two other infantry divisions were to follow as quickly as turn-around shipping became available. In all, then, nine divisions were to be initially employed in the assault and immediate followup period. The remaining 20 divisions were to be available for movement to the lodgement area as quickly as the build-up could be achieved.
The fact that simultaneous landing-craft lift for only five divisions had been allotted made mandatory a definite concentration of effort. The basic factor in determining where the initial assault was to be made. lay in the requirement that the lodgement area should contain sufficient port facilities to maintain a force of some 26 to 30 divisions and enable that force to be augmented by follow-up shipments from the United States or elsewhere of additional divisions and supporting units at the rate of three to five divisions per month.
For such purposes, the Pas-de-Calais region offered advantages in that its proximity to England would facilitate air support and a quick turn-around for shipping.
A second area considered was the Cotentin Peninsula where it was recognized that the assaulting forces would initially have a reasonable chance of success and would additionally gain the valuable port of Cherbourg. This area, however lacked suitable airfields and might have become a trap for the assault troops, since the enemy could, with relatively light forces, defend the neck of the peninsula, bottling Allied troops within the beachhead and denying them any expansion into the interior of France.
In the Caen sector the defenses were relatively light and the beaches were of high capacity and sheltered from the prevailing winds. The terrain, moreover, was suitable for airfield development and for the consolidation and subsequent expansion of the beachhead. Air support to the initial area at such a distance from the English coast presented the chief difficulty. From a beachhead in the Caen sector it was believed that it would be possible to seize the Brittany ports between Cherbourg and Nantes, and through them to build up sufficient forces for the subsequent advance eastward.
In view of these considerations, it was decided that the initial landing on the Continent should be effected in the Caen area with the subsequent seizure of a lodgement area comprising the Cherbourg-Brittany ports.
The assault itself, according to the COSSAC plan, was to be launched with a short air bombardment of the beach defenses, after which three assault divisions would be landed on the Caen beaches, followed by the equivalent of two tank brigades and a regimental combat team. At the same time, airborne forces were earmarked for the capture of the town of Caen, while subsidiary operations were to be undertaken by commandos and airborne units to neutralize certain coast defenses and to seize important river crossings. The object of the assault forces was to occupy the general line Grandcamp-Bayeux-Caen.
Action subsequent to the assault and early build-up was to take the form, under this initial plan, of a strong thrust southward and southwestward with a view to destroying enemy forces, acquiring sites for airfields, and gaining depth for a turning movement into the Cotentin Peninsula directed on Cherbourg, When sufficient depth had been gained, a force was to advance into the Cotentin and seize Cherbourg. At the same time a thrust was to be made to deepen the beachhead southeastward to cover the establishment of additional airfields in the area southeast of Caen. It was estimated that within 14 days of the initial assault Cherbourg would be taken and the beachhead extended to include the general line Trouville-Alenqon-Mont-St-Michel. By that time it should have been possible to land some 18 divisions and to have in use about 14 airfields from which 28 to 33 fighter-type squadrons could operate.
Later operations based upon this plan were necessarily to be dictated to a large extent by enemy reactions. If he proved sufficiently weak, an immediate advance might be undertaken to seize Le Havre and Rouen. More probably, however, it was felt that it would be necessary to take and bring into use the Brittany ports first in order to build up forces sufficient to breach the line of the Seine upon which it was expected the enemy would make a stand with the bulk of his forces. For this purpose a thrust southward would be made to seize Nantes and St-Nazaire, followed by Brest and the smaller Brittany ports. The beachhead would be consolidated on the left flank along the Eure River from Dreux to Rouen and thence along the Seine to the sea while Chartres, Orléans, and Tours were occupied. As soon as lines of communications in this area were developed and sufficient air forces established, operations would be instituted against Paris and the Seine ports, with subsidiary operations to clear the Biscay ports for the reception of additional United States troops and supplies.
In broad outline, this was the plan proposed for the assault upon Nazi Europe. Following approval by the Combined Chiefs of Staff and in accordance with their instructions, the COSSAC organization proceeded with more detailed planning, and by 29 November sufficient progress had been made to permit of directives being issued to 21 Army Group and to the United States First Army.
During the period of this staff planning for OVERLORD, I was personally occupied with the Mediterranean campaigns and was not in close touch with the plans evolved for the campaign in Northwest Europe, nor did I during this period know that I would ultimately be connected with the operation. In December, however, I was notified by the Combined Chiefs of Staff that I had been appointed Supreme Commander of the Allied Expeditionary Force and that prior to assuming command in England early in January I was to return briefly to Washington for conferences with General George C Marshall and the Combined Chiefs.
Prior to leaving my Headquarters in North Africa, I was able early in December 1943 to see a copy of the Outline Plan of OVERLORD and to discuss it with Field Marshal (then General) Sir Bernard L Montgomery, who was to command 21 Army Group, and with my Chief of Staff, Lieut Gen (then Maj Gen) Walter B Smith. I instructed them to consider the plan in detail upon their arrival in England because, while agreeing with the broad scope of the operation and the selection of the assault area, I nevertheless felt that the initial assaulting forces were being planned in insufficient strength and committed on too narrow a front. This they did, and shortly after my arrival in London on 15 January, I was able, with them and my other commanders, to reach an agreement which altered the OVERLORD operation in this respect.
While my appointment as Supreme Commander did not become official until the receipt of a directive1
1 the text of the directive is reproduced at the beginning of this report. It should be noted that the US Strategic Air Forces in Europe and the RAF Bomber Command remained under the control of the Combined Chiefs of Stafffrom the Combined Chiefs of Staff on 14 February, and while the status of my Headquarters to be known as SHAEF was not recognized until the following day, the basic work of planning continued during this transitional period. The staff brought into being as COSSAC came under my control and was greatly expanded as the pressure of time and the vast scope of our work required.
I patterned my Headquarters upon the closely integrated Allied establishment which it had been my policy to maintain at AFHQ in the Mediterranean, and in this respect I was fortunate in obtaining for my staff men whose proved ability had already been demonstrated in previous campaigns Air Chief Marshal Sir Arthur W Tedder as my Deputy Supreme Commander, General Smith as my Chief of Staff, and Lieut Gen Sir Humfrey M Gale as Chief Administrative Officer. General Morgan remained as Deputy Chief of Staff, his detailed knowledge of tactical plans making him absolutely indispensable.
Relationship between SHAEF and the Headquarters of my Commanders-in-Chief for the Navy, Army, and Air Forces was established on the operational planning level through a Joint Planning Staff which closely integrated the work of all. The Headquarters of COSSAC had been located at Norfolk House, St James's Square, with an annex at 80, Pall Mall, and it was here initially that my own Headquarters came into being. However, I was convinced by past experience that a Headquarters located in the heart of a great city would not be as unified as one located elsewhere. Accordingly SHAEF was moved in March to Bushy Park, near Kingston-on-Thames. Here we studied the operation in detail and ironed out all the numerous and frequently vexing problems relating to so vast an undertaking.
The chief changes which we were to make in the assault plan were considered at the first meeting which I held with my Commanders-in-Chief at Norfolk House on 21 January. Field Marshal Montgomery (Commanding General, 21 Army Group), Admiral Sir Bertram H Ramsay (Commander of the Allied Naval Expeditionary Force), and Air Chief Marshal Sir Trafford Leigh-Mallory (Commander of the Allied Expeditionary Air Force) reviewed operation OVERLORD as a whole with me and were in agreement upon certain amendments to the plan.
The COSSAC plan called for an initial assaulting force of three divisions. I had felt when I originally read the OVERLORD plan that our experiences in the Sicilian campaign were being misinterpreted, for, while that operation was in most respects successful, it was my conviction that had a larger assault force been employed against the island beachheads our troops would have been in a position to overrun the defenses more quickly. Against the better prepared defenses of France I felt that a three-division assault was in insufficient strength, and
In addition to increasing the assault force from three to five divisions, I felt that the beach area to be attacked should be on a wider front than that originally envisaged. Particularly, it was considered that an attack directly against the Cotentin Peninsula should be included in the plan, with a view to the speedy conquest of Cherbourg. In the event that our troops were able to attain a high degree of surprise in the attack, they would be in a better position to overwhelm the strung-out defenses before the enemy could regroup or mass for a counterattack. Conversely, in the event of strong resistance, we would be more advantageously situated, on a wider front and in greater force, to find "soft spots" in the defense.
The original COSSAC plan included the beachhead areas from Courseulles in the east to Grandcamp in the west. We decided to extend this area eastward to include the Ouistreham beaches, feeling that this would facilitate the seizure by rapidly securing the eastern flank of the important focal point of Caen and the vital airfields in the vicinity. Westward, we decided that the assault front should be widened to include the Varreville beaches on the eastern side of the Cotentin Peninsula itself. A strong foothold on the peninsula and a rapid operation to cut its neck would greatly speed up the capture of the port of Cherbourg.
For the operation against the neck of the Cotentin to be successful, it was believed that two airborne divisions should be employed in support of the troops assaulting the Varreville beaches, still leaving one airborne division to hold vital bridges in the Orne-Dives Rivers area to the northeast of Caen. Field Marshal Montgomery and Admiral Ramsay were in agreement on this point, but Air Chief Marshal Leigh-Mallory saw technical difficulties which it was necessary to consider closely.
It was his feeling, both then and subsequently, that the employment of airborne divisions against the South Cotentin would result in landing losses to aircraft and personnel as high as 75% - 80%. In the face of this estimate, however, I was still convinced of the absolute necessity of quickly overrunning the peninsula and attaining the port of Cherbourg, vital to the support and maintenance of our land forces. Without the airborne divisions an assault against the Varreville beaches would have been most hazardous, since our attack here could only be on a one-division front. Behind the landing beach was a lagoon, traversed only by a few causeways; the exits of these had to be captured from the rear, or else the strip of beach would quickly become a death trap. In addition, this beach was separated from the other four beaches to be assaulted by an estuary and marsh lands which would have effectively prevented the junction and link-up of the forces for several days, permitting the enemy in this sector more easily to dislodge us and threaten our right flank. Support by the airborne troops was essential, and I ultimately took upon myself the heavy responsibility of deciding that the airborne operation against the Cotentin be carried out. The decision, once taken, was loyally and efficiently executed by the airborne forces, and it is to them that immeasurable credit for the subsequent success of the western operation belongs. The airborne landing losses proved only a fraction of what had been feared, amounting in fact to less than 10%.
Our decisions to strengthen the forces employed in the initial assault, to widen the area of attack, and to employ the airborne forces in the Cotentin rather than at Caen, were communicated to the Combined Chiefs of Staff on 23 January, and at the same time I brought up the subject of the target date for the operation.
In the original plan, the target date for the D-day assault had been 1 May. A new factor, however, which made me doubt that the date could be adhered to was our deficiency in assault craft for the larger five-division attack. In the COSSAC plan, three divisions in the assault and two immediate follow-up divisions, a total of five, were to be preloaded in assault craft. Sufficient craft for five divisions had been planned. The new plan, calling for five divisions in the assault, still retained the two follow-up divisions, requiring therefore sufficient craft to preload seven divisions. There was considerable doubt that the additional craft could be made available by 1 May, and I informed the Combined Chiefs of Staff that, rather than risk failure with reduced forces on that date, postponement of the target date for a month would be preferable if I could be assured of then obtaining the strength required. My planners had advised me that a month's additional production of assault craft in both Great Britain and the United States would go far toward supplying the deficiency foreseen for the earlier date.
From the air point of view, the extension of the target date would afford a longer opportunity for the strategic bombing of Germany and the wearing down of German air strength. In addition, the tactical bombing of railheads and transportation centers, the preliminary softening of fortifications on the Channel coast, and the diversionary heavy air attacks in the Pas-de-Calais could be undertaken with greater thoroughness. The training of the invasion forces, and particularly the troop-carrier crews for the airborne operations, could also be carried on more thoroughly.
The Navy, moreover, desired additional time for the training of the assault craft crews and for the delivery and assembly of the extra vessels needed in the enlarged attack. From the naval viewpoint a postponement of the target date to the first of June was preferable to any briefer postponement, say of two weeks, since an early June date guaranteed the favorable tides necessary for the beach operations as well as a full moon.
From the strategic point of view the postponement seemed desirable, since weather conditions at the end of May would be likely to be more favorable for the mounting of a large-scale Russian offensive to assist the OVERLORD operation. Additionally, the situation in the Mediterranean might be sufficiently resolved by that time to preclude the .necessity of an operation against the south of France closely coordinated with our western assault. The German forces in that theater might be so heavily engaged by our armies that a diversionary and containing assault would not be required in direct and immediate assistance to OVERLORD.
The Combined Chiefs of Staff agreed on 1 February that OVERLORD would be mounted with a target date not later than 31 May. We indicated that the exact date of the assault should be left open and subject to weather conditions prevailing during the first week of June. Later, on 17 May, I set 5 June as the "final" date for the assault, subject, of course, to last-minute revision if the weather should prove unfavorable. The selection of this date was based primarily on tidal and light conditions. It was necessary that the title be sufficiently low to enable the initial assault elements to land and prepare lanes through the heavy obstacles which were above water only at or near a low tide. Also, this tidal condition had to coincide with a period of sufficient light to permit visual bombing by aircraft of the beach defenses and bombardment by the naval vessels. The dates of 5, 6, and 7 June were all acceptable on this basis, but any postponement beyond these dates would have necessitated waiting until 19 June for a similar favorable tidal period. This later date would have necessitated the acceptance of moonless conditions.
Strategically, the postponement of the target date proved to be a sound measure. By 1 May, the original date, our forces in Italy were still encountering heavy resistance south of Rome along the Gustav Line, while Russian forces were occupied in the Crimea and still forming for a western attack. By the first week in June, however, Rome had fallen, Kesselring's forces were in retreat, the Crimea had been cleared, and Germany was nervously predicting an all-out Russian offensive. Furthermore, the enemy had been keyed up to a 1 May Allied offensive from the United Kingdom, to judge from his "invasion any now" feelers. The month's delay served perhaps to lull him into believing that we would. now not attack until some time in July. The month's postponement also guaranteed, as events proved, the availability of assault craft and shipping to move the staggering number of men and vehicles required for the D-day assault.
It should be noted here, however, that had it been possible to adhere to the initial elate, the weather would have been much superior for the invasion than was the weather encountered during the first week of June. During the first week of May, in the full-moon period, the Channel was consistently calm and the skies cloudless, ideal both for naval and air operations. The weather was strikingly similar to that which favored England during the disastrous days of Dunkirk. In the first week of June, on the other hand, the Channel was choppy at best, with heavy seas running most of the time. The skies were overcast, and days of rain hampered air operations. The full extent to which this unfavorable weather influenced our operations will be considered later in this report.
With the settlement of the basic problems essential to firm planning the size of the assault and the target date the Army, Navy, and Air Forces were in a position to develop their final plans for the attack against the Normandy beaches. The best method of controlling the effort of the Strategic Air Forces was still under discussion, and will be referred to later in the section on "Preparatory Operations." Immediately under my command in the pre-D-day period were the Commanders-in-Chief already mentioned, Field Marshal Montgomery, Admiral Ramsay, and Air Chief. Marshal Leigh-Mallory.
Within 21 Army Group, Field Marshal Montgomery had under his command the Canadian First Army (2 Corps) under Lieut Gen H D G Crerar; the British Second Army (1, 8, 12, and 30 Corps) under Lieut Gen (then Maj Gen) Sir M C Dempsey; the British airborne troops (1 and 6 Divisions) under Lieut Gen F A M Browning; and the United States First Army (V, VII, VIII, and XIX Corps, with the attached airborne troops of the 82nd and 101st Divisions) under General (then Lieut Gen) Omar N Bradley. While plans called for eventual organization of American and British ground forces each under its own commander, directly responsible to me, the initial assault was foreseen as a single battle, closely interrelated in all its parts, and requiring the supervision of a single battle-line commander. All agreed on this necessity.
The army plans for the assault and subsequent build-up period were prepared, pursuant to periodical directives from Supreme Headquarters, by the planning staffs of the American and British Army Headquarters, coordinated by 21 Army Group Headquarters, and subsequently reviewed by the G-3 Division of my staff under Maj Gen H R Bull and his deputy, Maj Gen J F M Whiteley. Constant revision of the plans was necessary throughout the early months of 1944, due primarily to the continuing uncertainty as to the exact number of assault craft to be made available for the loading of the troops. Even with the extra month's production of craft in both the United States and the United Kingdom, it seemed that sufficient lift would not be forthcoming, and it became necessary during this period to consider drawing craft from either the Mediterranean or the Pacific to round out the figure needed. This entailed a constant exchange of views between Theaters and between my Headquarters and the Combined Chiefs of Staff until the problem was finally settled as late as 24 March. Since the problem was also related to the mounting of operation ANVIL, the assault against Southern France from the Mediterranean, reference will be made to the matter again in this report. Suffice it to say here, however, that before firm planning can be undertaken on any major amphibious operation, involving, as such an operation does, the forces of both the Army and the Navy, the primary factor of assault craft must be definitely determined. This decision should be made as early as humanly possible, for it is a matter of the first priority.
Based upon the COSSAC plan for the assault, together with the revisions as to date and size of attack which have been mentioned, the final plan produced by 21 Army Group and approved by Supreme Headquarters thus came into being.
Broadly, the army plan of attack involved a D-day assault on a five-divisional front on the beaches between Ouistreham and Varreville with the immediate purpose of establishing beachheads to accommodate follow-up troops. The initial objectives of the attack included the capture of Caen, Bayeux, Isigny, and Carentan, with the airfields in their vicinity, and the essential port of Cherbourg. Thereafter our forces were to advance on Brittany with the object of capturing the ports southward to Nantes. Our next main aim was to drive east on the line of the Loire in the general direction of Paris and north across the Seine, with the purpose of destroying as many as possible of the German forces in this area of the west.
Because it was ultimately intended to supply the United States forces engaged in Europe directly from American ports, American troops were assigned the right flank in the operations. They were to take Cherbourg and the Brittany ports as supply bases, while the British, driving east and north along the coast were to seize the Channel ports, as far north as Antwerp, through which they were to be supplied directly from England.
On the right, American forces of General Bradley's First Army were to assault the Varreville (Utah) beach and the St-Laurent (Omaha) beach. Lieut Gen (then Maj Gen) J Lawton Collins' VII Corps was to land with the 4th Infantry Division in the assault on Utah beach just north of the Vire Estuary. During the early morning hours of D-day the 82d and 101st Airborne Divisions were to drop in the area southeast and west of Ste-Mère-Eglise where their mission was to capture the crossings of the Merderet River, secure the line of the Douve River as a barrier, and assist the landing of the 4th Infantry Division at the Beach. By the end of D-day, we anticipated that VII Corps, with the airborne divisions under command, would control the area east of the Merderet from just south of Montebourg to the Douve.
Lieut Gen (then Maj Gen) Leonard T Gerow's V Corps planned its attack on a 7,000-yard stretch of beach known as Omaha, on the northern coast of Calvados near St-Laurent. One combat team of the 29th Infantry Division on the right and one combat team of the 1st Infantry Division on the left, both under the command of the 1st Infantry Division, were to assault in the initial wave.
The primary objective of VII Corps, supported by the airborne divisions, was to cut the Cotentin Peninsula against attack from the south, and, driving northward, to seize the port of Cherbourg we hoped by D-plus-8. While Cherbourg was being taken, troops of V Corps and follow-up forces were to drive south toward St-Lô, seizing the city by D-plus-9. With the reduction of the Cotentin Peninsula, the forces engaged there and follow-up forces subsequently landed were also to turn south, join with the forces landed over Omaha, and drive to a line Avranches-Domfront by approximately D-plus-20.
Forces of General (then Lieut Gen) George S Patton's Third Army were, during this period, to be landed across the American beaches and initially come under the operational control of First Army, passing to the control of Third Army when its Headquarters moved to the Continent at about D-plus-30. While First Army was to make an initial turning movement into the Brittany Peninsula in the direction of St Malo, it was planned that Third Army, with its growing forces, would take over the reduction of the peninsula and the Brittany ports from First Army on this same date. First Army, then, freed of the responsibility for Brittany, was to turn its forces south and east along the Loire, reaching a line beyond Angers-Le-Mans by D-plus-40.
British and Canadian forces, landing on the Ouistreham (Sword), Courseulles (Juno), and Asnelles (Gold) beaches were in the meantime to protect the left flank of the Allied forces against what was expected to be the main German counterattack from the east. An additional important task was to gain the ground south and southwest of Caen, favorable for the development of airfields and for the use of our armor. The first assault was to be made by three divisions of General Dempsey's British Second Army: the 3 Canadian and 3 British Infantry Divisions of 1 Corps, and the 50 Infantry Division of 30 Corps. British 6 Airborne Division was to be dropped behind the beach defenses to secure the vital bridges over the Caen Canal and the Orne River between Caen and the sea, together with certain other objectives in that locality. These forces with follow-up troops, advancing southward, were to occupy territory inland to a line Vire-Falaise, including the Caen road center, by about D-plus-20.
After occupation of this area, the British forces were to continue expansion along the general line of the Seine, advancing on the left of the American divisions until, by D-plus-90, the general Allied front was to stand on the Seine from Le Havre to Paris on the north, and along the Loire from Nantes to Orleans, Fontainebleau, and Paris on the south and east. In the west the Brittany Peninsula was to be fully occupied. By D-plus-90 the armies were to be ready to take Paris, force the crossing of the Seine in strength in an advance northward to the Somme, and continue east along the Marne in a drive toward the German frontier.
Early in May 1944 after I had approved Field Marshal Montgomery's plans for establishing our forces on the Continent, and for placing them in position prepared for eruption from the lodgement area, the planning staff presented their visualization of the several lines of action which might be followed for the continuance of the campaign, up to and including the final period, for a drive into the heart of Germany. The favored line of action was sketched on a map of the Continent. It contemplated an advance on a broad front with the main effort constantly on the left (north) flank and with another thrust toward Metz, passing north and south of Paris in the event the Germans determined to hold it as a fortress, joining up with Gen Jacob L Devers' forces coming from the south to cut off Southwest France; penetration of the Siegfried Line, still with the main effort in the north; elimination of the German forces west of the Rhine either by decisive defeat or by pressure which would force their withdrawal, with particular emphasis on the area from Cologne-Bonn to the sea; a power crossing of the Rhine north of the Ruhr, coupled with a secondary effort via the Frankfurt Corridor, the two thrusts to join in the general area of Kassel, encircling the Ruhr. Thereafter it was anticipated that the destruction of remaining German strength would be easy.
This estimate made at this early date is particularly interesting since the proposed scheme of maneuver was practically identical with that which was followed during the campaign.
Later in this report is described the supporting air plan, success in which was vital to the attainment of the ambitious objectives prescribed for the land forces. Also necessary to an understanding of the whole battle is a knowledge of the information we possessed, prior to the assault, regarding the enemy dispositions, a summary of which is also included in a subsequent chapter.
In the initial phases of OVERLORD, Field Marshal Montgomery, whom I had designated as tactical commander of the early land battles, was to have operational control of all land forces, including the United States
In the matter of command, it can be said here that all relationships between American and British forces were smooth and effective. Because of certain fundamental national differences in methods of military supply and administration, it was early agreed that no unit lower than a corps of one nationality would be placed under command of the other nationality except where unavoidable military necessity made this imperative.
To carry out the mission of invading Western Europe, there were to be available, by D-day, in the United Kingdom 37 divisions: 23 infantry, 10 armored, and 4 airborne. These were to be employed in the assault and subsequent build-up period in France. As the campaign progressed, the flow of divisions to the Continent was to be maintained at a rate of three to five divisions per month, and this flow was to be augmented by the divisions entering the European Theater with the assault against Southern France from the Mediterranean. Ultimately, at the time of the German surrender, I had under command a total of 90 divisions: 61 American, 13 British, 5 Canadian, 10 French, and 1 Polish. These divisions, with antiaircraft, antitank, and tank units habitually attached, averaged about 17,000 in combat strength, well over twice the strength of Russian divisions. In addition there were three French divisions which were not completely equipped, and lesser units of Czech, Belgian, and Dutch forces on the Continent, as well as the units of the French Forces of the Interior. Our Headquarters estimated that, at times, the value of these latter French forces to the campaign amounted in manpower to the equivalent of 15 divisions, and their great assistance in facilitating the rapidity of our advance across France bore this out.
The initial success of the land forces in the assault against Northwest Europe was dependent upon the operations of the Allied Naval Expeditionary Force under the command of Admiral Ramsay. In his operational orders issued on 10 April, he clearly defined the Navy's mission to those under his command:
"The object of the Naval Commander-in-Chief is the safe and timely arrival of the assault forces at their beaches, the cover of their landings, and subsequently the support and maintenance and the rapid build-up of our forces ashore."To accomplish this mission successfully months of detailed planning and training, closely coordinated with the ground and air forces, were necessary.
Reports on the North African and Sicilian Campaigns have made mention of the magnitude of the naval forces involved, but the sea power displayed there was to fade by comparison with the forces to be employed in this great amphibious assault. The extent of the problem of berthing, loading, and moving the forces involved may be realized with the knowledge that over 5,000 ships and 4,000 additional "ship-to-shore" craft were to be engaged in the Channel operations during the assault and build-up period. That everything went according to plan is a remarkable tribute to the hard work, coordinated effort, and foresight of the thousands engaged in the initial planning and training, and, as Admiral Ramsay stated in his report, to the "courage of the tens of thousands in the Allied navies and merchant fleets who carried out their orders in accordance with the very highest traditions of the sea."
With the expansion of the assault from a three-divisional to a five-divisional attacking force, increased naval forces were necessary both to protect the invasion fleet en route and to bring added fire power to bear on the beaches. These were allotted by the Combined Chiefs of Staff on 15 April 1944. The chief units in the final naval forces included 6 battleships, 2 monitors, 22 cruisers, and 93 destroyers.
Under the naval plan the assault area for the naval forces was bounded on the north by the parallel of 49°40' N, and on the west, south, and east by the shores of the Bay of the Seine. This area was subdivided into two Task Force Areas, American and British, the boundary between them running from the root of the Port-en-Bessin western breakwater in an 025° direction to the meridian of 0° 40' W, and thence northward along this meridian to latitude 49°40' N. Within these defined areas, the Western Task Force, operating in the American zone, was under the command of Rear Adm A G Kirk, and the Eastern Task Force, operating in the British zone, under the command of Rear Adm Sir P I Vian.
In order to insure the safe arrival of the assault troops on the beaches, the Navy was to provide adequate covering forces to protect the flanks of the routes of our assault and was, with mine sweeping vessels, to clear the Channel ahead of the assault craft. For this latter purpose 12 mine sweeping flotillas were to be employed. Once within range of the beachhead area, the heavy naval guns were to neutralize the enemy coastal batteries, supplementing the work of the Air Forces, and then, as the landing craft drove inshore, there was to be an intense bombardment of the beach defenses by every gun that could be brought to bear.
Some consideration had initially been given to the possibility of assaulting at night in order to obtain the maximum surprise, but it was decided that the lessons of the Pacific should be adhered to, and that, possessing superiority in air and naval forces, the assault against strong defenses should take place by day. This was palpably advantageous to the Navy in the coordinated movement of a vast fleet in relatively narrow waters. H-hour varied for most of the five assault forces, due to varying beach conditions such as the necessity for higher tide to cover certain rock obstacles and the length of time needed to remove enemy obstructions. Force "U" was to touch down at 0630 hours while Force "J" was not to land until 35 minutes later.
With the success of the assault determined, the naval forces were to maintain swept channels between France and England through which supplies and reinforcements could be shuttled to the Continent. In view of the initial limited port facilities and the fact that we did not anticipate seizing the Brittany ports for some time after the assault, the Navy was also charged with providing for the establishment off the French coast of five artificial anchorages (Gooseberries). Two of these were subsequently to be expanded into major artificial harbors (Mulberries); through these the bulk of our stores were to be unloaded during the early stages of the campaign. To provide oil and gasoline in bulk, the Navy was also to set up tanker discharge points off the French coast and to establish cross-Channel submarine pipe lines.
By 26 April, the five naval assault forces were assembled in the following areas: Force "U," Plymouth; Force "O," Portland; Force "S," Portsmouth; Force "G," Southampton; and Force "J," Isle of Wight. The two follow-up forces, Force "B" and Force "L," were assembled in the Falmouth-Plymouth and Nore areas. In addition to the berthing problems inherent in the assembly of these seven forces, other space had to be found for the many ships and craft which were assigned the tasks of supply, maintenance, repair, and reinforcement. The berthing problem was one of major proportions, but it was solved, as Admiral Ramsay reported, by making use of every available berth from Milford Haven to Harwich. Many units had, additionally, to be berthed in the Humber, at Belfast, and in the Clyde.
The concentration of ships in southern ports was bound, we felt, to be detected by the enemy and would thus give him some indication that our assault was about to be launched. In order to confuse him in this respect, arrangements were made with the British Admiralty to have the large number of commercial ships destined for the Thames and also the ships to be used in later supply convoys to our forces on the Continent held in Scottish ports until the operation was under way. The concentration of shipping thus spread itself automatically throughout the whole British Isles and was not confined to a single area. As was the case against Sicily, we did not believe that the growing preparations and the size of our forces could be entirely concealed from the enemy. We hoped, though, to be able to confuse him as to the time of the assault and the exact beachhead area of attack. In this we were to be successful for a variety of reasons which I shall consider later.
The air plan in support of the amphibious operation consisted of two parts, the preparatory phase and the assault phase, and was brought into being under the direction of Air Chief Marshal Leigh-Mallory, commanding the Tactical Air Forces. These forces, composed of the British Second Tactical Air Force and the US Ninth Air Force, were to operate in direct support of the land armies. The Strategic Air Forces also would be given definite tactical responsibilities during critical periods, although their principal mission would be to
Until January 1944, the view had been held that the heavy bombers of the Strategic Air Forces could make sufficient direct contribution to the assault in a period of about a fortnight before D-day. Further consideration, however, indicated the need to employ them for a much longer period about three months and a plan was finally adopted which aimed at the crippling of the French and Belgian railway systems and the consequent restriction of the enemy's mobility. The plan had a wider conception than the dislocation of the enemy's lines of communication in the zone in which the land forces were to be deployed. It was looked upon as the first of a series of attacks, which as they spread eastward, would ultimately affect the whole German war effort. The adoption of this plan entailed a major effort by the Strategic Air Forces.
In the preparatory phase, the striking power of the Tactical Air Forces was to be directed against rail targets, bridges, airfields in the vicinity of the assault area, coastal batteries, radar stations, and other naval and military targets. In addition to reserve aircraft, these forces had operationally available 2,434 fighters and fighter-bombers, and 700 light and medium bombers.
The program of attack on rail centers and bridges was designed to deprive the enemy of the means for the rapid concentration of men and material and to hinder: his efforts to maintain an adequate flow of reinforcements and supplies, forcing him to move by road with resultant delay, increased wastage in road transport and fuel, and increased vulnerability to air attack. Blows against the railroad centers were to be started about D-minus-60 and were to cover a wide area so as to give the enemy no clue to our proposed assault beaches. Shortly before D-day, however, the attacks would be intensified and focused on key points more directly related to the assault area but still so controlled as not to indicate to the enemy the area itself.
Attacks against coastal batteries, airfields, bridges, and other targets in the preparatory period were planned in such a manner that only one-third of the effort expended would be devoted to the targets threatening the success of our assault. The preliminary attacks upon the bridges in Northwestern France were scheduled to begin on D-minus-46 and to be intensified in tempo as D-day approached. The ultimate purpose of these attacks was to isolate the battle area from the rest of France by cutting the bridges over the Seine and the Loire below Paris and Orléans, respectively. The attacks upon the airfields had a similar purpose. Within a 130-mile radius of the battle area, all enemy airfields and air installations were to be attacked beginning not later than D-minus-21. By neutralizing the fields, we were certain to limit the maneuverability of German fighter forces, compelling them to enter the battle from fields situated a considerable distance from the Normandy beaches.
This preparatory bombing program was placed in effect as scheduled and, as D-day approached, the intensity of our attacks increased and the preparatory phase gave way to the assault phase. In the assault itself, the air forces were assigned the tasks, in conjunction with the navies, of protecting the cross-Channel movement of our forces from enemy air and naval attack. They were also to prepare the way for the assault by destroying the enemy's radar installations and by neutralizing coastal batteries and beach defenses between Ouistreham and Varreville, the area of our attack. Additionally, the air forces were to provide protective cover over the landing beaches and, by attacking the enemy, reduce his ability to reinforce and counterattack. Subsequent to the establishment of the beachhead, the Tactical Air Forces were to support the land troops in their advance inland from the assault beaches.
During the assault it was planned to maintain a sustained density of ten fighter squadrons to cover the beach area, Five over the British sector and five over the American. An additional six squadrons were to be maintained in readiness to support the beach cover if necessary. Over the main naval approach channels we agreed upon a sustained density of five squadrons centered at 60 miles and three at 80 miles from the south coast of England. Additionally, a striking force of 33 fighter squadrons was to be held in reserve for use as the air situation might require, subsequent to its initial employment as escort to the airborne formations.
The total fighter aircraft which we allocated for the D-day assault was as follows:
|Direct Air Support||36||Squadrons|
|Offensive Fighter Operations|
and Bomber Escort
The photographic reconnaissance units of the Allied Air Forces were the first to begin active and direct preparations for the invasion of Europe from the west. For more than a year, much vital information was accumulated which contributed very greatly to the ultimate success of the assault. The variety, complexity, and the detailed accuracy of the information gathered was of great importance in the preparatory phase of the operation. One of the most remarkable tasks accomplished by these reconnaissance units was the series of sorties flown to obtain low-level obliques of underwater beach defenses.
In support of operation OVERLORD it had been proposed at the Casablanca Conference that an assault against Southern France be mounted from the Mediterranean to coincide closely with the timing of the assault against Northwest France. I had been engaged in the planning phase of this operation, known initially as ANVIL and subsequently as DRAGOON, prior to leaving my command in the Mediterranean, and felt then that its contribution to the downfall of the enemy would be considerable. I continued to recognize its importance after leaving the Mediterranean Theater, fully conscious not only of the psychological effect upon the enemy and upon Europe as a whole of the double assault, but of the great military value the southern blow would have in splitting all enemy forces in France and of thus assisting OVERLORD.
Initially we had hoped that the ANVIL assault could be mounted with three divisions or, at the worst, with 2 divisions, building up to a strength of 10 divisions in the follow-up. However, on 23 January 1943, it became necessary to recommend to the Combined Chiefs of Staff that some consideration be given to reducing the ANVIL assault to one division, maintaining it as a threat until enemy weakness justified its employment. This recommendation was necessary because of our shortage of assault craft for the enlarged OVERLORD operation. We hoped that craft in the Mediterranean, originally allocated for ANVIL, would thus be freed for our use.
The Combined Chiefs of Staff did not agree with this proposal and on the basis of planning data available to them stated that sufficient craft would be on hand to mount an OVERLORD assault of seven divisions (including the two follow-up divisions) and an ANVIL of two divisions. These figures did not coincide with those of my own planners and the discrepancy was explained to the planners at Washington by my Chief of Staff. It was pointed out that the divisions involved in the assault each actually represented a division plus a regimental combat team and included the armor attached to it. Additionally, a number of subsidiary assaults by Commandos and Rangers necessitated craft for 5,000 personnel. Beyond this, the nature of the terrain, the heavy beach defenses, and the large rise and fall of tide in the Channel demanded the use of a very much larger number of engineer personnel and personnel for work on the beaches than would have otherwise been necessary. The scale of the problem may be understood by the fact that we intended on D-day and D-plus-1 to land 20,111 vehicles and 176,475 personnel. The vehicles included 1,500 tanks, 5,000 other tracked fighting vehicles, 3,000 guns of all types, and 10,500 other vehicles from jeeps to bulldozers.
This explanation helped to clarify our needs, and the Combined Chiefs of Staff recognizing the situation, met it by suggesting that the ANVIL assault be postponed rather than mounted simultaneously with OVERLORD. Field Marshal (then General) Sir Maitland Wilson as Supreme Commander in the Mediterranean Theater, and the British Chiefs of Staff in London, had at one time suggested that the ANVIL operation be canceled chiefly because of weakness in the initial assault and the length of time required to build up sufficient forces, However, this was held to be inadvisable from the strategic point of view and contrary to the decisions reached at Teheran. The military advantages to be gained through a force of an additional ten or more divisions operating on our right flank after clearing Southern France would, I believed, be of extraordinary value later in the campaign. Accordingly, on 24 March, ANVIL was postponed from a target date of 31 May to one of 10 July, some four weeks after the OVERLORD
While the problem of assault craft was being resolved, the build-up of American troops and supplies in the United Kingdom continued under the direction of Lieut Gen John C H Lee. Planning for BOLERO, the name by which this logistical program was known, had begun in the United Kingdom as early as April 1942. The small original staff was divided for the North African (TORCH) operation, but expanded in 1943 and 1944 as the OVERLORD task became larger until, by D-day, the Communications Zone establishment contained 31,500 officers and 350,000 enlisted personnel, By July 1943 some 750,000 tons of supplies were pouring through English ports each month and this amount was steadily increased until in June 1944 1,900,000 tons were received from the United States. Much of this material was used to supply the troops already arrived in England, and other amounts were stored for use as OVERLORD progressed, but the stock pile earmarked for the American forces, over and above basic loads and equipment, was a full 2,500, 000 tons for the invasion alone. By 1 June also, the number of US Army troops in the United Kingdom had risen from 241,839 at the end of 1942 to 1,562,000.
The operation of transporting supplies from the United States to the United Kingdom was facilitated by the fact that cargoes were discharged through established ports and over established rail lines. Additionally, large quantities of materials for the invasion were made directly available from British resources within the United Kingdom itself. These conditions could not, of course, exist on the Continent and plans were accordingly made to overcome the difficulties envisaged. It was recognized that the major tonnage reception on the Continent would be over the Normandy beaches during the first two months, with the port of Cherbourg being developed at an early date. Successively, it was anticipated that port development would proceed in Brittany, the major effort in that area to be an artificial port at Quiberon Bay with complementary development of the existing ports of Brest, Lorient, St-Nazaire, and Nantes. While these were being brought into use the flow of supplies over the beaches was to be aided by the two artificial harbors (Mulberry "A" and Mulberry "B"). As the campaign progressed, it was anticipated that the bulk of American supplies would flow directly from the United States through the Brittany ports, while the Channel ports to the north, including Ostend and Antwerp, would be developed for the British armies. These expectations, however, did not materialize, due primarily to enemy strategy and the vicissitudes of the campaign. That both the American and British supply systems were able, in spite of this, to support the armies to the extent they did is a remarkable tribute to the flexibility of their organizations and to their perseverance in a single purpose.
The importance of the steady supply of our forces, once landed, may be gauged by reference to German strategy. This was intended to insure that our supplies should never be permitted to begin flowing into the beachheads. The German philosophy was: "Deny the Allies the use of ports and they will be unable to support their armies ashore." For this reason the chain of Atlantic and Channel ports from Bordeaux to Antwerp was under orders from Hitler himself to fight to the last man and the last round of ammunition. The Germans fully expected us to be able to make a landing at some point on the Channel coast, but they were nevertheless certain that they could dislodge us before supplies could be brought ashore to maintain the troops. They had no knowledge of. our artificial harbors, a secret as closely guarded as the time and place of our assault. The impossible was accomplished and supplies came ashore, not afterwards to support a force beleaguered on the beachheads, but actually with the troops as they landed. The Germans were, by virtue of our initial supply, denied the opportunity of dislodging us and were subsequently, throughout the campaign, under sustained attack as the result of the feats of maintenance performed by our administrative organizations.
A captured enemy document, written by a division commander, perhaps pays as great a tribute to all the forces responsible for supply of the front-line troops as could be found. He wrote:
"I cannot understand these Americans. Each night we know that we have cut them to pieces, inflicted heavy casualties, mowed down their transport. We know, in some cases, we have almost decimated entire battalions. But in the morning, we are suddenly faced with fresh battalions, with complete replacements of men, machines, food, tools, and weapons. This happens day after day. If I did not see it with my own eyes, I would say it is impossible to give this kind of support to front-line troops so far from their bases."
While our plans developed and the build-up of supplies and men in readiness for the operation continued with regularity, we had been studying the possible action which the enemy might take in the expectation of an assault against him mounted from the United Kingdom. In any operation as large as OVERLORD it was palpably impossible to keep from the enemy the fact that we intended, during 1944 to launch an attack against Europe. Where, when, and in what strength the attack would be launched was another matter, and I was not without hope that he would not necessarily appreciate that our target was the Normandy beaches, Indeed we had some reason to believe that the enemy expected numerous attacks from many quarters and was continually uncertain as to the strength of any of them, unable in his own mind to determine or distinguish between a threat which we had no intention of launching, a diversion in strength, or an all-out main assault. Thus, he was stretched to the utmost in every theater.
We thought that to the German High Command an assault upon the Pas-de-Calais would be the obvious operation for the Allies to undertake. Not only was this the shortest sea journey where the maximum air cover would be available, but a lodgement in the Pas-de-Calais would lead the Allies by the shortest road directly to the Ruhr and the heart of Germany. Such an operation would have to be mounted mainly from Southeast England and the Thames area. Concentrated in the Pas-de-Calais was the German Fifteenth Army, which had the capability both of shifting its forces to Normandy prior to the assault if the intended area of the attack were to become known and also of quickly reinforcing the divisions in Normandy, after the assault.
Acting on the assumption that this would be the German estimate we did everything possible to confirm him in his belief. Without departing from the principle that the efficient mounting of the operation remained at all times the first consideration, we took every opportunity of concentrating units destined ultimately for the Normandy beachhead in the east and southeast rather than in the southwest. In this way it was hoped that the enemy, by his observations based on aerial reconnaissance and radio interception, would conclude that the main assault would take place farther to the east than was in fact intended. As a result of these measures, we also felt that had an enemy agent been able to penetrate our formidable security barrier, his observations would have pointed to the same conclusion.
Shipping arrangements were made with the same end in view. Surplus shipping was directed to the Thames Estuary where an enormous concentration was already assembled in preparation for the invasion, while landing craft were moored at Dover, in the Thames, and at certain East Anglian ports.
Further support was afforded by the aerial bombing program. The distribution of bombing effort was so adjusted as to indicate a special interest in the Pas-de-Calais. It was also hoped that the bombing of the V-1 sites would be misinterpreted in our favor. Finally the large and very visible components of the artificial harbors, which were subsequently set up on the Normandy beaches, were anchored in Selsey Bay immediately before the invasion, a point farther east than originally proposed.
After the assault had gone in on 6 June we continued to maintain, for as long as possible, our concentrations in the southeast and our displays of real and dummy shipping, in the hope that the enemy would estimate that the Normandy beachhead was a diversionary assault and that the main and positive blow would fall on the Pas-de-Calais when the diversion had fulfilled its purpose.
The German Fifteenth Army remained immobile in the Pas-de-Calais, contained until the latter part of July by what we now know from high-level interrogation was the threat of attack by our forces in the southeast of England. Not until 25 July did the first division of the Fifteenth Army advance westward in a belated and fruitless attempt to reinforce the crumbling Normandy front.
Every precaution was taken against leakage of our true operational intentions against Normandy. The highest degree of secrecy was maintained throughout all military establishments, both British and American, but additional broader measures affecting the general public were necessary as D-day approached.
On 9 February, all civilian travel between Britain and Ireland was suspended to prevent the leakage of information through Dublin, where German agents
Because even the most friendly diplomats might unintentionally disclose vital information which would ultimately come to the ears of the enemy, the British Government took the further unprecedented step of restricting diplomatic privileges. On 17 April it banned the movement of diplomats or their couriers into and out of the United Kingdom and subjected hitherto immune correspondence to censorship. At my request this ban was maintained until 19 June.
Lastly, it was considered expedient on 25 May to impose an artificial delay of ten days on the forwarding of all American mail to the United States and elsewhere and to deny to American personnel trans-Atlantic telephone, radio, and cable facilities. The mail of all British military personnel due to take part in the Normandy operation had been, even within England itself, subject to strict censorship since April.
Preparatory operations incident to the assault were already under way. These were the special concern of the Air Forces and the Navy, and consisted, apart from the Tactical Air Forces' operations already considered, primarily of the strategic bombing of Germany and the Channel exercises designed to afford training to the assault forces.
By a decision taken by the Combined Chiefs of Staff, prior to my arrival in the Theater, command of the strategic bombing forces the RAF Bomber Command and the United States Strategic Air Forces (composed of the Fifteenth Air Force in the Mediterranean Theater and the Eighth Air Force in the European Theater) ultimately rested with the Combined Chiefs themselves. This decision had been taken with the purpose of coordinating strategic bombing against Germany from all sides. Within the European Theater over-all command of the United States Strategic Air Forces rested with General (then Lieut Gen) Carl A Spaatz and command of the RAF Bomber Command with Air Chief Marshal Sir Arthur Harris. The Strategic Air Forces were thus not under my direct orders, their commanders being instead responsible directly to the Combined Chiefs in Washington. While understanding the long-range motives which brought this decision into being, I was nevertheless dissatisfied with the arrangement, feeling that, since responsibility for the principal effort against Germany fell upon my Headquarters, all the forces to be employed within the Theater by land, sea, and air should be responsible to me and under my direction, at least during the critical periods preceding and succeeding the assault.
I stated these views to the Combined Chiefs of Staff. At the same time I set forth the necessity for concentrated bombing of the rail network of Northwest Europe and particularly France, to which there was considerable opposition, the reasons for which will be considered shortly. I felt strongly about both these matters.
In a review of the matter, the Combined Chiefs of Staff, who were aware of my problems, gave me operational control of the air forces from 14 April. The Strategic Air Forces after this date were to attack German military, industrial, and economic targets in an order of priority established within the Theater and approved by the Combined Chiefs. Additionally, they were to be available to me upon call for direct support of land and naval operations when needed. This was a role for which they had not previously been normally used, but the Salerno campaign had afforded convincing evidence of their effectiveness for the purpose.
In the final command set-up of the air forces, then, the commanders of the Strategic Air Forces (RAF Bomber Command and the United States Strategic Air Forces)
Prior to my arrival in the Theater, the Combined Chiefs of Staff had approved a combined bomber offensive plan against Germany which included the strategic bombing of critical industrial and military targets in the Reich. It had been determined that Germany's vulnerability lay primarily in six industrial systems indispensable to the German war effort: submarines, aircraft, ball bearings, oil, rubber, and communications. Of these six targets, aircraft, oil, and communications became the three which were to occupy the continuing attention of the Strategic Air Forces throughout the war. The bombing attacks upon these targets were to assist materially in weakening the enemy's potentiality to resist our offensives and immeasurably to aid our ground forces in their advance.
An indispensable condition to the success of our Normandy assault was, at the very least, sufficient control of the air to insure the build-up in England and subsequently on the beachhead of our invasion forces and supplies. In anticipation of D-day, therefore, the Allied forces were first concerned with weakening the German Air Force through attacks upon its installations and resources on the ground and on the Force itself in the air. Quite apart from the direct assistance these attacks lent to the success of our landings, they were essential also as a preliminary to the intensive bombing of German industry.
We were aware that the Germans had planned, as far back as July 1942, to develop an air force equal to the task of smashing any invasion. Their aircraft expansion program had as its ultimate goal the production of some 3,000 combat aircraft per month. It was also estimated that the enemy planned to have a first-line strength of 10,000 aircraft, adequately supplied by reserves in depth and a steady flow of replacements. Considerable progress had been made with this program before the growth of Allied aircraft strength in this Theater permitted the intensive scale of air fighting which began in May 1943. Commencing with that date, our attacks upon German aircraft production centers checked the projected increase of manufacture, but the German Air Force was able, nevertheless, to survive 1943 with its front-line strength little changed. In December 1943 the Germans planned to produce 3,000 single-engine fighters per month, thus indicating that their production program was influenced as much by the necessity for countering the Allied bombing offensive as for stopping a possible ground invasion.
Beginning in January 1944, however, the assaults upon aircraft production centers were intensified and the effect of these attacks was such that the German Air Force had been robbed by midsummer of most of its production capacity and also deprived of the adequate reserves necessary to maintain its front-line strength. These conditions resulted not only from damage to production centers but also from such other factors as attrition of aircraft and crews in air battles, shortage of aviation gasoline for training purposes, and disruption of communications. As the invasion date approached, a clear sign of our superiority in the air was the obvious unwillingness of the enemy to accept the challenge to combat which we initiated with large-scale fighter sweeps over his territory. Our D-day experience was to convince us that the carefully laid plans of the German High Command to oppose OVERLORD with an efficient air force in great strength were completely frustrated by the strategic bombing operations. Without the overwhelming mastery of the air which we attained by that time our assault against the Continent would have been a most hazardous, if not impossible, undertaking.
This mastery of the air was maintained throughout 1944 and 1945 by continuing attacks against production centers. But the enemy was able, through factory reconstruction and dispersal, together with the development of jet aircraft, to maintain into 1945 a fighter force of a theoretical strength by no means negligible. Nevertheless, it still was not qualitatively good and proved incompetent to perform successfully for any substantial period any of the normal missions of an air force.
By D-day the Strategic Air Forces together with the Tactical Air Forces had so successfully performed their mission of disrupting enemy communications that there was a chronic shortage of locomotives and cars, repair facilities were inadequate, coal stocks were reduced to a six days' supply, and 74 bridges and tunnels leading to the battle area were impassable. The communications chaos thus produced had fatal effects upon the enemy's attempts at reinforcement after our landings.
The initial attacks upon the communications system in France were undertaken as the result of an
With mastery of the air achieved in the spring of 1944, it became more readily possible for the Allied Strategic Air Forces to concentrate their power overwhelmingly against the declining oil reserves of Germany. The attack against the German oil industry commenced in April and continued until the termination of operations. Within the first month of attack German production fell to 80 percent of its previous normal capacity, and by December 1944 it had fallen to a mere 30 percent. This 30 percent itself was only produced as the result of herculean efforts which diverted manpower and labor hours from other equally essential industries, such as, for example, the production of the new and ingenious weapons of war with which Germany hoped to decide the issue of the conflict.
The subsequent shortage of oil brought on by our operations contributed to the complete collapse of the German bomber force and must have had its effect upon the decline of the U-boat menace. Immobility from oil shortage caused the capture of tens of thousands of German soldiers and the destruction of their vehicles. Lack of oil and communications shattered by air bombardment retarded divisions arriving to reinforce the Normandy front in June. By December, when von Rundstedt's forces attacked in the Battle of the Ardennes, many units had to set out with extremely limited supplies of fuel, hoping desperately to overrun our positions so quickly that captured stocks would support their further advance. Within Germany the oil situation was so desperate that the recovery and repair program for the shattered industry was given the highest priority in the national war effort, above aircraft and submarine production and all other activities.
In addition to the strategic bombing of oil, aircraft, and communications targets, we were, during the campaign, to call upon the Strategic Air Forces for tactical support. At the time of the breakthrough in Normandy and several times later, including the Battle of the Ardennes, strategic bombers were employed in strength to attack enemy positions, supply bases immediately supporting the enemy front, and strongpoints and communication centers within the battle area. In these instances of tactical assistance, the Strategic Air Forces aided immeasurably in turning the decision of battle in our favor.
While the preparatory air operations of both the Strategic and Tactical Air Forces were growing in intensity as D-day approached, the naval and assault forces were engaged in Channel exercises designed not only to afford final training to the troops and crews but also to test enemy reaction to our mounting preparations. During the assembly of the five assault forces in the areas of Plymouth, Portland, Portsmouth, Southampton, and the Isle of Wight which was completed on 26 April, considerable enemy E-boat activity was noted which was primarily reconnaissance rather than offensive in nature. On 26 April the first full-scale exercise, TIGER, involving Force "U" under the command of Admiral Moon, took place from the Plymouth area. Owing to the fact that one of the escorting destroyers was damaged in a collision during the night of 26/27 April and was not on hand when the assault convoy was attacked by E-boats, there was an unfortunate loss of life in the sinking of two LST's. In other respects the exercises were successful and valuable lessons were learned, relating not only to the movement and handling of the task force ships but also to the assault against beaches. Areas such as Slapton Sands in southwest England, similar to those which the troops would encounter in France, were used for practice purposes.
Subsequent to Exercise TIGER, further Channel exercises involving the other task forces were undertaken during the first week of May. Considerable enemy reaction had been anticipated, but the exercises proceeded without any undue interference or even attention from the enemy. In certain cases it seemed apparent that he lacked information as to the extent and nature of the exercises. Our air superiority had driven his reconnaissance planes from the skies, the watch kept by our naval forces was unceasing, and the security precautions taken effectively neutralized the efforts of any agents whom he may have employed. Following the E-boat attack upon Force "U," the German radio had, for example, simply announced that ships of a Channel convoy had been torpedoed and sunk, indicating that the German command was unaware that the ships were assault craft and not the usual merchant ships in convoy. We also knew that the enemy was aware in other instances of our purposes, but preferred to reserve his forces for use on D-day itself rather than to expend them against local exercises.
In our planning for the assault, it was necessary and increasingly so as D-day approached to take into consideration the normal enemy capabilities which he might employ against our attack. We assumed that the enemy, once aware that a full-scale invasion was under way, would throw everything he possessed on the land, sea, and in the air against the assault. We accordingly made preparations to counter his reaction. Mention has already been made of the enemy's capability in the air and the over-all disruption of his plans as the result of strategic bombing of the German Air Force production resources and of the tactical bombing of airfields in the vicinity of the assault area. In spite of his losses, nevertheless, it was anticipated that he might, by carefully husbanding the Fighters and bombers remaining to him, attack the invasion forces with furious if brief air effort. Against this, our covering squadrons of fighters were allocated as already outlined in the air plan for the assault.
In addition to air attack, the ruthless and even reckless employment of all enemy naval forces was also expected. We estimated that the enemy was capable of employing within the first few days of the assault the following forces: 5 destroyers, 9-11 torpedo boats, 50-60 E-boats, 50-60 R-boats, 25-30 "M" class mine sweepers, and 60 miscellaneous local craft. In addition to the surface craft available, the enemy was also in a position to use 130 U-boats forthwith and to reinforce these by D-plus-14 to a total of 200. Against the anticipated attacks from these craft, the navy was to undertake preliminary mine laying outside the channels of our approach. Aircraft of RAF Coastal Command also were to maintain a constant patrol in sufficient density and over such an extended stretch of the Channel that no U-boat would be capable of reaching the battle area without first surfacing and becoming vulnerable to attack. In the event that any enemy vessels proved capable, in spite of these measures, of reaching the task forces and assault convoys, the Navy's protective screen of ships, together with the considerable air umbrella supporting the task forces, was felt to be in sufficient strength to neutralize any serious threat.
The enemy had, as early as February, disposed of 53 divisions in the west under the supreme command of Field Marshal von Rundstedt. By 3 June his strength in France, Belgium, and Holland had been increased to 60 divisions, including 10 panzer type and 50 infantry divisions. Of these, 36 infantry and 6 panzer divisions were located in the general coastal area opposite England, from Holland to Lorient in western France. In the immediate area of our Normandy assault the Germans had concentrated 9 infantry divisions and 1 panzer division, while their greatest strength the Fifteenth Army remained in the Pas-de-Calais. The
Apart from the estimates of normal enemy capabilities, one unusual danger hung as a threat over OVERLORD from July 1943 through D-day. The Germans were emplacing what appeared to be rocket or pilotless aircraft sites on the Channel coast, and while the weapons appeared to be largely oriented on London, there was the possibility that our concentration of shipping in the ports of southern England would prove an attractive target and that the mounting of the operation would meet with interference from the new menace. The staff consequently gave some consideration to changing the areas where the amphibious forces were to be mounted, but, because other places did not have adequate facilities and the whole naval plan would have had to be altered, we adhered to our original plans. Defensive and offensive countermeasures against the threat were taken, and the Pas-de-Calais area, where the majority of the sites were located, was subjected to severe and continual bombing which served to delay the employment of the V-weapons until after our assault had been launched.
With our land forces assembled in the areas where the assault was to be mounted and with the Channel exercises under way, I felt that the final decision as to the launching of the assault should be made from a forward command post located near the invasion bases on the Channel coast and, accordingly, my tactical headquarters were set up in the vicinity of Portsmouth. As 1 June approached I had visited the greater part of the divisions to be engaged in the operations as well as air force installations and several of the larger naval ships. Without exception, the morale of the men was extraordinarily high and they looked forward to the immediate task confronting them with sober confidence. This same confidence, born of the long hours of arduous preparatory toil, existed within all echelons of the services and was noticeably present when the final plans of all the commanders were formally presented at St Paul's School, 21 Army Group Headquarters in London, on 15 May.
With the planning and preparatory period completed, it now became necessary to make the supreme decision for which I was responsible the designation of the exact day for the assault against the continent of Europe.