Preparation for D-day

The various facets of the preparations for D-Day had to ensure that the chance of Allied victory was guaranteed.

The usefulness of the preparation

The preparation and planning for D-day played a crucial role in the further course and outcome of the Second World War. The objective to successfully establish a bridgehead and thus open a second front in Western Europe was essential.

We can divide the preparation for D-day into the following:

  • Logistics:
    The Western Allies, in the months before D-day, had to strengthen themselves both in terms of material and men before having enough clout to cross over.
  • Tactics:
    Deciding which units to deploy where and when, deceiving the Germans about the landing site and weakening the enemy through preliminary bombing.
  • Physical:
    The men underwent many simulations in Britain in the months before D-day. The intention was to give the relatively young boys a taste of combat situations beforehand.


The first plans there COSSAC

In January 1943, the first meeting was held in Casablanca to prepare for a landing in Europe.
Lieutenant General Sir Frederick Morgan was then appointed ‘Chief of Staff to the Supreme Allied Commander’, better known as ‘COSSAC‘.

Morgan had a very difficult task: he had to prepare the solid ground and the original plans. A preparation with weapons and vehicles that largely still had to be developed, with troops that still had to be allocated and a supreme commander that still had to be appointed. In short, there was absolutely no certainty or reference.

Quebec Conference

The plan by COSSAC was presented at the Quebec Conference (August 17 to 24, 1943):

The plan went as follows: the storming of the landing beach would be carried out by three divisions from the sea and two regiments from the air. Two other divisions were to be embarked in landing craft ready to follow. The landing was to take place between Caen and Carentan. As soon as they were ashore, they were to capture the port of Cherbourg. However, it would take several weeks before this port could be used. There were large quantities of obstacles and mines. So supplies would be delivered by two artificial ports, which had to be towed from Britain to the coast.

The final plans

The plans for D-Day were put on the table in their final form under the supervision of SHAEF (Supreme Headquarters Allied Expeditionary Force). This happened on May 15, 1944 at a meeting held at St Paul’s School. General Sir Bernard Montgomery used the school as headquarters for his 21st Army Group in the months leading up to D-Day. Montgomery, a former pupil of the school, was delighted with the occupation of the headquarters.

Among those present were the King of England, Prime Minister Winston Churchill, Field Marshal Smuts, the Chiefs of Staff, Commander-in-Chief Dwight Eisenhower and the highest commanders of land, sea and air forces.

Attack on Dieppe

The purpose of the Dieppe attack was to capture a port, hold it, gather information and see how the Germans would react. On August 19, 1942, the British Joint Operations Command sent 252 ships across the channel from southern England to the coast of eastern Normandy to attack Dieppe. These ships carried about 6,100 troops and 30 tanks. Most of the soldiers were Canadians, divided into two infantry brigades – almost 5000 men – supported by about 1000 British commandos plus small special units from the Americans and the Free French.

However, the attack turned out to be a disaster. The Allied troops hit a wall… It looked like a suicide mission. The only positive thing was that the Allies could draw their lessons from this in the run-up to D-Day.

Weakening the German war machine

Many bombardments of German positions were carried out to limit their power towards the invasion area of Normandy.

Operation Pointblank

The primary objective of Operation Pointblank was to weaken or destroy the German presence in the airspace. This was to prevent the Germans from providing air support to the front lines and to ensure that the Luftwaffe would not play a significant role in the invasion of Western Europe (D-day).

Transportation Plan

The Transportation Plan was an operation for strategic bombing of bridges, roads, tunnels, waterways, railways and railway stations mainly in Belgium, Nazi Germany and France with the aim of limiting all possible access routes to the invasion area of Normandy.

The Germans’ preparation for D-day

The Germans also knew that they had to prepare for a possible Allied invasion of Western Europe. Yet there were many uncertainties for the Germans. Amongst other things, the ignorance of the landing zone gnawed at the peace of mind of many German commanders. For example, there was the question of the positioning of the Panzer units, but also the doubt whether the Atlantic Wall would be as grand and as strong as Hitler made it out to be.


In addition to all the other plans, there were also operations to mislead the Germans throughout the preparations.

Operation Bodyguard

Operation Bodyguard was designed to mislead the Germans by keeping them wondering for as long as possible where and when the invasion itself would take place.

The deception worked so well that the German army command was unaware of the events and developments in the early hours of the invasion. This forced the Germans to wait as long as possible before sending reinforcements to Normandy.

Planning for Operation Bodyguard only began after Normandy was selected as the landing site. Operation Bodyguard consisted mainly of five different operations: Fortitude, Graffham, Royal Flush, Zeppelin and Vendetta.

Double agent GARBO

In January 1944, the Germans told Juan Pujol Garcia called GARBO that they expected a large-scale invasion of Western Europe. Therefore, they asked him to keep them informed in case he could get any information about it. An invasion was coming anyway. He sent more than 500 radio messages between January 1944 and D-day (June 6, 1944). Sometimes more than 20 messages a day. He played an important role by making the Germans believe that the landings would take place in the Strait of Dover instead of Normandy.

Artificial Mulberry harbours and Operation Pluto

The Mulberry artificial harbours were ingenious structures of immense size and complexity. These floating harbours provided port facilities to the Allies during the invasion of Normandy until the port of Cherbourg was captured.

In addition to the Mulberry artificial harbours, another project was designed: Pluto (Pipeline-under-the-ocean = pipeline under the sea). With this pipeline, oil would be transported from southern England to Cherbourg, and later to the French and Belgian coasts, because these were easier to reach.


Braunton Burrows

The shores of Braunton Burrows, in North Devon, were of great importance during the Second World War. In 1943, Lieutenant-Colonel Paul W. Thompson had to train the American soldiers in preparation for the final invasion in Normandy.

Exercise Tiger

Exercise Tiger was the penultimate large-scale preparation for the D-Day landings. It took place at Slapton Sands in Devon.

Exercise Fabius

The largest maritime training exercise, Exercise Fabius, took place between April 30, and May 4, 1944. The purpose was to train for the amphibious landings on D-Day and this with the intention to pursue the goals of Operation Neptune as good as possible.

The weather

The weather forecast for D-Day played a crucial role in determining the success of the invasion. The analysis made by hand by the meteorologists on June 3, 1944 in the evening hours caused great concern to the supreme command. This analysis contained several depressions. In the morning of June the 4th, the various meteorologists were so contradictory that Eisenhower was already thinking of postponing the invasion until June 7.

Sunday night on June 4 came an analysis by the weather team, led by James Stagg. Two depressions had merged into one layer just northwest of Scotland. It was clear that the cold front would pass over the Channel area and the invasion beaches on Monday afternoon June 5. Therefore the conditions for the landing on Tuesday morning June 6 were better than initially estimated.

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