Planning for Operation OVERLORD; When Objectives Exceed Resources
Insignia of the Supreme Headquarters Allied Expeditionary Force
It was late September 1943, and British Lieutenant General Frederick E. Morgan was not entirely a happy man. As a result of the Casablanca Conference (14-24 January 1943, codenamed SYMBOL),[1] the western Allies had affirmed their commitment to “an invasion in force” on the Continent in 1944,[2] and as a tangible example of that commitment had directed the creation of a planning staff to prepare for that invasion. As the commander of that future invasion had not yet been selected, in the interim the staff would be headed by the position called the Chief of Staff to the Supreme Allied Commander (designate). General Morgan was tapped for that job, and both he and his staff would be referred to by the acronym COSSAC. As there was not yet a Supreme Allied Commander (nor would there be one for about nine months), Morgan was at something of a loss for clear guidance from above.
His charter was broad: to plan for “A full scale assault against the Continent in 1944, as early as possible.”[3] Beyond that, the combined US and British Chiefs of Staff had little to offer. Initially he had not been given any idea what forces would be available for the landings, except that when it came to naval forces, he could only count on such shipping as would be available in the United Kingdom at the time the invasion would be launched – and as seen above, that date was another item left unspecified. Morgan was also hampered in that his new position was merely as a planning and coordination element, one that had no command or executive authority. Still, at least it was a start.
Morgan and his new staff – which only began forming in mid-March and did not hold its first meeting until 17 April - did have the advantage of a wealth of intelligence, several studies and a few plans developed earlier by various commands for various contingencies, all of which were related to some degree with landings on the Continent. COSSAC also benefitted from the lessons of the failed Dieppe Raid. Drawing from those sources and COSSAC’s own analyses, Morgan was able to eliminate the Dutch and Belgian coasts and focus on the French Coast. Of course, the selection of a landing area was necessarily influenced by the size of the force in the initial assault wave as well as the size of the immediate follow-on forces, and the size of both of those were limited by the assault shipping that would be available. And, again, both the size of these forces and amount of assault shipping to carry them were constraints which the Combined Chiefs of Staff had neglected to specify.
Lieutenant General Sir Frederick E. Morgan
Lacking guidance on the forces available for the landings, Morgan’s plan assumed an assault force of four divisions followed by an immediate reinforcement of six more divisions. These figures had been used in the most recent planning effort – Operation SKYSCRAPER - before COSSAC assumed responsibility for the planning.[4] But of course they were only an educated guess as there were many variables that could not be anticipated, not the least of which was future enemy strength and dispositions many months in the future. While the British Combined Commanders had previously rejected SKYSCRAPER’s four-plus-six division force level, COSSAC’s analysis considered it reasonable given the variables and unknowns, and since no better estimates were available, COSSAC folded in the four-plus-six force level as one of its own planning assumptions.
Morgan’s outline plan was fairly reasonable, given the limitations under which he worked, though there were some weaknesses. A major problem was, and would remain, the availability of assault shipping. In May COSSAC’s chief naval planner conducted a study that concluded there was enough sealift for four divisions in the assault, but only enough to permit simultaneously embarkation for one follow-on division - instead of six - to land the second day.
Until that point, there had been just one significant amphibious assault in the Mediterranean Theater, with another soon to begin. Both of these operations targeted areas that were geographically isolated to a greater or lesser degree from the enemy’s sources of reinforcements and supplies. French possessions in North Africa were separated from France by the Mediterranean Sea, and Sicily was separated from Italy by the Straits of Messina - both of which were subject to interdiction. More importantly both of those invasions faced defenders whose willingness to fight was questionable. In North Africa, there were no German forces defending the invasion beaches, and it was hoped the Vichy forces that were there would join the Allies (after some regrettable initial fighting they did). And in Sicily the bulk of the defenders would be poorly-equipped, low-quality Italian units with inadequate supplies and even lower motivation. Despite those strategic advantages, the Allies allotted more divisions to the assault for each of those two operations than what appeared to be supportable for the long awaited and much heralded Second Front invasion on the Continent. The well-developed rail network in western Europe could theoretically simultaneously support the movement of seven German reinforcing divisions, which, given the shortage of Allied shipping, would decisively outpace efforts for the Allies to reinforce and expand a continental beachhead.
The idea of assaulting the Atlantic Wall - where there were far more German forces close at hand, and much greater ability to reinforce the defenses - with less strength in the assault than previously used in much more favorable conditions, did not appear to be a sound strategic decision. But such were the constraints under which Morgan had to labor.
[The shortage of assault shipping and craft was tied to production priorities, which in turn were dictated by decisions on the matter of the Alliance’s grand strategy. Although those decisions would seem very shortsighted to those involved in OVERLORD planning, they were the results of trying to harmonize and rationalize many competing demands and often nearly irreconcilable national positions. It is remarkable that so little in the way of disconnects between strategy and materiel resulted. I will defer the discussion of the background concerning the shortage of assault shipping and craft to a later post.]
If that was not bad enough, worse was to come. At the Third Washington Conference (12-15 May 1943, codenamed TRIDENT), the US Joint Chiefs of Staff anticipated that by 1 April 1944 there would be 36 divisions available to support the invasion.[5] But, again, shipping was the limiting factor. The British presented the shipping bill for the invasion of the Continent: 8,500 ships and craft were needed to simultaneously lift ten divisions (four in the assault and six immediate follow-on). In the subsequent tension-charged discussions, the figure was “talked down” to 4,000 ships and craft. In addition, the debate was reopened concerning the rationale for four divisions in the assault. This discussion, however, was not focused on augmenting this assault force, but to revise downward the proposed force. As a result, the Combined Chiefs of Staff limited Morgan’s planning to that which could be supported by the 4,504 ships and craft assumed then to be available for the invasion.[6] This, the Combined Chiefs believed, would enable a simultaneous sealift of five divisions (three in the assault and two for immediate follow-on) with two more divisions following using the D-Day shipping upon its return. To partially compensate, the Combined Chiefs authorized the use of two airborne divisions, though at the time of their decision, there was not sufficient airlift for even one division. Twenty more divisions would be available to feed into the bridgehead in the ensuing months, but none of these were made available for the initial invasion.[7]
As a rough indication of the relative commitment to this invasion of the continent, the conference allocated 10% fewer major assault ships (APA, AP, LSI and LSH) to the operation than they allocated to the upcoming invasion of Sicily (45 vs 50). The strategic priority the Combined Chiefs had given the operation clearly was not matched by the necessary priority on resources.
The conference agreed on a proposed date of 1 May 1944 and settled on the codename OVERLORD.[8] Morgan received the TRIDENT directives in May 1943 and set to developing an outline plan using the latest guidance.
This map was produced by COSSAC to depict the factors that were considered in selecting suitable landing beaches. Their analysis settled on three beaches in the CAEN Sector for the three-plus-two division assault plan. With the expansion to a five division plan, a beach just inside the COTENTIN Sector was added; this would be area of the UTAH landings.
Being an outline plan, it did not attempt to determine the details of troop dispositions and maneuver, though it did attempt to allocate major formations to major objectives and forecast some sequence in which critical objectives would be secured. Morgan set his planners to work on refining the proposed landing sites and finally settled on three: Courseulles-sur-Mer in the east (entry point for operations aimed at Caen); Vierville-sur-Mer/ Colleville-sur-Mer to the west; and Arromanches-les-Bains in the center. Given his limited assault force, he had to abandon the idea of a landing west of the Vire estuary (the eventual Utah Beach area).
The shipping problem continued to hamstring planning. The inclusion of essential non-divisional assets (corps- or army-level armor, antitank, antiaircraft units, etc.) took away lift from that allocated for the assault and follow-on divisions, thereby slowing the reinforcing schedule. In addition, many of the smaller craft, which the Combined Chiefs had included in their analysis, were not capable of crossing the Channel so their capacity figures could not be used in deployment lift calculations. Also, essential minor operations to seize bridges or coastal defense batteries reduced airlift for the main airborne landings; he concluded he had sufficient aircraft only to lift 2/3 of a single airborne division at once.
The late-August 1943 Quebec conference would hold surprises – both good and bad - for COSSAC.[9] The latest version of the outline OVERLORD plan was presented to the conference and approved, although COSSAC’s predicted rates of advances after D-Day were deemed too optimistic (and events would prove they were!). Nevertheless, the Combined Chiefs directed him to continue planning and accepted his preconditions for success, which required efforts to attrit the Luftwaffe and tie down or divert German Wehrmacht forces. Realizing the assault force might be too weak, Churchill suggested it be increased by 25% and include a landing west of the Vire estuary, which Morgan had originally wanted but could not do with the forces allocated. General Marshall (Chief of Staff of the US Army) agreed that strengthening the assault would be a sound move.[10] As good as that appeared, there were two drawbacks. First, that suggestion was not put into writing as a directive. Second, no additional shipping was made available, so any increase in the size of the invasion was rather illusory. While Morgan considered the prospects for success were good (on the assumption German air and ground forces were whittled down in advance), he advocated an increase of at least 10% of shipping just to ensure the three-plus-two division concept could be on the beach by daylight D+2.[11]
The Combined Chiefs’ appetite for the operation was growing, but they still would not fully face up to the bill. Various plans and studies were suggested to comb out craft from other activities and increase production, but most of these were futile or had marginal impact, and it was felt no increase of production would reach the UK until April 1944. As his draft plan stood, its success depended on transferring substantial shipping from the Mediterranean, something that was far from guaranteed. Still, Morgan now had the latitude to explore the concept of a larger invasion, which would permit identification of the problems that would entail, and perhaps lead to steps necessary for solutions.
On the downside, one of COSSAC’s requests had come back to haunt them. They had requested a feint against southern France, timed to coincide with the OVERLORD landings in an effort to tie down German divisions. The Combined Chiefs endorsed the idea and directed GEN Eisenhower[12] to draw up plans. When he submitted his plans in November, however, it was for an actual landing, seizure of key ports and offensive follow-on operations to the north. While there were sound strategic reasons for this operation (codenamed ANVIL), as far as COSSAC was concerned, it was just one more demand on the very same limited pool of assault shipping they depended on drawing from in the Mediterranean. Thus it was that Eisenhower, the commander in the Mediterranean, would be for a time the worst obstacle for Eisenhower the Supreme Commander. in the UK In fact, ANVIL would have crippled the chances of success for the Normandy landings had not Eisenhower received permission to cancel ANVIL, which he did just a bit more than two months before OVERLORD.
The concerns raised by Churchill and Marshall would soon be validated by real events. On 9 September 1943, Operation AVALANCHE struck the beaches of Salerno, Italy. Despite an initial landing of the better parts of four divisions and strong attachments, swift German counterattacks came so close to splitting the beachhead that at one point evacuation of half of it was considered. And this despite the fact that the Germans had the rugged terrain working against their armored thrusts. In light of this, the three-plus-two division force slated for OVERLORD could hardly be considered adequate to ensure success. And yet neither greater force allocations nor shipping assets were devoted to OVERLORD.
With Sicily serving as a cautionary example, Morgan used his apparent authority to study the options for expanding the invasion. He decided that efforts should not be bent towards adding another assault division, rather to provide the assets necessary to overcome the shortfall in shipping for the two follow-on divisions in the initial three-division assault alternative. The problem of LCTs perhaps best illustrates the general scale of shortfalls facing COSSAC. The TRIDENT conference had allotted 653 LCTs for the invasion, a figure COSSAC considered a dangerous minimum. Almost immediately those began to melt away. By the end of September about a quarter of those LCTs had been diverted. Forty-four had been committed to anti-submarine net defense operations at Scapa Flow and many others were due to be converted to conduct fire support missions[13] – a task the Combined Chiefs had failed to anticipate and for which no new construction was authorized. While the latter group of LCTs were still part of OVERLORD planning, their decks could not be counted on for lift purposes.
On 30 September 1943, Morgan stated that there would be a deficit of 251 LCTs merely to fully embark the two follow-on divisions so that they could be landed on D+1 to support the three-division assault concept. To support the lift requirements of a four-division alternative, there would be a deficit of 389 LCTs. “In addition, for a four-division assault there would be a shortage of more than 150 support craft using LCT or equivalent hulls.”
And that’s where I will leave this introductory review, as it amply illustrates the minimalist planning assumptions and inadequate resource allocations that would dominate preparations for the eventual 6 June landings. Among the allied leaders there was the growing realization that not enough had been done to ensure success, but little would be done to find solutions for the next few months. The result of this would be that perhaps the dominant theme of OVERLORD preparations would be the continuing last-minute attempts to obtain critical ships, equipment and units, and slap them into the operation in the nick of time. This problem would be vastly complicated with the arrival of Eisenhower and Montgomery in January 1945. The two commanders were of the same mind: the operation was too weak and on too narrow a front. Therefore, the initial assault would be increased to five seaborne divisions and three airborne divisions, and would target five invasion beaches (to include one west of the Vire estuary to facilitate operations against Cherbourg). Strategically it was a sound decision; the weakness of the three-plus-two force option would have had much too low a chance for success. At the same time, however, this decision had seen the shortfall in shipping go from ‘critical deficiency’ to ‘near impossibility’.
It's true that many amphibious assault operations had successfully been planned and executed in far shorter windows than the five months Eisenhower had left to him (5 January to 6 June- including the delay from the planned 1 May target date). But in most cases, the choices of objectives were limited in scope to what the available resources in theater could support. But OVERLORD was different. To gain and secure a lodgment on the Continent in the face of strong German formations, a minimum level of forces and resources would be necessary. Allied strategists had committed to the operation, but failed to pony up the necessary ante. The deficit, especially in assault shipping and craft, simply could not be magically produced and delivered to the theater in time.
Any casual student of OVERLORD is probably aware of the shortfall of adequate assault shipping and craft, as well as the herculean strides that largely overcame those shortfalls (although too often at the last minute and with inadequate means). What is not commonly appreciated are the more subtle and less recognized impacts of this slap-dash, in-the-nick-of-time effort. Too often crews or units arrived very late to the party, inadequately trained for their tasks, and in some cases only semi-trained on their own craft. Too often they were committed to some of the most critical and most dangerous roles in the invasion. As if that weren’t bad enough, German initiatives (such as the sudden crash construction of beach obstacles) required additional equally last-minute responses from Allied commanders, again resulting in inadequately trained units committed to new and critical tasks.
The following series of posts will examine several cases where combat operations during OVERLORD were adversely affected by these last-minute efforts to redeem the shortfalls of planning. The tactical failures or near-failures that occurred on D-Day as a result of the inadequate planning and resources allocations have generally been glossed over and even completely ignored by many, so they have faded from history. In that regard, this series will place many of the events on Omaha Beach in their more complete context. The intent is not to affix blame on individuals (though that will probably happen in selected cases), rather to highlight the complexities of combined and joint planning, and explore the unintended consequences of flaws in that planning.
One final note of caution. We should never lose sight of the fact that despite everything, the invasion was a success. They pulled it off. But in so doing, a far greater burden – undiubtedly too great - was placed on the shoulders of the young Tommies and G.I. Joes who approached the beaches on 6 June, often ill-prepared for the ordeal ahead of them. That they measured up and succeeded despite all will forever be a testament to their courage and character.
Further Reading:
“HISTORY OF COSSAC (CHIEF OF STAFF TO SUPREME ALLIED COMMANDER), 1943 - 1944”. Prepared by The Historical Sub-Section, Office of Secretary, General Staff, Supreme Headquarters, Allied Expeditionary Force. May 1944
Cross Channel Attack, by Gordan Harrison, 1950
[1] The meeting included U.S. President Franklin D. Roosevelt and British Prime Minister Winston Churchill and their principal military advisors. Joseph Stalin was invited but did not attend due to ongoing military operations.
[2] Cross Channel Attack, pg.44. Much of this post is a summary of portions of Cross Channel Attack’s history of the planning leading up to 6 June 1944, with my summary focusing more tightly on the assault shipping and landing craft problem.
[3] He was also charged with two other responsibilities which have been omitted here as they don’t bear on the current theme. The first was a large deception effort to tie down German forces in the west (Operation COCKADE) and the second to quickly move forces to the continent in the case of a sudden German collapse Operation RANKIN.
[4] This outline plan was codenamed SKYSCRAPER and was produced in early 1943. It was developed by a planning cell working under the directions of the British Combined Commanders, and thus represented a solely British perspective on the issue (the Combined Commanders were essentially the British body equivalent to the US Joint Chiefs of Staff, with the notable exception that the British Combined Chiefs predated the creation of the US Joint Chiefs of Staff).
[5] See “The Trident Conference, May 1943: Papers and Minutes of Meetings”, CCS 215. CCS 215 also predicted 32 German division in France and the low countries, which could be reinforced to a total of 60 divisions.
[6] The British were to supply 3,257 of these, or 72% of the total.
[7] See “The Trident Conference, May 1943: Papers and Minutes of Meetings”, CCS 242/615.
[8] OVERLORD was the codename for the invasion of western Europe and the subsequent campaign to defeat Germany, while NEPTUNE was the codename for the amphibious landings in Normandy. Much of the discussion surrounding assault shipping and craft merges into the realm of what would later become NEPTUNE planning, but for simplicity’s sake, I will use only OVERLORD for the purposes of this article.
[9] Codenamed QUADRANT, held in that city 17-24 August 1943.
[10] See “Quadrant Conference, August 1943; Papers and Minutes of Meetings”, pg. 397.
[11] See “Quadrant Conference, August 1943; Papers and Minutes of Meetings”, C.C.S. 304.
[12] At this point, Eisenhower was the commander of the Mediterranean Theater. He would not take command of OVERLORD until January 1944.
[13] Such as those carrying hundreds of rockets to lay a barrage on the beaches just before the first waves would land (Landing Craft, Tank (Rocket) – LCT(R)). There was also a need to use LCTs as platforms for anti-aircraft guns (Landing Craft, Flak - LCF) and direct-fire medium caliber guns (Landing Craft, Gun – LCG).