American logistics in the Northern France campaign played a key role in the Allied invasion of northwest Europe during World War II. In the first seven weeks after D-Day, the Allied advance was slower than anticipated in the Operation Overlord plan because the well-handled and determined German opposition exploited the defensive value of the Normandy bocage country. The Northern France campaign officially commenced on 25 July, the day First United States Army began Operation Cobra, which saw the breakout from the Normandy lodgment, and ended on 14 September.
After Operation Cobra, the advance was much faster than expected, and the rapid increase in the length of the line of communications threw up unanticipated logistical challenges. The logistical plan lacked the flexibility to cope with the rapidly changing operational situation; the rehabilitation of railways and construction of pipelines could not keep up with the pace of the advance; and resupply by air had limited capacity. Major shortages developed, particularly of petrol, oil, and lubricants (POL).
Motor transport was used as a stopgap. The ADSEC organized the Red Ball Express to deliver supplies from the Normandy area, but there was a shortage of suitable vehicles because of political interference and production difficulties. The tardy delivery of vehicles slowed the training of motor transport unit personnel. As with many other service units, the European Theater of Operations (ETO) was compelled to accept partially trained units in the hope they would be able to complete their training in the UK. Approval for additional relief drivers was also slow, and the US Army's racial segregation complicated personnel assignment. The cost of inadequate training of truck drivers was paid in avoidable damage to vehicles through accidents and poor maintenance.
At critical junctures in the campaign, senior American commanders subordinated logistical imperatives to operational opportunities. Two decisions in particular had long-term and far-reaching effects. The decision to abandon plans to develop the ports of Brittany left only the Normandy beaches and the port of Cherbourg for the maintenance of the American forces. The subsequent decision to continue the pursuit of the defeated German forces beyond the Seine led to the attrition of equipment, failure to establish a proper supply depot system, neglect of the development of ports, inadequate stockpiles in forward areas, and a shortage of POL and ammunition as increased German resistance stalled the American advance. While the logistical system had facilitated a great victory, these problems would be keenly felt in the fighting in the months to come.
Background
After the American entry into World War II in December 1941, the European Theater of Operations, United States Army (ETOUSA) was formed, with a Services of Supply (SOS) organization under Major General John C. H. Lee beginning in May 1942. General Dwight D. Eisenhower became the Supreme Commander, Allied Expeditionary Force, on 16 January 1944, and ETOUSA and SOS were combined into a single headquarters, which was increasingly referred to as the Communications Zone (COMZ), although this did not become official until 7 June. To support Operation Overlord, the invasion of Normandy, COMZ activated two subordinate headquarters, the Forward Echelon, Communications Zone (FECOMZ), under Brigadier General Harry B. Vaughan, with Colonel Frank M. Albrecht as his chief of staff, and the Advance Section (ADSEC), under the command of Colonel Ewart G. Plank. ADSEC would take over the operation of base areas, supply dumps and communications from the First Army as it moved forward. In the initial stages of Overlord, ADSEC would be attached to the First Army.
In the first weeks after D-Day, the American forces were supported over the Omaha and Utah Beaches. Although the Mulberry artificial port at Omaha was specially constructed for supplying the invading military forces, it was abandoned after a storm damaged it on 19 June. Logistical support of the American armies on the continent in the longer term depended on the capture and repair of ports. The Overlord plan provided for the rehabilitation of eighteen ports in Normandy and Brittany. This task was assigned to port construction and repair (PC & R) groups. Each had a headquarters and headquarters company with specialists trained in port reconstruction, and a pool of heavy construction equipment with operators, which could be supplemented by engineer troops. Seven ports were expected to be captured and opened in the first four weeks: Isigny-sur-Mer, Cherbourg, Grandcamp, Saint-Vaast-sur-Seulles, Barfleur, Granville and Saint-Malo. Except for Cherbourg, all were small and tidal, and unable to berth vessels with a draft of more than at high water, which ruled out larger vessels. Much therefore depended on the early opening of Cherbourg, which was expected to occur by eleven days after D-Day (D plus 11), and was expected to handle of cargo per day by D plus 30, and per day by D plus 90, more than the other six ports combined.
Logistical support of the American armies would therefore depend on the ports of Brittany, principally Brest, Lorient and Quiberon Bay. Along with Saint-Malo, they were expected to have a capacity of per day. Of this, per day were expected to come through Quiberon Bay, as it was anticipated that the ports would suffer considerable damage in the fighting, or through German demolitions. Studies indicated that Quiberon Bay had an anchorage sufficient for 200 ships, of beaches with the required slope for landing craft, and four minor ports close by where deep-water piers could be constructed. A detailed plan known as Operation Chastity was drawn up to develop the area. Crucially, the Overlord plan called for a one-month pause at the Seine, which was expected to be reached by D plus 90, in order to build up supplies and logistical infrastructure before advancing further. The expectation of an advance at a prescribed rate, while necessary for planning purposes, built inflexibility into a logistics plan that already had little margin for error. Staff studies confirmed that Overlord could be supported if everything went according to plan, but no one expected that it would.
In the first seven weeks after D-Day, the skillful and determined German opposition exploited the defensive value of the Normandy bocage country, and the Allied advance was much slower than the Overlord plan had anticipated. The lodgment area was therefore very much smaller. The nature of the fighting created shortages of certain items, particularly artillery and mortar ammunition, and there were unexpectedly high rates of loss of bazookas, Browning automatic rifles (BARs), and M7 grenade launchers.
Breakout and pursuit The Northern France campaign officially commenced on 25 July, when the First United States Army began Operation Cobra, which effected a remarkable turnaround in the operational situation, and continued until 14 September. The breakout from the Normandy lodgment was successful, and the US forces threatened to envelop and encircle the German forces. Eisenhower ordered a regrouping of the US forces. The 12th Army Group became active on 1 August. Its headquarters was formed by renaming that of the First United States Army Group, which remained in the UK under the command of Lieutenant General Lesley J. McNair as part of Operation Fortitude, a deception operation aimed at convincing the Germans to maintain forces outside Normandy.
The 12th Army Group consisted of the First Army, commanded by Lieutenant General Courtney Hodges, and the Third Army, under the command of Lieutenant General George S. Patton Jr. Lieutenant General Omar N. Bradley commanded the 12th Army Group, but, until Eisenhower could open his Supreme Headquarters, Allied Expeditionary Force (SHAEF) in France, British General Sir Bernard Montgomery remained in command of all ground forces, British and American, channeling his orders to the US forces through the 12th Army Group, until SHAEF assumed direct command of the ground forces on 1 September.
By 3 August, Patton's Third Army was advancing into Brittany. Bradley fixated on Brest, which was only intended to be a port of reception for troops, and Saint-Malo, a minor port, whereas Patton focused on Lorient and Quiberon Bay. Due to being trained as a cavalryman, Patton conceived operational art—the level of war that sits between the means of tactics and the ends of strategy—very differently from the former infantrymen Bradley and Major General Troy H. Middleton, VIII Corps' commander. When the 4th Armored Division's commander, Major General John S. Wood incorrectly reported that Lorient was too strongly defended to rush, Middleton accepted this assessment.
Bradley ordered Patton to move east, leaving only minimal forces in Brittany. This did not immediately change the plan; Eisenhower informed the Chief of Staff of the United States Army, General George C. Marshall, that "the rapid occupation of Brittany is placed as a primary task, the difference being that in one case we believe that it would rather easily be done and in the other we would have to fight through the defensive line and commit more forces to the job." This was the first in a series of critical decisions that subordinated logistical considerations to short-term operational advantage. In the event, Lorient was not captured, and as a result Quiberon Bay could not be developed because the approaches were covered by German coastal guns at Lorient and on Belle Île. Saint-Malo was secured on 2 September, and Brest was taken on 19 September, but the port facilities were destroyed, and on 3 September SHAEF had abandoned plans to develop Quiberon Bay.
By 24 August, the left bank of the Seine had been cleared, and Operation Overlord was completed. In just 30 days, the Allied forces had conducted an advance that had been expected to take 70. Reaching the D plus 90 line on D plus 79 was not a grave concern, as the Overlord plan had sufficient flexibility to allow for a discrepancy of eleven days. The plan called for a pause on the Seine of at least 30 days, but in mid-August the decision was taken to continue the pursuit of the retreating German forces beyond the Seine. This had even more far-reaching effects than Bradley's decision to re-orient Patton's advance eastwards. Between 25 August and 12 September, the Allied armies advanced from the D plus 90 phase line to the D plus 350 one, moving through 260 phase lines in just 19 days. Although the planners had estimated that no more than 12 divisions could be maintained beyond the Seine, 16 were by mid-September, albeit on reduced scales.
Base organization ADSEC headquarters opened in Normandy on 16 June. FECOMZ, now under Albrecht's command, opened its headquarters at Château Servigny and Château Pont Rilly near Valognes on 15 July, but ADSEC remained subordinated to the First Army until 30 July. The First Army controlled all US forces in France until 1 August, when the 12th Army Group and the Third Army became active. The facilities at Valognes were greatly expanded, with tents to accommodate 11,000 personnel and of hutted office space, and special signal facilities installed to enable it to communicate with the UK and US. COMZ headquarters opened at Valognes on 7 August, a month earlier than originally planned, and FECOMZ therefore never operated in its intended role.