Chapter 11: COBRA Preparations
The perspective within which Operation COBRA was conceived was essentially the same as had bounded General Bradley’s July offensive. The objectives remained unchanged: Brittany was the eventual goal, the first step toward it the Coutances–Caumont line.
According to General Montgomery’s instructions of the end of June, repeated in July, the First U.S. Army was to pivot on its left at Caumont and make a wide sweep to a north-south line from Caumont to Fougères so that U.S. troops would eventually face east to protect the commitment of General Patton’s Third Army into Brittany.1 To set the First Army wheeling maneuver into motion, General Bradley decided to breach the German defenses with a massive blow by VII Corps on a narrow front in the center of the army zone and to unhinge the German defenses opposing VIII Corps by then making a powerful armored thrust to Coutances. With the basic aim of propelling the American right (west) flank to Coutances, COBRA was to be both a breakthrough attempt and an exploitation to Coutances, a relatively deep objective in the enemy rear—the prelude to a later drive to the southern base of the Cotentin, the threshold of Brittany.2
The word breakthrough, frequently used during the planning period, signified a penetration through the depth of the enemy defensive position. The word breakout was often employed later somewhat ambiguously or as a literary term to describe the results of COBRA and meant variously leaving the hedgerow country, shaking loose from the Cotentin, acquiring room for mobile warfare—goodbye Normandy, hello Brest.
Reporters writing after the event and impressed with the results stressed the breakout that developed rather than the breakthrough that was planned. Participants tended later to be convinced that the breakout was planned the way it happened because they were proud of the success of the operation, perhaps also because it made a better story. In truth, Operation COBRA in its original concept reflected more than sufficient credit on those who planned, executed, and exploited it into the proportions it eventually assumed. COBRA became the key maneuver from which a large part of the subsequent campaign in Europe developed.
During the twelve days that separated the issuance of the plan and the commencement of COBRA, command and staff personnel discussed in great detail the possible consequences of the attack. “If this thing goes as it should,” General Collins later remembered General Bradley
saying, “we ought to be in Avranches in a week.”3 Certainly it was reasonable to hope that COBRA would precipitate a breakthrough that might be exploited into what later came to be called the breakout, but a justifiable hope did not prove a firm intention—particularly when considered in relation to the stubborn German defense in the hedgerows. Perhaps in their most secret and wildest dreams American planners had visions of a COBRA that would slither across France, but as late as 18 July there were “still a few things that [First] Army has not decided yet.” One of those “few things” was that COBRA was to be synonymous with breakout.4
Perhaps the best a priori evidence of how difficult it would be to achieve even a breakthrough was the result of two limited objective attacks launched by the VIII Corps a week before COBRA.
Preliminary Operations
A basic feature of the COBRA plan was the encirclement and elimination of the Germans facing the VIII Corps on the Cotentin west coast. For an effective execution of this concept, VIII Corps had to advance its front quickly toward Coutances at the proper time. Yet two German strongpoints in the corps zone of advance threatened to block a speedy getaway by a portion of the corps. To have to destroy them during the COBRA operation would retard the initial momentum of the COBRA attack. To eliminate them before COBRA commenced, to move the corps front closer to a more desirable line of departure, and to get the entire corps out of Cotentin swampland became the objectives of two preliminary operations.
Because the German strongpoints were virtually independent positions, the preliminary operations initiated by the 83rd and 90th Divisions of VIII Corps were separate, local attacks. The actions were remarkably alike in the assault problems they posed, in the nature of the combat, which resembled the earlier battle of the hedgerows, and in the results attained.
The 83rd Division attacked first. Since its original commitment on 4 July, the division had fought in the Carentan–Périers isthmus, had gained the west bank of the Taute River near the Tribehou causeway, and had sent the 330th Infantry across the Taute to operate with the 9th Division on the east bank. The remainder of the 83rd Division had
attacked along the west bank of the Taute toward Périers and had reached a causeway leading to la Varde. In its pre-COBRA assignment, the division was to attack across the la Varde causeway to the east bank of the Taute. In possession of la Varde and near the Lessay–Périers highway, the division would have a water-and-swamp obstacle behind it and be in position to threaten encirclement of Périers from the east. At this point it would also regain control of the 350th Infantry. (See Map II.)
The Germans did not hold la Varde in strength. A reinforced company was sufficient since the flat ground around la Varde provided open fields of fire for more than a thousand yards in all directions. Only five machine guns were at la Varde, but they were able to fire as though “shooting across a billiard table.”5 From nearby positions at Marchesieux, German assault guns could provide effective support.
In contrast to the excellent assistance the terrain furnished the defense, there were no natural features to aid the attack. Between the 83rd Division on the west bank and the Germans holding la Varde on the east bank stretched the gray-brown desolation of the Taute River flats. The Taute River, at this point a stream fifteen feet wide and two feet deep with about a foot of soft mud on the bottom, flowed along the western edge of the marsh. The causeway that crossed the swamp was a tarred two-lane road little higher than the open area of stagnant marsh and flooded mud-holes. Over a mile long, the causeway ran straight and level through borders of regularly spaced trees that gave the appearance of a country lane. The road in fact was the approach—the driveway—to a small chateau on the west bank of the swamp. The small bridge over the Taute near the chateau had been destroyed by the Germans. Along both edges of the swamp, lush banks of trees and hedges concealed the chateau, which was the jump-off point, and the hamlet of la Varde, the objective. In between, there was no cover. Foxholes in the flats would quickly fill with water. The only feasible method of attack was to crawl forward and then charge the enemy machine guns with grenades and bayonets. The swamp was mucky, and vehicles could not cross the causeway unless the bridge near the chateau was repaired.6
The division commander, General Macon, decided that an attack launched around 1800 would give engineers five hours before darkness to lay temporary bridging across the stream. Thus, build-up and consolidation of a bridgehead established at la Varde could be accomplished during the night. Colonel York’s 331st Infantry was to make the assault, Colonel Crabill’s 329th Infantry a diversionary attack. A strong artillery preparation was to include considerable smoke. Though the division tried to get tracked vehicles capable of carrying supplies across the swamp in the event engineers could not repair the bridge over the Taute, their efforts
failed. First Army headquarters, after much prodding, agreed to lend the division eight “Alligators” for one day but refused to furnish drivers.7 Normally used on the Normandy invasion beaches to handle supplies unloaded from ships, the Alligators arrived in the division area too late for use in the la Varde attack.
In the afternoon of 17 July, shortly before the main attack, reconnaissance troops of the 330th Infantry, on the east side of the river, attempted to approach la Varde from the east. Enemy machine gun fire stopped the effort. The diversionary attack on the west bank, launched by the 329th Infantry in company strength, turned out to be little more than a demonstration that “just pooped out” after taking thirteen casualties.8 At 1830, half an hour after the diversion commenced, Colonel York sent one battalion of his 331st Infantry toward la Varde in the main effort.
Because the causeway was the natural crossing site and because the flat straight road would obviously be swept by German fire, Colonel York sent his assault battalion through the spongy swamp. Using prefabricated footbridges, the infantry struggled across muck and water sometimes neck deep. At nightfall the battalion reached la Varde and established an insecure bridgehead. Many infantrymen who had crawled through the swamp found their weapons clogged with silt and temporarily useless. The mud, the darkness, and enemy fire discouraged weapons cleaning. Though the regiment had planned to reinforce the battalion during the night over the causeway, engineers had been unable to erect a temporary bridge because of heavy enemy tank destroyer fire on the bridge site. Unable to get supply vehicles, tanks, and artillery over the flats to support the battalion at la Varde, and deeming it impossible either to transport a sufficient supply of ammunition by hand or to send reinforcements across the treacherous swamp, General Macon reluctantly agreed to let the battalion at la Varde—which shortly after daylight, 18 July, reported it was unable to remain on the east bank—fall back.
The 331st Infantry tried again at dawn, 19 July, in an attack keyed to fire support from the 330th Infantry on the east bank of the Taute and to concealment by smoke and an early morning haze. Eschewing the swampy lowlands, the assault battalion advanced directly down the causeway. Against surprisingly light enemy fire, the troops again established a foothold at la Varde. Engineers in the meantime installed a Bailey bridge across the Taute near the chateau. Unfortunately, a normal precaution of mining the bridge so it could be destroyed in case of counterattack backfired when enemy shellfire detonated the explosives. The bridge went up with a roar. Since tanks again could not cross the swamp, the foothold at la Varde was once more precarious. When the enemy launched a small counterattack that afternoon, the troops retired.
The failure of this attack ended the attempts to take la Varde. The participating rifle companies had taken casualties of 50 percent of authorized strength, and one battalion commander was missing in action. Difficult terrain and plain bad luck had contributed to
the failure, but more basic was the ineffectiveness of the 83rd Division. The division earlier that month had incurred more casualties and received more replacements in its short combat career than any other U.S. unit in Normandy in a comparable span of time. The loss of trained leaders and men in the combat echelons and their replacement by the large influx of relatively untrained personnel had diminished the division’s efficiency. “We have quite a few new men and they are really new,” Colonel York explained; “[they] don’t know their officers ... and the officers don’t know their men.”9
Recognizing the condition of the division, Generals Bradley and Middleton saw no purpose in continuing the futile pattern at la Varde. They saw more hope in revising the VIII Corps role in COBRA. In the meantime the 83rd Division was to train and try to assimilate its replacements.
In the same way, the results of the 90th Division’s attempts to execute a pre-COBRA mission also contributed to a modification of the VIII Corps role in COBRA. After twelve days of sustained action at Mont Castre and Beaucoudray, the 90th Division had also seen its ranks depleted in the wearing battle of the hedgerows. Less than six weeks after commitment in Normandy, the division’s enlisted infantry replacements numbered more than 100 percent of authorized strength; infantry officer replacements totaled almost 150 percent. In comparison to the veterans who had fought in the hedgerows, the replacements were poorly trained and undependable, as soon became obvious in the division’s new assignment.
The pre-COBRA objective of the 90th Division was a low hedgerowed mound of earth surrounded by swampland. Athwart the division zone of advance, the island of dry ground held the village of St. Germain-sur-Sèves. Possessing the island and across the Sèves River, the division would be in position not only to threaten Périers but also to get to the Périers–Coutances highway.
Only a weak German battalion held the island, but it had excellent positions dug into the hedgerowed terrain, good observation, and a superb field of fire. Several assault guns and a few light tanks supported the infantry; artillery was tied into the strongpoint defenses.10
Two miles long and half a mile wide, the island had been more than normally isolated by the heavy rainfall in June, which had deepened the shallow streams along its north and south banks. Linking the hamlet of St. Germain to the “mainland” was a narrow, tarred road from the western tip of the island. The Germans had destroyed a small bridge there, the only suitable site for engineer bridging operations. Several hundred yards away, a muddy country lane gave access to the island from the north, across a ford. How to cross level treeless swamps that offered neither cover nor concealment was the assault problem. Although a night attack seemed appropriate, the division commander, General Landrum, quickly abandoned the idea. With so many newly arrived replacements he dared not risk the problem
of control inherent in a night operation.11
To help overcome the terrain difficulties, General Landrum arranged for heavy fire support. Since his was to be the only attack in progress in the corps zone, more than normal fire power was available. He received the assistance of the entire VIII Corps Artillery. Because the 83rd Division had found the la Varde operation so difficult, preparatory bombardment by tactical air was promised for the 90th Division. To make certain of a preponderance of fire power, Landrum directed all nonparticipating infantry units to support the attack by fire.
General Landrum selected the 358th Infantry to make the attack. The regimental commander, Lt. Col. Christian E. Clarke, Jr., planned to attack with two battalions abreast, each advancing along one of the roads to the island. Once on the island, the two battalions were to form a consolidated bridgehead. Engineers were then to lay bridging so that tanks and assault guns could cross the Sèves and support a drive eastward to clear the rest of the island.
Initially scheduled for 18 July, the operation was postponed several times until artillery ammunition problems-matters affecting the COBRA preparations—were settled. The attack was finally set for the morning of 22 July. Poor visibility that morning grounded not only the fighter-bombers that were to make an air strike on the island but also the artillery observation planes. Though in great volume, the artillery preparation thus was unobserved.
Advancing Toward St. Germain
Since no other actions were occurring in the area, the Germans, like VIII Corps, were able to utilize all their fire resources within range to meet the American attack. Enemy fire prevented the assault troops from advancing beyond the line of departure. A battalion of the 90th Division not even taking part in the attack sustained forty-two casualties from enemy shelling.12 American counterbattery fires plotted by map seemed to have no real effect.
Three hours after the designated time of attack, one battalion moved forward along the muddy country lane. Taking 50 percent casualties in the assault companies, men of the battalion crossed the swamp, waded the stream, and reached
the island. The momentum of their advance carried them 200 yards into the interior. Colonel Clarke quickly ordered the other assault battalion to take the same route, but only one rifle company managed to reach St. Germain in this manner. Though Colonel Clarke replaced the battalion commander with the regimental executive officer, the new battalion commander had no more success in reinforcing the foothold. The Germans pounded the approaches to the island with artillery and mortars and swept the open ground with machine gun fire. The only practical method of crossing the exposed area was by infiltration, and most men sent toward the island lost their way.
By dark of the first day of attack, at least 400 men were on the island. One battalion reduced to half strength by casualties and stragglers, less its mortar platoon, plus little more than one company of another battalion, formed a horseshoe line on the island about 200 yards deep and a thousand yards wide, with both flanks resting on the swamp. The troops repelled a small German counterattack, and the positions seemed quite stable. Still, efforts to reinforce the bridgehead failed. Because enemy fire prevented engineers from bridging the stream, neither tanks nor tank destroyers could cross.
With the descent of darkness, the troops on the island began to experience a sense of insecurity. Lacking mortars, tanks, and antitank guns, the men withdrew to a defiladed road along the north edge of the island. In the pitch-black darkness, some of the demoralized troops began furtive movement to the rear. Stragglers, individually and in groups, drifted unobtrusively out of the battle area. Soldiers pretended to help evacuate wounded, departed under the guise of messengers, or sought medical aid for their own imagined wounds. German fire and the dark night encouraged this unauthorized hegira and added to the problems of unit commanders in recognizing and controlling their recently arrived replacements.
Shortly after nightfall, Colonel Clarke discovered that the battalion commander of the forces on the island had remained on the near shore. When he ordered him to join his men, the officer did so, but neglected to take his staff. Learning this later, Colonel Clarke dispatched the staff to the island, but the officers lost their way and did not reach St. Germain.
At daylight, 23 July, the German shelling subsided, a prelude to the appearance of three German armored vehicles on one flank of the American positions and an assault gun on the other. As these began to fire, a German infantry company of about platoon strength—perhaps thirty men—attacked. Only a few Americans in the bridgehead fired their weapons. Panic-stricken for the most part, they fell back and congregated in two fields at the edge of the island. Hedgerows surrounded each of these fields on three sides; the fourth, facing the swamp, was open and invited escape. Continuing German fire across the open ground provided the only restraint to wholesale retreat.
Officers at regimental headquarters on the “mainland” had begun to suspect that the situation was deteriorating when unidentified cries of “cease firing” swept across the two fields. A shell landed in
a corner of one field, inflicting heavy casualties on men huddling together in fear. At this moment, despite little firing and few Germans in evidence, a group of American soldiers started toward the enemy, their hands up, some waving white handkerchiefs. That was the end. The rest of the men either surrendered or fled across the swamp.
At the conclusion of the fight for St. Germain, about 300 men were missing in action. A later check revealed that approximately 100 men had been killed, 500 wounded, and 200 captured.
The causes for failure were clear. Weather, terrain, a resourceful enemy, command deficiency at the battalion level (caused perhaps by combat exhaustion during the preceding battle of the hedgerows) had contributed to the result. The main cause, however, was the presence of so many inadequately trained replacements. The 90th Division had not had enough time to fuse its large number of replacements into fighting teams.
It seemed as though the performance of the 90th Division at St. Germain was but a logical extension of earlier unsatisfactory behavior. General Eisenhower remarked that the division had been “less well prepared for battle than almost any other” in Normandy, for it had not been “properly brought up” after activation.13 Judging that the division needed new leadership, a commander not associated with experiences of the hedgerow battle, higher headquarters decided to relieve the division commander. “Nothing against Landrum,” General Eisenhower remarked, adding that he would be glad to have General Landrum in command of a division he himself had conducted through the training cycle.14
Failure in the preliminary operations was in many ways depressing, but American commanders still were hopeful that COBRA would not bring another recurrence of the difficult hedgerow fighting. The First Army that was to execute COBRA was not the same one that had launched the July offensive. Battle had created an improved organization, and a continuing continental build-up had strengthened it. What the army needed was the opportunity to get rolling, and Cobra might well provide just that.
The Troops
The hedgerow fighting that had exhausted and depleted the ranks had also made the survivors combat wise. Common mistakes of troops entering combat were “reliance on rumor and exaggerated reports, failure to support maneuvering elements by fire, and a tendency to withdraw under HE [high-explosive] fire rather than to advance out of it.”15 Each unit now had a core of veterans who oriented and trained replacements. Most combat leaders had taken the test of ordeal by fire. The great majority of divisions on the Continent were battle trained.
An assurance had developed that was particularly apparent in dealings with
enemy armor. Earlier, when a regiment had blunted a tank-infantry counterattack, the significant and gratifying result was that it had stopped German armor. “Glad to know they can hold their own against tanks,” was the comment.16 But such experience was becoming increasingly common, and definite identification of a knocked-out Mark VI Tiger proved conclusively that even the German tank with the strongest armor was vulnerable to American weapons. Artillery, tanks, bazookas, tank destroyers, and tactical aircraft could and did destroy German tanks. By 11 July the First Army Ordnance Section had accumulated in collecting points 36 Mark IIIs and IVs, 5 Mark Vs and VIs. The hedgerowed terrain had neutralized to a great extent the ability of the Tiger’s 88-mm. gun and the Panther’s 75-mm. gun to penetrate an American tank at 2,500 yards. Tanks generally engaged at distances between 150 and 400 yards, ranges at which the more maneuverable Sherman enjoyed a distinct superiority.17
Though a tank destroyer crew had seen three of its 3-inch armor-piercing shells bounce off the frontal hull of a Mark V Panther at 200 yards range, a fourth hit had penetrated the lower front hull face and destroyed the tank.18 A soldier who had met and subdued an enemy tank later reported, “Colonel, that was a great big son-of-a-bitch. It looked like a whole road full of tank. It kept coming on and it looked like it was going to destroy the whole world.” Three times that soldier had fired his bazooka, but still the tank kept coming. Waiting until the tank passed, he had disabled it with one round from behind.19
The ability to destroy German armor generated a contagious confidence that prompted some units to add a two-man bazooka team to each infantry battalion, not principally for defense but to go out and stalk enemy armored vehicles.20 With this frame of reference becoming prevalent, the troops displayed a decreasing tendency to identify self-propelled guns as tanks. Even such a battered division as the 83rd manifested an aggressiveness just before COBRA when it launched a reconnaissance in force that developed spontaneously into a coordinated limited objective attack. Not the objective gained but the indication of a spirit that was ready to exploit favorable battle conditions was what counted.21
One of the major problems that had hampered the First Army—how to use tanks effectively in the hedgerow country—appeared to have been solved just before COBRA. The most effective weapon for opening gaps in hedgerows was the tank dozer, a comparatively new development in armored warfare. So recently had its worth been demonstrated that a shortage of the dozers existed in Normandy. Ordnance units converted ordinary Sherman tanks into dozers by
Rhino Tank with hedgerow cutter crashing through a hedgerow.
mounting a blade on the front. Some hedgerows, however, were so thick that engineers using satchel charges had first to open a hole, which the dozers later cleared and widened.22
Because the use of demolitions and tank dozers was time consuming, the tanks in offensive activity had often remained on the roads, and when cross-country movement became necessary, progress was inevitably slow. In order to speed up the movement of armor, Ordnance units and tankers throughout the army had devoted a great deal of thought and experimentation to find a device that would get tanks through the hedges quickly without tilting the tanks upward, thereby exposing their underbellies and pointing their guns helplessly toward the sky. The gadgets invented in July 1944 were innumerable.
As early as 5 July the 79th Division had developed a “hedgecutter,” which Ordnance personnel began attaching to the front of tanks. Five days later the XIX Corps was demonstrating a “salad fork” arrangement, heavy frontal prongs originally intended to bore holes in hedgerow walls to facilitate placing engineer demolition charges but accidentally found able to lift a portion of the hedgerow like a fork and allow the tank to crash through the remaining part of the wall. Men in the V Corps invented a “brush cutter” and a “green-dozer” as antihedgerow devices.
The climax of the inventive efforts was achieved by a sergeant in the 102nd Cavalry Reconnaissance Squadron, Curtis G. Culin, Jr., who welded steel scrap from a destroyed enemy roadblock to a tank to perfect a hedgecutter with several tusk-like prongs, teeth that pinned down the tank belly while the tank knocked a hole in the hedgerow wall by force. General Bradley and members of his staff who inspected this hedgecutter on 14 July were so impressed that Ordnance units on the Continent were ordered to produce the device in mass, using scrap metal salvaged from German underwater obstacles on the invasion beaches. General Bradley also sent Col. John B. Medaris, the army Ordnance officer, to England by plane to get depots there to produce the tusks and equip tanks with them and to arrange for transporting to France by air additional arc-welding equipment and special welding crews.
Every effort was made to equip all tanks with this latest “secret weapon,” for it enabled a tank to plough through
a hedgerow as though the hedgerow were pasteboard. The hedgecutter sliced through the earth and growth, throwing bushes and brush into the air and keeping the nose of the tank down. The device was important in giving tankers a morale lift, for the hedgerows had become a greater psychological hazard than their defensive worth merited.
Named Rhinoceros attachments, later called Rhinos, the teeth were so effective in breaching the hedgerows that tank destroyer and self-propelled gun units also requested them, but the First Army Ordnance Section carefully supervised the program to make certain that as many tanks as possible were equipped first. By the time COBRA was launched three out of every five tanks in the First Army mounted the hedgecutter. In order to secure tactical surprise for the Rhinos, General Bradley forbade their use until COBRA.23
Not the least beneficial result of the July combat was the experience that had welded fighting teams together. “We had a lot of trouble with the tanks,” an infantry commander had reported; “they haven’t been working with us before and didn’t know how to use the dynamite.”24 Co-operation among the arms and services had improved simply because units had worked together. Part of the developing confidence was generated by the fact that increasing numbers of medium tanks had received the newer and more powerful 76-mm. gun to replace the less effective 75-mm. gun, and thus were better able to deal with the enemy.25
Perhaps the most significant improvement in team operations was the increasing coordination that was developing between the ground forces and the tactical airplanes. In addition to performing the primary mission of trying to isolate the battlefield by attacking enemy lines of communication, the IX Tactical Air Command had employed a large portion of its effort in direct and close ground support. The pilots had attacked such targets as strongpoints retarding the ground advance, troop concentrations, gun positions, and command posts. They had also flown extensive air reconnaissance for the ground troops.26 On a typical day of action the fighter bombers of the IX TAC exerted 40 percent of their air effort in close support of the First Army, 30 percent in direct support of the Second British Army, 10 percent against rail lines and communications 50 to 70 miles behind the enemy front, and 20 percent in offensive fighter activity and ground assault area cover.27
Ground-air communications were being improved. “Wish you would tell the Air Corps we don’t want them over here,” an irate division staff officer had pleaded early in July after a few strafing planes had struck an American artillery battalion and wounded several men. “Have them get out in front [and] let them take pictures [but] no strafing or bombing.”28 Complaints of this nature were decreasing. Pilots of a tactical reconnaissance group attended courses of instruction in artillery fire adjustment, and as a result high performance aircraft began to supplement the small artillery planes with good effect.29 Particularly interested in developing a practical basis for plane-tank communications, General Quesada, the IX TAC commander, had very high frequency (VHF) radios, used by the planes, installed in what were to be the lead tanks of the armored column just before COBRA was launched. Tankers and pilots could then talk to each other, and the basis for the technique of what later became known as armored column cover was born. The success of the technique in August was to exceed all expectations.30
The development of new air operational techniques and weapons such as rocket-firing apparatus and jellied gasoline, or napalm, also promised more effective support for the ground troops. Experiments with radar-controlled blind dive bombing and with the technique of talking a flight in on target indicated that night fighter operations might soon become more practical. Since no fields for night fighters were operational on the Continent, the craft were based in England. Employment of night fighters in tactical support was not usually considered profitable even though ground forces requested it.31 In July work with radar-controlled night flights and projects for eventually basing night fighters on continental airfields promoted hope of round-the-clock air support.
Fighter-bomber groups in direct tactical support of the First Army were moving to continental airfields at the rate of about two each week. By 25 July twelve had continental bases. Their nearness to the battle zone eliminated the need to disseminate ground information across the channel to airfields in England as prerequisite for ground support. American ground units desiring air support channeled their requests to the First Army joint air operations section, which secured quick action for specific missions.32
During July, the American ground build-up proceeded steadily. Four infantry and four armored divisions reached the Continent during the month
before COBRA. The arrival in England early in the month of the 80th Division brought the theater total of U.S. divisions to 22: 14 infantry, 6 armored, and 2 airborne. Four more were expected in August. During the first twenty-five days of July, almost half a million tons of supplies were brought into France, the bulk across the beaches. Although the Cherbourg harbor began to be used on 16 July, port operations there were not to become important until the end of the month.33
To launch COBRA, the First Army had four corps controlling fifteen divisions actually on the army front.34 General Patton’s Third Army headquarters had assembled in the Cotentin during July and was ready to become operational. Similarly awaiting the signal for commitment, two additional corps headquarters were in France at the time COBRA was launched and another was to reach the Continent soon afterward. An infantry division and an armored division, not in the line, were available for use by the First Army in COBRA; another armored division was scheduled to land on the Continent before the end of the month. The First Army also was augmented by many supporting units that belonged to the Third Army: engineer and tank destroyer groups, evacuation hospitals, and Quartermaster railhead, general service, gas supply, graves registration, and truck companies. The Forward Echelon of the Communications Zone headquarters was established at
Valognes by 22 July, and the entire Communications Zone headquarters would soon arrive.35
Obviously, one field army, the First, could not much longer effectively direct the operations of such a rapidly growing force. To prepare for the commitment of General Patton’s army and to meet the necessity of directing two field armies, the U.S. 1st Army Group headquarters began to displace from England to the Continent on 5 July, a move completed one month later.36 In order to maintain the fiction of Operation Fortitude, the Allied deception that made the Germans believe a landing in the Pas-de-Calais might take place, ETOUSA activated the 12th Army Group under the command of General Bradley. Transferred to the 12th Army Group were all units and personnel that had been assigned to the U.S. 1st Army Group “except those specifically excepted,” in actuality, none. The 1st U.S. Army Group, under a new commander, thus became a nominal headquarters existing only on paper until its abolition in October 1944. The 12th Army Group became the operational headquarters that was to direct U.S. forces on the Continent.37
The presence of uncommitted headquarters in Normandy proved an embarrassing largess. General Montgomery did not utilize General Crerar’s First Canadian Army headquarters until 23 July, when it assumed a portion of
the Second British Army front.38 And, on the American side of the beachhead, General Patton’s Third Army, along with several corps headquarters, was still not employed in combat. Since Brittany had been selected as the stage for General Patton’s initial operations, the U.S. First Army had to reach the base of the Cotentin peninsula to provide the Third Army a means of ingress. A successful COBRA was a vital step toward this achievement.
General Eisenhower on 25 July gave General Bradley authority to change the existing command structure of the U.S. forces and erect the organization envisioned by the OVERLORD planners. At General Bradley’s discretion in regard to timing, the 12th Army Group headquarters was to become operational, assume control of the First Army, and commit under its control the Third Army.39
Between the end of the earlier July offensive and the launching of COBRA, there was a lull for about a week. Not only did the period of inactivity permit plans to be perfected and the troops to be better organized for the attack, it also gave the men some rest and time to repair the equipment damaged in the battle of the hedgerows. Units were able to integrate replacements. By the time COBRA got under way, all the divisions on the Continent were close to authorized strength in equipment and personnel and most had undergone a qualitative improvement.40
The quiet period before COBRA also made possible increased comforts such as hot meals, showers, and clothing changes. Even though B rations—a nonpackaged food affording a variety of hot meals-had reached the Continent early in July and were ready for issue to the troops, the battle of the hedgerows had prevented their being substituted for combat 10-in-1, K, and C rations until later in the month. With kitchens set up to serve hot meals, “it was amazing how many cows and chickens wandered into minefields ... and ended up as sizzling platters.”41
As Allied leaders searched rain-filled skies for a break in the clouds that might permit the air bombardment planned for COBRA, a phrase of the Air Corps hymn came to mind: “Nothing can stop the Army Air Corps.” Nothing, they added, except weather. While impatient commanders waited anxiously for sunshine, and while General Bradley facetiously assumed the blame for having “failed to make arrangements for proper weather,” the First U.S. Army rested and prepared for the attack.42
The Plot Against Hitler
During the lull over the battlefield in the west that followed GOODWOOD and preceded COBRA, and while defeats in the east gave the Germans increasing worry over the eventual outcome of the war, a dramatic attempt was made on Hitler’s life on 20 July. In a speech
the following day, Hitler himself released the news to the world. “A very small clique of ambitious, unscrupulous and stupid officers” he announced, “made a conspiracy to kill me, and at the same time to seize hold of the German Supreme Command.”43 Within a short time Allied intelligence officers had pieced together a remarkably accurate account of the occurrence: a cabal of high-ranking Army officers had tried to assassinate Hitler with a bomb in order to seize political power in Germany. The bomb had inflicted only minor wounds on Hitler, and the Führer moved swiftly to suppress the revolt. He named Heinrich Himmler—already Reich Minister of Interior, Reichsführer of the SS (and Waffen-SS), and Chief of the Gestapo and German Police—Commander of the Home Forces and gave him control of the military replacement system. Hitler replaced the ailing Generaloberst Kurt Zeitzler, chief of staff of OKH and vaguely implicated in the conspiracy, with Generaloberst Heinz Guderian. High-ranking officers of Army, Air Force, and Navy were quick to reaffirm their loyalty to Hitler. The immediate result of the conspiracy was to tighten centralized control of the military in Hitler’s hands.44
Allied intelligence had not only the facts but a plausible interpretation. The cause of the Putsch was “undoubtedly the belief ... that Germany had lost the war.”45
That a “military clique,” as Hitler calls them, should have been plotting to liquidate him is encouraging; that they should have chosen this moment is exhilarating. ... The very fact that plotters reckoned that the time was ripe for a venture so complicated as the assassination of the Führer argues that they had good reason to hope for success. ... There seems ... no reason to disbelieve Hitler’s assertion that it was an Army Putsch cut to the 1918 pattern and designed to seize power in order to come to terms with the Allies. For, from the military point of view, the rebels must have argued, what other course is open? How else save something, at least, from the chaos? How else save the face of the German Army, and, more important still, enough of its blood to build another for the next war?46
Colonel Dickson, the First Army G-2, believed that the Hitler government would remain in office by suppressing all opposition ruthlessly. He saw no evidence to suppose that the existing German Government would be overthrown by internal revolution or by revolt of one or more of the German field armies. He was certain that only the military defeat and the surrender of the German armies in the field would bring about the downfall of Hitler. The first step toward that goal was to intensify “the confusion and doubt in the mind of the German soldier in Normandy” by “an Allied break-through on the First Army front at this time, which would threaten to cut him off from the homeland, [and which] would be a decisive blow to the German Seventh Army.”47 On its knees, the Seventh Army had no future “save in the fact that so long as the battle
continues the miracle may still take place. Buoyed up by accounts of what V-1 had done, no less than by the promise of V-2, and still imbued with a discipline that has been impaired only by the substitution of apathy for enthusiasm, the German soldier is still on the [Nazi] party’s side.”48
The fact was that very few officers in the west were implicated in the plot against Hitler. A small but important group in the headquarters of the Military Governor of France at Paris staged a coup that was successful for several hours, but except for isolated individuals who knew of the conspiracy, and rarer still those who were in sympathy with it, the military elsewhere on the Western Front were overwhelmingly loyal to Hitler, even though some might be doubtful of the eventual outcome of the war. Those who did play some small role in the plot had not deliberately or unconsciously hindered field operations by treasonable conduct. The conspiracy had virtually no effect on the military situation in the west. The combat soldier in the “you-or-me” life-and-death struggle was too busy trying to remain alive.49 The higher officers pledged their continuing loyalty to Hitler. All Germans were more or less impressed with the miracle that had saved Hitler’s life.50
As a result of the Putsch, the efficiency of the German war machine under Hitler increased, for Himmler took immediate steps to unify the military replacement system and eventually improved it. The Putsch also intensified Hitler’s unfounded suspicion that mediocrity among his military commanders might in reality be treason. Rommel, recuperating at home from an injury received in Normandy, was eventually incriminated and forced to commit suicide. Speidel, the Army Group B chief of staff, was later imprisoned on evidence that indicated involvement. Kluge, the principal commander in the west, fell under suspicion nearly a month later when battlefield reverses in Normandy seemed to give substance to whispered accusations of his friendliness with known conspirators. Thus the Putsch, while giving Hitler the opportunity to consolidate military control even more in his own hands, pointed a blunt warning that the symptoms of military defeat were spreading an infectious distrust and suspicion among the higher echelons of the German military organization.51
On the battlefield in Normandy the half-hearted planning for an offensive action near Caen in August came to an end. Even before GOODWOOD had violently disrupted German operational planning, Rommel, just before his near-fatal accident, had estimated that the Germans could hold the Normandy front only a few more weeks at the maximum.52 Several days later Kluge endorsed
Rommel’s view. In a letter to Hitler he stated the hard facts clearly:
In the face of the total enemy air superiority, we can adopt no tactics to compensate for the annihilating power of air except to retire from the battle field. ... I came here with the firm resolve to enforce your command to stand and hold at all cost. The price of that policy is the steady and certain destruction of our troops. ... The flow of materiel and personnel replacements is insufficient, and artillery and antitank weapons and ammunition are far from adequate. ... Because the main force of our defense lies in the willingness of our troops to fight, then concern for the immediate future of this front is more than justified. ... Despite all our efforts, the moment is fast approaching when our hard-pressed defenses will crack. When the enemy has erupted into open terrain, the inadequate mobility of our forces will make orderly and effective conduct of the battle hardly possible.53
When GOODWOOD seemed to confirm Rommel’s and Kluge’s opinions, OKW became doubtful of the value of planning an offensive. Until the Germans learned where Patton was, they could not dispel their uncertainty about Allied intentions and consequently could not intelligently plan offensive action or weaken the Pas-de-Calais forces to bolster the Normandy front. On 23 July, immediately upon receipt of Kluge’s letter, Jodl proposed to Hitler that it might be time to begin planning for an eventual withdrawal from France. Surprisingly enough, Hitler agreed.54 But before anything came of this conversation, COBRA raised its head.
The Breakthrough Plan
The persons most intimately connected with COBRA were General Bradley, who conceived it, and General Collins, who executed it. These officers, warm personal friends, each of whom seemed to be able to anticipate what the other was about to do, worked together so closely on the plans and on the developing operations that it was sometimes difficult to separate their individual contributions. Their teamwork was particularly effective within the American concept of command where the higher commander often gives his subordinate great leeway in the detailed planning of an operation. On the basis of reconnaissance, terrain study, road conditions, and photo analysis, the subordinate commander could recommend modifications that might alter quite basically the original idea. With fine communications at their disposal, the American commanders at both echelons (indeed at all levels of command) could and did exchange information and suggestions, and measures proposed by the subordinate could be approved quickly by the higher authority. Where mutual confidence abounded as it did in the case of Generals Bradley and Collins, the closest co-operation resulted, with great credit to both.
General Bradley presented the COBRA idea at a conference with his staff and his corps commanders on 12 July. He characterized the battle of the hedgerows as “tough and costly ... a slugger’s match ... too slow a process,” and spoke of his hope for a swift advance
made possible by “three or four thousand tons of bombs” from the air. He stated that aggressive action and a readiness to take stiff losses if necessary were the keys to the success of COBRA. “If they [the Germans] get set [again],” he warned, “we go right back to this hedge fighting and you can’t make any speed.” He insisted, “This thing [COBRA] must be bold.”55
Requisites for the COBRA operation were many and complex, and General Bradley could only estimate that they in fact were fulfilled. He assumed that the Germans in the Cotentin, under the pressure of the July offensive, would withdraw to an organized and stable defensive line. He had to determine where they would be likely to erect their defense. He had to be certain that the Americans were in contact with the main line of resistance when the operation commenced. He had to be sure that the enemy line would not be so strongly fortified as to defy rapid penetration. He had to have firm ground beyond the Cotentin marshes that would not mire and delay mobile columns. He had to have a region traversed by a sufficient number of roads to permit quick passage of large numbers of troops. Finally, he had to be reasonably sure he could shake his armor loose before the Germans could recuperate from the penetration.56
Reasoning that the Germans would withdraw to the vicinity of the Lessay–St. Lô highway, General Bradley chose that road as the COBRA line of departure. The COBRA battleground—the Coutances–St. Lô plateau—was to be south of the highway. It was a region of typical bocage, an area of small woods and small hills, land bounded on the west by the ocean, on the east by the Vire River. The sombre hedgerowed lowland gave way to rolling and cheerful terrain, the swamps disappeared, arable land was more plentiful and fertile, the farms more prosperous, the hedgerowed fields larger. Pastoral hillsides replaced the desolation of the prairies and the over-luxuriant foliage of the Carentan lowlands. Roads were plentiful, for the most part tarred two-lane routes. There were several wider highways—four main roads leading south and three principal east—west roads across the Cotentin. Road centers such as Coutances, Marigny, St. Gilles, le Mesnil-Herman, and Notre-Dame-de-Cenilly assured an adequate communications network. Streams were relatively small.
A jumble of small ridge lines and low hills at first glance, the Coutances–St. Lô plateau contains a series of east-west ridges that rise toward the south for about eight miles from the Lessay–St. Lô highway. Forming cross-compartments that would hinder an advance to the south, the ridges favored lateral movement across the First Army front. When in July the VII Corps had attacked down the Carentan–Périers isthmus toward the plateau, General Collins had indicated awareness of the advantages of swinging the offensive to a lateral axis in that region. He had pointed out that if infantry forces reached Marigny, armored troops might well drive westward
along the highway from St. Lô to Coutances in exploitation.57 General Bradley’s COBRA plan took advantage of the terrain in the same way. After air force bombs facilitated the infantry penetration, mobile troops were to veer westward and drive to the Coutances, thereby encircling the Germans on the west coast of the Cotentin.
General Bradley called upon the VII Corps to make the main effort. He therefore changed the corps boundary to reduce the corps zone to a width of four and a half miles. He also enlarged General Collins’ force to a total of three infantry and two armored divisions. (Map 10 )
As outlined by the army plan, COBRA would start with a tremendous air bombardment designed to obliterate the German defenses along the Périers–St. Lô highway opposite the VII Corps. Two infantry divisions, the 9th and the 30th, were to make the penetration and keep the breach open by securing the towns of Marigny and St. Gilles, thereby sealing off the flanks of the breakthrough. Two armored divisions, the 3rd and the 2nd (the latter after being moved from the V Corps sector), and a motorized infantry division, the 1st (also after having been moved from the V to the VII Corps zone), were then to speed through the passageway—the three-mile-wide Marigny–St. Gilles gap—in exploitation. Tactical aircraft were to have already destroyed river bridges around the limits of the projected COBRA area to isolate the battlefield, and the exploiting forces on the left were to establish blocking positions on the eastern flank and along
the southern edge of the battlefield to prevent the Germans from bringing in reinforcements. The forces in the main exploiting thrust, on the right (west), were to drive toward the Cotentin west coast near Coutances and encircle the enemy opposite VIII Corps. The VIII Corps in turn was to squeeze and destroy the surrounded enemy forces. At the conclusion of COBRA, the First Army would find itself consolidating on the Coutances–Caumont line. If the air bombardment and ground attack paralyzed German reaction completely, the troops were to be ready to exploit enemy disorganization still further by continuing offensive operations without consolidation.58
Since the larger and basic American maneuver defined by Montgomery was to be a sweep through the Cotentin around a go-degree arc with the pivot at Caumont, the U.S. troops east of the Vire had the subsidiary role of containing the enemy forces. While XIX Corps remained in place and supported the VII Corps effort, V Corps was to make a diversionary attack on the second day of the COBRA operation. Both corps
Map 10: Operation COBRA—VII Corps Plan, 20 July 1944
were to tie down German troops that might otherwise be moved to seal off a COBRA penetration. The XIX Corps was also to be ready to displace west of the Vire River and assume a new zone; as VII Corps veered westward toward Coutances, XIX Corps was to be prepared to take over the left portion of the VII Corps zone and drive to the south along the west bank of the river.59
The rather general concept expressed in the army outline plan was developed into a detailed course of action by the VII Corps. Corps planners also made two major modifications that affected the weight of the infantry assault and the routes as well as the relative strengths of the exploiting units.
Because the 9th and 30th Divisions were near exhaustion from their battle in the Taute and Vire region, General Collins requested and received the 4th Division as well, and assigned to it a role in the initial infantry assault. Though General Bradley had planned to retain the 4th in army reserve, he acceded to Collins’ request in order to insure a quick follow-up of the air bombardment and a speedy penetration.60
More important was the modification of the exploitation, which virtually changed the character of COBRA. According to the army plan, the mobile forces were to use two main highways leading south, the Marigny–Carantilly road on the right (west) and the St. Gilles-Canisy road on the left. One armored division, presumably the 3rd, after moving south for six miles to Carantilly, was to swing in a wide arc for eleven miles—southwest, west, and northwest—to encircle Coutances in the corps main effort. The other armored division, the 2nd, after pushing five miles south to Canisy, was to split into three columns and drive southeast, south, and southwest in order to protect the main effort developing toward Coutances. At the conclusion of its advance, the 2nd Armored Division was to set up blocking positions across the fronts of both the VII and the VIII Corps—at Bréhal, Cérences, Lengronne, St. Denis-le-Gast, and Hambye, also inferentially at Villebaudon and Tessy-sur-Vire—and thereby across the entire Cotentin. In advance of the forces actually encircling and destroying the enemy near Coutances, the blocking positions were to prevent the Germans from bringing in reinforcements from the southeast and from the south. The motorized 1st Infantry Division was to provide reserve strength to reinforce either armored thrust, or both.61
Less concerned with the possible arrival of enemy reinforcements than with the strength already facing the VII and VIII Corps in the Cotentin, General Collins redistributed the power available to him. He re-formed and strengthened
the main attack force and rerouted it along a more direct approach to Coutances. He transformed the drive along the original and longer route to Coutances into a subsidiary and protective effort. He consolidated the blocking force on the left from three dispersed columns into two compact thrusts.
As formulated by Collins, the plan of exploitation assigned the main encirclement to the motorized 1st Division, with Combat Command B of the 3rd Armored Division attached. Armor and infantry, after driving south to Marigny, were to attack westward along the excellent highway directly to Coutances in order to block and help destroy the Germans facing the VIII Corps. The 3rd Armored Division, less CCB, was to follow the original and more roundabout route to Coutances; it was to seize the southern exits of Coutances and provide flank protection on the south for the main effort. The 2nd Armored Division, strengthened by the attachment of the 22nd Regimental Combat Team of the 4th Division, was to drive along the left (east) flank of the corps. One thrust was to go directly to le Mesnil-Herman to cover the movement of the other exploiting forces and prepare for further movement to Villebaudon and Tessy-sur-Vire, two critical points of entry for possible German reinforcements from the southeast. Another 2nd Armored Division force was to be ready to go southwest from Canisy through Notre-Dame-de-Cenilly to block German reinforcement from the south, but instead of driving all the way to Bréhal near the Cotentin west coast it was to stop at Cérences. The armor was to halt at Cérences in order to provide a coastal corridor for an advance to the south by the VIII Corps, to avoid “a hell of a scramble” likely to come if VII and VIII Corps units intermingled south of Coutances, and to prevent the 2nd Armored Division from being “strung out too badly.”62
The COBRA plan in final form thus called for three infantry divisions, the 9th, 4th, and 30th, to make the initial penetration close behind the air bombardment and create a “defended corridor” for exploiting forces, which were to stream westward toward the sea. The motorized 1st Division, with CCB of the 3rd Armored Division attached, was to thrust directly toward Coutances. The reduced 3rd Armored Division was to make a wider envelopment. The 2nd Armored Division, with the 22nd Infantry attached, was to establish blocking positions from Tessy-sur-Vire to the Sienne River near Cérences and, in effect, make a still wider envelopment of Coutances.63
The VII Corps plan expressed a concept quite different from the army idea. The corps plan reinforced the initial infantry assault. It massed more power against Coutances. It strengthened blocking positions. It projected three encircling columns across the Cotentin and around Coutances. Instead of cutting across the VIII Corps zone of advance, it provided a corridor for the VIII Corps to exploit further a successfully completed COBRA. As a result of these changes, COBRA was no longer a plan designed primarily to encircle Coutances after penetration; it had become
a plan to encircle and secure Coutances, disrupt the German defenses west of the Vire River, and set up a situation suitable for further exploitation, presumably by the VIII Corps.
Expecting the VII Corps ground attack to complete the penetration six hours after the bombardment, General Bradley originally scheduled the VIII Corps attack for that time. The failure of both preliminary operations in the VIII Corps zone caused him to modify this arrangement. If the German resistance to the pre-COBRA operations at la Varde and St. Germain was typical of what the Americans could anticipate in COBRA, then six hours was not enough time. General Bradley consequently postponed the VIII Corps attack. If COBRA were launched in the morning, VIII Corps would attack at dawn of the following day; if COBRA were launched in the afternoon, VIII Corps would attack on the morning of the third day.64
One other change in plan came as a result of the preliminary operations. Instead of reverting to control of the 83rd Division, the 330th Infantry east of the Taute River flats remained a separate unit. Although still considered formally under control of the VIII Corps, the regiment was to begin the COBRA attack with the VII Corps.
Since COBRA’s success depended essentially on VII Corps progress, General Collins had six divisions under his control, virtually an army. The armored units augmented the corps strength still more since both were “old type” or “heavy” armored divisions, the only ones in the theater. All the divisions scheduled to make the VII Corps COBRA attack were combat experienced; three—the 2nd Armored, the 1st, and the 9th—had fought in North Africa and Sicily. While the 9th and 30th manned the corps front in mid-July, the other divisions slated for commitment in COBRA assembled in the rear, careful to avoid contact with the enemy lest their identity be revealed. Tactical surprise was to be as important in COBRA as was the concentration of strength.
In keeping with the mission of VII Corps, First Army gave the corps a large part of its artillery: 9 of its 21 heavy battalions, 5 of its 19 mediums, and all 7 of its nondivisional lights. Non-divisional artillery pieces of all types under corps control totaled 258.65 For the anticipated duration of the attack—five days—the army allocated the VII Corps almost 140,000 rounds of artillery ammunition.66 Because ammunition restrictions made all-inclusive prearranged fires difficult, the VII Corps Artillery (Brig. Gen. Williston B. Palmer) did not draw up an over-all fire plan. Attaching to the divisions all seven of the light battalions the army had made available, the corps sub-allocated to the divisions the greater part of its supply of ammunition.67 The division fire plans included
concentrations on known or suspected enemy installations, some to strike as far as 3,000 yards south of the Périers–St. Lô highway, most to fall on the main enemy defenses near the road. All fire plans emphasized striking specific targets rather than furnishing general support.68 The VII Corps Artillery was to control 174 pieces of medium and heavy caliber, plus the artillery of the divisions initially in reserve. Adjacent corps artillery units were to assist.
The major preattack bombardment was to come from the air. Planes were to assume the normal artillery missions of disrupting the enemy’s communications, neutralizing his reserves, and reducing his will to fight. Far beyond the resources of the artillery available to the First Army, the air bombardment that General Bradley had in mind encompassed terrifying power. To be certain that air commanders appreciated the extent of the support desired, General Bradley went to England on 19 July to present his requirements to the air chiefs in person.
Bradley’s primary desire was to obtain “blast effect” by the use of heavy bombers.69 He wanted the air attack concentrated in mass, the planes to strike in a minimum duration of time. To avoid excessive cratering, which might impede the ground troops, and to prevent the destruction of villages located at critical road junctions, he requested that only relatively light bombs be used.70 He designated a rectangular target immediately south of the Périers–St. Lô highway, 7,000 yards wide and 2,500 yards deep. To prevent accidental bombing of VII Corps front-line troops, Bradley planned to withdraw them 800 yards from the bomb target. Though 800 yards left no real margin of safety, General Bradley wanted the ground troops close enough to the target for immediate exploitation after the bombardment. To provide additional protection for the ground forces, General Bradley recommended that the planes make their bomb runs laterally across the front, parallel to the front lines, instead of approaching over the heads of American troops and perpendicular to the front. Recognizing that pilots preferred a perpendicular approach to minimize antiaircraft interference, he suggested that the planes use the sun for concealment—if the attack occurred in the morning, the bombers could fly from east to west; in the afternoon, they could attack over a reverse course. In either case, the straight road between Périers and St. Lô would be an unmistakably clear landmark as a flank guide.
For their part, the air chiefs were unable to meet all the requirements. Although they promised blast effect by a mass attack, agreed to use comparatively light bombs, and concurred in the choice of the target, they demurred at making lateral bomb runs and objected to the slender 800-yard safety factor.
A lateral bomb run, the air chiefs
pointed out, meant approaching the target area on its narrow side, that is to say along a narrow corridor. In an operation on the scale requested by General Bradley, this would cause congestion over the target and make the completion of the attack impossible in the brief time desired. To gain the effect of mass, the bombers had to approach from the north over the heads of the ground troops. Admitting that this posed some dangers to the ground troops, the air chiefs noted that the highway would serve as a clearly distinguishable “no bomb line.” In addition, the less effective enemy aircraft interference during a perpendicular approach would enable pilots and bombardiers to bomb more accurately.71
Despite the fact that the highway made an excellent landmark, the air chiefs wished a true safety ground factor of 3,000 yards. They nevertheless agreed, in light of General Bradley’s desire to get the ground troops to the target area quickly, to reduce the safety factor to 1,500 yards. Bradley, for his part, refused to withdraw his troops more than 1,000 yards from the highway.72 The final result was a further compromise. The ground troops were to withdraw only 1,200 yards, but the heavy bombers were to strike no closer to the ground troops than 1,450 yards. The interval of 250 yards was to be covered by fighter-bombers, which attacked at lower altitudes than the heavies and thus could bomb more accurately.
Participating units in the COBRA air attack were to include all the heavy bombers of the Eighth U.S. Air Force and all the medium bombers and fighter-bombers of the Ninth U.S. Air Force. Fighter planes from the Eighth U.S. Air Force and from the RAF 2nd Tactical Air Force were to fly cover. The RAF Heavy Bomber Command, with planes equipped to carry only large bombs, were excluded because of Bradley’s desire to avoid excessive destruction and cratering.73 Air Chief Marshal Tedder, Deputy Supreme Commander, provided top-level supervision. Air Chief Marshal Leigh-Mallory, commander of the AEAF, was to set the time and the date of the operation. General Brereton, commanding the Ninth U.S. Air Force, was to plan the attack of the bombers. General Quesada, commander of the IX Tactical Air Command, was to coordinate the air attack with the ground forces.74
The air bombardment was to begin eighty minutes before the ground attack with a twenty-minute strike by 350 fighter-bombers. Most fighter-bombers were to attack the narrow target strip immediately south of and adjacent to the road, although several flights were to bomb and strafe six enemy strongpoints north of the Périers—St. Lô highway.75
Following immediately, 1,800 heavy bombers, in an hour-long strike, were to blast the main target area, a rectangular “carpet” adjacent to and south of the narrow strip. Upon conclusion of the heavy bomber attack—the beginning of the ground attack—350 fighter-bombers were to strafe and bomb the narrow strip again for twenty minutes. Ten minutes after the completion of this strike, 396 medium bombers were to attack the southern half of the rectangle for forty-five minutes. Throughout the duration of the bombardment, 500 fighters were to fly bomber cover.76
For the ground troops, the narrow strip was the threshold, the target area the entrance to the Marigny–St. Gilles gap. To blast open a passageway on the ground, approximately 2,500 planes in a bombardment lasting two hours and twenty-five minutes were to strike a target area of six square miles with almost 5,000 tons of high explosive, jellied gasoline, and white phosphorus.
This kind of air power, many times the equivalent of available artillery, required careful coordination to avoid striking U.S. troops, particularly since the employment of heavy bombers intensified the usual problems and dangers of close air support. The size of the individual plane bomb load gave each bomber a considerable casualty-producing potentiality, but since heavy bombers attacked in units, with a lead bombardier controlling the bomb release of a dozen or so planes, an error in computation or a failure to identify a landmark properly could easily result in disaster. The absence of direct radio communication between the troops on the ground and the heavy bombers in flight made reliance on visual signals necessary. To define the northern limit of the heavy bomber target area during the air attack, artillery was to place red smoke every two minutes on the narrow fighter-bomber strip.77 This precaution was far from foolproof, for strategic aircraft bombed from high altitudes, and ground haze, mist, dust, or a sudden change of wind direction might render visual signals worthless. Ground troops on the front were to withdraw one hour before the air attack, leaving a protective shell of light forces in position until twenty minutes before the air bombardment, when they too were to withdraw. After the withdrawal, the ground troops were to mark their locations with fluorescent panels. All units participating in COBRA were to have repainted the Allied white-star insignia on their vehicles and tanks.78
In the same way that infantry failure to follow an artillery preparation closely tends to cancel the effect of a well-delivered concentration, the inability of the COBRA ground attack to take quick advantage of the bombardment would waste the blast effect of the bombs on the enemy. The ground troops were to cross the three quarters of a mile that
separated them from the air target at the conclusion of the heavy bomber strike while fighter-bombers still were strafing and bombing the narrow strip immediately south to the Périers–St. Lô road. The arrival of the infantry at the line of departure and the conclusion of the fighter-bomber strike were to be simultaneous. Medium bombers were then to commence attacking the southern half of the carpet and to continue until the ground troops were across the road and the narrow strip. To insure coordination, the units on the ground were to move forward at the rate of one hundred feet a minute.79 Artillery was to deliver normal preparatory fires, reinforced by tank destroyer concentrations and antiaircraft artillery ground fire, on the area between the troops and the bombarding planes.
One hour after the ground attack jumped off, all the fighter-bombers of the IX Tactical Air Command and one group of RAF Typhoon planes were to be available to support the First Army for the rest of the day with assault area cover, offensive fighter operations, armed reconnaissance, and air support request missions. Six hours after the ground attack, medium bombers, after having returned to England for refueling and reloading, were to become available for
additional missions as necessary. Dive bombers were to be ready for missions on one hour’s notice. If the infantry divisions made rapid progress and the exploiting forces were employed at once, fighter-bombers were to furnish column cover by flying protection and reconnaissance for the armored spearheads.80
This was the plan on which the Allies counted so much, and on 23 July Allied weather experts expressed a cautious hope that COBRA might soon be launched. Predicting that a slight overcast might break in the late morning of 24 July and that morning haze and light fog would disappear later that day, the forecasters reported that the weather on 24 and 25 July would be favorable for ground operations and moderately favorable for air activity.81 After a week of waiting, the Allies found the prospect tempting. With Caen and St. Lô in Allied hands, the arrival of fresh infantry and armored divisions on the Continent, mounting stocks of supplies and equipment increasingly available, and the Germans suffering from attrition, a lack of supplies, and an absence of air support, the situation appeared favorable for the breakthrough operation. Air Chief Marshal Leigh-Mallory gave the green light, and the dormant body of COBRA prepared to strike.