Thursday, March 12, 2015

Interdiction WWII Part VI - Northwest Africa November 1942-May 1943




In the early days of the Tunisian Campaign Allied air commanders had tried to attack enemy merchantmen in port. They soon found that the turnaround time of the B-17s was too slow. Poor though the facilities of the Tunisian ports were, many convoys unloaded and put to sea before a strike could be mounted. Occasionally, B-17s attacked shipping at sea, but their slow turnarounds and inaccurate bombing thwarted attempts to catch convoys in midpassage. B-26 medium bombers attached to the Coastal Air Force therefore became the chief weapon of the aerial antishipping campaign. The airfields to support their operations were ready by February 1, 1943, but three weeks of bad weather over the Strait of Sicily delayed operations. The Marauders almost always attacked ships at sea because they had suffered heavy losses earlier when they braved the heavy antiaircraft defenses of Tunis and Bizerte. At first they employed a skip-bombing technique developed in the Pacific: The flyers approached their prey abeam and at low altitude, releasing their bombs so that they caromed from the surface of the sea into the sides of the targeted vessels. The tactic was at first highly effective, but was defeated when heavier antiaircraft armament on the merchantmen forced the bombers to attack from about 10,000 feet. From this altitude bombing accuracy was abysmal. The aviators then resorted to attacking in staggered flights at low and medium altitudes in an attempt to divide and confuse the antiaircraft gunners. These attacks, one pilot recalled, were “never entirely successful.” Toward the close of the campaign a weakening of antiaircraft fire permitted a return to skip bombing; at this stage, the weakness of the Luftwaffe permitted employing as dive bombers the P-38s originally detailed to escort the B-26s. The B- 26s were aided by British aircraft from Malta, which now used against Tunisia-bound convoys the deadly skills they had honed attacking the Libyan convoys. Royal Air Force Malta, which had been placed under Tedder’s operational control, used two kinds of aircraft for antishipping operations: the Albacore torpedo-bomber and the versatile Beaufighter.

Despite the difficulties posed by antiaircraft fire and a late start, the antishipping campaign was eminently successful in reducing the flow of supplies to Heeresgruppe Afrika. The Allies learned from ULTRA that of all the merchantmen that set sail for Tunisia in March, nearly half had been sunk-but a fifth had been lost in February. Because of the shortage of ships and general derangement of its logistical system, during the critical months of March and April the Axis was able to load only 140,572 tons of supplies for Tunisia. This equates to a barely adequate average monthly shipment of 70,286 tons, which was then subjected to a frightful loss rate. In April, 41.5 percent of all cargos were lost. This was slightly less than the percentage lost in March, but in April only 29,233 tons of supplies reached Tunisia-March’s figure had been 43,125. Of the vessels lost in these months, aircraft claimed about two-thirds. By the end of April, Admiral Friedrich Ruge, sent to Rome to expedite the flow of supplies to Africa, had come to agree with the conclusion reached some time before by the Italian Navy-that the losses on the run to Tunisia had become so great that they could no longer be justified by Heeresgruppe Afrika’s slim chance for survival. Berlin, however, continued to insist on throwing good money after bad.

The effect of the curtailed flow of supplies on the German and Italian forces in Tunisia was great. Even before the interdiction campaign became effective, their logistical position was weak. On February 13, Rommel’s quartermaster reported that he had not received enough supplies to cover consumption; the shortage of ammunition was critical when the attack through the Kasserine Pass began the next day. With the beginning of serious interdiction in late February, the logistical position of the Axis’ armies grew steadily worse. In early March, Rommel was still able to mount the Axis’ last offensive of the campaign. He struck at the advancing Eighth Army near Medenine, only to be repelled with heavy losses in tanks. Thereafter, the fortunes of Heeresgruppe Afrika declined rapidly. By the end of March, Montgomery had outflanked the Mareth Line, forcing the Germans to retreat north up the coast and to yield the ports of Sousse and Sfax. At this point the ailing Rommel left Africa, never to return. Von Arnim succeeded him as commaqder of Heeresgruppe Afrika. On the western front the First Army began a sustained offensive that by March 17 succeeded in capturing Gafsa. Not far from there, the two Allied armies linked up on April 7; four days later the First Italian Army joined the Fifth Panzerarmee. As the Tunisian Campaign entered its last month the forces of the Axis were completely hemmed in a small bridgehead defined by a front that stretched 100 miles from Cape Serrat just west of Bizerte to Enfidaville southeast of Tunis.

Heeresgruppe Afrika lacked the fuel and ammunition to counter the final Allied offensive. It reported on March 28 that it had entirely depleted its reserves of both commodities. On April 1 the quartermaster described the logistical situation as “very bad.” On April 10 the Allies intercepted a message that told of an armored division that for want of fuel had abandoned its equipment and retreated on foot.

From the earliest days of the Tunisian Campaign, the Germans had attempted to compensate for their inadequate supply of shipping by the extensive use of air transport. Nine groups of Ju 52 transports-468 aircraft- carried urgently needed supplies, particularly fuel and ammunition. They were aided by thirty large six-engine Me 323 transports. On some days as many as 585 tons were ferried across the Strait of Sicily, although the average appears to have been close to 172 tons a day. The Allies knew the details of the airlift from ULTRA, but the same problems that delayed antishipping operations stayed action against the German airlift. Strategic considerations dictated further delay. The assault upon the aerial convoys, Operation FLAX, was planned in early February but not implemented until April. FLAX was a card that could not be played more than a few times, as shown by the relative impunity with which the surviving Axis transports operated at night after the trap had been sprung. The flight time across the Strait of Sicily was so short that interception could be made only with precise intelligence. The Germans, understanding this but not knowing that their codes had been compromised, operated by day. Since their enemy had the option of flying by night, the Allies delayed implementation of FLAX until the most German transport aircraft were in operation so that the blow would be as decisive as possible. They also wanted to destroy the transports when they were most needed, and therefore timed FLAX to coincide with both a high point of the antishipping campaign and the final assault on Tunis.

The transport aircraft were mostly based at fields near Naples and Palermo; a few staged from Bari and Reggio di Calabria. Flights usually began at Naples and proceeded after stops in Sicily to the main Tunisian terminals, Sidi Ahmed and El Aouina. Occasional flights went directly to Tunisia, picking up their escorting fighters over Sicily.68 FLAX called for fighters to intercept the aerial convoys over the strait. There were also bombing attacks on the overcrowded staging fields in Sicily and unusually ambitious antishipping sweeps. On April 6 P-38s intercepted a large formation of Ju 52s a few miles from the Tunisian coast while bombers attacked airfields in Sicily and Tunisia. Further attacks on aerial convoys followed on April 10, 11, 18, and 19. These resulted in the destruction of about 123 Ju 52s and 4 Italian SM 82s. On April 22 an entire convoy of twenty-one Me 323s was destroyed; two of these giants had been destroyed earlier for a total loss of twenty-three. Thereafter reduced numbers of Ju 52s flew at night. FLAX dealt the German air transport fleet a blow from which it never recovered-and ended Heeresgruppe Afrikds last chance for any significant resupply of its rapidly dwindling supply of fuel.

Having been prevented by logistical problems from employing the strategy that might have permitted a prolonged stand in Africa, Heeresgruppe Afrika was in its last days hard put to defend itself at all because of crippling shortages of ammunition and, especially, of fuel. Near the end, von Arnim had been able to move his headquarters only because of the providential discovery of a drum of aviation gasoline on a beach flotsam, presumably, from one of FLAX’S victims. He surrendered himself and his army on May 12, having with his own hands set fire to his headquarters caravan.

The Tunisian Campaign affords a clear example of the decisive importance of logistics in modern warfare. In Tunisia, and North Africa generally, the Axis had usually prevailed when it met its foes on anything like equal terms. Heeresgruppe Afrika was neither outfought nor outgeneraled; starved of supplies, it yielded at length to the superior numbers of a lavishly equipped enemy. “The final decision was fought out on the ground,” a German study concluded, “but the effect of the air war on supplies and morale had already determined the outcome of the battle.” As Kesselring had foreseen, supply had indeed been “everything.”

The great success of the Allies in Tunisia had several consequences. It represented a triumph for the three-stage concept of aerial operations that the British had developed in the eastern desert. For the rest of the war, the basic pattern for Allied combined arms offensives remained air superiority, interdiction, and close air support for the ground forces. Tunisia also saw final acceptance of the idea that the control of air power in a theater of operations should reside in a single commander, equal in authority to the ground commander with whom he worked closely in executing the plans of the theater commander. This organizational conception, together with the three-stage concept of aerial operations, was in the summer of 1943 written into FM 100-20, Command and Employment of Air Power, which many airmen regarded as a virtual charter of independence from the ground forces.

So powerful an argument was the victory in Tunisia for the centralization of air power and the coequal status of air commanders with those of the ground forces, that some American airmen came perilously close to attributing the Allied victory in Northwest Africa entirely to the triumph of their views in the reorganizations of December 1942 through February 1943. But however fruitful the organizational changes of February 1943 might have been, the primary reasons for the success of Allied interdiction are to be found elsewhere. The material advantage of the Allied air forces was ultimately so crushing that it is difficult to see how the Anglo-Americans could have failed once they dealt with their problems of inadequate supply and improved their airfields. The Axis’ logistical system was inherently inadequate. Too few suitable ships remained to Italy by 1943 to support Tunisia adequately; the loss of a comparatively small number of vessels therefore quickly pitched Heeresgruppe Afrika into logistical crisis. There was, moreover, a strategic asymmetry between belligerents that greatly favored the Allied side: The Axis’ supply lines were open to attack while those of the Allies were virtually exempt because of Germany’s lack of strategic bombers. The Anglo-Americans were therefore able to go on the offensive even before they had general air superiority over Tunisia. The Luftwaffe was forced to divide and redivide its aircraft in an ultimately futile attempt to protect convoys, ports, and airfields from a foe who could usually concentrate his aircraft to win local air superiority. From ULTRA, finally, Tedder and his colleagues had essentially complete information about the movements of the enemy’s convoys through the constricted channels in the minefields of the Strait of Sicily.

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