Chapter 11: Rome
The failure of the Anzio landings to achieve substantial results and the unsuccessful attempts of the Fifth Army to break the Gustav Line focused attention on the idea of using air power to disrupt the enemy’s lines of communication to an extent that would deny him the power to stop a major Allied ground offensive. The possibility and advantage of such a program had been pointed out by General Eisenhower at the Cairo conference in December 1943, and thereafter General Wilson in February had formulated a plan for an operation of that type.1 Air leaders had been urging the program for several months. General Spaatz, during a visit to the theater in February, declared that with good weather the air forces could so thoroughly interdict communications that the breaking of the ground stalemate would be inevitable.2 General Eaker, early in March, assured General Arnold that powerful air attacks on the enemy’s rail, road, and sea communications could interdict them and keep them interdicted, with the result that the enemy would be driven past Rome to the Pisa–Rimini line.3 Such opinions were not pulled out of thin air: in the closing weeks of the Tunisian campaign, throughout the Sicilian campaign, during the drive of the Fifth and Eighth Armies past Naples and Foggia, and as a preliminary to SHINGLE, the air forces, although directing only a part of their total effort toward cutting lines of supply, had so successfully interfered with movement as to indicate that an all-out air offensive would result in very nearly complete interdiction of the enemy’s lifeline.
A study prepared by the British bombing survey unit headed by Professor Solly Zuckerman on the results of air interdiction in the Sicilian and southern Italian campaigns bore out the collective opinion of Eisenhower, Wilson, Spaatz, and Eaker.4 However, the so-called Zuckerman
thesis, which had been accepted as air doctrine even before it was published on 28 December 1943 and which had the indorsement of the Air Ministry and Tedder’s strong support, insisted that communications targets should be large rail centers, where tracks, locomotives, rolling stock, warehouses, and repair sheds were concentrated, and held it categorical that rail and road bridges were “uneconomical and difficult targets” which in general were not worth attacking.5
With the latter contention the MAAF Target Section, XII Bomber Command, G-2 of AFHQ, A-2 of Twelfth Air Force, and others were in sharp disagreement. They conceded that in the Italian campaign up to the present battle line it had been entirely logical to concentrate on rail centers, for all traffic into southern Italy had to pass through only a few yards, notably those at Naples and Foggia; but they argued that in central and northern Italy the rail system contained so many yards that it would be very difficult to knock out all of them, whereas every important line ran over bridges and viaducts, many of them in isolated sections and few of them capable of being by-passed. They noted that the purely military needs of the German forces in the field could be supplied by only about 5 per cent of the normal Italian rail traffic and that this amount could be moved without using extensive marshalling yard facilities. It seemed apparent that to be effective an interdiction program would have to cut all lines quickly and simultaneously – which could not be accomplished solely by knocking out rail centers. They pointed to a brief period of bridge-busting in late October and early November 1943* which had so successfully cut the main rail lines in central Italy that, according to General D’Aurelio, former chief of the Italian liaison staff with Kesselring, the Germans were “mentally preparing themselves” for a withdrawal to above Rome-and might well have done so had not the Allies abandoned the program before the end of November because of other commitments and bad weather.6 The exponents of attacks on bridges received a strong boost early in March when an OSS report concluded that an air assault on marshalling yards and repair shops by any force likely to be available in the theater would not produce significant military results, and asserted that “nothing in the record to date shows that a simultaneous interdiction of all north-south rail lines by bombing bridges is beyond the capabilities of MAAF, given a scale of effort comparable to that currently being expended against other transport targets.”7
Topographical and railway maps of central and northern Italy gave strong support to the arguments of the anti-Zuckerman school. In both areas mountains, valleys, and streams had forced the engineers who built the rail system to resort to use of an enormous number of bridges, viaducts, tunnels, and embankments, most of them highly vulnerable to air attack. On the other hand, in German-held Italy there were in March 1944 at least 48 major marshalling yards, more than 100 others with 10 tracks or more, and countless small sidings. To achieve real interdiction by knocking out yards appeared to be too big a job, especially since operations from late October 1943 to the end of January 1944 had shown that an average of 428 tons of bombs had to be dropped for every complete blockage of an M/Y, whereas only 196 tons were required to destroy a bridge. Moreover, experience had shown that tracks were much more easily repaired or replaced than were bridges.8
The question of whether rail centers (which usually meant yards) or bridges offered the better objective was not nearly so important as the fact that both air and ground leaders believed that the best way to insure a successful ground offensive up the Italian peninsula was for the air forces to disrupt the enemy’s lines of supply to the point where he could not maintain his armies in the face of a powerful assault by the Allied armies. Hence, it was not the yards-versus-bridges controversy which delayed until after the middle of March the initiation of an all-out air assault on communications but the demands of Anzio and the Fifth Army front and the hindering effects of consistently bad weather. After the failure of the ground troops at Cassino and the stabilizing of the Anzio sector, both fronts became quiet and so remained while the Allies began to regroup for a big offensive to be launched as soon as the winter rains were over. This freed almost all of the tactical air units from operations on behalf of the ground troops. At the same time flying conditions began to improve.9 On 19 March, MATAF issued a definitive directive for the interdiction program, which in code soon was appropriately designated Operation STRANGLE.10
The directive of 19 March, which followed in most respects earlier ones of 18 and 25 February, stated the purpose of STRANGLE as follows: “to reduce the enemy’s flow of supplies to a level which will make it impracticable for him to maintain and operate his forces in Central Italy.” It gave first priority to the destruction of marshalling
yards and repair facilities and charged Tactical’s medium bombers with carrying out the major part of this phase of the program. Specifically, their primary task was to attack railroads south of and including the Pisa–Florence–Pontassieve line and west of and including the Pontassieve–Arezzo–Orvieto–Orte line; secondary objectives (and weather alternates) were ports on the west coast and rail targets between Ventimiglia and Spezia. Strategic, whose first priority still would be POINTBLANK, was to hit marshalling yards in a few major cities in northern Italy through which flowed the bulk of men and supplies from beyond the Alps but which were outside the effective range of the mediums. Coastal would harass coastal supply routes.
The most interesting feature of the directive was the provision that XII ASC and DAF were to participate in STRANGLE. XII ASC was assigned to work on rail lines from Rome to Terni, Viterbo, Montalto di Castro, and south to the battle areas and from Orte to Orvieto. These operations were to be the primary mission of the light and fighter-bombers located around Naples, taking precedence even over cooperation with the ground forces.” In addition, the 57th Fighter Group was to move to Corsica with orders to attack rail and road communications south of the Pisa–Pontassieve line and west of and including Arezzo and Chiusi as well as a coastal strip from Spezia to Montalto di Castro. DAF was to hit lines from Terni to Perugia, Fabriano, and Pescara and from Pescara to Ancona.11
The decision to employ large numbers of fighter-bombers was based upon the principle that the success of STRANGLE would depend upon “simultaneous interdiction,”12 a phrase which meant that, irrespective of whether yards or bridges got top billing, complete interdiction could be achieved only if all lines leading south from the Po Valley were cut simultaneously. It was felt that to accomplish this the work of the mediums must be supplemented by that of fighter-bombers, which could operate on days when weather precluded missions by the mediums, cut stretches of open track, and smash motor transport when the enemy shifted the bulk of his supply from rails to roads. The scheme thus to employ the fighter-bombers was one of the significant experiments of the war in the use of a tactical air force to prepare the way for a large-scale ground offensive.
Another significant principle followed by the mediums and fighter
* With the entire battle front static and with the GAF very inactive, the ground forces needed little more than moderate defensive patrols.
bombers in STRANGLE – and one which made this interdiction program different from earlier ones-was that of attacking whole sections of rail lines rather than concentrating on a particular type of rail target.13 Instead of directing the effort primarily against bridges or yards, a whole system of bridges, yards, tunnels, defiles, even open stretches of track, was brought under more or less simultaneous attack. This plan of action indicates a failure by Zuckerman to win full approval for his idea of concentrating principally on rail centers. Although the directive of 19 March gave the mediums a first priority of hitting yards and repair facilities, as STRANGLE progressed the mediums paid more and more attention to bridges, and before the campaign ended their main effort was being directed toward that type of target. When STRANGLE was no more than two weeks old, Eaker reported that experience had shown the best way to cut lines of communication was by attacks on bridges and viaducts.14
Railways received primary consideration because in the last analysis road transportation in Italy was nothing more than a continuation or supplement of rail transportation, and since the invasion of Italy the maintenance and use by the Germans of railways had been “the main issue of all transport questions.”15 The objective of STRANGLE was to interdict rail transportation to the point where it could not supply the enemy’s needs and, when he turned to roads, to concentrate on that system of transportation. With both types of communications interdicted the enemy could not meet the supply requirements of a major campaign.
Because MAAF’s bombers had been working on lines of communication in central Italy since early in January in connection with SHINGLE and the Fifth Army offensive, it is difficult to give a specific date for the beginning of STRANGLE. In a sense, it represented simply a sudden and very large expansion of the old program, which, in spite of the constant demands on the air forces by the Anzio and Cassino fronts, had been carried on steadily – as is evidenced by the fact that in January and February more than one-third of the tonnage of bombs dropped by MAAF’s planes had been directed against communications and that between 1 January and 19 March the heavies had expended more than 2,500 sorties and mediums 133 missions against rail targets.16 For convenience, 19 March (date of the directive which set up STRANGLE) may be used. Almost two months later, on 11 May,
the operation merged into DIADEM, a ground and air offensive that broke the Gustav and Hitler lines.
During STRANGLE both fronts were quiet, which allowed the air forces to devote a full effort to communications. Medium bombers flew 176 missions against rail targets, 113 of them against objectives on the Florence–Rome line. This, the most important line in central Italy, was attacked at twenty-two different points between Florence and Orte; at nineteen of these points there were bridges. Nineteen attacks were directed against the Perugia–Terni–Orte line at five points of interdiction: four bridges and the yard at Terni. Seventeen attacks were delivered on the Empoli–Siena line; again four out of five points of interdiction were bridges. The mediums hit nine targets on the Pisa–Rome line a total of fifteen times; only four of the missions were against yards. The only low-level attack by mediums during STRANGLE was sent against this line on 15 April, when four B-25’s of the 310th Bombardment Group went in at 400 feet against a tunnel north of San Vincenzo.17
No other rail line received major attention from the mediums, although they flew four missions against three bridges between Marseille and Genoa, two against bridges near Acquaviva on the Sinalunga–Chiusi line, and one each against bridges at Pontedera and Fano and the yards at Prato and Avezzano. Mediums also attacked west-coast harbor installations as a part of the interdiction program, flying six missions against the ports of Leghorn and five against Piombino and San Stefano.18
As early as 24 March the mediums had cut every through rail line which supplied the German front, and with able assistance from fighter-bombers they kept them cut right through the last day of STRANGLE.19 Because of the demands of the ground forces, especially around Cassino, planes of XII ASC and DAF did not really get into full swing against lines of communication until April but thereafter they fully supplemented the work of the mediums.20 Their primary targets were bridges and open stretches of track, but they also went for supply centers, tunnels, and viaducts. On many days the fighter-bombers and light bombers were able to operate on a large scale when the mediums were grounded by weather. The extent of XII ASC’s operations is indicated by the more than 4,200 sorties which it flew against communications between 1 April and 12 May.21 Closely
allied to these attacks were missions by fighter-bombers and light bombers against supply dumps. Thirty such missions were flown in March, sixty-two in April, and seventy in May. Slightly more than half of these missions in April and May were flown by A-20’s of the 47th Bombardment Group, which were rarely employed in STRANGLE against rail or road targets.22
Desert Air Force, besides hitting targets similar to those attacked by XII ASC, harassed the enemy’s road movement by night attacks. But, whereas day attacks to cut communications were handled by as many as six groups of mediums and six of fighter-bombers, the same task had to be accomplished at night by only two squadrons of Bostons and two of Baltimores.23 The lack of a strong night bomber force was one of the principal handicaps to carrying out a fully effective interdiction program.24
Results of the operations by XII ASC and DAF were excellent, bearing out the belief that only by their supplementary efforts could “complete, simultaneous, and continuous” interdiction be achieved. The “little fellows” were remarkably successful against bridges – so long as they stayed away from the more massive ones – averaging 1 hit for every 19 sorties while the best that the mediums could average was 1 hit per 31 sorties. On one particularly good day the 57th Fighter-Bomber Group alone knocked out 6 bridges. On some days the fighter-bombers put as many as 100 cuts in rail lines, and for all of STRANGLE they averaged 30 cuts per day. On a number of days the combined efforts of the mediums and fighter-bombers resulted in more than 100 definite interdiction points on rail lines, and before STRANGLE was over the average number of cuts per day was 75.25
An examination of Tactical’s operations against rail lines shows that it worked largely against bridges; only about 12 per cent of its missions were against marshalling yards. This was a complete reversal of the pattern of operations from 1 January to 19 March, when two-thirds of all attacks by mediums had been against yards. The bridge-busting campaign justified the expectations of its proponents: as early as the middle of April no fewer than 27 bridges had been knocked out; on the vital Rome–Florence line (to use a single example), mediums and fighter-bombers had accomplished full interdiction well before the beginning of the Allied ground offensive in May simply by cutting the main bridges.26 Authentic reports from the Italian ministry of communications show that the most effective results in STRANGLE came
from the destruction of bridges rather than of yards because there was so little marshalling of trains. General Eaker considered that the campaign against bridges had been highly successful, as did Maj. Gen. Fred Anderson of the Eighth Air Force after a visit to Italy.27
Weather during STRANGLE was intermittently bad so that on al-most one-half of the fifty-three days the mediums were grounded or their missions aborted; they achieved their fine total of some 200 missions only because on a number of days the crews flew several missions.28 In compensation, Tactical’s planes conducted their operations without too much interference from the enemy. AA fire was light and spasmodic up to about 20 April, after which it was still generally spasmodic but at a number of points became intense, accurate, and heavy. Opposition by the Luftwaffe was not serious. Enemy fighters were encountered consistently only over the sector between Rome and Orvieto, and even there the fifteen to thirty-five fighters which usually came up seldom offered battle.29 In fact, throughout the seven weeks of the interdiction program MATAF’s planes were so little bothered by the GAF that mediums flew with no escort, or very little escort, and fighter-bombers were able to go out in small flights, some of which contained only four to eight planes.30 This allowed an almost constant stream of aircraft to operate over the interdiction area, a vitally important factor in the success of the program because it permitted simultaneous and continuous interdiction, while at the same time it gave the enemy’s trains and vehicles little chance to move without being attacked. One result was that bombing accuracy steadily improved; in three B-26 groups, for example, the average effort needed in November 1943 to achieve 1 hit on a bridge had been 59 sorties and 106 tons of bombs, whereas at the end of March 1944 it was only 31 sorties and 68 tons.31
One reason for the lack of opposition by the GAF could be traced to a well-planned and ably executed blow on 18 March by Strategic against fields around the head of the Adriatic. Three hundred and seventy-three heavies dropped more than 43,000 x 20-pound frag bombs on Udine, Villaorba, and three smaller airfields on which enemy fighters were heavily concentrated as the result of a preliminary sweep by Allied fighters and a clever ruse by a part of the bomber force. Claims were fifty-six enemy aircraft destroyed on the ground and twenty-three in the air by the bombers and seventeen shot down by the escorting fighters. Strategic lost seven bombers and three fighters.32
While Tactical bore the brunt of STRANGLE (in the last month of the operations its planes flew around 22,000 sorties)33 both Strategic and Coastal assisted with the program, although both had duties which carried higher priorities. Strategic worked largely against yards in northern Italy which were beyond the range of TAF’s planes. These provided increasingly lucrative targets, for supplies accumulated in the yards as a result of cuts in the rail lines south of the Pisa–Rimini line. The principal targets were at Padua, Verona, Bolzano, Turin, Genoa, and Milan, and these and other rail centers were attacked whenever weather or other conditions forbade operations on behalf of POINTBLANK. The high point in Strategic’s campaign was a series of seven missions in five days flown by the Fifteenth at the end of March. Three of the attacks – on the 22nd, 28th, and 29th – were especially heavy, involving a total of close to 1,000 effective sorties by heavies and featuring (on the 28th) the Fifteenth’s first “thousand-ton” raid laid on by planes from the 2nd, 97th, 98th, 99th, 301st, 376th, 449th, 450th, 445th, 454th, 455th, 456th, and 459th Groups. The seven raids inflicted tremendous damage on yards and adjacent industrial targets at Verona, Mestre, Turin, Bolzano, Milan, Bologna, and Rimini, while a number of through lines were blocked. These daytime operations were complemented by the night-flying Wellingtons and Liberators of RAF 205 Group. On the 28th’ six heavies from the Fifteenth tried low-level (200 feet) attacks on the Fano and Cesena bridges, but the experiment was such a signal failure that thereafter the heavies stayed at their proper altitude.34
In April good weather over German industrial targets and Balkan rail centers allowed Strategic’s heavies to devote most of their effort to POINTBLANK and to cooperation with the Russian armies. This resulted in two changes in the pattern of SAF’s operations against Italian lines of communication. The emphasis was shifted from day attacks by heavies to night attacks by mediums, and from yards to ports. During the month heavies struck only three major blows against rail lines: on the 7th against yards on the Udine–Florence line, on the 20th against bridges at Fano and near Udine and the yards at Ancona, and on the 30th against very congested yards at Milan and Alessandria. Results everywhere were good. Meanwhile, Wellingtons operated against ports on almost half of the nights in the month; targets were San Stefano, Piombino, Leghorn, and to a lesser extent Genoa, Spezia, and Malfalcone. Day attacks by Strategic on ports were few in number, but included
a major assault on 28 April when 168 heavies hit San Stefano with 418 tons, 108 hit Orbetello with 267 tons, and 188 hammered Piombino with 563 tons, the blow on Piombino being supplemented by 34 B-25’s and 98 P-47’s which dropped 100 tons. On the 29th, 573 heavies dropped 1,312 tons on Toulon harbor; the mission involved the largest number of bombers dispatched and the greatest weight of bombs dropped on a single target in the theater to date.35 In the first eleven days of May bad weather so hampered Strategic that it flew only one heavy bomber mission against Italian communication targets, and that was largely spoiled by that same weather.36
A recapitulation of the Fifteenth’s operations during STRANGLE shows that its heavies dropped more than 5,000 tons of bombs on communications. They hit ten major targets, damaging trackage, rolling stock, and installations and blocking – at least temporarily – most through lines. At Milan, in particular, the attacks were most successful. It is important to note, however, that Strategic’s attacks on yards accomplished only a small reduction in the enemy’s flow of supplies, for main through lines were quickly repaired or traffic was diverted to bypass lines. The truth is that it was the work of Tactical’s mediums and fighter-bombers against bridges, rail lines, and M/T that made STRANGLE a success.37
Coastal Air Force rounded out the interdiction program by taking care of ports and coastal shipping. During the whole of STRANGLE it laid on around fifty attacks on nineteen ports; fighter-bombers delivered most of them. B-25’s of the 310th Group added to the pressure during March, and Wellingtons and Beaufighters made it an around-the-clock offensive with night raids.38 The latter type of operation assumed increasing importance as Tactical’s successful interdiction of rail lines forced the enemy to put more dependence on transport by sea, especially in F-boats* which moved mostly at night so as to take advantage of a principal Allied weakness, MAAF’S lack of night bombers. For all of STRANGLE, Coastal claimed the sinking of more than 50 craft and the damaging of over 100 in the coastal stretches of the Ligurian and Tyrrhenian seas and along the coast of southern France. It was estimated that this offensive, together with Strategic’s blows against ports, kept to less than 700 tons per day the amount of water-borne supplies reaching Italy. Equally important, these operations against ports contributed to Coastal’s steady campaign against submarines,
* A shallow landing craft, about 120 feet long.
which by the end of April had been pretty well eliminated as a threat in the Mediterranean39
Coastal also paid some attention to land communications. It attacked motor convoys and hit rail targets. It made sixty-three attacks, most of them by the 310th Fighter Group, on bridges; nineteen structures were left impassable, fifteen were damaged, and eight had their approaches blown up. Meantime, 242 Group, which was the wholly British element of Coastal, carried out from its bases in eastern Italy a strong offensive which covered the Adriatic Sea from end to end.40 242 Group – as well as Troop Carrier, which was dropping supplies and personnel to Yugoslav Partisans – found useful a landing strip built on the Dalmatian island of Vis by engineers; as many as 120 planes were refueled in a day at this forward base. The extent of Coastal’s operations is indicated by the fact that in March its several elements flew 3,500 sorties, and in April around 2,250; and that for the whole of STRANGLE it claimed the destruction of more than 100 motor vehicles, locomotives, and surface craft and the damaging of over 200.41
After the war Kesselring expressed the opinion that STRANGLE might have come closer to achieving absolute interdiction if MAAF had concentrated its attacks on certain key points.42 The opinion is highly debatable, especially since the system which MAAF used certainly blocked the lines most effectively – just how effectively is demonstrated by the fact that before STRANGLE came to an end all rail lines as far north as the line Cecina–Fano were blocked and no through traffic approached closer than fifty miles above Rome.43
The accomplishment becomes the more impressive when it is remembered that as STRANGLE progressed the enemy made frantic and skilful efforts to repair his rail lines and to construct by-passes. He tried transshipping around breaks and shuttling trains over open segments of track, but neither scheme greatly improved his situation, for he was never quite able to keep up with the damage inflicted by MAAF’s planes. Then he began to depend more and more on motor transport which he first used to “bridge” cuts in rail lines by carrying supplies from one train to another. When, in time, the strain on his repair facilities and the damage to his lines became so great that he had to abandon whole sections of track, he turned very largely to roads in order to move troops and supplies over long stretches. Well before the end of STRANGLE the rail lines were in such bad shape that most
movement below the Pisa–Rimini line was by motor transport alone, and a large part of that was over secondary roads.
As soon as the Germans began to shift from rails to roads Tactical’s fighters and fighter-bombers, bombing and strafing, ripped into the enemy’s motor transport. By 11 May they had destroyed an estimated 800 vehicles and damaged close to 1,000. Although the Germans supplemented their own M/T with several thousand requisitioned Italian vehicles (whose drivers proved to be distressingly unreliable) by the end of STRANGLE the destruction wrought by MAAF’s planes, together with overuse and inadequate repairs, had taken such a heavy toll that the enemy’s road transport was incapable of handling the demands of both the forward and rear zones of communication. Nor could he improve the situation by an increase in coastal shipping, for MAAF’s attacks on ports and surface craft had reduced that type of transportation to an unimportant minimum.44
It is true that the enemy’s shift of much of his transportation from rail to road in the month before the Allies renewed their ground offensive enabled him to maintain extensive lines of communication, but it is equally true that this was at the expense of local distribution immediately behind the front and at the cost of hundreds of vitally important motor vehicles. It could be expected, then, that when the Allies unleashed their ground offensive Kesselring would find himself unable to shift men and supplies into, out of, or along the battle front quickly enough to meet constantly and rapidly changing situations. Too, with the enemy depending so heavily on motor vehicles, MAAF could concentrate on roads during the ground offensive to the further discomfiture of a Wehrmacht which could not always wait until night to move.45
After the Allied armies launched their ground offensive in Operation DIADEM on 12 May and swept past Rome, the results of STRANGLE became a matter of record, and even before that many of them were evident. Up to the very end of STRANGLE, a static battle front permitted the enemy, by carefully husbanding his stores, obtaining food at the expense of the Italians, and moving in supplies under cover of darkness by whatever means, to retain and maintain all of his forces on the peninsula.46 But the air attacks had so disrupted transport that the enemy was existing on fewer than 4,000 tons per day – which was 1,000 to 1,500 tons less than he would have to have during
an Allied ground offensive. with his lines cut and his transport crippled, it would not be possible to meet the full needs of a protracted battle. Already he lacked enough food and clothing. Motor fuel and some types of heavy ammunition were severely rationed, fuel being down to a ten-day supply. Military transport and heavy equipment were either in short supply or badly scattered, and the movement of supplies and reserves was exceedingly difficult. Units coming down from the north were forced to proceed by motor transport, horse-drawn vehicles, or on foot for long distances and were so often under air attack that they reached the battle area only after suffering heavy casualties, losing much of their equipment and vehicles, and being so dispersed that unit integrity was impossible. Many tanks, unable to get gasoline because of the shortage of transportation, had to be towed by oxen.47
For almost two months Tactical, Strategic, and Coastal had staged the largest program of interdiction of lines of communication ever attempted up to that time.* The purpose of the program was to make it impossible for the Germans to stop an all-out Allied ground offensive. When STRANGLE came to an end on 11 May, such an offensive was ready to jump off. The effectiveness of the interdiction program was to be given an immediate test.
DIADEM and the Capture of Rome
The decision to launch a full-scale ground offensive on 12 May† and to press the offensive beyond Rome had been made less than a month before D-day, and made then only after sharp disagreement between the Americans and the British. The basic reason for the difficulties over DIADEM was that all operations on the peninsula were tied up with the projected invasion of southern France (Operation ANVIL) which was to complement the cross-Channel invasion of France, currently scheduled for some time in May. In large measure the Anzio landings and the strenuous efforts to break through at Cassino had been for the
* During STRANGLE (19 March-11 May ) MAAF’s operations against lines of communication, including ports, totaled about 50,000 effective sorties and around 26,000 tons of bombs. In all operations during the period its planes flew close to 65,000 effective sorties and dropped 33,000 tons of bombs. Of these the USAAF accounted for 36,000 sorties and 26,000 tons. (MAAF, Operations in Support of DIADEM, Vol. VII, Annex V.)
† Technically, DIADEM started at 2300 hours on 11 May, when the Allies began a forty-minute artillery barrage. But because the ground troops did not push off until the morning of the 12th this writer prefers that date for the beginning of the offensive.
purpose of clearing the way for ANVIL; their failure further complicated an already complex situation by giving the Fifth Army two fronts instead of one, tying down troops earmarked for ANVIL, increasing logistical problems, and adding to the burdens of the air force. By March these conditions demanded that plans for future operations in the Mediterranean be re-examined.
General Wilson, as has been noted above,* had recommended in February that ANVIL be canceled, but Roosevelt, Churchill, Eisenhower, and the U.S. and British chiefs of staff had decided instead that it would stay on the planning agenda as first alternative to the Italian campaign at least until 20 March, at which time the situation in the Mediterranean would be reviewed.48 By that date matters had not improved, and Wilson again pressed for cancellation of ANVIL, with the warning that there was no hope of a junction of the two Fifth Army fronts before 15 May, which would be too late by several weeks to permit ANVIL to be launched concurrently with OVERLORD. Wilson was supported by Eaker, who was afraid that ANVIL would take so many long-range fighters out of Italy that it would jeopardize the Fifteenth’s strategic bomber offensive, and by Slessor, who “hated” ANVIL and preferred an offensive in the Balkans.49 The British chiefs also agreed with Wilson. But the American chiefs insisted that ANVIL be deferred, not canceled; they proposed to start an offensive in Italy earlier than 15 May, unite the main front with Anzio, continue heavy pressure on the Germans in Italy, threaten southern France with an amphibious operation while OVERLORD was being launched, and then set the real ANVIL in motion not later than 10 July. Because of the need for an immediate decision, however, the Americans accepted an indefinite postponement of the invasion of southern France and agreed that the land battle in Italy should remain the mission of first priority.50 On 18 April, General Wilson was given a directive to that effect and told to launch an all-out offensive in Italy as soon as possible for the purpose of giving maximum support to OVERLORD.51
Wilson already was well along with preparations for such an offensive, the most important of which involved moving the greater part of the Eighth Army into the Cassino sector alongside the Fifth Army as a preliminary to an assault from Cassino to the Tyrrhenian Sea. It was also decided that a part of DAF would operate in the west with XII ‘Tactical Air Command (XII TAC, formerly XII Air Support Command),
* See above, pp. 364-65.
the latter to be responsible for coordination with the Fifth and Eighth Armies until the course of the land battle allowed the reestablishment of the old Fifth Army-XII TAC, Eighth Army-DAF combinations.52
The decision to launch DIADEM as soon as practicable caused no change in the activities of the air forces, which kept right on hitting lines of communication. By mid-April the success of STRANGLE had become so evident that clearly the best contribution which the air arm could make to the approaching ground offensive was to continue the program.53 Accordingly, when the outline air plan for DIADEM was issued on 28 April, two of the three principal jobs given to the air forces were simply continuations of STRANGLE: to keep the GAF in its present state of ineffectiveness; to maintain the current interruption of supply lines and by increased activity so to reduce the supplies available to the enemy’s forward troops that they could not possibly offer sustained resistance to the ground offensive. The third job, which would only begin with DIADEM, was to assist the land battle by normal close support. Tactical Air Force, which would bear the brunt of the air phase, would operate generally from the battle line to the Pisa–Rimini line, Strategic north of it; Coastal would attack shipping and ports. Later directives made no important changes in these basic assignments.54
Beginning at 2300 hours on the night of 11 May, the main Fifth Army and a part of the Eighth listened to a barrage from more than a thousand guns roll across the front from the Tyrrhenian Sea to Cassino.55 Early on the 12th the ground troops jumped off along the narrow front. Polish troops drove into the ruins of the Abbey of Monte Cassino; the British and Canadians swept across the Rapido and into the Liri Valley; the French made spectacular gains across the Garigliano, breaching the Gustav Line; the Americans, on the Tyrrhenian flank, moved forward against stubborn resistance. By the 14th the enemy was in retreat, although slowly; by the 19th all of Cassino was in Allied hands and the Gustav Line was thoroughly broken, while along the coast the U.S. II Corps had taken Formia and Itri. On the 22nd the British and the French broke the Hitler Line, and Kesselring went into full retreat.56
With nice timing, Fifth Army’s VI Corps at Anzio launched an attack on the 23rd against German forces stripped of reserves to support the southern front. Aided by more than 700 air sorties the troops
quickly broke out of the bridgehead, cutting Highway 7 below Cisterna. Next day, the town was virtually encircled. On the 25th it fell, and during the day patrols from Anzio and the main Fifth Army front linked up. Now Anzio was paying dividends. The German retreat threatened to become a rout.57 With his established defense lines lost, his reserves fully but vainly committed, his transportation inadequate, and his forces under constant air attack, the enemy was faced with the delicate task of attempting a coordinated withdrawal on a fluid front. The task proved not only delicate but impossible.
By 1 June the Allies had captured Frosinone, Arce, Sora, and Carroceto. Kesselring now hoped to check the Allied advance at a hastily formed defensive line extending from Velletri to Valmontone, and General Alexander thought that his own forces might have to halt, rest, and regroup before the tired divisions of the Fifth and Eighth Armies could break through. But at this point the full impact of the air force’s long interdiction campaign hit the Germans: their reserves of the two all-important commodities – fuel and ammunition – had fallen below the danger point and the state of their transport made adequate distribution from depots impossible; this, with the delays and disorganization imposed on reserve units by air attacks broke the enemy’s back. The Americans quickly overran both Velletri and Valmontone, and early on the 4th seized Centocelle, just east of Rome. Farther to the east, British troops took Alatri, Indians took Veroli, and New Zealanders drove up Highway 82 toward Avezzano. On the evening of 4 June American troops entered Rome.58
For the first three days of this advance the combat elements of MAAF worked not only to maintain the destruction and disruption already caused to lines of communication but also directly to support the ground forces driving against the Gustav Line. MAAF’s great superiority over the GAF – its almost 4,000 combat aircraft outnumbered the Luftwaffe in Italy by at least 10 to 1 – allowed it to operate with almost complete freedom. On D-day, Strategic struck briefly but viciously at Kesselring’s headquarters and the headquarters of his Tenth Army, then went for northerly yards and ports, hitting Spezia, San Stefano, Piombino, Civitavecchia, Trento, Bologna, and a dozen other targets in an assault which lasted through D plus 2. Results generally were good. Tactical’s mediums* and fighter-bombers pounded
* Except for a few B-26’s in the RAF’s Desert Air Force all B-26’s were flying from Sardinia, and all B-25’s from Corsica. Both were given fighter escort by Tactical’s 87th Fighter Wing (based on Corsica), which also attacked targets in western Italy south of Florence. Thus the Allies had a bomber and a fighter force operating off the enemy’s right flank. (See 87th Ftr. Wing Historical Records, in MATAF Operations Record Book, 1944, pp. 16–19, 21, 23, and History, 57th Bomb. Wing.)
objectives close to the front: command posts, strongpoints, gun positions, concentrations, bridges, defiles, and towns. A major accomplishment was the creation of road blocks to restrict the enemy’s mobility. Light and fighter-bombers worked in close coordination with the ground troops, their principal task being to silence the enemy’s two main gun areas, in the Liri Valley and around Atina. Tac/recce squadrons, flying almost continuous patrols, kept the guns under constant observation. Fighter-bombers, operating directly with the ground forces, were aided materially by spotters (Rover Joes and Davids);* one such element, atop Mt. Trocchio, controlled nine fighter-bomber missions on 12 May alone. Fighters patrolled the entire front but found the GAF little in evidence. For the three days MAAF’s planes averaged 2,700 sorties per day.59
As soon as the ground troops were rolling (14 May and after) Tactical’s mediums returned to operations which were simply a continuation of STRANGLE. Its B-26’s raised their sights to rail lines between Spezia and Rimini; the B-26’s did likewise, then shifted temporarily to road junctions, then returned to the railways. The most important lines in the Spezia–Rimini area were from Bologna to Florence and from Parma to Pisa. These were attacked and blocked by the end of the first week of DIADEM.60 Below them the fighter-bombers of XII TAC and DAF reblocked lines which the enemy had repaired since the end of STRANGLE; by 20 May cuts were claimed at ninety-two points. Bad weather from the 20th to the 23rd hindered the mediums, and in spite of all that they and elements of Strategic could do the Germans were able to reopen the Florence–Arezzo–Rome line as far south as Orte and to clear the Perugia–Spoleto by-pass. But on the 24th, a day which saw Tactical’s planes set a new record of 1,791 sorties, B-26’s reclosed the Florence–Orte line by cutting the Pontassieve bridge, and the next day blocked the line at eleven different points. By this time MAAF’s three “specialist” groups of bridge-busting mediums (310th, 321st, 340th) were putting one direct hit on bridges for every twenty sorties.61
During the last week of May the mediums divided their attention
*Rover Joes (US.) and Rover Davids (British) were spotters who used a jeep equipped with a VHF set which put them in communication with aircraft, airdromes, or air headquarters and with ground troops; operating from an observation post overlooking the battle area they coordinated air-ground operations.
between targets just below Rome and objectives on the west-coast, east-coast, and northern Apennine rail routes as well as the more immediately important lines in central Italy. Their work south of Rome helped to make an enemy stand impossible, while above that city on 1 June, in spite of excellent repair work by the Germans, there were 124 cuts (47 of them major bridge cuts), which was the highest point of interdiction yet achieved.” For a time, only one route was open between the Po Valley and central Italy. By the end of May the enemy had abandoned large sections of lines and was concentrating his repairs on a few key segments, notably the main lines Chiusi–Florence–Bologna and Foligno–Fano–Rimini–Bologna, which had both a supply and an escape value. Nonetheless, in the first week of June, MAAF maintained the interdiction of the western and central sectors. All lines in the central area were thoroughly blocked, except for the line Florence–Terontola–Orvieto, where single-line traffic was possible. On the east coast, where lines were less heavily attacked, the enemy was able to effect repairs which kept rail traffic moving at least as far south as Rimini62
In the first week of DIADEM light and fighter-bombers had worked mostly against close-in targets such as command posts, strongpoints, guns, and troop concentrations. In the second week, as the Anzio and southern front forces approached one another, intensive and effective air-ground coordination was achieved.63 When the two fronts were joined the light bombers went back to dumps while the fighter-bombers began the armed reconnaissance missions which were to be their principal type of operation for the next several weeks. Mostly, the fighter-bombers sought targets of opportunity, which turned out to be motor transport and troop concentrations on the congested roads, for targets such as supply dumps, command posts, and strongpoints became scarce as Allied ground troops overran German positions and kept the enemy in constant retreat. Fighter-bomber attacks on roads, rails, and bridges powerfully implemented the medium’s interdiction program. The planes gave Kesselring’s reserves, moving down from the north, a severe mauling; in fact, as Slessor later pointed out, the inability of the Germans to establish the so-called “mass of reserves or to coordinate
*An analysis by MAAF’s Operational Research Section of medium and fighter-bomber attacks on railways between 17 March and 31 May revealed that pilots’ reports of damage were usually too low in comparison with reports from the Italian state railways, Partisans, and photo interpretation.
divisional counter-attacks, both of which are so vital to the halting of an offensive,” was the result of the Allies’ destructive air attacks. Occasionally, elements of XII TAC and DAF were called on to assist in breaking up some particularly stubborn bit of resistance or in checking a local counterattack; and before each major ground attack, aircraft destroyed the enemy’s system of control by bombing headquarters and also restricted his power of movement close to the battle area by attacking signals systems, command posts, communications, dumps, vehicle parks, and repair shops.64 Cooperation between ground and tactical air forces was excellent. Mediterranean Allied Photographic Reconnaissance Wing (MAPRW) further aided the ground forces by flying in the first week of DIADEM around 160 direct cooperation sorties, half of them at the request of the ground troops, a scale of operation which was maintained throughout the next several weeks65
After the first few days of DIADEM, Strategic’s participation in the Italian campaign dropped off sharply as it returned to its primary objectives: POINTBLANK targets around Vienna, oil and communications in the Balkans, and support of Yugoslav Partisans. However, up to the fall of Rome, it aided Tactical’s campaign against supply lines by a few attacks on yards between Piacenza and Bologna and Faenza and Cesena, and on the trans-Alpine supply routes, particularly the Brenner Pass line. These attacks, which were closely coordinated with the operations of Tactical in central Italy, resulted in cutting the two main lines into northeast Italy: B-17’s cut the Brenner Pass line; Wellingtons cut the Tarvisio line, and when the enemy partially repaired it the 483rd Bombardment Group’s B-17’s promptly recut it by knocking out two spans of the Casarsa bridge. In addition, two attacks on Spezia and two on Porto Marghera damaged both communications and oil tanks, while sharp blows on the night of 16/17 May by Wellingtons and on the 17th by B-24’s of the 98th, 376th, 450th, 451st, 460th, 461st, 464th, 465th, 484th, and 485th Bombardment Groups laid heavy destruction on Piombino, San Stefano, and Porto Ferraio (Elba) harbors.66
Strategic also flew two special sets of missions on behalf of the ground offensive. From the 22nd to the 26th of May as VI Corps broke out of Anzio, Strategic devoted most of its effort to troop movements, communications, and other military targets in the rear of the battle area and in central Italy.67 On 25 May, when heavies hit three yards in the Lyon area and one at Toulon, Strategic began a series of attacks on lines of communication in southern France. On the 26th and 27th the Fifteenth, with every bombardment group participating, dropped more
than 3,000 tons of bombs on eight yards (and two airfields) between Lyon and Marseille. Then on 4, 5, and 7 June a total of 1,400 heavies with plentiful escort hit the Antheor viaduct near Nice, the Var River bridges north of that city, the Recco and Vado viaducts south and west of Genoa, yards at Genoa, Bologna, Turin, Forli, and Novi Ligure, port facilities and shipping at Genoa, Voltri, and Leghorn, and other communications targets. Damage was severe to the viaducts and bridges and to the yards at Genoa and Bologna and effective, although moderate, elsewhere except at Antheor. The attacks between Lyon and Leghorn were for the purpose of interfering with the movement of reinforcements from southern France to Italy; at the same time they were an important part of the Allied preparations for OVERLORD68 and, in the long-range view, were preliminary to ANVIL.
Although Tactical carried the brunt of the interdiction and support programs, it received strong assistance from Coastal Air Force. Coastal’s primary responsibility was to protect the sea lanes from Gibraltar to Greece, but MAAF’s bombing of submarines and facilities had so reduced the German threat to Allied shipping by the beginning of DIADEM that CAF was able to devote a very large part of its activities to offensive operations over the Italian mainland and to the enemy’s effort to supply his troops by sea. The 63rd Fighter Wing (USAAF, but including units of RAF, SAAF, RAAF, and FAF), flying from Corsica, hit shipping in the Ligurian and Tyrrhenian seas, the western Mediterranean, and along the coasts of western Italy and southern France; over the Italian mainland it attacked installations, dumps, docks, warehouses, yards, gun positions, radar stations, headquarters, bridges, trains, airfields, factories, motor transport, and other targets. Its British counterpart, RAF 242 Group, based in eastern Italy, hit similar targets along both sides of the Adriatic; it also aided Tito’s Partisans until July when a special air force” took over that responsibility.69
During the advance on Rome, Troop Carrier’s principal job was the evacuation of wounded. Its only offensive mission in DIADEM was to fly one small paratroop mission (Operation HASTY), in which eleven aircraft dropped sixty-one paratroopers near Trasacco on the night of 1 June. The drop was successful but the troops were unable to accomplish their objective of preventing the destruction of bridges on the Sora–Avezzano road by the fleeing Germans.70
The tasks of carrying out the interdiction program and of cooperating
* See below, p. 399.
with the ground advance from 11 May to 4 June were made infinitely easier by the weakness of the German Air Force. There were only about 325 enemy aircraft in central and northern Italy at the beginning of DIADEM, as contrasted with close to 4,000 Allied planes in the Mediterranean.71 Obviously the Luftwaffe could not pose much of a threat either to Allied ground troops or to mediums and fighter-bombers flying against communications. Nevertheless, MAAF played safe by occasionally blasting airfields. On 14 May the 99th, 463rd, 456th, and 459th Bombardment Groups, escorted by P-51’s of the 31st Fighter Group, dropped 368 tons on Piacenza airfield and 135 tons on Reggio Emilia. These were the only large-scale counter-air attacks against Italian bases until July, although many forward fields as well as some farther north were targets for bombing and strafing attacks, mostly by fighter-bombers.72 Outside of Italy the largest collection of GAF offensive planes within reach of the battlefield and Allied convoys in southern France, where the enemy had an estimated 210 planes, 155 of which were long-range bombers. On 27 May, primarily as a diversion for OVERLORD, 246 B-24’s mauled Montpellier/Frejorgues and Salon airfields with 515 tons. This was the only significant attack on French landing grounds until after the fall of Rome.73 Nor were more attacks necessary, for the GAF effort over Italy never reached 200 sorties a day throughout DIADEM, and averaged scarcely more than 50.74 The enemy’s outstanding bomber operation came on the night of 12/13 May when Ju-88’s hit the Corsican fields of Poretta and Alesan in a powerful and effective double attack, destroying twenty-three planes and damaging close to ninety and killing more than a score of personnel. Even so, B-25’s of the badly injured 340th Bombardment Group at Alesan flew a mission the day after the attack. Other GAF offensive operations consisted of a single raid on a convoy off Algiers, a few weak and ineffective passes at Allied bases (such as Naples), some small raids on communication points, and one or two attacks during the first week of DIADEM by Ju-88’s on ground targets around Minturno-the first time the enemy had used such planes in direct support of his troops. Targets included road movement, concentrations, and communications centers. For a time the night-flying Ju-88’s continued this limited aid to the ground forces, but early in June they were withdrawn for use in France. Their place was taken by some forty shorter-range Ju-87’s, whose activities steadily diminished in the face of losses inflicted by Allied night fighters and AA. Both the Ju-88’s
and 87’s worked on such a small scale that they accomplished little.75
German fighters made little effort to interfere with the activities of MAAF’s medium and light bombers, fighters, and fighter-bombers. Even Strategic’s heavies saw few fighters over northern Italy and those which did appear were remarkably lacking in aggressiveness. On the eve of the fall of Rome the GAF had begun to withdraw its planes to fields around Perugia, Siena, and Pistoia, and its fighters had all but disappeared from the battle area by day.76 As a result, MAAF’s claim of enemy aircraft destroyed rarely exceeded five in any one day, and totaled only 176 claimed destroyed, 44 probably destroyed, and 93 damaged for the period 12 May-22 June. Against these small losses, MAAF lost 438 planes, virtually all of them to flak, as the enemy concentrated his AA guns at key points on his lines of communication77 Actually, MAAF’s losses in terms of sorties was small. In the first week of DIADEM, for example, it dispatched around 20,500 aircraft. From the beginning of STRANGLE to 22 June its planes flew some 137,000 sorties and dropped around 84,000 tons of bombs in all types of operations, better than two-thirds of its effort being against lines of communications and ports in Italy. Since the first of May the Fifteenth, although only about one-half the size of the Eighth in heavy bomber strength, had almost equaled the latter in number of sorties and bomb tonnage78
The weakness of the GAF, together with MAAF’s counter-air operations, gave the Allies real air supremacy during the drive on Rome. Troops, supplies, even headquarters, moved with complete freedom – a matter of the greatest importance in the fast-moving campaign. Headquarters of Tactical, for example, was at Caserta on 11 May, moved to Frascati around 15 June, and at the end of the month was at Lake Bolsena. Headquarters of XII TAC, within a 30-day period, was successively at San Marco, Sermoneta, Rome, and Orbetello79 Combat air units also moved steadily northward, thanks to the rapidity and skill with which new airfields were made available. Only a few of the fields captured from the enemy met the operational requirements of Tactical’s planes – as late as July only two such fields were being used and they had undergone alterations-and, in addition, all were badly damaged, so that the only answer to the demand of the fighters and fighter-bombers for more northerly fields was to build new ones. On an average the engineers built a field in five days. Many were constructed within range of enemy guns; on one occasion an engineer survey party
actually got ahead of the infantry, was captured by Fifth Army troops and was held prisoner for a time, it being difficult to persuade the ground troops that anything could get ahead of them80
While the Allies moved with complete freedom, every move of the enemy was made with the keenest difficulty and usually was attended with severe losses. This was especially true after 24 May. Then, with the enemy’s rail lines in such bad shape that he was forced to depend almost wholly on M/T and with his ground forces so close to disaster that he could not wait for darkness to move them, Allied bombers created road blocks which forced traffic jams; fighters and fighter-bombers blasted the jams with bombs, cannon, and machine guns.81 Allied armies in Italy noted after the fall of Rome that the success of the air attacks on transport “is now obvious from the wreckage to be seen all along the road” ; yet so great was the destruction that the airmen’s reports of vehicles and equipment destroyed would not have been credited had not their claims frequently been confirmed by ground force survey parties. For example, the air force claimed the destruction of 117 motor transport and armored vehicles on a short stretch of road near Forli; the ground forces counted 122 blown up or burned out by air attacks82 In three days (4, 5, 6 June), as the Germans took wholly to roads in a desperate effort to escape to the Pisa–Rimini line, almost 1,100 vehicles were destroyed and more than 1,100 damaged.83 Thereafter, the toll of motor transport fell off rapidly; the enemy simply had lost so many of his M/T that very few were left to serve as targets. By the end of DIADEM (22 June) the air forces claimed to have destroyed more than 5,000 vehicles and damaged another 5,000 in the six weeks since 12 May.84
In April, General Eaker had predicted that the interdiction campaign would so weaken the enemy that when the ground forces struck they would simply “be following a German withdrawal made necessary by his inadequate supply.”85 Events had proved that there was much truth in his prediction, although it cannot be forgotten that when the Allied armies did strike it was on such a narrow front and with such superior strength that it is doubtful if the Germans could have prevented a breakthrough. But it is certain that the collapse of enemy transport, especially the breakdown of local distribution immediately behind the front, greatly accelerated the Allied breakthrough as well as the pace of the advance on Rome which followed, a fact which the ground forces fully recognized and appreciated.86 As the Allies swept
into and then beyond Rome, it was evident that the enemy’s front line troops were seriously short of fuel, ammunition, clothing, food, and M/T. So much of his M/T was committed to the haul of supplies south from the Po Valley and Florence that not enough remained to take care of the needs of his forward troops; nor could Kesselring move his troops-or bring in reinforcements-with the speed and certainty which the battle demanded. Local shortages, of men as well as supplies, became common, and when the Germans, in a desperate effort to relieve the situation, put their M/T on the roads during daylight, MATAF’s fighter-bombers simply made the enemy’s transportation problem the more critical.87
DIADEM did not end officially until 22 June, but as early as the 4th of the month (when Rome fell) it was possible to draw several conclusions from the air phase of the operation and its predecessor, STRANGLE. The first point to note is that the ultimate objective of STRANGLE, which was to make it impossible for the enemy to maintain his armies south of Rome, could not be achieved until the Allied armies in Italy forced him into a real battle. As Slessor put it, air power “can not by itself enforce a withdrawal by drying up the flow of essential supplies” when the enemy “is not being forced to expend ammunition, fuel, vehicles, engineer stores, etc. at a high rate.”88 But as soon as the Germans were involved in a major fight it was immediately evident that STRANGLE had fully accomplished its purpose: the interdiction of supplies, the cutting of rail lines, and the destruction of motor vehicles had so crippled the enemy that he speedily used up his stores and motor transport, lost his mobility, and had no choice but to retreat. The effects of STRANGLE then turned an orderly withdrawal into a rout. The second point is that bombing policy against lines of communication must not be oversimplified. Zuckerman was wrong when he limited targets to one type, rail centers; but MATAF would have been equally wrong had it attacked bridges to the exclusion of everything else. Sound bombing policy calls for a balanced program of attacks, with emphasis at any one time to be dictated by geographic, economic, and military considerations.
Two other points are worth mentioning. When the ground forces are rolling and when they are encountering no effective enemy air opposition, it is best for their own tactical air force to concentrate on the enemy’s supply lines rather than on close support of ground operations. DIADEM also proved again the principle which had been
demonstrated repeatedly during the past year-that tactical air operations are most effective when air and ground are coequal partners, neither dominated by the other but both working toward a common objective89
From Rome to the Arno
Prior to the capture of Rome the Fifth and Eighth Armies had advanced along a narrow front, roughly from the west coast to Highway 6, while 5 Corps of Eighth Army had moved up the east coast. After the fall of Rome the Fifth Army moved north-northwest along the axis Rome–Viterbo–Siena, with its principal objectives the Viterbo airfields, the ports of Civitavecchia and Leghorn, and the Arno River; the Eighth advanced northeast along the line Rome–Terni–Foligno Perugia, with its main objective the city of Florence, while its 5 Corps continued up the east coast, ultimately rejoining the main Eighth90 Hence, in the second phase of the drive from the Gustav to the Gothic line the main battle front expanded laterally so that the operational areas of the Fifth and Eighth became distinct and separate. It then was more efficient to divide operational control of the units of Tactical Air Force between two commanders, each responsible for air operations in support of a separate army. Under this arrangement XII TAC again became responsible for operations with the Fifth Army and Desert Air Force for the Eighth and its 5 Corps.* The operational boundary separating the two air forces was identical with the boundary between the two armies, and each of the air organizations set up its headquarters in close proximity to that of the army with which it was working, But XII TAC and DAF maintained close liaison, and each was prepared to support the other when the situation demanded and resources permitted91
The division of responsibility between XII TAC and DAF was concerned primarily with direct tactical operations by fighters and fighter-bombers But since the first duty of all elements was to impede the enemy in his efforts to escape the Allied armies, they not only worked closely with the two armies but also with MATAF’s mediums which, while hampering the German withdrawal, were primarily concerned with disrupting communications in the general area above Pisa–Arezzo–Fano.92 From 4 to 17 June, while the ground forces drove beyond
* The 87th Fighter Wing was to attack sea communications along the Italian west coast and communications above the Pisa–Rimini line; DAF was to take care of sea communications on the east coast.
Rome toward Viterbo and Rieti, Tactical’s planes kept interdiction in a very satisfactory condition. On the 15th, for example, there were seventy-eight effective rail blocks. All lines between the Po Valley and Florence were blocked, while the east-coast route was cut at three points. The very important Florence–Orte and Empoli–Siena lines, in spite of strenuous German efforts to repair them, were kept blocked by mediums and fighter-bombers. As a result of the continuing interdiction Kesselring’s forces found themselves increasingly short of supplies, especially fuel and transport.93 Then ten days of bad weather from 17 to 28 June so interfered with Tactical’s operations – its planes flew only 175 to 200 sorties on the 18th – that the enemy was able to open the Bologna–Pistoia and Bologna–Prato lines. However, the other central Italian routes and the east and west-coast routes remained cut to the end of the month so that the enemy was unable materially to improve his wretched supply situation.94
Strategic, which on 2 June had made history by inaugurating shuttle bombing via Russian bases,* concerned itself very little with Italy in the two weeks following the fall of Rome. The ten days of bad weather at the end of the month grounded its planes even more thoroughly than Tactical’s, so that it was able to operate only on two days. But on one of them it struck a mighty blow against Italian lines of communication. The enemy was taking full advantage of the weather to rush repairs on his battered lines, and Strategic’s blow came at the right time. On the night of 21/22 June, 55 Wellingtons, 8 Halifaxes, and 2 Liberators hit the Ventimiglia yards with excellent results. Next day 580 heavies, protected by 513 fighters, dropped close to 1,400 tons of bombs on yards at Parma, Modena, Bologna, Ferrara, Castel Maggiore, and Fornova di Taro, rail and road bridges at Neversa della Battiaglia and Rimini, the Turin motor transport works, and the Chivasso motor transport depot. The bombing ranged from good to excellent. After this operation, and with the return of good flying weather at the end of June, Strategic, now at full fighting strength with 21 heavy bombardment groups, 7 fighter groups, 1,957 aircraft, and 81,000 personnel, turned its attention so fully to the Combined Bomber Offensive that its activities over Italian targets consisted only of an occasional mission when weather precluded operations elsewhere.95
Strategic was not the only air organization operating outside of Italy.
* See above, p. 312.
During the winter and spring of 1944 the Allies had added to their strategic bombing of oil refineries at Ploesti, fighter factories in Austria, and rail centers at Sofia and elsewhere, a steadily growing support of Marshal Tito and his Yugoslav Partisans. This latter activity, which had begun in the fall of 1943,* had involved air attacks by Tactical and Coastal against shipping and ports on the Adriatic, marshalling yards in and beyond Yugoslavia, airfields, transport, warehouses, dumps, camps, headquarters, and RDF stations, as well as the delivery of thousands of tons of supplies. The increasing importance of such operations led to the establishment on 4 June of the Balkan Air Force (BAF),consisting of two offensive fighter wings, a light bomber wing, and a Special Operations Wing. The units, taken largely from Coastal’s 242 Group and Tactical’s Desert Air Force, were mostly RAF, but there were several USAAF elements (always on detached service from Troop Carrier), a number of Italian Air Force units, a Yugoslav squadron, a Greek squadron, and a Polish flight. They brought with them a wide assortment of planes, including P-39’s, P-51’s, Spitfires, Baltimores, Halifaxes, Macchis, C-47’s, and Hurricanes. The new air force was allotted six airfields in eastern Italy and the landing ground and fighter control on the island of Vis, off the Dalmatian coast.96
When BAF, under Air Vice Marshal W. Elliot, became fully operational early in July, it took over all of MAAF’s activities across the Adriatic except strategic bombardment, air-sea rescue, and sea reconnaissance.† During the month, it increased activities over the Balkans to almost 2,400 sorties. Its principal targets were rail traffic on the Zagreb–Belgrade–Skopje and Brod–Sarajevo–Mostar routes (where it claimed the destruction of more than 250 locomotives), steel and chrome works, repair shops, river craft on the Danube, and shipping on the Adriatic. The dropping of supplies and the evacuation of wounded Partisans and women and children also were stepped up.97
Just as the Fifth Army reached and passed Grosseto and the Eighth took Foligno (16–19 June) the Allies swung wide to seize the island of Elba. The operation (coded BRASSARD) was originally scheduled to take place soon after 25 May, with the French supplying the invading forces, but preoccupation with DIADEM pushed it into the
* See below, pp. 472-77.
† AOC, BAF, in addition to being responsible (under the air C-in-C, MAAF) for air operations over the Balkans, was charged with coordinating the planning and execution of trans-Adriatic operations by air, sea, and ground forces.
background, and command difficulties with the French soon caused the project to be postponed. On 12 June, General Alexander urged that it be canceled, on the ground that it could serve no useful purpose in view of the rapidity of the German retreat north of Rome. This reasonable opinion did not suit the French, and AFHQ agreed that the invasion should take place on the 17th.98
BRASSARD involved. an amphibious assault by French troops, with Tactical’s 87th Fighter Wing providing air cooperation, Coastal protecting the convoys and (at night) the assault troops, and the Royal Navy furnishing landing craft, escort vessels, and mine sweepers. In order not to jeopardize surprise there was no preassault air bombardment, although on the night of 16/17 June twenty-six Wellingtons softened up Porto Ferraio and Porto Longone.99 At first light on the 17th the French went ashore. Resistance was stubborn but Porto Ferraio fell on the 18th and twin drives into the northeastern part of the island completed the conquest on the 19th. Tactical’s 87th Wing took care of the air phase of the operation without having to call on the mediums of the 57th Wing – contingency which had been provided for. Twenty-four dive-bombing and fifty-eight patrol missions were flown, in the course of which ten barges and twelve motor vehicles were destroyed, two ships sunk and nineteen damaged, and two heavy guns silenced. The GAF failed to put in an appearance. On 20 June the 87th stepped out of the picture and Coastal’s 63rd Fighter Wing assumed responsibility for the defense of the island.100 BRASSARD really was an unnecessary operation – the advance of the Fifth Army beyond Grosseto made Elba untenable – but it boosted French morale, which probably made it worth while.
The beginning of the period of bad weather near the end of June which so handicapped the air forces also marked a break in the steady sweep of the Allied ground forces toward the Arno River and the cities of Pisa, Florence, and Ancona. Between the fall of Rome and 20 June the Fifth Amy had added Civitavecchia, Grosseto, and the Viterbo airfields to its bag; the French, on Fifth Army’s right, had reached the south bank of the Orcia River; in the center, the Eighth was at the line Lake Trasimeno–Chiusi and farther east was above Perugia; on the, Adriatic coast Pedaso had fallen.101 on the 20th, Kesselring, considering the Allied threat to his center as the most dangerous one, had managed to draw up hastily formed defense lines in that sector; he also had contrived to restore some semblance of order to his forces farther to
the west; in both areas his troops offered the strongest resistance since the first week of DIADEM a month before. Temporarily, but only temporarily, he checked the Allied advance, the delay coinciding with the onset of the period of bad weather.102
The Allies promptly lashed back. The Fifth Army took Piombino on 25 June and occupied the strongpoints of Cecina and Cecina Marina on 1 and 2 July; the French were in Siena on 3 July, and the British were within a few miles of Arezzo. For the next month, in spite of stubborn resistance and extensive use of demolitions by the enemy, the Allied ground troops pushed steadily toward the Arno. Leghorn fell on 18/19 July, Pontedera on the 18th, and that portion of Pisa south of the Arno on the 23rd. The going was slower in the center, where the terrain was tougher and where the Eighth Army had to take over the French sector when the French troops were withdrawn on 22 July for reassignment to the Seventh Army and ANVIL, but by 4 August Eighth Army units had occupied the southern half of Florence. On the Adriatic, Polish and Italian troops were south of Ancona. Thus, by early August the battle line ran along the south bank of the Arno from Pisa to just east of Florence, thence southeast to a few miles above Perugia, and from there to above Ancona. For the next two weeks there was little fighting while the Allies prepared to renew the assault with the object of crossing the Arno and driving into the Pisa–Rimini line (officially the Gothic Line, twenty miles to the north at its closest point.103
*Tactical’s fighters and fighter-bombers moved forward almost as rapidly as did the ground forces – thanks to the aviation engineers who fixed up advance bases and to Troop Carrier which flew in personnel and supplies.* Thus the planes were enabled to cooperate closely with the ground forces during the period from 20 June to the first week of August. Even during the ten days of bad weather at the end of June they were fairly active against transport and gun positions as well as against rail and road communications close to the enemy’s rear, where they cut or damaged several bridges, notably at Cattalia and Fano, blocked rail tracks, hit a tunnel six times, and bombed dumps. Night bombers hit the harbor and shipping at Ancona, Rimini, and Senigallia, on the east coast, and roads in the Arezzo, Pistoia, Bologna, and Prato areas.104 When the weather cleared the efforts were increased-the
* General Clark also credits Troop Carrier with the evacuation of some 8,000 ground force casualties during the advance to the Arno. (Clark, Calculated Risk, p. 378.)
night-flying light bombers, for example, in spite of a limited force put in over 300 sorties during the first week of July-but there was a shift in emphasis. Military transport targets had about disappeared, partly because so many had been destroyed and partly because the vehicles were hard to find in the hills south of the Arno, so the fighters and fighter-bombers went for lines of communication, ranging as far north as the Po Valley in missions against rails, bridges, yards, roads, and trains in the Pisa–Rimini sector, Cremona–Bologna area, and SpeziaParnia–Florence–Leghorn rectangle. XII TAC’s effort was down considerably, however, from what it had been in the DIADEM period, not only because of the weather but because of the loan of the 79th Fighter Group to DAF and the return to that air force of two of the RAF wings which XII TAC had borrowed earlier in the year.105
Beginning with the second week of July, XII TAC and DAF switched the main part of their offensive from rearward communications to the battle area. In the six days prior to the Eighth Army’s entrance into Arezzo (16 July) Kittyhawks and Mustangs flew around 900 sorties against gun positions and troop concentrations in front of the Eighth. Baltimores, Marauders, and Spitbombers added to this assault, while Spitfires directed a strong effort against roads and supply dumps close to the battle line. Night bombers continued armed reconnaissance of rear areas, attacking roads, strongpoints, and harbors.106
By 18 July, XII TAC had moved its units to Corsica,107 from where it was to participate in the invasion of southern France (formerly Operation ANVIL, now Operation DRAGOON) which again had been set, this time definitely and for mid-August. The move left DAF with the job of cooperating with both the Fifth and Eighth Armies, although for the next two weeks XII TAC, flying from its new bases, operated almost entirely over the western half of Italy north of DAF’s target area, which allowed DAF to concentrate on the battle area during the period of hard fighting from 20 July to 4 August in which the Allies reached the line of the Arno.108
DAF met its commitment, even though it was operating with only thirteen squadrons of fighters and fighter-bombers, four of mediums, two of light bombers, and one of night fighters.109 The impotence of the Luftwaffe in Italy helped, for it allowed DAF to devote only a small part of its effort to defensive patrols. Its principal fighter and fighter-bomber targets were close to the battle front: gun positions, observation posts, assembly areas, and communications. Its medium and
light bombers went for yards, shipping, supply centers, and, on a few occasions, airfields.110
During July, Tactical operated under a new directive which authorized it to attack targets, especially bridges, between the Apennines and the Po River. These operations were assigned to TAF rather than SAF because the heavies were fully occupied with targets in Germany, the Balkans (especially Ploesti), and southern France, as well as because XII TAC from its bases in Corsica could operate to, and even beyond, the Apennines.111 In the first week of July the mediums hit viaducts at Piteccio, Ronta, and between Florence and Faenza, bridges at Villa-franca, Pontremoli, and on the Pistoia–Bologna, Parma–Spezia, and Bologna–Prato lines, cut at least three rail bridges north of Florence, successfully attacked the Lugo and Imola yards, cut the tracks on the Spezia–Pisa line at Pietrasanta, blocked the tracks and tunnel at Canneto, and hit the lines between Parma and Piacenza.112
The second week of July marked the beginning of a sustained offensive against the Po River bridges by mediums of the 42nd and 57th Bombardment Wings. For some time it had been apparent that, despite the damage inflicted on his rail lines, the enemy still would have access to all places of importance on his Gothic Line unless certain key bridges across the Po were cut.” Air leaders had been urging this program for almost a month, having come to the conclusion that the destruction of six railway bridges across the Po and one across the River Trebbia at Piacenza, together with the viaduct at Recco on the west coast, would stop all rail traffic from Germany, Austria, and France into the area south of the river and east of a line from Genoa to Florence.113
Plans for the operation (coded MALLORY) were ready on 17 June, but bad weather first stopped the operation and then the plan was dropped because General Alexander and his ground leaders hoped for a quick breakthrough of the Pisa–Rimini line and a sweep up to the Po, in which event his troops might seize some of the bridges intact.114 The air leaders did not believe that a breakthrough was possible within a measurable period of time unless the enemy’s supply lines were fully interdicted – which meant that the bridges must be knocked out. By the second week of July, following the decision to invade southern France
* The Germans fully appreciated the importance of the Po bridges. Generalmajor Karl Koerner, chief of transportation, said that if the Allies had attacked the Brenner Pass and the Po bridges in 1943 as steadily as they did after mid-1944, “German resistance in Italy would have collapsed.” (Karl Koerner, Rail Transportation Problems in Italy, 8 Apr. 1947.)
with troops from Italy, it became obvious that the ground forces could not achieve a quick breakthrough. Whereupon MALLORY was revived, re-coded MALLORY MAJOR, and put into effect.115
The final plan called for the destruction of five rail bridges, two rail ;lid road bridges, and fourteen road bridges over the Po between Piacenza and the Adriatic, the destruction of the rail and road bridges over the Trebbia between Piacenza and Genoa, and the continuation of the interdiction of rail and road bridges between Spezia and Genoa which had been constructed as the result of the destruction of viaducts at Recco, Zoagli, and Bogliasco. Half of the bridges were of permanent construction; the remainder were pontoons. The actual job of knocking them out was assigned to Tactical’s mediums, while its fighter-bombers were to prevent repairs and to destroy reserve pontoons.116
The mediums went into action on 12 July. Flying conditions were ideal, and an average of almost 300 sorties was flown each day against the twenty-one bridges east of Piacenza. Although half of the bridges were of steel or concrete and were the strongest and heaviest in Italy,117 the mediums achieved an amazing degree of success. At the end of two days, one bridge was completely destroyed, three were at least one-half destroyed, and seven others were impassable. At the end of the fourth day, twelve bridges were either totally destroyed or had gaps in them more than 500 feet long; eight were cut, blocked, or otherwise so damaged that they were closed to traffic; only one, a reinforced concrete and steel structure at Ostiglia on the Bologna–Verona line, was open (in spite of four attacks), but the line itself was cut at a second bridge a little south of the Po. From Piacenza eastward all north-south through rail traffic was stopped.118
MALLORY MAJOR as such was limited to the attacks during the four days of 12–15 July. But Tactical immediately expanded the scope of its medium bomber operations in an effort to interdict completely all north-south traffic by cutting the Po bridges west of Piacenza and to paralyze east-west traffic by cutting a number of key bridges throughout the Po Valley. On the 16th mediums knocked out three arches of the Bressana bridge and put a 600-foot gap in the bridge at Torreberetti, and on the 17th they left the Monferrato bridge unserviceable; these blows interdicted southbound rail traffic from Milan. Concurrently, B-25’s and B-26’s interrupted east-west rail connections north of the Po by destroying the bridge at Bozzolo on the Cremona–Mantova line and cutting the viaducts at Brescia, and disrupted lateral traffic
south of the river by cutting bridges at Sassuolo and Piacenza and four bridges between Piacenza and Turin. As of 20 July the bridge-busting program had brought to ninety the number of cuts in rail lines in northern Italy.119
Continuous interdiction required close observation and frequent return visits. The mediums therefore continued to bomb the primary bridges. After 26 July all rail bridges over the Po east of Torreberetti were impassable; by 4 August, Genoa was isolated, communications from Turin eastward were limited, all rail lines from Milan to the south and east were cut, and all routes along the northern Apennines were useless, except that the Bologna–Pistoia line was open to Piteccio and there was only one cut on the Bologna–Prato line. Road communications east of Piacenza were almost as completely-although not as permanently-cut as were the rail lines. By 23 July every main bridge from Ostiglia to Cremona had been destroyed.120
The bridge-busting plan called for fighter-bombers to supplement the work of the mediums by preventing repairs and destroying pontoons.121 Actually, they do not seem to have operated against pontoons, but they did fly a large number of missions against bridges and open stretches of track. Their efforts against the heavy, permanent structures across the Po proved ineffective so that most of their operations were against smaller bridges above and below that river on lines leading to the main bridges. Even against smaller bridges they were not too successful, but they did a good job of cutting and blocking tracks – for example, the 87th Fighter Wing alone put 221 cuts in tracks during the last three weeks of July – and strafing and bombing motor transport and rolling stock. Most of the fighter-bomber operations were from Corsican bases, the 27th, 79th, and 86th Fighter-Bomber Groups and the 47th Bombardment Group (L) having joined the 87th Fighter Wing there in mid-July in anticipation of ANVIL.122
In the interdiction program from 1 July to 4 August the mediums and fighter-bombers received a small amount of assistance from Strategic’s heavies. Their first mission of the period was flown by 711 bombers and 292 fighters on 6 July when weather barred all targets except those in northern Italy. In addition to hitting oil installations and the Bergamo steel works the bombers plastered the yards at Verona and cut the Tagliamento River–Casarsa rail bridge in two places and rail lines to Venice in twelve places, but apparently failed to inflict serious damage on the Avisio viaduct.123 On the night of 10/11 July, sixty-seven
RAF 205 Group Wellingtons and a few Halifaxes and Liberators flew a successful mission against the Milan-Lambrate yards.124 On the 13th – which was the second day of MALLORY MAJOR – Strategic’s entire effort was directed against Italian oil storage facilities and communications. Soon after midnight twenty-two Wellingtons and Liberators, with Halifax pathfinders, dropped 62 tons on the Brescia yards; later in the day 196 of the Fifteenth’s heavies severely damaged yards at Mestre, Verona, Brescia, and Mantova, and the rail bridge at Pinzano. On 2 August, heavies dropped 312 tons on the yards at Genoa, scoring heavily on rolling stock, buildings, and sidings, while on the 3rd other heavies knocked out two spans and damaged two others of the Avisio viaduct and damaged the Ora bridge below Bolzano, which disrupted traffic on the Brenner Pass line for some ten days.125
Coastal also aided in the interdiction program. It operated against shipping and ports on both sides of the peninsula, and attacked supply centers, factories, and communications in northwest Italy. Its efforts were on a much smaller scale than in the early spring, owing to the transfer of a large number of its squadrons to Tactical and to the newly created Balkan Air Force. However, by taking over the defense of the western one-third of the peninsula as far north as Piombino it freed many of Tactical’s planes for offensive operations. Coastal could afford to assume this responsibility because of the extreme offensive weakness of the Luftwaffe.126
By 4 August the combined efforts of Tactical, Strategic, and Coastal toward interdicting the enemy’s supply lines in northern Italy had achieved such remarkable success* that Kesselring was finding it extremely difficult to supply his front-line troops. At times he was virtually isolated from the rest of Europe. Direct rail traffic across the Po between Piacenza and the Adriatic was not possible; farther west he had the use of only a few lines, with Genoa isolated and traffic generally disrupted, especially east of Turin and south of Milan. All routes from France were closed, as was the Tarvisio line from Austria. The Brenner Pass line was temporarily blocked. Between the Po and the Arno there were around ninety cuts in rail lines. Roads also were badly battered, all but three permanent bridges over the Po between Torreberetti and the Adriatic being cut. With almost all rail lines in the Po Valley closed, with the road system disrupted, and with motor transport
* Some of the credit must go to the Italian Partisans, whose activities steadily increased throughout the summer.
shot to pieces, the enemy was faced with a tremendous problem in trying to maintain his army in front of the Gothic Line.127
Yet the enemy’s defenses south of the valley did not disintegrate. That they did not was attributable to the German’s skill, ingenuity, and to his strenuous repair efforts. Railway repair and construction units were reinforced by Italian labor units, which were dispersed along the most important lines; repair material was scattered along the rail lines. The enemy assembled pontoon bridges at night, used them, then broke them up before dawn. He used ferries at more than fifty points along the Po. He moved mostly at night and in rainy weather, and went in heavily for camouflage, especially at the Po bridges.128 The very complexity of the lines of communication in northern Italy helped him, for the air forces could not achieve that basic requirement of simultaneous interdiction on all lines, as had been possible in central Italy. The Allies helped him, too, by withdrawing during June and July nine full infantry divisions from Fifth Army for use in an invasion of southern France, which lessened the pressure on the Wehrmacht.129
In spite of the great success of the air campaign, it cannot be claimed that the Allies completely won the logistical battle of the Po Valley, for the Germans maintained their forces well enough to stop the Fifth and Eighth Armies at the Gothic Line.
With Fifth Army already denuded of many of its troops, the Allied armies in Italy on 5 August began a two-week period of regrouping, and the land battle died down. At the same time, MAAF turned its attention very largely away from Italy and toward southern France. For the next six weeks air and ground operations on the Italian peninsula would be secondary in importance to operations on behalf of ANVIL-DRAGOON.