The Ansaldo 65mm/64 was the only new gun project of the wartime Royal Italian Navy.
The Royal Italian Navy developed radar but, as with the Germans, mainly for gunnery (LA range-finding). The only wartime anti-aircraft gun project (indeed, the only wartime gun project at all) was a new 65mm/64 HA gun intended specifically for the projected conversion of two small cruisers, Etna and Vesuvio, laid down pre-war for Siam, and left incomplete at the end of the war. Each was to have been armed with three twin 135mm/45 LA guns (as in the ‘Capitani Romani’ class) and a total of ten 65mm/64. Twelve were to have been mounted on board the carrier Aquila, left incomplete in 1943. The gun would also have armed ‘Capitani Romani’ class cruisers (a single mount would have replaced each twin 37mm/54). It was begun by the two gun manufacturers (Ansaldo and OTO) in collaboration in 1939 and was nearly ready in 1943. Production was cancelled in the summer of 1943, just before the Italian armistice. Length was originally to have been 56 calibres, increased to 62 calibres and then to 64 calibres. It fired a 4kg (about 8.8lbs) shell at a muzzle velocity of 950ft/sec (3117ft/sec). Originally it had an all-elevation electric loader, but that proved difficult to develop, and before the programme died altogether the gun was to have been hand-loaded. On that basis it could fire about 20 rnds/min. Maximum elevation was 80°.
Wartime anti-aircraft upgrades were limited. Thus the Littorios received a few additional twin 20mm/65 (fourteen rather than the original ten in Littorio and Roma). Other ships received small numbers of additional twin 37mm/54s (two more in the Dorias, to supplement the existing six). Some cruisers had their pre-war twin 13.2mm machine guns replaced by larger numbers of 20mm/65s. Destroyers were more heavily rearmed with 37mm/54s and 20mm/65s. For example, as completed Maestrale class destroyers had four twin 20mm/65s as their sole anti-aircraft weapons. In 1942 Maestrale had another two single 20mm/65s. In 1943 her sister Grecale had a twin 37mm/54 and four single 20mm/65. These short-range weapons were apparently quite effective against low-flying attackers, as the RAF suffered badly from intense anti-aircraft fire in the war to cut the supply line across the Mediterranean.
Effective machine gun range, as estimated in January 1942, was 1500m for the 37mm and 1200m for the 20mm, based on the capability of the predictors (alzi calcolatori and correttori rapidi), which took several tens of seconds to produce solutions. They were considered effective against aircraft flying a straight course, such as torpedo bombers.
During the war, the main Italian fleet encountered only a few air attacks in the open sea (as opposed to attacks in harbour, as at Taranto). Much of the Italian naval effort was devoted to running small convoys to North Africa in support of the Italian and German armies there. The destroyers and smaller ships fought an intense battle against RAF bombers, many of them operating out of Malta. At the same time they had to deal with submarines and with surface striking forces, also based on Malta. In this sense Italian convoy operations were a kind of microcosm of the larger British operations intended to resupply Malta. The Italian convoys generally did not enjoy air support, apart from the indirect effect of attacks on Malta. Neither the Germans nor the Italians ever seem to have developed effective shipboard fighter control, although on occasion their fighters formed a CAP over a convoy. That was probably adequate in view of the limited number of attacking aircraft, although the RAF did mount mixed bomb and torpedo attacks from time to time. In turn, the situation on Malta decided how effectively the convoy route could be squeezed. For example, limited workshop facilities limited the use of aerial torpedoes by strike aircraft operating from Malta. The alternative was masthead bombing. Alexandria suffered similar limitations, particularly after the depot ship Medway, with her torpedo workshops, was lost.
The RAF used low-level tactics from the autumn of 1941 up to the autumn of 1942. Losses were due not only to anti-aircraft fire but also to crashing into the ships’ masts. For example, an RAF Blenheim V crippled a tanker almost inside Tobruk in October 1942, but his wingman crashed after colliding with the ship’s mast. Many of the combat narratives in the official RAF history of the maritime war in the Mediterranean refer both to intense anti-aircraft fire and to heavy losses. Often it is clear that pilots were unable to observe hits due to heavy smoke screens, and the narrative relies heavily on official estimates of how well the pilots did. It is not clear how accurate those estimates, which are far more pessimistic than the pilots’ reports, were.
Initially the British rules for dealing with merchant ships from the air were related to rules for submarines; for example aircraft could not attack at sight, and ships in convoy were not regarded as part of the enemy fleet. Presumably the British hoped to limit enemy air attacks on shipping. In August 1940 the Italians announced that any ships within 30nm of enemy territory would be attacked, and the rules were dramatically relaxed.
At the outset the demand on shipping was limited because the German objective in setting up the Afrika Korps was to stop the British advance into Italian North Africa. Transport across the Mediterranean to Tripoli began in mid-February 1941. In March Hitler ordered a blitzkrieg, which pushed the British out of their conquests in the area. At the same time the Germans attacked in Greece and within a month they occupied Crete. With the loss of Crete, the Admiralty considered that it could no longer use carriers in the Eastern Mediterranean. Its torpedo bombers moved ashore to Malta; by December 1940 a Swordfish squadron (830) was on the island. Until the fall of Greece Swordfish also operated there. However, the Swordfish lacked the range to attack convoys in transit, and by December the Mediterranean and Middle East commanders were asking for longer-range torpedo bombers (Beauforts) to challenge the Axis supply route across the Mediterranean to Tobruk.
The Germans later complained that commitment of their air forces to the offensive in North Africa and also to the Russian campaign opened the convoys to air attack. Convoy losses in February and March 1941 were negligible, but in April and May they amounted to about 32,000 tons each month out of totals of 143,000 and 112,000 tons respectively. The situation was further complicated in that the army in North Africa was soon 1000km from its main port of Tripoli, and Tripoli itself had insufficient capacity. Thus a substantial fraction of the limited transport capacity had to go to repairing the port and to extending the key coastal road. To put the loss figures in perspective, in May 1941 the British Ministry of Economic Warfare estimated that the Axis was getting very short of shipping, because the enemy had nearer 500,000 tons than 1,000,000 tons available, excluding tankers and ships over 10,000 tons (useless for this service). They needed 250,000 tons to supply Albania and Tripoli, 100,000 tons for commercial service in the Adriatic, and 100,000 tons would always be under repair, leaving 100,000 tons for expeditionary warfare (at that time for Greece). Italian successes in getting tonnage across the Mediterranean in the face of British attacks can be attributed both to successful defence and to evasion based on code-breaking; evasion was similarly a vital element in Allied success in the Battle of the Atlantic.
Most of the damage to the Italian convoys during the first half of 1941 was by submarines, as the Swordfish had only limited capability. By this time the British were coming to sea attacks on the convoys as the best way to limit supplies going to North Africa; VCNS said that a successful attack on a ship in transit by an aircraft was worth the effort of fifty aircraft attacking the same cargo once it was ashore. For his part Winston Churchill wanted the largest possible submarine force based at Malta.
Air Staff wanted to use bombers. For the moment it was impossible to base Beauforts at Malta. With so few torpedoes on the island, Blenheim light bombers were sent out again, supplemented by Beaufighters (with IFF so that they could co-operate with ships) to help protect convoys. The Beaufighters operated in detachments of six aircraft at a time, the first six arriving on 27 April 1941 and carrying out their first anti-shipping strike on 1 May against a 3000-ton merchant ship escorted by a destroyer near the Kerkenna Islands. They claimed three hits on the destroyer and one on the merchant ship, both later confirmed as having been sunk. This detachment returned to England on 11 May, to be replaced by a second, which began its attacks on 22 May. A further detachment arrived on 21 May, suffering the first losses (two aircraft) during a 26 May convoy attack. In all, Blenheims of No. 2 Group made thirty-four sorties and attacked fifteen ships, sinking two, seriously damaging five and somewhat damaging another five, at the cost of two aircraft lost and two damaged. Blenheim detachments continued to operate from Malta through at least late 1941. The Blenheims attacked at low level, a very dangerous tactic. Typically Blenheims operated by day, torpedo-armed Swordfish at night. By the end of August 1941, there were thirty-two Blenheims on Malta, together with seven Marylands (typically used for reconnaissance, but now fitted with bomb racks), fifteen Wellingtons and twelve Swordfish. The Blenheims were having increasing trouble due to stronger convoy escorts and also fighter escorts, and AOC Mediterranean (Air Marshal Tedder) wanted to shift to attacks on enemy ports, but the Air Ministry considered it more useful to attack shipping in transit, so it decided to send another Blenheim squadron to Malta (this squadron, No. 18, did not leave for Malta until 10 October). At the time it was estimated that twenty-two ships had been sunk in August, of which submarines sank ten, torpedo bombers five, Blenheims four and heavy bombers (Wellingtons) three in harbour. In 1942 Malta continued to operate as an effective air-striking base but it was gradually choked by heavy enemy attacks (and very limited resupply, due to difficulties in running convoys), which nearly closed it down in March–April 1942.
In June the British air effort had to be cut back as the German- Italian army advanced towards Egypt: only 8500 tons out of 118,000 tons total were damaged or lost. Then British attacks increased, presumably partly because air pressure on Malta was relaxed due to the demands of the Russian campaign. In July, out of 153,000 tons sent out, nearly 20.000 tons were sunk and 7000 tons damaged. In August losses were 36.000 tons sunk and nearly 13,000 tons damaged out of 150,000 tons sent. In September losses were 49,000 tons sunk and nearly 14,000 tons damaged out of 163,000 tons sent out. Losses squeezed the capacity to ship heavy material, particularly vehicles such as tanks. There was no industrial capacity to replace heavy shipping losses. The large convoys could not be sustained, so in October shipping fell to 50,000 tons, of which 18,800 tons were lost and 12,800 tons damaged. Even had all the supplies gone through, they would have been grossly insufficient. In November, shipments fell to 37,000 tons – of which 26,000 tons were sunk and 2100 tons damaged. This was the worst damage ratio of the war, and the remaining 8400 tons was the least which had been delivered to Libya to date. In December only 36,000 tons was despatched, of which 13,000 tons was lost and 4800 tons damaged. These disasters coincided with the opening of a British offensive. Interdiction has always been most effective when the force being starved is also being forced to fight. The British advance into Cyrenaica greatly reduced Axis options to starve Malta, because it improved their prospects for convoy operations in the Eastern Mediterranean.
Three long-range Wellingtons fitted with ASV radar (sea-search radar) were deployed to Malta towards the end of September 1941 specifically to work with the Royal Navy surface force based at Malta, with the Malta-based naval torpedo bombers (Albacores at this time), and to shadow and attack enemy shipping. These aircraft acted as snoopers.
British anti-ship activity out of Malta was particularly intense in November 1941 in connection with the Crusader offensive in North Africa. It included a 19 November masthead-height attack on a convoy, escorted by one destroyer, by five Blenheims in the face of heavy anti-aircraft fire. Three were shot down. At this time the RAF was also flying Wellingtons out of Malta, armed with semi-armour-piercing bombs. One night thirteen of them, working with four Swordfish, attacked a large convoy: five merchant ships escorted by a cruiser and five destroyers. The Swordfish opened with torpedoes (one hitting the cruiser escorting the convoy). The Wellingtons followed at low and medium altitude. No hits could be observed due to the thick smoke screen the convoy generated. The Wellingtons claimed straddles, which might damage the ships, but there was no assessment. One Swordfish failed to return. A particular effort was made to attack enemy ships in harbour, presumably because bombs were more likely to be effective against static ships.
For their part the Germans felt compelled to divert U-boats from the Atlantic to the Mediterranean (initially twenty-one, ultimately thirty-six) specifically to deal with the convoys reinforcing Malta. For example, U-boats sank the carriers Ark Royal and Eagle, the latter during the ‘Pedestal’ convoy. By late 1941 it had become far more difficult to run convoys to Malta, and the onset of war in the Far East reduced the British capacity to make up losses in the Mediterranean. During the autumn of 1941 strikes from Malta became less effective both because the Italians learned to route their convoys out of range and because Malta itself was heavily bombed. The see-saw land war in North Africa did not help because bases seized there were too far from the Italian convoy routes for naval torpedo bombers.
The effect of renewed attacks against Malta showed in an improving Italian shipping situation. In January 1942, 60,000 tons were delivered to North Africa without loss. In February only 5000 tons of the 60,000 tons sent that month was lost. In March, 70,000 tons were sent, of which 15,800 tons were damaged and 1000 tons lost. None of these shipments was on the earlier scale, but in April 145,000 tons was sent, of which only 3500 tons was lost. The April shipment was the first and last time that it exceeded demands. At that time Rommel required 12.000 tons each month, but that did not include amassing supplies for any major operation. The more numerous Italian troops fighting alongside Rommel needed about twice the tonnage. With the reduction of air activity on Malta, at the end of March the Italians began to run single ships with heavy AA armament instead of convoys. The situation on Malta improved with the arrival of strong reinforcements of Spitfires in May 1942.
In April the total requirement for the German forces was 32,000 tons, the army taking 14,000 tons of fuel, as well as 1565 vehicles (including thirty-four tanks). May was even better: over 170,000 tons sent out, and only 10,000 tons lost. However, Rommel’s needs were also escalating, because on 26 May he began the offensive which took him to El Alamein. As he advanced, he needed not only convoy traffic across the Mediterranean but also coastal shipping from the main ports in North Africa (Tobruk to Mersa Matruh). Both convoys and coastal shipping were vulnerable to air and surface attack. In June the combination of cross-Mediterranean and coastal shipping depended on a total of about 107.000 tons of shipping, of which about 10,000 tons were lost or damaged.
The improvement in the Axis convoy position seems traceable directly to the worsening situation on Malta, which affected both strike aircraft and submarines based there. The British were well aware of the connection between Malta-based interdiction and the campaign in North Africa, and that explains the very costly convoy operations mounted in June and August 1942 (‘Pedestal’). Air attacks on the Axis convoys through the end of June 1942 were very limited, the bulk of Italian losses being by submarine.
The convoys were, however, still in range of RAF torpedo bombers. The first two Beaufort squadrons were sent out from the United Kingdom at the end of 1941. They began operating from Malta and Egypt early in 1942 (the second squadron soon moved to India). The day-attack Beaufort squadrons benefitted heavily from escort by Beaufighters. These aircraft carried out synchronised attacks after flying from their bases at very low altitude. Beaufighter escorts provided a diversion by strafing escorting destroyers and anti-aircraft ships. Converted Wellington medium bombers intended for night attack were successfully tested early in 1942, one squadron becoming operational by the end of May 1942. A second followed late in 1942. Few Wellingtons were lost.
Convoy losses began to rise in August (figures for July are not given): 114,000 tons despatched, of which 38,000 tons were sunk and 2000 tons damaged. In September 108,000 tons were despatched, of which 23,000 tons were sunk and over 9000 tons damaged. The situation continued to worsen, so that in October of over 96,000 tons sent, 24,000 tons were sunk and 14,000 tons damaged. In November demand exploded, because with the Allied landings in French North Africa, and with the offensive in the east, the Germans and Italians were fighting on two fronts. They made a supreme effort: 178,000 tons were sent out – but Malta was now fully operational, and 31,500 tons were sunk and 25.000 tons damaged. In December, even more was sent: 212,500 tons; but over 68,000 tons were sunk and over 15,000 tons damaged. The damaged ships were all hit in harbour. From August on the weight of the offensive against Axis shipping moved from submarines to bombers. Of the twenty-eight ships sunk in December, thirteen were sunk by air attack. Most of the sinkings by air attack seem to have been by torpedo. Attacks on convoys destroyed a large percentage of the Italian merchant fleet. They also wiped out many of the destroyers and seagoing torpedo boats which might otherwise have screened the Italian battle fleet.