The sinking of the cruiser Armando Diaz

On the moonless night of 24–25 February 1941, off the east coast of Tunisia, the British submarine Upright fired four torpedoes at a formation of Italian warships covering a convoy carrying German troops to Tripoli. Two struck the light cruiser Armando Diaz below the bridge. The explosion of the forward magazine tore apart the fore part of the ship, which went to the bottom within six minutes. According to Italian figures 464 members of her crew were killed, including her captain. Roughly a quarter of the crew survived – in proportion to the size of the crew, one of the heaviest losses suffered by the Regia Marina in this war.

The Afrika Korps convoys

After the defeat of the Italian Tenth Army in Cyrenaica, sealed at Beda Fomm, the Germans began sending their own troops to Libya. In mid-February the first transports of the 5th Light Division reached Tripoli, and Erwin Rommel took command of the forces that were soon named the Afrika Korps. Men, tanks, fuel and ammunition were shipped from Naples and Palermo through the Strait of Sicily. To avoid Malta, the ships kept to the western route along the coast of French Tunisia, where a buoyed channel led across the shoals around the Kerkennah Islands. This narrow corridor was also the best place for a submarine ambush.

At the end of February three convoys to Libya were at sea at the same time, among them a fast convoy of large liners carrying troops (Conte Rosso, Esperia, Marco Polo and Victoria) and a convoy of the German motor ships Marburg, Reichenfels, Ankara and Kybfels. The naval high command, Supermarina, also sent out Rear Admiral Alberto Marenco di Moriondo’s 4th Cruiser Division: the cruisers Giovanni delle Bande Nere (flagship) and Armando Diaz with the destroyers Ascari and Corazziere. The force left Palermo on the morning of 24 February, met the Marburg convoy before noon and sailed ahead of it as distant cover. Some Italian accounts criticise this decision: there were no British surface ships at Malta at the time from which the cruisers could have protected the convoy, while against submarines, the main threat, they were helpless and themselves became targets.

“Cardboard cruisers”

The ship, named after Marshal Armando Diaz, the victor of Vittorio Veneto, belonged to the series of light cruisers known as the Condottieri. Together with her sister Luigi Cadorna she formed the second group of the series, a slightly improved version of the four ships of the Alberto di Giussano class, to which the Giovanni delle Bande Nere belonged, as did the Bartolomeo Colleoni, sunk in July 1940 off Cape Spada. Built at the Muggiano yard near La Spezia, launched on 10 July 1932 and commissioned on 29 April 1933, she displaced about 5,400 tons standard and carried eight 152 mm guns.

The early Condottieri were designed to counter the large French destroyers, sacrificing armour for speed. The Diaz reached 39 knots on trials, but after a few years in service could make no more than 31–32, and her side armour and underwater protection were very weak. In 1934 she made a cruise to Australia and New Zealand, during the Spanish Civil War she operated in the western Mediterranean, and in July 1940 she sailed with the fleet during the Battle of Calabria, in which she played no significant part. Supermarina concluded that ships of this type were unsuitable for fleet action and used them to cover convoys to Albania and Libya. From November 1939 she was commanded by Captain Francesco Mazzola.

Submarines from Malta

The large British submarines, built for ocean work, had suffered heavy losses in the shallow, clear waters of the Mediterranean in 1940. From the end of the year small, handy U-class boats of about 600 tons began to arrive in Malta. In January 1941 command of them was taken by Commander George Simpson, who set up a base on Manoel Island. From this group grew the famous 10th Submarine Flotilla. The boats came under the Commander-in-Chief of the Mediterranean Fleet, Admiral Andrew Cunningham, for whom cutting the supply routes of the army in Libya was one of the fleet’s principal tasks. They operated from an island on which the bombs of the German X Air Corps had been falling since January, and in February the raids grew heavier still.

HMS Upright, commissioned in September 1940, had arrived in Malta at the beginning of December. From January she was commanded by the thirty-year-old Lieutenant Edward Dudley Norman, who had already been awarded the Distinguished Service Cross for patrols off the Norwegian coast. On 5 February his four torpedoes fired off Kerkennah at a German transport missed. On 19 February Upright sailed on another patrol to the same area and on the night of 22–23 February sank the Italian steamer Silvia Tripcovich there. None of her crew survived.

Six minutes

After dark on 24 February the cruisers were sailing ahead of the convoy. At about 2 a.m., after passing buoy No. 4 on the Kerkennah shoals, Marenco di Moriondo decided that on so dark a night submarines would not see them, and stopped zigzagging. The force was heading south in line ahead: Corazziere leading, followed by Bande Nere and Diaz, with Ascari at the rear. The sea was calm. Aboard the Diaz the watch was at action stations and the rest of the crew asleep.

Upright was meanwhile charging her batteries on the surface. At 3.22 a.m. Italian time (the submarine’s British log, kept in a different time zone, gives an hour earlier) her lookouts sighted three dark silhouettes at a range of about two and a half miles. Norman identified two cruisers and a destroyer. Remaining on the surface – on a moonless night the small boat was almost invisible – he worked into an attacking position and chose as his target the second ship in the line, which seemed to him the largest. At about 3.40 a.m. he fired four torpedoes and dived at once.

At 3.43 a.m. two torpedoes struck the Diaz on the starboard side, below the bridge and slightly forward of it. The magazine of the forward turrets and the boilers in use blew up. A column of fire hurled glowing debris into the sky, and the bridge and forward superstructure ceased to exist. Captain Mazzola, the officers on the bridge, the crews of both forward turrets and almost all the men in the boiler rooms were killed instantly. No boats could be lowered; only some of the rafts reached the water. At about 3.49 a.m. the Diaz, listing to port, sank bow first in about fifty metres of water, south-east of the Kerkennah Islands, off Sfax.

The Ascari, which according to Italian accounts had herself narrowly avoided one of the torpedoes, and the Corazziere dropped depth charges for about forty minutes, and their explosions also injured men in the water. Upright rode out the counter-attack submerged without damage. The Bande Nere did not stop and sailed on with the convoy. Many sailors died in the cold February water from exposure or choked by fuel oil. Those who survived had reached the rafts or clung to wreckage. The Ascari began rescue work at 4.30 a.m., and the Corazziere joined in after seven. Upright, with her last two torpedoes, returned to Malta on 26 February.

The dead

The figures given in the sources vary. According to Italian nominal rolls 464 men were killed: 13 officers, 62 petty officers, 382 ratings, four civilian employees of the navy and three airmen. Among the dead were Mazzola and his executive officer, Commander Mainardo De Nardis. The Ascari picked up about 150 survivors and nine bodies, the Corazziere three survivors. Other accounts give between 484 and about 500 dead and between 133 and 153 survivors. The differences probably stem from different counts of the crew (between 611 and 633 men) and from deaths among the wounded after the action. Mazzola was posthumously awarded the Gold Medal of Military Valour, and Norman the Distinguished Service Order.

The German transports that the Diaz had been covering were unharmed. The sinking of the cruiser was a prestige success for the British, but it did not stop the movement of German troops. According to some accounts, the ships that carried the first Afrika Korps units to Libya arrived without loss until the end of March.

Place in the war

The sinking of the Diaz heralded the long struggle for the routes to Libya that the Italians called the “battle of the convoys”. Once Rommel was established in Tripoli and his troops needed ever more fuel and ammunition, submarines, aircraft and surface ships from Malta sank a growing share of Axis shipping, more and more often guided by decrypted enemy signals. On 24 May 1941 Malcolm Wanklyn’s HMS Upholder sank the Conte Rosso, which in February had sailed in one of the convoys covered by the Diaz. Nearly 1,300 men died.

The fate of the Diaz also confirmed the weakness of the first Condottieri. Of the six ships of the first two groups, only the Cadorna survived the war. The Alberto di Giussano and the Alberico da Barbiano were sunk on 13 December 1941 at the Battle of Cape Bon, and the Giovanni delle Bande Nere was sunk by the British submarine Urge on 1 April 1942. The cruisers of the later series, heavier and better armoured, mostly lasted until the end of the war.

Norman later commanded HMS Graph, the German submarine U-570 captured in the Atlantic, and after the war he was the first head of the Malayan navy. Upright survived the war. The wreck of the Diaz was located in 1952 by an Italian salvage firm, which blew it in two while recovering metal from it. In 2004 it was identified by Italian divers, who left on it a plaque reading “The Italians have not forgotten you”.