Italian cruiser Bartolomeo Colleoni

On 10 June 1940, Italy declared war on Britain and France, entering World War II on the side of Germany. At that time, Bartolomeo Colleoni was assigned to II Division of II Squadron, along with her sister ship Giovanni delle Bande Nere. The two ships were moved to Palermo, Sicily, and on the evening of 10 June, they sortied to lay mines in the Strait of Sicily. On 22 June, the two cruisers departed to search for French ships that were reportedly west of Sardinia, but they returned to port two days later, having failed to locate any French vessels. By the end of the month, France had signed the Armistice of Villa Incisa, ending their participation in the war. As a result, Bartolomeo Colleoni and Giovanni delle Bande Nere were moved to Augusta in eastern Sicily. On 2–3 July, the ships carried another sweep that failed to locate any British ships, and the next day they covered a convoy from Tripoli in Italian Libya to Italy.[7]

On 7 July, Bartolomeo Colleoni and Giovanni delle Bande Nere sortied as part of the escort for a large convoy sailing to Benghazi in Libya.[9] The convoy consisted of five freighters and a passenger liner that were carrying some 2,200 men, 72 tanks, 237 other vehicles, and a large amount of supplies and fuel; these were intended to fortify the planned invasion of Egypt. II Division, along with the 10th Destroyer Squadron (which consisted of Maestrale, Libeccio, Grecale, and Scirocco) and the torpedo boats Pegaso, Orione, Orsa, Procione, Abba, and Pilo, formed the convoy's close escort.[10][11] Significant elements of the Italian fleet were at sea as part of the convoy, which the British attempted to intercept. In the ensuing Battle of Calabria on 9 July, the ships of II Division were assigned to make sure the convoy arrived in port undamaged. The convoy arrived in Benghazi the next day, but Bartolomeo Colleoni and Giovanni delle Bande Nere soon moved to Tripoli to avoid attacks from British aircraft based in Egypt. The Italian naval command considered sending the two cruisers to bombard British positions on the coast at Sollum, but decided against it; instead, they were to be sent to Portolago in the Dodecanese. From there, they were to attack British convoys in the Aegean Sea.[9]

Bartolomeo Colleoni during the action with HMAS Sydney

Bartolomeo Colleoni and Giovanni delle Bande Nere left Tripoli on the evening of 17 July and sailed to the north of Crete, bound for the Aegean. On the 19th, the four British destroyers HMS Hyperion, Ilex, Hero, and Hasty were sent on an anti-submarine patrol in the area, while the Australian light cruiser HMAS Sydney and the British destroyer Havock searched the Gulf of Athens. At around 06:00 on 19 July, the Italians spotted the four British destroyers off Cape Spada of western Crete, which were some 17,000 m (19,000 yd) away; Sydney and Havock were around 60 nautical miles (110 km; 69 mi) to the north. The British ships immediately signaled Sydney and turned to flee at high speed. The Italian commander, Rear Admiral Ferdinando Casardi aboard Giovanni delle Bande Nere, ordered his ships to pursue the retreating British ships, believing them to be part of the escort for a convoy he hoped to attack. At 06:27, the Italian cruisers opened fire on the destroyers, but the faster destroyers were able to pull out of range without having been hit.[9][lower-alpha 1] At around this time, a Greek freighter passed between the formations but quickly withdrew from the area.[12]

Casardi pursued the British blindly, deciding not to launch any of his reconnaissance aircraft (both because of the sea state and not wanting to slow down to launch them), and he was also not supported by any land based aircraft in the area. As a result, they had no way to know that Sydney was in the area, and when she arrived on the scene at around 07:30 and opened fire, it took the Italians completely by surprise. The Australian cruiser had opened fire from a range of about 12,000 m (13,000 yd) while in the middle of a fog bank; almost immediately, she hit Giovanni delle Bande Nere near her aft funnel. The Italian cruisers quickly returned fire, but had difficulty locating the target in the fog, as they only had Sydney's muzzle flashes to aim at. They also rolled badly in the heavy seas, which further hampered their gun laying.[9] Captain Collins of Sydney detached Havock to join the other destroyers, Collins ordered to make a torpedo attack on the cruisers. Casardi responded by turning his ships south and then southwest to move to less restricted waters further from Crete. As the Italians withdrew, Sydney alternated fire between the two cruisers, depending on which was more visible, but she focused her fire on Bartolomeo Colleoni, as she was generally closer.[14]

Bartolomeo Colleoni, capsized and sinking

At 08:24, Sydney struck Bartolomeo Colleoni with a salvo of 152 mm shells; one of the rounds jammed her rudder in the neutral position. The ship was now unable to steer, but she remained on the course she had been steaming. Shortly thereafter, another salvo from Sydney hit the ship amidships, causing extensive damage and starting several fires. One shell struck her conning tower and killed much of the bridge crew. The ship lost speed, which allowed the British destroyers to come into range. Further hits disabled two of the boilers and destroyed the main steam condenser, which was used to feed water back into the boilers. Without water to boil, the engines quickly shut down, leaving Bartolomeo Colleoni dead in the water. The ammunition hoists for her main battery guns were also disabled. Her 100 mm guns kept firing, as they could be operated manually. Within six minutes of the first hit, the ship had been effectively neutralized and her captain issued the order to abandon ship.[13][15]

At about that time, Ilex and Havock closed to launch torpedoes at the stricken cruiser, though their initial attacks missed. Hyperion joined the two destroyers, which had launched a further round of torpedoes, one of which hit Bartolomeo Colleoni. The torpedo, from Ilex, struck forward and blew off the first 30 m (98 ft) of her bow.[16][17] Casardi circled back at 08:50 to attempt to come to her aid, but quickly determined that the situation was hopeless, so he turned back to the west and fled at high speed.[18] Hyperion then launched a torpedo that struck amidships. The second hit caused serious flooding, and Bartolomeo Colleoni quickly capsized and sank. Sydney, Hero, and Hasty continued the pursuit of Giovanni delle Bande Nere, but Ilex, Havock, and Hyperion approached the area that survivors from Bartolomeo Colleoni were afloat. They picked up 525 men between the three of them, of whom 8 died of their wounds and were buried at sea. The British had to suspend rescue efforts when Italian bombers appeared and attacked the ships. A further fifty men attempted to swim to the coast of Crete, but only seven survived to be picked up by a Greek fishing boat. Four more men, including the ship's captain, died after arriving in Alexandria, Egypt. These men were buried there, and the captains of Sydney and the destroyers served as the pallbearers. In total, 121 out of a crew of 643 were killed in the sinking.[16][17]

In their assessment of the battle, the naval historians Jack Greene and Alessandro Massignani note that Casardi had been too cautious in the initial stage of the battle, and that if he had closed to attack the destroyers, he might have defeated them. Instead, he chose to fire at long range to keep his cruisers far enough away that the destroyers would not be able to return fire. They also point out that Italian gunnery was less accurate than their British counterparts, which compounded Casardi's decision to fight at long range. Lastly, they suggested that the Italians might have had a better outcome if they had sent a stronger force, instead of just the two light cruisers.[19] The naval historian Vincent O'Hara pointed out that the Italian cruisers fired some 500 shells between the two of them, scoring one hit on Sydney, while the latter vessel had fired around 1,300 shells alone and scored five hits, noting that the better British shooting was the result of a much higher volume of fire.[20]