Italian submarine Corallo

Guido Guidi
Occupation	Submarine captain
Years active	1942 (at least)

Italian submarine Corallo was a Perla-class submarine constructed for the Royal Italian Navy (Regia Marina) during the 1930s. The vessel was named in honor of the precious gemstone Coral.

Design and description

The Perla class represented a continuation of the earlier Sirena class design, with primarily incremental enhancements. Key upgrades included a larger false tower atop the hull, more advanced engine models, and the integration of a radiogoniometer operable from within the submarine. Additional improvements involved new air conditioning systems and increased fuel capacity, which collectively resulted in a modest rise in displacement and extended operational range compared to preceding models. Their intended full load displacement was approximately 695 metric tons (684 long tons) when surfaced and 855 metric tons (841 long tons) submerged, though figures varied slightly depending on specific vessels and shipyards. These submarines measured around 197 feet 6 inches (60.20 m) in length, with a beam of 21 feet (6.4 m) and a draft ranging from 15 feet (4.6 m) to 15 feet 5 inches (4.70 m).

Propulsion on the surface was provided by two diesel engines, each connected to its own propeller shaft, delivering between 675–750 hp (503–559 kW) total power. When submerged, each propeller shaft was powered by a 400 horsepower (300 kW) electric motor. The class could achieve speeds up to 14 knots (26 km/h; 16 mph) on the surface and 7.5 knots (13.9 km/h; 8.6 mph) while submerged. Surface cruising range reached approximately 5,200 nautical miles (9,600 km; 6,000 mi) at a speed of 8 knots (15 km/h; 9.2 mph), whereas underwater endurance allowed for around 74 nautical miles (137 km; 85 mi) at 4 knots (7.4 km/h; 4.6 mph).

Armament consisted of six internal torpedo tubes measuring 53.3 centimetres (21.0 in), with four located forward and two aft. Each tube had one reload torpedo available, totaling twelve torpedoes onboard. Surface combat capabilities included a single 100 millimetres (3.9 in) deck gun. For anti-aircraft defense, one or two twin mounts of 13.2 millimetres (0.52 in) machine guns were installed.

Construction and career

The submarine Corallo was constructed by CRDA at their Monfalcone shipyard. Its keel was laid down on 1 October 1935, it was launched on 2 August 1936, and the vessel was finalized by 26 September 1936.

Upon completion, Corallo joined the 34th Squadron (III Submarine Group) stationed at Messina. Following a short period of training, the submarine undertook an extended endurance mission across the Dodecanese and the Adriatic Sea. In 1937, she participated in a training campaign, which was followed by another in 1938. On 15 October 1938, she was temporarily assigned to the Flotilla Submarine School. Returning to active service in 1939, Corallo was assigned to the 72nd Squadron (VII Submarine Group) based in Cagliari, where she remained until the end of her operational life.

When Italy entered World War II, Corallo was at Monfalcone undergoing repairs that concluded in late August 1940. On 3 September 1940, under Captain Loris Albanese’s command, she was dispatched to patrol approximately 60 miles south of Crete, between Gaudo and Alexandria. At 18:00 on 17 September, Corallo located a British naval formation zigzagging toward Alexandria at coordinates 33°34′N 25°34′E. The British group included the aircraft carrier HMS Illustrious, battleship HMS Valiant, and five destroyers returning after bombarding Derna and Benghazi. At 18:30, Corallo fired two torpedoes from a distance of 1,500 meters targeting HMS Illustrious before diving to a depth of 80 meters. After about 75 seconds, two loud detonations were heard; however, no hits were confirmed. Subsequently, the submarine endured depth charge attacks from destroyers lasting three hours. These assaults inflicted damage that reduced her combat effectiveness and resulted in the loss of two crew members. Unable to repair the damage at sea, Corallo aborted her mission and reached Tobruk on 18 September.

On 5 November 1940, Corallo, along with four other submarines (Topazio, Fratelli Bandiera, Pier Capponi, and Goffredo Mameli), was deployed roughly 90 miles southeast of Malta. Their objective was intercepting a British convoy involved in Operation "Coat". These submarines formed a barrier with spacing between 20 and 30 miles. Despite this deployment, Corallo did not encounter any enemy vessels.

On 21 January 1941, both Corallo and Diaspro conducted patrols off northern Tunisia. However, Corallo had to terminate her mission shortly after due to mechanical failure and returned to base.

In February of that year, while patrolling north of Cape Bougaroun, engine troubles again forced an early return. Similarly, in April she patrolled south of Sardinia, but adverse weather conditions curtailed her mission prematurely.

During May 1941, she operated approximately 50 miles west of the Galite Islands without spotting any targets. An uneventful patrol southwest of Sardinia followed in July. In October, she was positioned off Cap Zebib, again without success.

Commanded by Captain Andreani on 3 November 1941, Corallo deployed west of Malta to serve as a protective screen for a large Italian "Beta" convoy en route to Libya. Her role involved detecting and reporting British naval activity west of Malta and engaging enemy ships when feasible. On 9 November, British Force K intercepted and destroyed the convoy during the Battle of the Duisburg Convoy. Force K departed Malta without being detected by Corallo, as it navigated through an area monitored by Luigi Settembrini instead. At sunset that day, Corallo left her operational zone and moved towards an area off Algeria and Tunisia.

In January 1942, she patrolled between Malta and Capo Passero, returning there for another patrol in March.

In April, while assigned to patrol off Cape Bon, at approximately 04:10 on April 28 near Bona, Algeria, Corallo intercepted two Tunisian sailboats: Dar es Salaam (138 GRT) and Tunis (41 GRT). Though flying Vichy France flags, these vessels lacked authorization for navigation. The submarine took all thirteen crew members aboard before sinking both sailboats with gunfire at coordinates 37°01′N 11°09′E.

During May and June of the same year, she patrolled east of La Galite Island. On June 7 at around 02:00, Corallo stopped another Tunisian sailboat named Hady M'Hammed (26 GRT). Believing it transported Allied materials, Captain Andreani ordered its six crewmen to abandon ship; they were taken prisoner before the vessel was sunk with gunfire at 37°24′N 09°10′E. Subsequently ordered to patrol northwest of Algiers, upon returning to base command passed to Captain Guido Guidi.

On June 11, alongside four other submarines (Onice, Ascianghi, Aradam, and Dessiè), Corallo patrolled the triangle formed by Malta, Pantelleria, and Lampedusa, tasked with intercepting a British convoy during Operation Harpoon. No enemy vessels were sighted during this mission.

By October 1942, she was assigned to patrol south of the Balearic Islands.

Following the launch of Operation Torch in November 1942, Corallo operated off Bizerta. She also entered Philippeville harbor but found no targets to engage.

In early December, she formed part of a defensive screen in the western Mediterranean alongside submarines such as Alagi, Argento, Bronzo, Galatea, Porfido, Volframio, Mocenigo, Diaspro, and Malachite protecting Axis convoys bound for Tunis.

Departing from Cagliari on December 10, 1942, Corallo headed toward an operational area between Bona and Bizerta, with orders to infiltrate Bougie harbor during the night of December 13 and destroy any ships encountered. After setting sail on this mission, no further communications were received from her.

Post-war examination of British records revealed that on the night of December 13 near Bougie—approximately fourteen miles offshore—four British escort vessels (HMS Enchantress (L56), HMS Fleetwood (U47), HMS Velox (D34), and HMS Venomous (D75)) from convoy KMS-4 detected and attacked Corallo. The submarine suffered damage from depth charges that forced her to surface. According to some reports, upon surfacing she attempted to engage HMS Enchantress with her deck gun; however, the British sloop accelerated and rammed her. While this collision inflicted severe structural damage on HMS Enchantress, it proved fatal for Corallo, which sank with all hands lost—including Commander Guidi, five officers, and forty-three crew members—at coordinates 36°58′N 05°07′E.

References

• Bagnasco, Erminio (1977). World War Two Submarines. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6.
• Chesneau, Roger, ed. (1980). Conway's Complete Guide to Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7.
• Rohwer, Jürgen (2005). Naval War Chronology 1939–1945: World War Two at Sea (Third Revised ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1-59114-119-2.
• Giorgerini, Giorgio (2002). Men Beneath the Surface: History of Italian Submarine Service from Origins to Present (Second ed.). Mondadori. ISBN 8804505370.
• Pollina, Paolo (1963). Italian Submarines 1895–1962. Rome, Italy: SMM.
• Bertke, Donald; Smith, Gordon; Kindell, Don (2012). World War II Naval Combat, Volume 3: Mediterranean Royal Navy Engagements. Bertke Publications. ISBN 978-1937470012.
• Ranieri, Attilio Duilio (May 19, 2024). "R.Smg. Corallo Operational History". regiamarina.net. Cristiano D'Adamo. Retrieved May 19, 2024.

External links

• Regia Marina The Italian Navy during the Second World War