Italian submarine Adua

Adua

Company type	Submarine
Industry	Naval military vessel
Founded	1 February 1936 (keel laid)
Headquarters	Monfalcone , Italy
Products	Military submarine

The Italian submarine Adua belonged to the Adua-class submarine series constructed in the 1930s and operated by the Regia Marina during World War II. Its designation was inspired by the town of Adwa located in northern Ethiopia.

Design and description

The Adua-class submarines were essentially replicas of the earlier Perla-class submarine class. They had a displacement of approximately 680 long tons (690 t) when surfaced and about 844 long tons (858 t) while submerged. Their overall length measured around 60.18 meters (197 ft 5 in), with a beam spanning 6.45 meters (21 ft 2 in) and a draft close to 4.7 meters (15 ft 5 in).

For surface propulsion, these vessels utilized two diesel engines manufactured by CRDA, each delivering roughly 600-brake-horsepower (447 kW), powering individual propeller shafts. When operating underwater, each propeller was driven by an electric motor rated at approximately 400-horsepower (298 kW). The maximum speeds achievable were around 14 knots (26 km/h; 16 mph) on the surface and about 7.5 knots (13.9 km/h; 8.6 mph) submerged. Their operational range extended to roughly 3,180 nautical miles (5,890 km; 3,660 mi) cruising at 10.5 knots (19.4 km/h; 12.1 mph), while underwater endurance reached approximately 74 nautical miles (137 km; 85 mi) at a speed of 4 knots (7.4 km/h; 4.6 mph).

Armament included six internal torpedo tubes with a diameter of 53.3 centimetres (21.0 in), arranged as four forward-facing and two aft-facing tubes. Additionally, they were equipped with a single deck gun measuring 100 millimetres (3.9 in), intended for surface combat engagements. The anti-aircraft defense consisted of one or two pairs of machine guns chambered for the 13.2 millimetres (0.52 in) Breda cartridges.

Construction and career

The submarine Adua was constructed at the CRDA shipyard located in Monfalcone. Her keel was laid on 1 February 1936, followed by her launch on 13 September of the same year. She officially entered service on 14 November 1936. After undergoing rigorous training exercises in the waters surrounding the Dodecanese, Greece, and Libya throughout 1937, Adua was assigned to the 23rd Squadron, which was based in Naples. In 1939, she was reassigned to Cagliari, becoming part of the 71st Squadron within the VII Submarine Group.

At the moment Italy declared war on 10 June 1940, Adua was already deployed at sea, positioned south of Sardinia between Cape Teulada and the island of La Galite. On 13 June, she shifted her patrol area to a zone between Ibiza and Mallorca, later moving to a location approximately 15 miles (24 km) east of Cape Creus in the Gulf of Lion. During the night of 17 June, Adua spotted a destroyer but was unable to engage. The next morning, she encountered a French convoy consisting of five merchant vessels escorted by two warships along the Marseille–Toulon route. Due to escort presence preventing a close approach, she fired a single torpedo from about 1,800 meters (5,900 ft) targeting a larger transport ship. However, there is no verified evidence confirming any damage or sinkings from this attack.

Between 22 October 1940 and 12 March 1941, Adua served as a training submarine at the Pola Submarine School, completing a total of 46 instructional missions during this period. In mid-March 1941, she returned to Taranto. From March through May that year, Adua conducted three operational patrols without success in various locations: 40 miles (64 km) west of Lefkada and within the Gulf of Taranto in March; south of Cape Krio and through the Kythira Strait in April; and initially between Alexandria and the Kasos Strait, then south of Crete in May.

On 10 May 1941, Adua was redeployed to Leros. In the early hours of 3 June 1941 at approximately 01:30, she intercepted a small motor barge transporting gasoline alongside 72 British soldiers—including eight officers—attempting to land on the Egyptian coast. The submarine detained the officers as prisoners and escorted the barge to Crete where the remaining troops were captured. The following day, she returned to Taranto for an extensive three-month maintenance period at its naval arsenal.

In mid-September, Adua operated near Menorca, returning to Cagliari on 16 September. On 23 September, she departed Cagliari with three other submarines to ambush a British convoy heading to Malta as part of Operation Halberd. By 26 September, Adua was patrolling near Cape Palos, north of Cartagena. The British convoy evaded detection and successfully reached Malta. On their return journey, Adua and accompanying submarines engaged British vessels. At approximately 03:50 on 30 September 1941, she detected eleven British destroyers and launched a salvo of four torpedoes but failed to hit any targets before moving northward. Shortly after, at around 05:25, Adua transmitted a radio report to command detailing the convoy’s location. After this communication, no further contact with her was established.

Postwar investigations revealed that two British destroyers, HMS Gurkha and HMS Legion, likely triangulated Adua’s position—possibly aided by her radio transmission—and engaged her using ASDIC sonar detection followed by depth charge attacks. Around 10:30, they succeeded in sinking Adua with all hands lost near coordinates 37°10′N 00°56′E or 36°50′N 00°56′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.
• Giorgerini, Giorgio (2002). Men Underwater: History of Italian Submarine Warfare from Origins to Present (Second ed.). Mondadori. ISBN 8804505370.
• Rohwer, Jürgen (2005). Sea War Chronology 1939–1945: Naval History of World War II (Third Revised ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1-59114-119-2.