The ''Adua''-class submarines were essentially repeats of the preceding . They displaced surfaced and submerged. The submarines were long, had a beam of and a draft of .Chesneau, pp. 309–10
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the ''Adua'' class had a range of at , submerged, they had a range of at .Bagnasco, p. 154
The boats were armed with six internal torpedo tubes, four in the bow and two in the stern. They were also armed with one deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of machine guns.
Construction and Career
''Alagi'' was built in the CRDA shipyard, in Monfalcone. She was laid down on 19 March 1936, launched on 15 November that year and commissioned on 6 March 1937.
On 11 May 1937 ''Alagi'' was assigned to the 23rd Squadron based in Naples, from where she conducted training in the
Dodecanese
The Dodecanese (, ; el, Δωδεκάνησα, ''Dodekánisa'' , ) are a group of 15 larger plus 150 smaller Greek islands in the southeastern Aegean Sea and Eastern Mediterranean, off the coast of Turkey's Anatolia, of which 26 are inhabited. ...
. During the Spanish Civil War, between 27 August and 4 September 1937, she carried out a special mission. In 1939 she was reassigned for some time to the base in
Cagliari
Cagliari (, also , , ; sc, Casteddu ; lat, Caralis) is an Italian municipality and the capital of the island of Sardinia, an autonomous region of Italy. Cagliari's Sardinian name ''Casteddu'' means ''castle''. It has about 155,000 inhabitant ...
and then to
Messina
Messina (, also , ) is a harbour city and the capital of the Italian Metropolitan City of Messina. It is the third largest city on the island of Sicily, and the 13th largest city in Italy, with a population of more than 219,000 inhabitants in ...
.''Alagi'' at Monfalcone Naval Museum /ref> In 1940 ''Alagi'' was assigned to 71st Squadron (V Submarine Group) based at
Cagliari
Cagliari (, also , , ; sc, Casteddu ; lat, Caralis) is an Italian municipality and the capital of the island of Sardinia, an autonomous region of Italy. Cagliari's Sardinian name ''Casteddu'' means ''castle''. It has about 155,000 inhabitant ...
.
On 10 June 1940, at the outbreak of hostilities, ''Alagi'' was on patrol in the waters off Bizerta. She remained on station until 20 June without sighting any enemy ships.
From 5 to 11 June 1941, ''Alagi'', under command of captain Giulio Contreas, patrolled 20 miles northeast of Ras Azzaz. She sighted a small enemy ship and tried to launch an attack, but it was interrupted by a second ship which detected ''Alagi'' and headed in her direction, forcing her to disengage.
At 10:47 on 12 June 1941, while returning to
Messina
Messina (, also , ) is a harbour city and the capital of the Italian Metropolitan City of Messina. It is the third largest city on the island of Sicily, and the 13th largest city in Italy, with a population of more than 219,000 inhabitants in ...
, ''Alagi'' was attacked with two bombs and machine guns off
Benghazi
Benghazi () , ; it, Bengasi; tr, Bingazi; ber, Bernîk, script=Latn; also: ''Bengasi'', ''Benghasi'', ''Banghāzī'', ''Binghāzī'', ''Bengazi''; grc, Βερενίκη (''Berenice'') and ''Hesperides''., group=note (''lit. Son of he Ghazi ...
by a British
Sunderland
Sunderland () is a port city in Tyne and Wear, England. It is the City of Sunderland's administrative centre and in the Historic counties of England, historic county of County of Durham, Durham. The city is from Newcastle-upon-Tyne and is on t ...
aircraft. The boat's crew responded with anti-aircraft weapons forcing the plane to turn away, probably because it was hit.
On 18 July 1941 she patrolled off of Cap Bougaroûn. On 22 July she detected Force H but was unable to attack it, and was subject to anti-submarine search by escorts.
During August 1941 ''Alagi'' patrolled between Sardinia and La Galite Island.
She spent November and December 1941 patrolling off Cape Fer.
In the late afternoon of 14 January 1942, in the
Strait of Sicily
The Strait of Sicily (also known as Sicilian Strait, Sicilian Channel, Channel of Sicily, Sicilian Narrows and Pantelleria Channel; it, Canale di Sicilia or the Stretto di Sicilia; scn, Canali di Sicilia or Strittu di Sicilia, ar, مضيق ص ...
, ''Alagi'' sighted a British naval formation and at 21:05 launched two torpedoes, which did not hit any targets.
On 8 June 1942, roughly 20 nm North of
Cape Bon
Cape Bon ("Good Cape") is a peninsula in far northeastern Tunisia, also known as Ras at-Taib ( ar, الرأس الطيب), Sharīk Peninsula, or Watan el Kibli;
Cape Bon is also the name of the northernmost point on the peninsula, also known as Ra ...
''Alagi'', under command of captain Sergio Puccini, fired three torpedoes at a naval column (later identified as friendly convoy from Naples to
Tripoli
Tripoli or Tripolis may refer to:
Cities and other geographic units Greece
*Tripoli, Greece, the capital of Arcadia, Greece
*Tripolis (region of Arcadia), a district in ancient Arcadia, Greece
* Tripolis (Larisaia), an ancient Greek city in t ...
). One torpedo hit and sunk the Italian destroyer ''Antoniotto Usodimare'' in a friendly fire incident (141 killed and 165 survivors).
On 12 July 1942 at 20:04, at , northwest of Tripoli, Syria, ''Alagi'' fired two torpedoes and scored one hit in the engine room of the Turkish tanker ''Antares'' (3723 GRT, 1893) on a trip from Iskanderun to Haifa, causing her to be beached on
Ruad Island
Arwad, the classical Aradus ( ar, أرواد), is a town in Syria on an eponymous island in the Mediterranean Sea. It is the administrative center of the Arwad Subdistrict (''nahiyah''), of which it is the only locality. The tanker was later re-floated, towed to Turkey and scrapped in late 1943.
In August 1942 ''Alagi'' operated along the Regia Marina and Luftwaffe to intercept and block an Allied convoy to Malta (
Operation Pedestal
Operation Pedestal ( it, Battaglia di Mezzo Agosto, Battle of mid-August), known in Malta as (), was a British operation to carry supplies to the island of Malta in August 1942, during the Second World War. Malta was a base from which British ...
).
On 12 August 1942 at 21:05, at , ''Alagi'' fired a spread of 4 torpedoes against a merchant and a cruiser, and immediately dove. 3 explosions were heard. At 21:12 cruiser was hit forward by one of four torpedoes and sustained damage to bow structure. was able to make 25 knots and remained with the convoy to continue operating in defense of merchants. The other 2 torpedoes hit and sunk M/V ''Clan Ferguson'' which was previously damaged by a bomb from Ju 88.
On 8 November 1942, while sailing submerged to her area of operation near Bizerta, she collided underwater with another Italian submarine and suffered serious damage to her tower and had to turn back and return to Naples.
In December she first patrolled between Cape Bougaroun, island of
La Galite
The Galite Islands (Tunisian Arabic: جالطة ''Jalita'', French: ''La Galite'', Italian: ''Isola della Caletta'') are a rocky group of islands of volcanic origin that belong to Bizerte Governorate, northern Tunisia. They are located northwe ...
and Cape Fer and then from 29 December near Bona, Algeria.
In January 1943 ''Alagi'' patrolled northeast of Bona.
From February to June 1943 she conducted several patrols south and southwest of Sardinia.
In July 1943 ''Alagi'' first patrolled south of Sardinia, and later provided defensive screen in the waters of Sicily. On 16 July at 6:13, at , she intercepted a column of three destroyers. ''Alagi'' launched three torpedoes while on surface. After a minute and 45 seconds a violent explosion was heard, but no information about this action was ever reported in British official documentation.
On 3 September 1943 ''Alagi'' was deployed to the Gulf of Salerno, and on 7 September under the Zeta Plan, she was sent along with ten other submarines to the Tyrrhenian Sea, between the
Gulf of Gaeta
The Gulf of Gaeta is a body of water on the west coast of Italy and part of the Tyrrhenian Sea. It is bounded by Cape Circeo in the north, Ischia and the Gulf of Naples in the south, and the Pontine Islands in the west.
The gulf is named for th ...
and the Gulf of Paola to intercept an anticipated Anglo-American landing in southern Italy.
On 9 September 1943, following the announcement of the Armistice, ''Alagi'' which at that time was about sixty miles from Augusta headed for Malta, where she arrived on 16 September 1943 along with five other submarines escorted by destroyer . Upon arrival she surrender to the Allies. On 13 October 1943 ''Alagi'' together with fifteen other submarines left Malta for mainland Italy.
In October 1943, ''Alagi'' was transferred to Haifa where she was employed as a training unit for British troops and as a shipping vessel for supplies to the Aegean Islands. She returned to Taranto in December 1944, where she remained inactive until the end of the war. She was sold for scrap on 1 February 1948.