|Operators:||Regia Marina, Brazilian Navy|
|Preceded by:||Perla class|
|Succeeded by:||Acciaio class|
|Length:||60.18 m (197 ft 5 in)|
|Beam:||6.45 m (21 ft 2 in)|
|Draft:||4.7 m (15 ft 5 in)|
|Test depth:||80 m (260 ft)|
The Adua-class submarine was the fourth sub-class of the 600 Series of coastal submarines built for the Royal Italian Navy (Regia Marina) during the 1930s. There were 17 submarines in this class, almost all named after places in Ethiopia which had been an Italian colony since 1936, but only one, Alagi, survived World War II. Three submarines of this class (Gondar, Ascianghi, and Neghelli) were sold to Brazil before the war and replaced with submarines of the same names.
Design and description
The Adua-class submarines were essentially repeats of the preceding Perla class design. They displaced 680 metric tons (670 long tons) surfaced and 844 metric tons (831 long tons) submerged. The submarines were 60.18 meters (197 ft 5 in) long, had a beam of 6.45 meters (21 ft 2 in) and a draft of 4.7 meters (15 ft 5 in).
For surface running, the boats were powered by two 600-brake-horsepower (447 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 400-horsepower (298 kW) electric motor. They could reach 14 knots (26 km/h; 16 mph) on the surface and 7.5 knots (13.9 km/h; 8.6 mph) underwater. On the surface, the Adua class had a range of 3,180 nautical miles (5,890 km; 3,660 mi) at 10.5 knots (19.4 km/h; 12.1 mph), submerged, they had a range of 74 nmi (137 km; 85 mi) at 4 knots (7.4 km/h; 4.6 mph).
The boats were armed with six internal 53.3 cm (21.0 in) torpedo tubes, four in the bow and two in the stern. One reload torpedo was carried for each tube, for a total of twelve. They were also armed with one 100 mm (3.9 in) deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of 13.2 mm (0.52 in) machine guns.
|Adua||CRDA||13.9.1936||sunk on 30 September 1941, by destroyers HMS Gurkha and HMS Legion, Western Mediterranean sea|
|Alagi||CRDA||15.11.1936||sold for scrap on 1 February 1948|
|Aradam||CRDA||18.10.1936||sunk on 4 September 1944 in Genoa by Allied bombers|
|Ascianghi||OTO||5.12.1937||scuttled near Augusta, Sicily on 23 July 1943, after attack by destroyers HMS Laforey and HMS Eclipse|
|Axum||CRDA||27.9.1936||scuttled near Morea on 28 December 1943, during a mission for the Allies|
|Beilul||OTO||22.5.1938||sunk by Allied air attack, May 1944|
|Dagabur||Tosi||22.11.1936||sunk during Operation Pedestal by the British destroyer HMS Wolverine|
|Dessiè||Tosi||22.11.1936||sunk on 28 November 1942 by destroyers HMS Quiberon and HMS Quentin, near Bona, Algeria.|
|Durbo||OTO||6.3.1938||scuttled on 18 October 1940 east of Gibraltar after attack by destroyers HMS Firedrake and HMS Wrestler|
|Gondar||OTO||3.10.1937||scuttled on 30 September 1940, near Alexandria, after a 14 hour long attack by destroyers HMAS Stuart, HMS Diamond and Sunderland flying boats|
|Lafolè||OTO||10.4.1938||sunk on 20 October 1940, north of Melilla by destroyers HMS Gallant, HMS Hotspur and HMS Griffin|
|Macallé||OTO||29.10.1936||assigned to the Red Sea Flotilla and ran aground on 15 June 1940 when the crew was disabled by central nervous system poisoning from a chloromethane leak in the ship's air conditioning system.|
|Neghelli||OTO||7.11.1937||sunk on 19 January 1941 by destroyer HMS Greyhound|
|Scirè||OTO||6.1.1938||sunk on 10 August 1942 off Haifa by HMT Islay|
|Tembien||OTO||6.2.1938||sunk on 2 August 1941, west of Malta, by HMS Hermione|
|Uarsciek||Tosi||19.9.1937||sunk on 15 December 1942, south of Malta, by HMS Petard and the Greek destroyer Vasilissa Olga|
|Uebi Scebeli||Tosi||3.10.1937||sunk on 29 June 1940 by HMS Dainty and HMS Ilex|
The boats, once commissioned, were assigned to complete the squadrons of "600" submarines strengthening the 11th and 14th Squadrons at La Spezia and 43rd at Taranto. After initial training, many of these boats carried out training cruises in the Dodecanese and along the coast of North Africa.
During the Spanish Civil War (1937-1938) five of the submarines already in service made seven special missions on behalf the Franco's regime without much success.
During 1938-39 the boats largely changed their assignment locations: there was at first a single squadron on four submarines at La Spezia four other submarines formed the 23rd Squadron at Naples, and five more were assigned to Leros. In 1939 there was not a single boat of the series at La Spezia, while the squadron at Leros was strengthened. In 1939 four boats from Naples and Taranto bases were sent to Tobruk.
At the outbreak of the World War II, there were four submarines assigned to each of the bases of La Spezia, Cagliari, Messina and Taranto, and one subamrine, Macallé was located at the Red Sea base of Massawa.
- Chesneau, pp. 309–10
- Bagnasco, p. 154
- "THE MILITARY OPERATIONS OF THE ITALIAN FLEET ON RED SEA JUNE 1940 - APRIL 1941". Arnaldo Borsa. Retrieved 2012-08-02.
- Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6.
- Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7.
- Rohwer, Jürgen (2005). Chronology of the War at Sea 1939-1945: The Naval History of World War Two (Third Revised ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1-59114-119-2.