The Adua-class submarine was the fourth sub-class of the 600 Series of coastal submarines built for the Italian: [[Regia Marina]] (Royal Italian Navy) during the 1930s. There were 17 submarines in this class, almost all named after places in Ethiopia which had been an Occupied by Italy since 1936, but only one,, 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.
The Adua-class submarines were essentially repeats of the preceding design. They displaced 680LT surfaced and 844LT submerged. The submarines were 60.18m (197.44feet) long, had a beam of 6.45m (21.16feet) and a draft of 4.7m (15.4feet).[1]
For surface running, the boats were powered by two 6000NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 400hp electric motor. They could reach 14kn on the surface and underwater. On the surface, the Adua class had a range of 3180nmi at, submerged, they had a range of 74nmi at .[2]
The boats were armed with six internal 53.3cm (21inches) 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 100mm deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of 13.2mm machine guns.[1]
| Ship | Builder | Launched | Fate | ||
|---|---|---|---|---|---|
| CRDA | 13 March 1936 | data-sort-value="30 September 1941" | sunk on 30 September 1941, by destroyers and, Western Mediterranean sea | ||
| 15 November 1936 | data-sort-value="1 February 1948" | sold for scrap on 1 February 1948 | |||
| 18 October 1936 | data-sort-value="4 September 1944" | sunk on 4 September 1944 in Genoa by Allied bombers | |||
| OTO | 5 December 1937 | data-sort-value="23 July 1943" | scuttled near Augusta, Sicily, on 23 July 1943, after attack by destroyers and | ||
| 27 September 1936 | data-sort-value="28 December 1943" | scuttled near Morea on 28 December 1943, during a mission for the Allies | |||
| OTO | 22 May 1938 | data-sort-value="1 May 1944" | sunk by Allied air attack, May 1944 | ||
| Tosi | 22 November 1936 | data-sort-value="" | sunk during Operation Pedestal by the British destroyer | ||
| Tosi | 22 November 1936 | data-sort-value="28 November 1942" | sunk on 28 November 1942 by destroyers and, near Bona, Algeria. | ||
| OTO | 6 March 1938 | data-sort-value="18 October 1940" | scuttled on 18 October 1940 east of Gibraltar after attack by destroyers and | ||
| OTO | 3 October 1937 | data-sort-value="30 September 1940" | scuttled on 30 September 1940, near Alexandria, after a 14-hour-long attack by destroyers, and Sunderland flying boats | ||
| OTO | 10 April 1938 | data-sort-value="20 October 1940" | sunk on 20 October 1940, north of Melilla by destroyers, and | ||
| OTO | 29 October 1936 | data-sort-value="15 June 1940" | 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.[3] | ||
| OTO | 7 November 1937 | data-sort-value="19 January 1941" | sunk on 19 January 1941 by destroyer | ||
| OTO | 6 January 1938 | data-sort-value="10 August 1942" | sunk on 10 August 1942 off Haifa by | ||
| OTO | 6 February 1938 | data-sort-value="2 August 1941" | sunk on 2 August 1941, west of Malta, by | ||
| Tosi | 19 September 1937 | data-sort-value="15 December 1942" | sunk on 15 December 1942, south of Malta, by and the Greek destroyer Vasilissa Olga | ||
| Tosi | 3 October 1937 | data-sort-value="29 June 1940" | sunk on 29 June 1940 by and |
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 submarine, was located at the Red Sea base of Massawa.