Italian submarine Diamante

History
Kingdom of Italy
Name	Diamante
Builder	Cantieri navali Tosi di Taranto, Taranto
Laid down	1931
Launched	21 May 1933
Fate	Sunk, 20 June 1940
General characteristics
Class and type	Sirena-class submarine
Displacement	691 t (680 long tons) (surfaced) 850 t (837 long tons) (submerged)
Length	60.18 m (197 ft 5 in)
Beam	6.45 m (21 ft 2 in)
Draft	4.7 m (15 ft 5 in)
Installed power	1,350 bhp (1,010 kW) (diesels) 800 hp (600 kW) (electric motors)
Propulsion	2 shafts; diesel-electric 2 × diesel engines 2 × electric motors
Speed	14 knots (26 km/h; 16 mph) (surfaced) 7.5 knots (13.9 km/h; 8.6 mph) (submerged)
Range	5,000 nmi (9,300 km; 5,800 mi) at 8 knots (15 km/h; 9.2 mph) (surfaced) 72 nmi (133 km; 83 mi) at 4 knots (7.4 km/h; 4.6 mph) (submerged)
Armament	1 × single 100 mm (3.9 in) deck gun 2–4 × single 13.2 mm (0.52 in) machine guns 6 × 533 mm (21 in) torpedo tubes (4 bow, 2 stern)

Diamante was one of a dozen Sirena-class submarines, the second sub-class of the 600 Series of coastal submarines built for the Regia Marina (Royal Italian Navy) during the early 1930s.

Design and description

The Sirena class was an improved and enlarged version of the preceding Argonauta-class submarines. They displaced 691 metric tons (680 long tons) surfaced and 850 metric tons (837 long tons) submerged. The submarines were 61.5 meters (201 ft 9 in) long, had a beam of 5.7 meters (18 ft 8 in) and a draft of 4.7 meters (15 ft 5 in). Their crew numbered 45 officers and enlisted men.

For surface running, the boats were powered by two 675-brake-horsepower (503 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 Sirena class had a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 8 knots (15 km/h; 9.2 mph); submerged, they had a range of 72 nmi (133 km; 83 mi) at 4 knots (7.4 km/h; 4.6 mph).

The boats were armed with six 53.3-centimeter (21 in) torpedo tubes, four in the bow and two in the stern for which they carried a total of 12 torpedoes. They were also armed with a single 100 mm (3.9 in) deck gun forward of the conning tower for combat on the surface. The anti-aircraft armament consisted of two or four 13.2-millimeter (0.52 in) machine guns.

Construction and career

Diamante was laid down by Cantieri navali Tosi di Taranto at their Taranto shipyard in 1931, launched on 21 May 1933 and completed the following year. The boat was lost on 20 June 1940 off Tobruk sunk by the British submarine Parthian.

References

• Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6.
• Brescia, Maurizio (2012). Mussolini's Navy: A Reference Guide to the Regina Marina 1930–45. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-59114-544-8.
• 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.
• Colombo, Lorenzo (May 27, 2024). "R.Smg. Diamante". regiamarina.net. Cristiano D'Adamo. Retrieved May 27, 2024. Operational History