Italian submarines in World War Two

Diamante (DI)

TypeCoastal / Sea going 
ClassSirena (21) 
Laid down 11 May 1931 Cantieri Navale Tosi di Taranto, Taranto
Launched21 May 1933
Commissioned18 Nov 1933
End service
Loss date20 Jun 1940
Loss position32° 41'N, 23° 49'E
Fate Torpedoed and sunk about 35 nautical miles north-north-west of Tobruk, in position 32°41.5'N, 23°49'E by the submarine HMS Parthian.


CommanderDate fromDate toCommand notes
T.V. Angelo Parla24 Mar 194020 Jun 1940

Ships hit

No ships hit by this submarine.

Patrols and events

 CommanderDateTimePortArr. dateArr. timeArr. portMilesDescription
1Parla, Angelo9 Jun 19401800Tobruk20 Jun 19401445Sunk with all handsSailed with Lafolè and patrolled 030° - Ras Azzaz - 50 miles (or 40 miles?) (on a line with Lafolè, Nereide and Topazio, 20 miles apart). Apparently, she had an engine breakdown as Lafolè sighted her slowing down at 0020 hours on 10th June. On 13rd June 1940, was shifted to 030° (or 025°?) - Tobruk - 35 miles. At 1935 hours on the 19th, she was informed by MARICOSOM of the presence of an enemy submarine off Tobruk and at 1025 hours on the 20th, she was ordered to return quickly to Tobruk on the surface. She signalled that she expected to reach Sidi Abeida (23°45'E) about 15 miles to the west of Tobruk and a destroyer of the Turbine division was to sail from Tobruk to meet her. Sunk by HMS Parthian in 32°35'N, 24°10'E, about 30 miles north of Tobruk. Five officers and thirty-eight ratings were lost. No survivors.
  10 Jun 1940
2145 (e)
At 2145 hours, the destroyer HMS Decoy sighted a surfaced submarine. The range was only 300 yards and the destroyer attempted to ram but could not turn in time and missed the conning tower by 30 yards. As the submarine submerged stern first, one 4in round was fired from the “B” gun but the close range (100 yards) meant that the gun could not be depressed enough. One depth charge was dropped and a flare dropped to mark the position of the submarine followed shortly after by a pattern of four depth charges.

A strong smell of oil was observed. It is likely that the submarine was Diamante as the position was very close to her patrol area (an oil slick 2 miles long was reported to have been seen). Technically, this attack occured before the state of war was declared, which was to occur at 0001 hours on 11th June. Diamante was lost on her return, but we shall never know for sure.
  20 Jun 1940
1502 (e)
At 1445 hours, HMS Parthian was patrolling off Tobruk when a submarine of the PERLA class was sighted at 6,500 yards. Parthian had been informed that submarines were expected at Tobruk as a decrypt from GC & CS (Government Code and Cypher School) had revealed instructions to Lafolè and another submarine (Diamante was not named). The British submarine closed to 400 yards and fired four torpedoes at 3-second intervals. They all hit and the submarine disintegrated.

This was Diamante returning from patrol. There were no survivors. Five officers and thirty-eight ratings perished. This was the first success of British submarines in the Mediterranean.

On 19th June, the German B-Dienst had deciphered a signal made to HMS Parthian indicating that the Italian submarine Lafolè had entered Sidi-El-Beida and had requested a pilot from Tobruk. Obviously, B-Dienst could conclude that Italian signals were read by the British. Lafolè was luckier and reached Tobruk without mishaps.

2 entries. 1 total patrol entries (1 marked as war patrols) and 2 events.

All Italian submarines