Italian submarines in World War Two

Gemma (GE)

TypeCoastal / Sea going 
ClassPerla (22) 
Laid down 7 Sep 1935 Cantieri Riuniti dell'Adriatico, Monfalcone
Launched21 May 1936
Commissioned8 Jul 1936
End service
Loss date8 Oct 1940
Loss position35° 30'N, 27° 18'E
Fate Torpedoed and sunk in error to the west fo Karphatos in position 35°30'N, 27°18'E by the Italian submarine Tricheco.


CommanderDate fromDate toCommand notes
C.C. Guido Cordero Di Montezemolo10 May 19408 Oct 1940

Ships hit

No ships hit by this submarine.

Patrols and events

 CommanderDateTimePortArr. dateArr. timeArr. portMilesDescription
1Cordero Di Montezemolo, Guido4 Jun 19402307Brindisi15 Jun 19400633Leros655,4Transfer to Leros and patrol in 112° - Cape Mastiko (Chios) - 11 miles. Uneventful patrol, sighted an Hellenic destroyer of the PERGAMOS class off Zante, only four neutral vessels and an Italian destroyer of the SELLA class.

Cordero Di Montezemolo, Guido22 Jun 19400807Leros22 Jun 19401320Leros1,2Trials.

2Cordero Di Montezemolo, Guido28 Jun 19401700Leros10 Jul 19401345Leros1260,6Patrolled from a point 30 miles northeast of Ras Haleima (Sidi Barrani) on line 15 miles long NE and 15 miles SW. The area was delimited by (1) 31°49' N, 26°08' E (2) 32°13' N, 26°30' E (3) 32°04' N, 26°44' E (4) 31°40' N, 26°22' E.
  29 Jun 1940122634° 14'N, 27° 09'E
(0) 148° - Cape Sidero - 76 miles (SE of Crete).
At 1226 hours, an aircraft attacked Gemma with two small bombs which fell 30 metres astern. The submarine crash-dived. C.C. Cordero di Montezemolo noted in his report that, by an odd coincidence, his submarine had been attacked exactly at one of the points she was to go through (which suggests that signals had been compromised).

In fact this was a case of mistaken identity as the aircraft was Italian.
  1 Jul 19400247-0250
(0) North of Ras Haleima (Sidi Barrani) [probably about 25 miles north of Sidi Barrani].
At 0247 hours, the conning tower of a submarine was sighted at a distance of 2,000 metres. The submarine disappeared before an attack could be made.

At 0437 hours, hydrophone effects were detected, probably coming from the same submarine, but without result.

This was probably HMS Parthian (Lieutenant Commander M.G. Rimington, RN) returning to Alexandria. An opportunity was thus lost to avenge the loss of Diamante sunk by this submarine during this patrol.
  5 Jul 19401928-2200
(0) North of Ras Haleima (Sidi Barrani).
At 1928 hours, an enemy submarine was detected with hydrophones. C.C. Guido Cordero Di Montezemolo waited for the submarine to surface to attack.

At 2050 hours, two large surface vessels were detected approaching. The attempt to attack the enemy submarine was abandoned and Gemma surfaced and to close the newcomers, but only sighted distant lights. At 2200 hours, she abandoned the chase.

Cordero Di Montezemolo, Guido23 Jul 19400717Leros23 Jul 19401014Leros5Trials.

3Cordero Di Montezemolo, Guido5 Aug 19401529Leros17 Aug 19401056Leros981Patrolled off north and north-east of Crete, from Cape Sidero and Cape Spada and Cerigo Channel, visiting the anchorage of Grandes Bay and the port of Megalocastro. Sighted only Greek vessels.

4Cordero Di Montezemolo, Guido30 Sep 19401555Leros8 Oct 19400121Sunk with all handsPatrolled in Kaso Strait (east of Crete) for Operation C.V. (reinforcements for the Dodecanese). At 2000 hours on 3rd October, she was ordered to operate between Rhodes and Scarpanto until 2100 hours on the 8th. British Naval Intelligence had been informed that Gemma was ordered to leave her patrol at 2000 hours on the 9th and make landfall at Kandeluisa. Sunk in error by the submarine Tricheco. No survivors, five officers and forty ratings were killed. Tricheco would herself be sunk by the famous HMS Upholder in 1942.
  8 Oct 1940012135° 30'N, 27° 18'EDuring the evening of 7th October, Gemma had received the order to leave her patrol at 2100 hours on 8th October to return to Leros.

Unknown to her, two ratings of the submarine Tricheco had gotten into a fight and one suffered a serious head injury, which was bleeding profusely. The submarine was patrolling the southern approaches of the Kasos Strait. Her commander, C.C. Alberto Avogrado di Cerrione Trotti Bentivoglio decided to interrupt his patrol. He had informed EGEOMIL of his decision but he was not aware that Gemma had shifted position and could be met on his return.

At 0100 hours on the 8th, belatedly, EGEOMIL sent a signal to both submarines that an Italian submarine could be in their vicinity. It was already too late.

At 0115 hours, Tricheco observed a submarine bearing 320° on a parallel course (i.e. on a northward course). The witnesses were adamant that it did not look like an Italian submarine. The signal from EGEOMIL had not been yet processed. Tricheco turned to port and fired two torpedoes (533mm) from bow tubes at a range of 800 metres. The first missed ahead, but the second squarely hit amidship the target. Tricheco dived immediately and resumed her passage. Another explosion was heard which was attributed to the first torpedo hitting the coast. Tricheco arrived at Leros the same afternoon at 1530 hours. It was quickly understood that Gemma had been the unfortunate victim.

There were no survivors. C.C. Guido Cordero Di Montezemolo, four officers and forty ratings perished.

8 entries. 6 total patrol entries (4 marked as war patrols) and 4 events.

All Italian submarines