Italian auxiliary ship Olterra
Italian auxiliary ship Olterra | |
---|---|
Part of the Mediterranean | |
Result | 42,000 tn of Allied shipping sunk[1] |
Ernesto Notari
9 manned torpedoes
2 sailors killed
3 prisoners
2 manned torpedoes lost
The auxiliary ship Olterra was a 5,000 ton Italian tanker scuttled by her own crew at Algeciras in the Bay of Gibraltar on 10 June 1940, after the entry of Italy in World War II. She was recovered in 1942 by a special unit of the Decima Flottiglia MAS to be used as an undercover base for manned torpedoes in order to attack Allied shipping at Gibraltar.[2]
Construction and early career
Olterra started life as the
Previous operations
From 24 September 1940 to 15 September 1942, there were six submarine-borne assaults on Gibraltar. Three of them resulted in the destruction or sinking of a number of Allied freighters,[6][7][8][9][10] with a total tonnage of some 40,000 tn.[11] Three of them were carried out by human torpedoes launched from the submarine Scirè; the other two were the work of combat swimmers.
Villa Carmela
After the attacks carried out by Scirè, the commander of the Decima MAS realised that, given the limitations of using a submarine as a mother ship for human torpedoes in Gibraltar, it would be more feasible to mount a secret base in neutral Spain. A first step in that direction was taken when a member of the Decima, Antonio Ramognino, rented a bungalow along the coast road near Algeciras, right in front of a bay used by Allied convoys to drop anchors. The operations from Villa Carmela were carried out by
Five merchant ships were sunk or damaged from July to September 1942 by
Refitting
At the same time, another officer of the Italian special unit, Lieutenant
First incursion
By the end of the autumn of 1942, Olterra was ready for her mission. The workshop works were completed and all the supplies smuggled from Italy had reached Spain without raising any suspicion.[21] On 6 December 1942, after taking part in Operation Torch, a naval squadron consisting of the battleship HMS Nelson, the battlecruiser HMS Renown, the aircraft carriers HMS Furious and HMS Formidable and a number of escort units entered Gibraltar. Visintini planned a three manned torpedoes mission, each of them carrying two divers: the leading torpedo, driven by Visintini himself and Petty Officer Magro, the second by 2nd Lieutenant Cella and Sergeant Leone and the third by Midshipman Manisco and Petty Officer Varini. The targets were designated in the following order: for Visintini, Nelson, for Manisco, Formidable and for Cella, Furious.
The assault craft departed from Olterra during the early hours of 8 December. At 2:15 AM, the first human torpedo reached the area of the boom defences. The motor launches and sentries inside the British base were quietly active and alert, conscious of the danger of a potential attack on the fleet at anchor. One of the security measures taken by the Royal Navy after the summer incursions of combat swimmers was the deployment at Gibraltar of an underwater bomb disposal unit, under the command of Lieutenant
Second incursion
After the death of Visintini, Lieutenant Ernesto Notari took charge of the Ursa Major unit onboard Olterra. Replacements of personnel and materials were also sent from Italy.[24] Owing to the improvements in the boom defenses, the next missions were planned against transport and cargo ships in the anchorage area around the naval base.[25] The end of the war in North Africa and the subsequent Allied landings on Sicily also made the attacks on logistic ships a priority.[26] In May 1943, Commander Borghese, of Scirè, was appointed commander of the Decima. The night of the 8th was chosen for the next assault, taking advantage of the bad weather and the phase of the moon. Lieutenant Notari, along with his second, Petty Officer Ario Lazzari, was the head of another three-torpedo wave heading for Gibraltar. The second human torpedo was manned by Lieutenant Tadini and Petty Officer Mattera, and the third by Second Lieutenant Cella and Petty Officer Montalenti. In order to divert any British suspicion from Olterra, the selected targets were merchant ships at anchor in the farthest point from Algeciras. The gale that was raging at the time hampered the mission, because the current forced them to dive around the targets before they could attach the limpet mines to the hulls. At dawn, all the Italian craft reached their mother ship safely. They had mined three vessels, the American Liberty ship Pat Harrison (7,000 tons), and the British freighters Mahsud (7,500 tons) and Camerata (4,875 tons). When the charges exploded, the American transport was heavily damaged and became a total loss. One American sailor was killed by the blast.[27] Mahsud rested on the bay’s bottom with much of the ship still above the water line, while Camerata sank outright. To mislead the British into thinking of combat swimmers instead of manned torpedoes, members of the Italian secret service scattered diving equipment along the shore. The second attempt from Olterra had been a stunning success.[28]
Last mission
On 25 July, Mussolini was removed from power, a clear signal that Italy was on the brink of collapse. The course of the war and the political changes were no deterrent for the Decima MAS, which continued to plan and execute attacks on Allied shipping in all fronts. On 10 June, the unit was awarded the Medaglia d’oro as a tribute to their deeds. On the night of 3 August 1943, the Ursa Major carried out the last operation against Gibraltar. Again, three craft left the Olterra in search of their targets: three transport ships at anchor in the bay. Notari led the "pigs" close to the Spanish coast to avoid the searchlights aimed at open sea. His second man was Petty Officer Andrea Gianoli, whose training on piloted torpedoes was poor. While the crew was clamping the explosive charge to the keel of a Liberty ship, their torpedo spun out of control. Notari opened the diving valves, and the "pig" suddenly
Aftermath
Italy submitted to Allied terms on 8 September 1943. The war was over, this time for good, for Olterra. Until then, the British in Gibraltar had no proof to link the presence of the tanker at Algeciras with the raids on their ships. In Leon Goldsworthy's words:
We never found any proof of the part played by the Olterra in this affair. From British Naval Headquarters on Gibraltar we could see, with the naked eye, the Olterra’s superstructure above the exterior mole at Algeciras. The possibility that the Olterra might be associated in some way with the attacks of human torpedoes did not escape us, but there was never the least visible evidence to suggest the actual nature of her participation.[31]
The Spanish authorities tried to hide the evidence, but when Crabb’s diving team boarded Olterra after the
Relics from the Olterra
Though the ship was broken up and disposed of in 1961, some bits of her outer plating, bearing the ship's name and a few portholes were salvaged and put into display at the Italian Naval Museum in La Spezia, along with other Decima Flotilla MAS artifacts (a barchino assault explosive motor boat and a maiale manned torpedo).[35]
See also
- Decima MAS
- Human torpedo
- Military history of Gibraltar during World War II
- Spain in World War II
Notes
- ^ a b O’Donnell, p. 131
- ^ Breuer, pp. 29-32
- ^ Zapotoczny, Walter S. (2017). Decima Flottiglia MAS: The Best Commandos of the Second World War. Fonthill Media.
- ISBN 978-1-922488-09-1.
- ISBN 978-0-8108-6760-4.
- ^ Borghese, Chapter IV
- ^ Borghese, Chapter VI
- ^ Borghese, Chapter VIII
- ^ Borghese, Chapter X
- ^ Borghese, Chapter XV
- ^ Borghese, Appendix
- ^ Borghese, pp. 208-209
- ^ Borghese, ppp 212 and 219
- ^ Borghese, p. 210
- ^ a b Schofield & Carisella, p. 152
- ^ They were the skipper and the chief engineer. Borghese, p. 214
- ^ Borghese, p. 217
- ^ Bragadin, p. 290
- ^ Borghese, p. 219
- ^ Other Italian authors said that the name was given after the war. Longo, p. 85
- ^ O’Donnell, p. 154
- ^ Borghese, pp 213-226
- ^ Schofield & Carisella, pp. 151-154
- ^ Borghese, p. 241
- ^ Breuer, p. 32
- ^ Borghese, p. 242
- ^ a b Official USN Chronology (1943)
- ^ Borghese, pp. 242-243
- ^ Borghese, pp. 257-259
- ^ "M/T Thorshøvdi - Norwegian Merchant Fleet 1939-1945". www.warsailors.com. Retrieved 2 August 2021.
- ^ Borghese, p. 244
- ^ Pugh, p. 101
- ^ Greene & Massignani, p. 115
- ^ Pugh, p. 110
- ^ Sidoli, Osvaldo. "El "Olterra" - Un petrolero que hundió 8 barcos enemigos sin navegar" (in Spanish). Histarmar.com.ar. Retrieved 9 March 2016.
External links
Sources
- ISBN 1-55750-072-X.
- Bragadin, Marc'Antonio (1957). The Italian Navy in World War II, ISBN 0-405-13031-7.
- ISBN 0-471-40419-5
- Cocchia, Aldo (1958). The hunters and the hunted. United States Naval Institute, Annapolis. ISBN 0-405-13030-9.
- Greene, Jack & Massignani, Alessandro (2004).The Black Prince and the Sea Devils: The Story of Valerio Borghese and the Elite Units of the Decima MAS. ISBN 0-306-81311-4.
- Longo, Luigi Emilio (1991). "Reparti speciali" italiani nella seconda guerra mondiale: 1940-1943. (in Italian) Mursia. ISBN 88-425-0734-2.
- ISBN 0-8065-2798-6
- Pugh, Marshall(1956). Frogman: Commander Crabb's Story. Scribner.
- Schofield, Williams, Carisella P. (2004). Frogmen: First Battles. Branden Books. ISBN 0-8283-2088-8.