Length |
60.2 metres |
Wide |
6.4 metres |
Draught |
4.7 metres |
Tonnage |
695 |
Propulsion |
two diesel engines, two electric motors |
Armour |
– |
Armament |
- four bow 53.3 centimetre torpedo tubes
- two stern 53.3 centimetre torpedo tubes
- 12 torpedoes
- single 100 millimetre deck gun
- two pairs of 13.2 millimetre machine guns
Perla-Class Submarine |
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The Perla-class submarines are the third sub-class of the 600 Series coastal submarines constructed for the Regia Marina during the 1930’s. Named after gemstones, this class consists of ten submarines, of which only three survive the Second World War.
The Perla-class is essentially a continuation of the preceding Sirena-class, incorporating a series of incremental upgrades. Modifications include an enlarged false tower, modernised diesel engines, and the addition of a radiogoniometer controllable from within the vessel. Improved air conditioning systems enhance crew comfort, while increased fuel storage provides greater operational range. These upgrades result in a slight increase in displacement compared to earlier designs. The Perla-class has a full-load displacement of approximately 695 metric tons surfaced and 855 metric tons submerged, although minor variations exist depending on the builder. The submarines measure 60.2 metres in length, with a beam of 6.4 metres and a draught ranging from 4.6 to 4.7 metres.
For propulsion on the surface, each submarine is powered by two diesel engines, generating a combined output of 675–750 horsepower, each driving one propeller shaft. When submerged, propulsion is provided by two 400-horsepower electric motors. These submarines achieve a maximum surface speed of 14 knots and 7.5 knots underwater. Their surface range extends to 5,200 nautical miles at 8 knots, while their submerged range is 74 nautical miles at 4 knots.
Armament includes six internal 53.3 centimetre torpedo tubes, with four mounted in the bow and two in the stern. Each tube is accompanied by a reload, allowing the submarines to carry a total of 12 torpedoes. For surface combat, they are equipped with a single 100 millimetre deck gun. Anti-aircraft defence consists of one or two pairs of 13.2 millimetre machine guns, providing light protection against aerial threats.
Submarine Iride |
The Perla-Class Submarine Iride is despite the shortcomings identified in Siluri a Lenta Corsa transport arrangements trialled aboard Ametista, hastily converted in July 1940 at the La Spezia Shipyards to carry four Siluri a Lenta Corsa devices on simple deck saddles. This urgent modification is undertaken to meet the pressing need for deploying manned torpedoes in upcoming operations.
Under the command of Lieutenant Francesco Brunetti, Iride sets out on a test cruise in preparation for Operation GA 1, a mission intended to infiltrate Alexandria Harbour using the Siluri a Lenta Corsa’s. On August 22nd, 1940, at 12:00 hours, the submarine Iride is anchored in the bay of Ain El Gazala (also known as Menelao Bay) in the Gulf of Bomba, approximately 2.8 kilometresfrom Ras Megara. The submarine becomes the target of an air attack by Swordfish aircraft of No. 824 Squadron, based at Dekheila and operating under H.M.S. Eagle. The strike is prompted by air reconnaissance from the previous day, which had reported Iride’s presence. To ensure the operation’s success, Swordfish aircraft are repositioned to Ma’aten Bagush, near Sidi Barrani, to bring them within range of the target.
At 12:58 hours, three Swordfish torpedo bombers, piloted by Captain Oliver Patch, Royal Marines (mission leader), Lieutenant Neville Addison Fyers Cheesman, Royal Navy, and Lieutenant John Walter George Wellham, Royal Navy, launch their attack. The flight navigator, Midshipman Gordon John Woodley, RNVR, expertly guides the aircraft over the sea, with the land coming into view only at the moment of the strike. Approaching from the northwest at an altitude of just 9 metres, the aircraft focus their attack on Iride, which is cruising approximately 6.4 kilometres off the coast.
The Iride opens fire with two twin-mounted machine guns, and other vessels in the area join in the defensive fire. Captain Patch releases his torpedo, which strikes Iride, breaking the submarine in half and causing it to sink in water 14–16 metres deep. Lieutenant Wellham targets the auxiliary minelayer Monte Gargano, launching his torpedo from a range of 460 metres. The Monte Gargano catches fire and sinks after being struck. Lieutenant Cheesman is reported to have aimed at a second submarine alongside a destroyer, but there is no evidence of another submarine in the area. Italian sources confirm that Iride was hit by two torpedoes.
At the time, it is claimed that four ships were sunk or heavily damaged with three torpedoes. However, it is later confirmed that only Iride and Monte Gargano (with three wounded) are lost. The torpedo boat Calipso sustains minor damage, suffering two killed or missing and four wounded.
The Iride is in the process of receiving Siluro a Lenta Corsa’s from the torpedo boat Calipso, which had transported them from La Spezia. Of the Iride’s crew, five men are rescued immediately, and six more are pulled from the sunken submarine. Tragically, three officers and thirty ratings perish. Rescue operations commence quickly, with assistance from Calipso and the tugs Egadi and Luigi Rizzo.
Eight crew members are located within the sunken submarine, and rescue divers work to free them. Seven successfully escape, while the eighth man, paralysed with fear, refuses to leave. Sub-Lieutenant Luigi Durand De La Penne, who would later achieve fame for his role in the Alexandria raid, enters the submarine. Using his own Davis apparatus, he spends 12 minutes rescuing the trapped man. In total, 15 crew members, including Tenente di Vascello Brunetti, survive the attack.
In the aftermath of the attack, the operators of the assault craft demonstrate exceptional determination, working tirelessly over the next 24 hours to rescue crew members trapped inside the submarine’s hull. Their efforts save several lives, although many perish in the disaster. The four Siluri a Lenta Corsa’s aboard Iride are later recovered, though they are likely damaged by the attack and subsequent sinking.
Submarine Ambra |
Perla-Class Submarine Ambra is selected for conversion into an assault craft carrier in October 1941. The transformation is carried out at the La Spezia Shipyards, involving the removal of its deck gun and the installation of three watertight cylinders similar to those on Sciré. The conning tower is modified and reduced in size to improve surface concealment. By early 1942, Ambra is ready for its new role and assigned to the operational control of the Xa Flottiglia MAS to begin training.
Under the command of Lieutenant Arillo, later promoted to Lieutenant Commander, and subsequently Lieutenant Commander Renato Ferrini, Ambra undertakes three major missions transporting assault craft:
On May 13th, 1942, at 21:10 hours, the Italian submarine Ambra approaches its designated target for Operation GA 4, near Alexandria. The searchlights of the city are observed from approximately 3.2 kilometres north of Ras el Tin. At 23:40 hours, the British detect the crossing of the western loop and respond by launching a series of depth charge attacks at 01:30 and 01:40 hours.
By 01:30 hours on May 14th, 1942, anti-aircraft fire is visible over the city, as an air raid is underway to provide cover for the operation. At 03:00 hours, Ambra proceeds submerged, with Tenente di Vascello Mario Arillo using bathometric readings to guide the submarine. At 19:25 hours, the submarine reaches the seabed, halting at a depth of 10.5 metres near the Ras el Tin light, which is still visible at 3.2 kilometres. Between 20:25 and 20:50 hours, three Siluro a Lenta Corsa’s are launched. Each is piloted by a two-man team:
- Guardiamarina Giovanni Magello and (Secondo Capo Palombaro Giuseppe Morbelli
- Tenente Generale Navale Luigi Feltrinelli Sottocapo Palombaro Luciano Favale
- Sottotenente di Vascello Giorgio Spaccarelli and Sergente Palombaro Armano Memoli
Despite careful planning, strong currents cause the Siluro a Lenta Corsa’s to drift several thousand metres off course, rendering the mission unsuccessful.
The operatives scuttle their Siluro a Lenta Corsa’s near Agami, Mex, and Anfouchy, west of Alexandria’s harbour entrance, setting them to explode at 10:30 hours. Two Italian crew members are captured at Mex around 06:00 hours, while another two are apprehended near Anfouchy at 10:30 hours after taking refuge near the wreck of the City of Pittsburgh. The third team, consisting of Sub-Lieutenant Feltrinelli and Leading Diver Favale, manages to evade capture until 19 June.
The British Mediterranean Fleet is already on heightened alert, having received intelligence as early as 6 May suggesting an Italian attack on Alexandria. It is believed that the operation’s primary target is the city’s floating dock.
On December 11th, 1942, at 21:45 hours, the Italian submarine Ambra positions itself for Operation NA 1, approximately 2,000 metres from the southern entrance of Algiers harbour. The mission, known as Operazione N.A.1, aims to attack Allied shipping in the heavily guarded port. By 23:00 hours, ten Gamma men exit the submarine to begin their mission. At 23:20 hours, three Siluro a Lenta Corsa’s, are launched, each crewed by a two-man team.
The Siluro a Lenta Corsa teams are led by Tenente di Vascello Giorgio Badessi, accompanied by Secondo Capo Palombaro Carlo Pesel. The second Siluro a Lenta Corsa is piloted by Tenente Navale Generale Guido Arena and Sottocapo Palombaro Ferdinando Cocchi. The third Siluro a Lenta Corsa is manned by Guardiamarina Giorgio Reggioli and Secondo Capo Palombaro Colombo Pammolli.
The Gamma men are deployed in five teams, each targeting specific objectives in the harbour. The first team consists of Sergente Alberto Evangelista and Sergente Luigi Rolfini. The second team is made up of Sergente Gaspare Ghiglione and Soldato Luciano Luciani. The third team includes Secondo Capo Fuochista Rodolfo Lugano and Marò Giovanni Lucchetti, who defies orders to return to the submarine and continues with the mission. The fourth team comprises Secondo Capo Palombaro Giuseppe Feroldi and Marò Evideo Boscolo. Feroldi is unable to reach his target, but Boscolo successfully attacks his assigned objective. The final team includes Sottotenente Agostino Morello and Secondo Capo Fanteria Oreste Botti.
Two reserve personnel remain aboard Ambra: Tenente di Vascello Augusto Jacobacci and Secondo Capo Armando Battaglia.
The Allied ships in Algiers harbour include the British Empire Centaur (7,041 GRT), the Norwegian Berto (1,493 GRT), the British Harmattan (4,558 GRT), the British Ocean Vanquisher (7,174 GRT), and an unidentified vessel later identified as the U.S.S. Thomas Stone, which had been beached after a previous attack. Also present are the light cruisers H.M.S. Sirius and H.M.S. Dido and the sloop H.M.S. Deptford, ensuring that the harbour is heavily defended.
By 06:20 hours on December 12th, 1942, the Berto is sunk, with all her crew surviving. The Empire Centaur suffers heavy flooding in her No. 2 and No. 3 holds. The Harmattan has her engine room flooded and beaches herself to avoid sinking. The Ocean Vanquisher runs aground, with both her engine and boiler rooms flooded.
Despite the success of the mission in damaging and sinking key targets, all 16 operatives of the Xa Flottiglia MAS are captured by Allied forces. Operazione N.A.1 is nevertheless considered a significant success, highlighting the ingenuity and courage of the Italian naval special forces.
On July 14th, 1943, the Italian submarine Ambra departs La Spezia at 15:32 hours, carrying three Siluro a Lenta Corsa intended to attack the harbour of Syracuse (or, according to some sources, three explosive boats targeting Augusta). On July 16th, at 20:30 hours, she rendezvouses with the torpedo boat Partenope at Point M3 for an escort through the Strait of Messina. Later that evening, at 22:43 hours, Ambra passes a hospital ship traveling on an opposite course at position 38°23’N, 15°46’E.
At 00:35 hours on July 17th, 1943, while being escorted by Partenope near the San Rainieri Light in the Strait of Messina, Ambra is ordered to stop off Messina to allow the light cruiser Scipione Africano to cross the strait. At 02:10 hours, Scipione Africano engages unidentified naval targets, sinking MTB-316, whose entire eleven-man crew perishes. MTB-313 is also damaged, suffering one fatality and one injury. Despite the MTB’s claiming two torpedo hits, Scipione Africano emerges unscathed.
Later that evening, at 22:32 hours, Ambra observes five enemy vessels at a distance of 12,000 metres but refrains from attacking, as she is under orders to remain covert until her special mission is completed.
At 03:20 hours on July 18th, 1943, Ambra is attacked by a Wellington aircraft (HZ.116) from 221 Squadron, piloted by Pilot Officer E. Austin. The aircraft, having detected the submarine from a range of 10 kilometres, makes an approach along the moonpath and drops five 250-pound depth charges and three 100-pound anti-submarine bombs from a height of 60 metres. Ambra suffers near-misses that damage her hull and wound several crew members, rendering her unable to submerge. Forced to abort her mission, she retreats through the Strait of Messina, escorted by the corvette Cicogna and torpedo boat Partenope. At 19:15 hours, a lurking submarine is reported, prompting Cicogna to detach and investigate, while Ambra and Partenope continue to Naples.
On July 25th, 1943, at 14:00 hours, Ambra departs Naples for La Spezia, accompanied by the steamer Saluzzo and escorted by the torpedo boats Ardito and Animoso. On July 26th, 1943, at 18:40 hours, Ambra leaves the convoy near Piombino and continues alone to La Spezia. Upon arrival, it is determined that her damage is more severe than initially assessed. Plans are proposed to revert her to standard submarine operations following the commissioning of Murena in late September and Grongo in October 1943.
On September 9th, 1943, following the announcement of the Italian armistice, Ambra is scuttled at La Spezia to prevent her capture. This marks the end of her service in the Regia Marina.
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