Operazione Baia di Gibilterra 1 e 2

Allied Forces

• Gibraltar Harbour, British Territories

Axis Forces

Operazione Baia di Gibilterra 1

• Adua-Class submarine Scirè
• 1^a Flottiglia MAS
  • Tenente di Vascello Gino Birindelli
  • Capo di 2^a Classe Mario Paccagnini
  • Capitano di Corvetta Teseo Tesei
  • Sergente Alcide Pedretti
  • Sottotenente di Vascello Luigi Durand de la Penne
  • Capo di 2^a Classe Emilio Bianchi
  • Tenente del Genio Navale Gian Gastone Bertozzi
  • Sergente Enrico Ario Lazzari
  • Three Siluro a Lenta Corsa’s

Operazione Baia di Gibilterra 2

• Adua-Class submarine Scirè
• 1^a Flottiglia MAS
  • Tenente di Vascello Gino Birindelli
  • Capo di 2^a Classe Mario Paccagnini
  • Capitano di Corvetta Teseo Tesei
  • Sergente Alcide Pedretti
  • Sottotenente di Vascello Luigi Durand de la Penne
  • Capo di 2^a Classe Emilio Bianchi
  • Tenente del Genio Navale Gian Gastone Bertozzi
  • Capo di 2^a Classe Giuseppe Viglioli
  • Three Siluro a Lenta Corsa’s

Operation

After Italy joined Germany in World War 2 the need for weakening the British fleet in the Mediterranean became very urgent. The British had a far bigger fleet in the area than the Italians could handle. On September 16^th ,1940, General Pietro Badoglio of the Italian Supreme Command writes a letter that makes this matter clear.

The British naval forces in the Mediterranean are currently concentrated at the two bases of Gibraltar and Alexandria. The Gibraltar fleet consists of three battleships, one aircraft carrier, and several smaller ships, while the Alexandria fleet comprises five battleships, two aircraft carriers, and smaller vessels. It is always possible for the Home Fleet to send reinforcements, either to replace losses or to increase the strength of the Mediterranean fleet.

Our fleet is composed of five battleships, no aircraft carriers, and smaller ships. With this strength, it could engage in battle with the Gibraltar fleet. However, it would be at a marked disadvantage against the Alexandria fleet. No reinforcements can be expected for our fleet, nor can replacements for potential losses.

In the first three months of the war, the British fleet has achieved certain objectives. It has fully carried out its mission to block the Suez Canal and has partially succeeded in restricting access to the Strait of Gibraltar, although our submarines have consistently been able to pass through. It has managed to secure convoy routes from Turkey and Greece, albeit with serious disruptions and significant losses, and has been strongly supported by the unwaveringly pro-British stance of these two nations. It has failed to damage our maritime traffic meaningfully and has inflicted only minor harm on our Libyan coasts. It has defended its bases effectively, even though they are frequently attacked by our aviation forces.

In the same period, our fleet has guaranteed uninterrupted and secure communication with Libya and Albania, ensuring continuous and unimpeded maritime traffic. It has not had to intervene against attacks on our coasts, as none have been attempted by the enemy, but it has not been able to prevent the occasional enemy incursions on the Libyan coastline. It has effectively supported aviation efforts against enemy convoys using light vessels and submarines, causing losses to the enemy. It has also successfully defended its bases, which have only rarely been threatened by enemy air or submarine forces.

Despite the British fleet being twice the size of ours, both fleets have so far conducted similar types of operations. Examining the results, it must be concluded that the balance of outcomes is more favourable to us. The losses and damage sustained by both sides are roughly equivalent. It is clear that the more powerful navy, the British, has a greater interest in changing this state of affairs, whereas we should aim to preserve the current situation. Despite being weaker, we are fully able to carry out the missions assigned to our Navy under the existing conditions. There is therefore no reason to alter the course of action pursued so far.

A naval battle could arise from two possible situations: either an encounter between enemy fleets where one seeks to prevent the other from completing a mission, or a deliberate effort by one fleet to seek out and destroy the other. The first scenario could occur at any moment, as happened in the brief clash at Punta Stilo. In such a case, our Navy will face the battle with the utmost determination if success seems likely. The second scenario is beyond our capability, as we are the weaker side. If the British Navy initiates such an action, we will be prepared to face the consequences. Conceiving a naval battle as an end in itself is illogical and does not warrant further discussion.

The conclusion is to continue along the path followed so far.

General Pietro Badoglio

After the failed Operazione Golfo di Alessandria 1 and the aftermath of the submarine Iride’s sinking, Admiral Domenico Cavagnari, Chief of Staff of the Royal Italian Navy, assigns Commander Mario Giorgini a new mission. The 1^a Flottiglia MAS is to conduct near-simultaneous attacks using Siluro a Lenta Corsa’s against Alexandria, Egypt, and Gibraltar. The submarines Gondar and Scirè, currently undergoing modifications at the La Spezia Arsenal to serve as Siluro a Lenta Corsa carriers, are selected for this operation: Gondar targets Alexandria for Operazione Golfo di Alessandria 2, while Scirè is directed towards Gibraltar for Operazione Baia di Gibilterra 1.

Gibraltar is a British Overseas Territory located at the southern tip of the Iberian Peninsula, covering an area of 6.8 square kilometres. It sits at the entrance to the Mediterranean Sea, controlling the Strait of Gibraltar, the narrow waterway that separates Europe from Africa. This position makes it one of the most strategically significant locations in global naval operations. the Territory consists of the Rock of Gibraltar: A towering limestone promontory, rising 426 metres above sea level, which houses an extensive network of tunnels used for military fortifications. The Bay of Gibraltar: A deep-water port accommodating naval and commercial vessels, and the Strait of Gibraltar: A 13-kilometre-wide passage between Spain and Morocco, serving as a chokepoint for naval operations and maritime trade.

Gibraltar has been a crucial naval stronghold for centuries due to its ability to control maritime traffic between the Atlantic Ocean and the Mediterranean. During the Second World War, it serves as a heavily fortified British naval base, providing logistical support to Allied fleets and disrupting Axis operations in the region. Throughout the war, Gibraltar is a critical base for the Royal Navy, serving as a launch point for Mediterranean operations, including support for Malta convoys and North African campaigns. It remains under constant threat from Axis forces, leading to extensive defensive measures, including underwater anti-sabotage patrols, minefields, and anti-aircraft defences.

The British Force H stationed at Gibraltar compromised the Cruisers H.M.S. Enterprise, H.M.S. Arethusa, H.M.S. Sheffield, H.M.S. Coventry, and H.M.S. Calcutta, Aircraft Carrier H.M.S. Ark Royal, Battlecruiser H.M.S. Renown, and Battleships H.M.S. Hood, H.M.S. Resolution, and H.M.S. Valiant.

September 6th, 1940

The Adua-Class submarine Scirè under command of Adriano Pini departs La Spezia at 12:50 and returns at 18:10 after covering a distance of 43 kilometres. This is one of several exercises conducted to improve operational readiness.

September 17th, 1940 – September 21st, 1940

Capitano di Corvetta Junio Valerio Borghese conducts a series of training exercises after assuming command of the submarine Scirè.

September 24th, 1940

Scirè, under Borghese’s command, departs La Spezia at 05:40 for a mission targeting Allied naval assets in Gibraltar. The submarine carries three teams of human torpedo operators and one reserve team:

• Tenente di Vascello Gino Birindelli and Capo di 2^a Classe Mario Paccagnini
• Capitano di Corvetta Teseo Tesei and Sergente Alcide Pedretti
• Sottotenente di Vascello Luigi Durand de la Penne and Capo di 2^a Classe Emilio Bianchi
• Reserve: Tenente del Genio Navale Gian Gastone Bertozzi and Sergente Enrico Ario Lazzari

While en route, the mission is aborted 92.6 kilometres from Gibraltar after learning that British Force H has sailed.

October 3rd, 1940

The submarine Scirè returns to La Maddalena, part of the Maddalena Archipelago in northern Sardinia, Italy at 12:15.

October 8th, 1940

Scirè departs La Maddalena at 14:30 and

October 9th, 1940

Scirè arrives at La Spezia, Italy at 08:45, covering 383 kilometres.

October 17th, 1940

With document Fg. n° 6430 (S), the Supermarina, the headquarters of the Regio Marina, issues Commander Junio Valerio Borghese of the Adua-Class Submarine Scirè the detailed orders for Operazione Baia di Gibilterra 2. These directives reaffirm the provisions already established for Operazione Baia di Gibilterra 1 while specifying the date and time for Scirè’s departure from La Spezia, the precise routes to be followed during transit, and the procedures for the final approach to the designated exit point for the operators.

The order also includes instructions on the deployment of the Siluro a Lenta Corsa’s and their operators, detailing the methods for their exit and the routes they are to follow during the attack. It specifies the preparation requirements for accompanying aircraft and provides a general allocation of targets to be attacked during the operation. Additionally, the document outlines the procedures for recovering the operators following the mission and the planned return route for the Scirè after the attack is completed.

This comprehensive set of instructions demonstrates the meticulous planning and coordination required for such a complex operation, highlighting the importance of precision and discipline to ensure the mission’s success.

October 19th, 1940

The submarine departs La Spezia at 15:00 for a short training exercise, returning at 17:55 after covering 46 kilometres.

October 20th, 1940

Scirè departs La Spezia at 09:24 for an exercise with 1^a Flottiglia MAS units. The submarine returns at 12:05, covering 5.6 kilometres.

October 21st, 1940

Scirè departs La Spezia at 05:15 to commence Operazione Baia di Gibilterra 2, carrying three Siluro a Lenta Corsa teams and two reserve operators. The team is the same as for Operazione Baia di Gibilterra 1 only Sergente Enrico Ario Lazzari is replaced by Capo di 2^a Classe Giuseppe Viglioli.

• Tenente di Vascello Gino Birindelli and Secondo Capo Mario Paccagnini
• Capitano di Corvetta Teseo Tesei and Sergente Alcide Pedretti
• Sottotenente di Vascello Luigi Durand de la Penne and Secondo Capo Emilio Bianchi
• Reserve: Tenente del Genio Navale Gian Gastone Bertozzi and Capo di 2^a Classe Giuseppe Viglioli

October 27th, 1940

Near Almina Point, Scirè encounters a destroyer at 02:10, approximately 800 metres away, and crash-dives to avoid detection. At 23:45, another destroyer is sighted travelling at high speed. The submarine dives once more to evade pursuit.

October 28th, 1940

Between midnight and 06:00, Scirè evades four destroyers conducting anti-submarine operations near Almina Point by stopping its motors and drifting with the current. At 02:45 on 29 October, the submarine submerges to 70 metres and begins its passage through the Strait of Gibraltar at 6.5 kilometres/hour.

October 30th, 1940

At 01:21, Scirè reaches its designated launch point, bottoming at a depth of 10 metres, 350 metres from the Spanish coastline. Intelligence confirms the presence of two British battleships in Gibraltar’s harbour. Based on this information, Borghese issues the following orders for the attack: Siluro a Lenta Corsa 1 is assigned to target the outermost battleship. Siluro a Lenta Corsa 2 is tasked with attacking the innermost battleship using a specially modified SLC with extended range. Siluro a Lenta Corsa 3 is ordered to conduct a visual reconnaissance between the harbour buoys to confirm the presence of cruisers or aircraft carriers. If no such targets are identified, he is to proceed against the outermost battleship, specifically targeting the stern and propeller shaft. The aim is to maximise damage, potentially impacting both the outer and inner battleships.

Two reserve operators, Gian Gastone Bertozzi and Giuseppe Viglioli, are tasked with supporting the main teams during the critical phase of deployment. Their duties include helping to open the submarine’s cylinder hatches and carefully extracting the Siluri a Lenta Corsa’s. The first phase of the operation unfolds smoothly, as noted in the report by Tenente del Genio Navale Gian Gastone Bertozzi. Observations confirm that the submarine begins to submerge again after the operators successfully exit, indicating no complications during deployment. Attention is then directed to opening the port cylinder, which contains the device assigned to Lieutenant Durand de la Penne.

Sottotenente di Vascello Durand de la Penne arrives shortly afterward and assists in releasing the final catches on the hatch. Once opened and securely fastened, the apparatus is carefully removed, Sottotenente di Vascello De la Penne and Petty Officer Emilio Bianchi deploy their Siluro a Lenta Corsa into the water under challenging conditions, and thorough operational checks are conducted to ensure it is ready for deployment. They encounter immediate issues. The connections that maintain air circulation in the battery compartment is disconnected, and it quickly becomes clear that the pumps are unable to draw water from the tanks, rendering the device significantly heavier than expected.

Simultaneously, Tenente di Vascello Gino Birindelli and Capo di 2^a Classe Paccagnini commence work at the stern of the submarine, focusing on opening the starboard cylinder. The device inside is partially extracted and undergoes a detailed inspection by Tenente di Vascello Birindelli, who performs multiple tests on the pumps and the starting rheostat to verify its functionality. Their Siluro a Lenta Corsa, identified as No. 1, suffers from a malfunctioning transfer pump. After extracting the device, Birindelli finds it nearly impossible to surface without completely emptying the buoyancy tank.

Capitano del Genio Navale Teseo Tesei, a pioneer of the X^a Flottiglia MAS, leads the third team alongside Sergeant Pedretti. Upon deploying their Siluro a Lenta Corsa, Tesei immediately identifies significant problems. The instrument panel, particularly the compass, is heavily fogged, and the transfer pump operates irregularly. At approximately 03:20 hours, Captain Teseo Tesei departs on schedule, as reported by Capo di 2^a Classe Viglioli. Once all tasks are completed, the agreed-upon signals for surfacing are sent from the turret.

The report concludes with observations of the physically demanding conditions faced by the team, including exhaustion, cold shivers, and dizziness. Despite these challenges, the initial phase of the operation proceeds successfully, with all devices more or less prepared and deployed as planned.

Reserve operators Gian Gastone Bertozzi and Giuseppe Viglioli are recovered at 02:57. The submarine then begins its return journey to La Spezia, Italy.

Tenente di Vascello Gino Birindelli and Capo di 2a Classe Mario Paccagnini (SLC 1)

Once underway, complications worsen when Paccagnini reports that his breathing apparatus is damaged. Birindelli instructs him to discard the faulty unit and use the backup apparatus, despite its significantly reduced autonomy. These issues mean the Siluro a Lenta Corsa can no longer operate underwater and barely stay afloat.

Navigating by the faint glow of city lights, Birindelli approaches Gibraltar Harbour. After passing the second barrier, he estimates their position to be about 200 metres from the target. Using the compass to align their heading, they advances carefully. However, Paccagnini’s backup breathing apparatus begins failing, forcing him to surface. Birindelli orders him to remain at the surface while avoiding detection.

Moments later, the Siluro a Lenta Corsa comes to a sudden stop. Despite multiple attempts to restart the engine, the device remains immobile. Birindelli concludes that repeated impacts with rocks on the seabed have broken the coupling between the engine and propeller. Left with no other options, he manually drags the device toward the target, keeping his oxygen usage to a minimum. After 30 minutes of strenuous effort, the lack of oxygen and physical exhaustion overwhelms him.

Realising further attempts are futile, Birindelli activates the warhead’s timer and surfaced. He finds himself still 70 metres from the target. With no other options, he abandons the device and begins swimming towards the Spanish coast. After an exhausting journey, Birindelli and Paccagnini reach safety.

Capitano del Genio Navale Teseo Tesei and Sergente Alcide Pedretti (SLC 2)

The issues that are noticed during the extraction of the Siluro a Lenta Corsa, significantly hamper their progress. However, by 05:00, Tesei identifies the northern pier and begins navigating towards Gibraltar’s northern entrance. As they approach, he begins using his respirator to pass underwater obstructions but discovers it is flooded. Switching to a backup unit stored in the Siluro a Lenta Corsa’s tail compartment, he finds it to be in poor condition after ten days of use. The device causes nausea and severely limits his capacity to continue. Pedretti faces similar issues with his own respirator.

Deeming the mission impossible under these conditions, Tesei decides to abort. At 05:15, he detaches the warhead and sink it. The pair then heads north toward the lights of La Línea, reaching the Spanish shore at 07:10. Evading a police checkpoint, they climb the road to their rendezvous point, where they meet with an Italian agent.

Sottotenente di Vascello Luigi Durand de la Penne and Capo di 2a Classe Emilio Bianchi (SLC 3)

After extracting, Durand de la Penne manage to bring the Siluro a Lenta Corsa to the surface by completely emptying the rapid tank and advancing to the fourth notch on the buoyancy control. Alone in the water after losing contact with Bianchi, he spends time circling the area, searching for the other teams. Failing to locate them, he proceeds towards Gibraltar as planned.

However, the device’s inability to shed weight continues to plague him. It remains afloat only with the rapid tank empty and the control at its maximum forward position. Eventually, the Siluro a Lenta Corsa begins to submerge slowly and, within seconds, settles on the seabed at a depth of approximately 40–50 metres. Determined to complete the mission, Durand de la Penne attempts to detach the warhead but soon finds himself losing consciousness, experiencing visual disturbances described as “white flashes.”

He surfaces in a semi-conscious state and eventually locates Bianchi. Together, they spend two gruelling hours in the water, focusing more on staying afloat than advancing. At dawn, they finally reach the Spanish shore. Hours later, they reunite with their vehicle and head towards La Línea. Along the way, they encounter Captain Teseo Tesei, who informs them of his own failed mission. The two men subsequently return to Italy.

November 3rd, 1940

Scirè completes its journey, arriving at La Spezia at 19:30 after overcoming challenging breathing conditions during the voyage.

Aftermath

British divers recover parts of the damaged Siluro a Lenta Corsa used by Birindelli and Paccagnini. The Spanish authorities find Tesei’s Siluro a Lenta Corsa nearly intact, as its self-destruction mechanism fails. This craft is returned to the Italian Navy in 1975 and preserved as a memorial.

Despite the failure of Operazione Baia di Gibilterra 2, it highlights the ingenuity and bravery of Decima MAS operators. Commander Borghese reflects that the mission demonstrated the potential of their tactics, influencing future operations.

Junio Valerio Borghese, commander of the X^a Flottiglia MAS, who receives the Medaglia d’Oro al Valore Militare for his strategic leadership during Operazione Baia di Gibilterra 2. Gino Birindelli earns the same honour despite being captured. Operators like Teseo Tesei, Alcide Pedretti, Emilio Bianchi, and Luigi Durand de la Penne are promoted for bravery. Gian Gastone Bertozzi and Giuseppe Viglioli receive the Medaglia d’Argento al Valore Militare for their contributions.

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