On Dec. 19, 1941, in the pre-dawn darkness, six Italian commandos slipped into Alexandria harbor in Egypt. British troops and sailors had spotted an Italian reconnaissance plane days earlier, and intercepted intelligence suggested Italy was planning a strike. They were anxious, but alert, keeping an eye out for the enemy.
The commandos, known as frogmen, piloted three human torpedoes called Maiale, or “pigs.” Each torpedo had two seats and steering controls, allowing the men to guide them toward British warships. Their primary targets: the battleships HMS Queen Elizabeth and HMS Valiant.
The men were members of the elite Italian Decima Flottiglia MAS, under Lt. Luigi Durand de la Penne. Following several British destroyers through the harbor gates, the frogmen dodged several depth charges from patrolling boats. One torpedo slipped beneath the Valiant, another attached to the Queen Elizabeth, and the third targeted the tanker Sedonia, which was refueling the destroyer Jarvis.
British sailors spotted and captured two commandos near the Valiant as they tried to escape. Interrogated aboard ship, the frogmen initially refused to speak. Alarmed at the possibility of a bomb, the British rushed to secure the vessel. Finally, one commando demanded to see the captain and warned him of the imminent explosion, forcing them to evacuate the ship. Minutes later, massive blasts rocked Alexandria harbor. Both battleships sank, and the Sedonia exploded, heavily damaging the Jarvis. Eight British sailors were killed or wounded, and the remaining commandos were captured in the following days.
In just a few minutes, six men had achieved what the entire Italian navy had found impossible: naval supremacy in the Eastern Mediterranean.
Origins of the Decima Flottiglia MAS
The roots of Italy’s naval commandos date to Nov. 1, 1918 shortly before the end of WWI, when two Italian commandos attached limpet mines to an enemy battleship in Pula harbor, sinking it and killing more than 300 crew members. It was the first time in history that naval commandos inserted by sea and managed to sink an enemy warship. Despite this, the Italian navy invested little in commando tactics after the war.
Throughout the interwar period, underwater sports like spearfishing and snorkeling grew popular along Italy’s coasts, leading to innovations in fins, wetsuits, and breathing apparatus. Recognizing the potential, Teseo Tesei, one of Italy’s top naval commanders, later adapted these tools for military use. He also spearheaded the development of the Maiale torpedoes, giving individual commandos the same firepower as a submarine. Commandos, however, could sneak into areas that submarines would find difficult.
In 1941, Italy officially formed the Xª MAS (10th Light Flotilla), a special forces unit of naval commandos designed to use these new technologies to sabotage Allied shipping. The group would use a mix of human torpedoes, torpedo-laden speedboats, and combat divers armed with limpet mines.
The frogmen’s raids were devastating: in Suda Bay, they sank the heavy cruiser HMS York, two tankers, and a cargo ship. The Alexandria raid claimed two battleships, while operations in Malta and Gibraltar sank multiple cargo and transport vessels. The unit even planned and prepared a strike targeted at New York Harbor which was only canceled after Italy surrendered to the Allies in 1943.
By the end of their campaigns, Xª MAS had sunk 72,190 tons of Allied warships and 130,572 tons of merchant vessels. Despite several losses and failed missions, including one which caused the death of Tesei, the unit was one of the only successful parts of the Italian navy’s efforts during the war.
American Underwater Demolition Teams
The Allies were quick to notice the effectiveness of Italy’s combat divers. Though angered by their losses, the British began training their own combat divers to counter the Italians. Meanwhile, the U.S. Navy created Underwater Demolition Teams (UDTs) to support their island-hopping campaign in the Pacific.
UDTs conducted beach reconnaissance, obstacle removal, and amphibious landing prep, contributing greatly to the success of the Marines and soldiers in the Pacific. They carried explosives for clearing obstacles but were typically unarmed and vulnerable if discovered.
After several American ships were attacked in Gibraltar by enemy frogmen, American planners took note of their impact. British forces captured several Maiale torpedoes; the Allied nations studied the devices. Several captured frogmen also revealed their rigorous training and innovative stealth tactics.
The Allies were highly impressed by the psychological effect these frogmen had on Allied naval crews. American planners took these studies and began theorizing what effect UDTs could have if they were given more combat-focused missions.
The lesson was clear: even a handful of commandos could shift the balance of naval power. The U.S. saw an opportunity to adapt these methods for future conflicts.
The Birth of the Navy SEALs
By the Korean War, UDTs were taking on more direct-action roles. They cleared mines and obstacles before the Inchon landing, engaged in firefights with North Korean and Chinese forces, attacked the North Korean fishing industry, and detonated 20 tons of explosives in Hungnam Harbor during the UN withdrawal. They even trained with CIA operatives and occasionally led guerrilla operations behind enemy lines.
Chief of Naval Operations Adm. Arleigh Burke recognized the growing scope of Green Beret missions in Vietnam and directed his branch to prepare its own covert force. In 1961, President John F. Kennedy authorized the creation of a new special operations team capable of conducting direct-action maritime raids against the enemy. With that, the UDT teams, some of whom were already deployed to Vietnam, became the U.S. Navy SEALs.
Their mission: utilize sea, land and air insertions to conduct unconventional warfare, counter-guerrilla operations, and clandestine missions. The SEALs later refined the maritime infiltration and sabotage techniques pioneered by Italian frogmen at Alexandria. Using the Maiale as inspiration, the military eventually developed the modern SEAL Delivery Vehicle (SDV) to covertly transport divers to their objectives.
While uniquely American, SEAL doctrine owes a technical and conceptual debt to Italy’s WWII combat divers, who first combined modern diving equipment with military objectives.
What began as a stealthy raid in Alexandria harbor ultimately reshaped maritime warfare and inspired the creation of America’s elite warriors of sea, air, and land.
