Decima Flottiglia MAS


The Decima Flottiglia MAS was an Italian flotilla, with commando frogman unit, of the Regia Marina created during the Fascist regime.
The acronym MAS also refers to various light torpedo boats used by the Regia Marina during World War I and World War II.
Decima MAS was active during the Battle of the Mediterranean and took part in a number of daring raids on Allied shipping. These operations involved surface speedboats, manned torpedoes and Gamma frogmen. During the campaign Decima MAS took part in more than a dozen operations which sank or damaged five warships and 20 merchant ships.
In 1943, after the Italian dictator Benito Mussolini was ousted, Italy left the Tripartite Pact. Some of the Xª MAS men who were stationed in German-occupied northern Italy enlisted to fight for Mussolini's newly formed Italian Social Republic and retained the unit title, but were primarily employed as an anti-partisan force operating on land. Other Xª MAS men in southern Italy or other Allied-occupied areas joined the Italian Co-Belligerent Navy as part of the Mariassalto unit.

Historical background

In World War I, on November 1, 1918, Raffaele Paolucci and Raffaele Rossetti of the Regia Marina rode a manned torpedo into the harbour of Pula, where they sank the battleship Jugoslavija, of the navy of the State of Slovenes, Croats and Serbs, formerly the Austro-Hungarian battleship, and the freighter Wien using limpet mines. They had no underwater breathing sets, and thus had to keep their heads above water to breathe. They were discovered and taken prisoner as they attempted to leave the harbour.
In the 1920s, sport spearfishing without breathing apparatus became popular on the Mediterranean coast of France and Italy. This spurred the development of modern swimfins, diving masks and snorkels.
In the 1930s Italian sport spearfishermen began using industrial or submarine-escape oxygen rebreathers, starting scuba diving in Italy.

Unit origins

This new type of diving came to the attention of the Regia Marina which founded the first special forces underwater frogman unit, later copied by the Royal Navy and United States Navy. Capitano di Fregata Paolo Aloisi was the first commander of the 1ª Flottiglia Mezzi d'Assalto, formed in 1939 as a result of the research and development efforts of Majors Teseo Tesei and Elios Toschi of the naval combat engineers. The two resurrected Paolucci's and Rossetti's concept of manned torpedoes.
In 1941, Commander Vittorio Moccagatta re-organised the First Flotilla into the Decima Flottiglia MAS, and divided the unit into two parts – a surface group operating fast explosive motor boats, and a sub-surface weapons group using manned torpedoes called SLC, as well as "Gamma" assault swimmers using limpet mines. Moccagatta also created the frogman training school at the San Leopoldo base of the Italian Naval Academy in Livorno.

Combat record

The Decima MAS saw action starting on June 10, 1940, when Fascist Italy entered World War II. In more than three years of war, the unit destroyed some 72,190 tons of Allied warships and 130,572 tons of Allied merchant ships. Personnel from the unit sank the World War I-era Royal Navy battleships and , wrecked the heavy cruiser and the destroyer, damaged the destroyer and sank or damaged 20 merchant ships, including supply ships and tankers. During the course of the war, the Decima MAS was awarded the Golden Medal of Military Valour and individual members were awarded a total of 29 Golden Medals of Military Valour, 104 Silver Medals of Military Valour and 33 Bronze Medals of Military Valour.

Chronicle of operations

1940

in Valletta, which was destroyed in the attack of 26 July 1941
es launched from the Italian base-ship Olterra, August 1943

Successor units

Following the armistice of Italy on September 8, 1943, the Xª MAS was disbanded.
The Badoglio government in the south of Italy under Allied occupation declared war on Germany and became a co-belligerent.
Some Decima MAS sailors joined the Allied cause to fight against Nazi Germany and what remained of the Axis as part of the Italian Co-Belligerent Navy.
A new unit was formed, led by Forza and joined by some of the pioneers such as de la Penne newly released from British POW camps.
The new unit was named Mariassalto, but continued to be an elite naval force mounting special operations at sea.
In the German-occupied north of Italy Mussolini set up the
Italian Social Republic to continue the war as part of the Axis. Led by Borghese, Decima Flottiglia was revived, as part of the National Republican Navy of the RSI with its headquarters in Caserma del Muggiano, La Spezia. By the end of the war, it had over 18,000 members, and although Borghese conceived it as a purely naval unit, it gained a reputation as a savage pro-fascist, anti-communist, anti-resistance force in land campaigns alongside the German forces, under the command of SS General Karl Wolff.

Mariassalto

The Mariassalto was set up at Taranto alongside the British frogman force in the Mediterranean. Forza was pleased to demonstrate Italian expertise in this area to the British, and the group was also keen to be in action, though if they were caught they would almost certainly have been shot.
In June 1944 came an opportunity to take action, in Operation QWZ, a joint mission against targets in La Spezia harbour.
The attack was against the Italian cruisers Bolzano and Gorizia, which had been taken by the Germans after the Italian surrender. This was to thwart a German plan to sink them where they would block the harbour entrance. The mission also aimed to attack German U-boats in the harbour. British chariots would attack the cruisers whilst Mariassalto's Gamma Frogmen would attack U-boats penned in the harbour.
On 2 June 1944 the Italian destroyer sailed from Bastia in Corsica to La Spezia carrying three speedboats, and Italian frogmen including Luigi Durand De La Penne, and two British chariots.
One chariot broke down and was abandoned, though the other successfully sank Bolzano. However the Gamma men were unsuccessful in their attack on the U-boat pens. All the participants escaped to link with partisan groups on land.
In April 1945 a final mission, Operation Toast, was planned. This was aimed at sinking the newly converted shipping liner now the aircraft carrier Aquila, just completed in Genoa.
For this Mariassalto men would make use of two British chariots, as they had none of their own SLCs available.
On 18 April 1945 the destroyer, carrying two high speed motorboats equipped with chariots sailed from Venice for Genoa led by Captain Chavasse SOE and Forza. Both chariots were deployed and succeeded in penetrating the defences but found the hull of Aquila so encrusted with barnacles and seaweed the limpet mines could not be attached to it. The frogmen had to lay the charges on the seafloor of the outer harbour mole and when the charge exploded as planned the ship remained afloat in spite of the attack. All of the frogmen escaped safely. The German commander never put his extensive demolition plans for Genoa into action and thus Aquila was never sunk as a blockade to the harbour.

Decima MAS (RSI)

Some Xª MAS men who were in German-occupied Italy remained part of the Axis forces, joining the Italian Social Republic under the command of Captain Borghese. His reputation and that of the Xª MAS enabled him to negotiate an agreement with the German forces that gave the Xª MAS significant autonomy, allowed them to fight under an Italian flag, and not to be employed against other Italians. Borghese was recognized as the leader of the corps.

Ideology

The main themes in the Xª MAS's ideology became "honour" in defending Italy from the "betrayal" of the armistice with the Allies and a call to defend the territorial integrity of Italy against the Allies.
The corps had its own weekly magazine, L'orizzonte, in which authors such as Giovanni Preziosi wrote vehemently anti-Semitic articles about Jewish conspiracies. The magazine had problems in its distribution, as it was thought that Borghese's popularity among the Fascist hardliners might reduce Mussolini's influence.

Relations with the RSI

Relationships with the Italian Social Republic were not easy. On January 14, 1944 Benito Mussolini arrested Borghese while receiving him in Gargnano, in order to gain direct control of the Xª MAS. Word of the arrest reached the officers of the Decima, who considered marching on Mussolini's capital at Salò. However, the German command used their influence to have Borghese released, as they needed the equipment, expertise and manpower of the Xª MAS as an anti-partisan force.

Naval actions

The Xª MAS took little part in the war at sea. Its equipment had been abandoned in the south, and its naval activities were frustrated by Allied action.
In November 1944 four frogmen, who had stayed under German command, were delivered by fast motorboat and swam into Livorno harbor to set up a secret sabotage base, but were captured.

Anti-partisan actions

The Decima was mostly employed in anti-partisan actions on land, rather than against the Allies at sea. However, their actions were mostly reprisals following the massacre of soldiers of "Decima" by partisans forces – see Bardelli's homicide. Their anti-partisan actions usually took place in small villages, where the partisans were stronger. Some examples:
However, the Xª MAS units also earned a good combat reputation fighting on the frontline against the Allies at Anzio and on the Gothic Line. In the last months of the war Xª MAS units were dispatched to the eastern Italian border against Josip Broz Tito's partisans who marched into Istria and Venezia Giulia.

Demobilization

On April 26, 1945, in what is now the Piazza della Repubblica in Milan, Borghese finally ordered the Xª MAS to disband. He was soon arrested by partisans, but rescued by OSS officer James Angleton, who dressed him in an American uniform and drove him to Rome for interrogation by the Allies. Borghese was tried and convicted of war crimes, sentenced to 12 years imprisonment, but released from jail by the Italian Supreme Court in 1949. The Americans were keenly interested in infiltrating the Italian Communist groups, something which Borghese had done, and he was enlisted to help create counterintelligence units for the Americans.

Organization of RSI Xa MAS

In 2006 the admiralty of the Italian republic recognized the Xth M.A.S. RSI veterans as combatants of WWII and gave the association the battle flag.
Counter-operations against Italian frogmen by British frogmen in Gibraltar was the subject of a 1958 British film The Silent Enemy based on the exploits of the team of Lionel Crabb.
Today the Comando Raggruppamento Subacquei e Incursori Teseo Tesei is the frogman corp currently serving the Italian Republic.

In popular culture

Prince Valerio Borghese escaped capital punishment after the war in the cold war context and remained an active neo-fascist activist: He attempted a failed fascist coup in the early 1970s.
The Golpe Borghese and its leader are wittingly spoofed in a film by Mario Monicelli called Vogliamo i Colonelli where Borghese part is played by Italian actor Ugo Tognazzi impersonating an ultra right wing parliament representative called Tritoni. One of the best scenes features a boisterous and crazy assault diver and parachute Commando frogman called Barbacane.