The 'Action in the Strait of Bonifacio' was the German sinking of the modern Italian battleship Roma with air-launched missiles in the immediate aftermath of Italy’s signature of an armistice with the Allied powers (9 September 1943).
Along with many of the principal warships of the Italian navy, including Roma's sisterips Vittorio Veneto and Italia (ex-Littorio), the cruisers Eugenio di Savoia, Raimondo Montecuccoli and Emanuele Filiberto Duca d’Aosta and eight destroyers, Roma sailed from La Spezia on Italy’s north-west coast on 9 September. In command of the Italian force was Ammiraglio di Armata Carlo Bergamini. This was one day after the proclamation of the 1943 Italian armistice. The group was later joined from Genoa by the cruisers Luigi di Savoia Duca degli Abruzzi, Giuseppe Garibaldi and Attilio Regolo.
On this same day, the fleet had been scheduled to sail toward Salerno in order to attack the Allied shipping heading toward the 'Avalanche' invasion of Italy. However, the proclamation of the armistice on 8 September, had led to the cancellation of this undertaking and, as German forces launched 'Achse' (ii) to occupy Italy, Bergamini was instructed instead to depart La Spezia in order to prevent the fleet from falling in German hands, and to reach Allied-controlled ports. Bergamini was initially reluctant to take his ships to Malta as he did not know the details of the armistice and what would be the fate of the fleet once it was in Allied-controlled ports, and was also mindful of the early Italian plan to transfer of King Victor Emmanuele III, his court and the government from Rome to La Maddalena in the north of the island of Sardinia: the destroyers Ugolini Vivaldi and Antonio da Noli sailed from Genoa and La Spezia for Civitavecchia for this very purpose. Thus initial destination of Begamini’s ships was the naval base at La Maddalena. Here Bergamini was to receive further orders to proceed to Malta from Ammiraglio di Divisione Bruno Brivonesi, the naval commander of Sardinia, as well as some documents regarding the armistice’s conditions for the navy. The transfer of the king to La Maddalena was cancelled, however, and when the fleet arrived off La Maddalena, German troops had occupied that base to transfer their troops from Sardinia to Corsica. Thus the stop at La Maddalena was also cancelled and the Supermarina, the Italian naval high command, ordered Bergamini to head for Allied-controlled Bône in North Africa, and the fleet thus changed course.
When the Germans learned that the Italian fleet was sailing toward an Allied base, they despatched Luftwaffe Dornier Do 217 twin-engined bombers armed with Ruhrstahl SD-1400 X (Fritz X) radio-controlled armour-piercing bombs to attack the ships. These aircraft approached the Italian force in the Strait of Bonifacio. The German warplanes trailed the fleet for some time, and the Italian fleet did not open as the bombers were trailing the ships at a range that made it impossible for their identification as German or Allied aircraft. Bergamini believed that they were the air cover promised by the Allies. However, the start of the attack on Italia and Roma at 15.37 settled the identification matter and the Italian ships opened fire with their anti-aircraft batteries and started to manoeuvre defensively. After about 15 minutes, Italia was hit on the starboard side below her forward 15-in (381-mm) main turrets, while Roma was hit on the same side somewhere between frames 100 and 108. This latter bomb passed through the ship and exploded beneath her keel, damaging the hull and allowing water to flood the after engine room and two boiler rooms. The resulting loss of power caused the inboard propellers to stop and started a large amount of arcing, which caused many electrical fires in the after half of the battleship.
Losing power and speed, Roma began to fall behind the rest of the Italian force. At about 16.02, a second Fritz X guided bomb smashed into the starboard side of Roma's deck, penetrated into the ship and in all probability detonated in the forward engine room, sparking flames and causing heavy flooding in the magazines of main battery’s no. 2 turret and the forward port-side turret of the 6-in (152-mm) secondary battery. This laced still greater strain on the previously overstressed hull, and just a few seconds after the initial blast, the no. 2 main-battery turret was blown over the side by a massive explosion as the turret’s magazine detonated.
This caused still more catastrophic flooding in the bow, and the battleship began to settle by the bow while listing increasingly to starboard. The ship quickly capsized and broke in two.
According to the official inquest, Roma had departed La Spezia with a crew of 1,849 men: there were 596 survivor’s of the battleship’s sinking, suggesting that 1,253 men went down with the ship. There is a realistic suggestion that there were also on board some 200 men of Bergamini’s staff not included in the official complement, and if true this would mean a death toll of 1,393 men.
In her service life of 15 months, Roma sortied from port on 20 occasions, most of these being transfers between bases: none of them was a combat sortie.