In November 1940, the British Royal Navy carried out a surprise attack on the Italian fleet in Taranto Harbor using carrier aircraft. It was a model for the Japanese air strike on Pearl Harbor a year later.
In September 1939, Nazi Germany invaded Poland, and World War 2 began. After a long pause (known derisively as the “Sitzkreig”), Hitler invaded France in May 1940. A month later Mussolini’s Fascist Italy, seeing a chance to gain control of French colonies in North Africa, declared war on the Allies. The tiny island of Malta, located in the middle of the Mediterranean Sea, became an enormously important strategic point for Britain—it protected the English supply lines to Egypt and also provided a base to intercept the Italian and German supply line to North Africa.
The biggest threat to Malta (and to the Royal Navy convoys that passed it) was the Italian fleet stationed at the port of Taranto, 320 miles away in the “boot-heel” of Italy. The Regia Marina’s First Squadron consisted of 6 battleships, 7 heavy cruisers, 2 light cruisers and 8 destroyers. The Royal Navy did not have a battleship force in the Mediterranean strong enough to engage the Italians. But it did have the two aircraft carriers Eagle and Illustrious and their Swordfish torpedo bombers.
The British, under Admiral Andrew Cunningham, began planning a surprise air raid on the Taranto harbor. The Swordfish were old and slow, and vulnerable to both enemy fighters and anti-aircraft fire, so it was decided that the best chance lay with a night attack. This had to be done during a bright moon, when there would be enough light for the bomber pilots to see their targets but not enough light for enemy gunners to find their mark. And so the night of October 21 was selected for the raid.
Then problems appeared. Eagle had an engine breakdown and had to withdraw for repairs. Several of Eagle’s Swordfish transferred to Illustrious, leaving 24 torpedo bombers available. It was decided that Illustrious would carry out the raid herself, escorted by two heavy cruisers, two light cruisers, and four destroyers. The next time that moon conditions would be suitable was November 11.
The attack was meticulously planned. A series of photo-reconnaissance flights revealed that, although the Italians were protecting their fleet with barrage balloons and anti-torpedo nets, there weren’t enough of these, and there were large gaps in their defenses. The attacking planes would arrive in two waves. Part of the first wave was armed with bombs, to cause a diversion by attacking the cruisers. A small number of planes would drop flares to illuminate the harbor. And the rest would attack the Italian battleships.
In order to successfully strike the ships with torpedoes, a technical difficulty had to be solved. Normally, aerial torpedoes required a water depth of at least 75 feet, allowing them to be dropped, submerge, then run to the target at their set depth. But the harbor at Taranto was shallow—only 30 feet deep. After much testing, the British found a solution: a wire was rigged to the torpedo which was attached to a spinning drum on the airplane. When it was dropped, the torpedo pulled this wire out from the drum, and the tension held the torpedo up and prevented it from diving deep enough to hit the harbor floor while still allowing it to get underneath the Italian anti-torpedo nets. The torpedoes had magnetic triggers that would detonate them as they passed underneath the Italian hulls.
On the evening of November 11, Illustrious was off the coast of Greece, about 170 miles southeast of Taranto, and began launching planes; the first wave at 8:40pm and the second wave an hour later. Equipment malfunction and an accidental collision on the flight deck caused four Swordfish to abort.
When the first wave of twelve Swordfish arrived over Taranto, they split up as planned. Four planes, armed with bombs, attacked the cruisers to distract the Italian searchlights and anti-aircraft fire. They scored two hits. Two more planes released illumination flares, then dropped bombs on the harbor’s oil storage tanks and a fighter airfield.
Each of the remaining six Swordfish, armed with a torpedo, then attacked the battleships. The Conte di Cavour was hit, followed quickly by the Vittorio, which was struck twice. The Libeccio was also hit, but this torpedo failed to explode. One of the Swordfish was lost to anti-aircraft fire.
The second wave consisted of eight bombers, half of them carrying torpedoes and half with bombs. The Vittorio was hit again, and the Caio Duilio was struck below the waterline in the forward compartments. One of the cruisers was also hit by a bomb and damaged. Another Swordfish was shot down by AA guns.
The attack was a success. Just 20 obsolete planes had crippled half of the Italian battleship fleet, for the loss of just two Swordfish. The Vittorio and Caio Duilio took several months to repair. The Conte di Cavour was actually sunk, but the harbor was so shallow that she came to rest on the bottom and was later raised, though she remained out of action for the rest of the war.
Elated by their coup, the British planned to repeat their attack the following night but bad weather closed in and the strike had to be called off. By the next morning, the Regia Marina had already begun withdrawing its undamaged ships to Naples.
For those naval officers around the world who still held to the battleship as the supreme weapon at sea, the Taranto raid was a spectacular warning. As Admiral Cunningham noted in his reports of the battle, “Taranto, and the night of 11–12 November 1940, should be remembered forever as having shown once and for all that in the Fleet Air Arm the Navy has its most devastating weapon.” But the lesson would not fully be driven home until a year later, at Pearl Harbor.
Hidden History 
I wonder if the pilots of the downed Swordfish survived…