The Regia Marina was one of the busiest navies of the interwar period. Four old battleships were rebuilt so completely that they barely resembled their original configuration. This helped Italy achieve what was really, by the late 1930s, significant ship-to-ship superiority over the French Navy. The re-construction of these ships helped generate ideas as to what their new battleships should look like. The new ships were to have enough speed to catch Dunkerque and Strasbourg, and enough firepower to destroy them. The result was the first post-treaty class of genuine fast battleships, the Littorio class.
Littorio displaced 42000 tons, could make 32 knots, and carried 9 15″ guns in three triple turrets. Although well protected from shellfire, Littorio was built with an experimental underwater protection system designed by Italian naval architect Umberto Pugliese. This system proved disastrous in practice, and limited the effectiveness of Littorio and her sisters, and they were forced to be unusually wary of torpedo attacks. Like the German Tirpitz but unlike Allied battleships of the day, Littorio did not carry a dual purpose secondary armament, a measure that would have saved weight and improved her anti-aircraft capabilities. The Italian 15″ gun was also something of a disappointment, as it fired a very heavy shell at a high velocity, but was difficult to reload, inaccurate, and incurred serious barrel wear. Finally, Littorio had a very short range, although this was of little concern in the Mediterranean. All in all, Littorio and her sisters were probably the least capable of the final generation of fast battleships, with the likely exception of Bismarck and Tirpitz. Nevertheless, they were useful ships, and in battle the difference between Littorio and, say, Prince of Wales, Richielieu, or Washington probably would have been minimal.
Littorio had an active war career. She participated in numerous convoy escort actions, resulting in the first and second Battles of Sirte, in which she briefly exchanged fire with Royal Navy vessels. Littorio also engaged in occasional missions to hunt and intercept British convoys. Her most notable battle service, however, was less than distinguished. On November 11, 1940 HMS Illustrious, escorted by a few Royal Navy cruisers and destroyers, launched an air attack on the Italian fleet anchorage at Taranto. One of three ships hit, Littorio suffered three torpedo impacts. The damage sank Littorio at anchor, although the damage was not so severe that she couldn’t be salvaged. Repairs took about four months, limiting the effectiveness of the Italian Navy at a critical point in the war. The Taranto attack was carefully studied by Japanese naval planners, and provided a model for the Pearl Harbor attack of December, 1941.
In September 1943, the Italian govenment decided to seek an armistice with the Western Allies. The surrender of the Italian fleet was a prominent condition of this agreement. Littorio had been renamed Italia upon the fall of the Fascist government, and was in preparation with her two sisters (Roma and Vittorio Veneto) to attack the Allied landing force at Salerno when the armistice was signed. Instead of heading to Salerno, Italia and her sisters laid a course for Malta. Along the way, the fleet was attacked by German glider bombs, of the same sort that later damaged HMS Warspite. Italia narrowly avoided one of the bombs, but Roma was hit twice, exploded, and sank with nearly all hands. Italia and Vittorio Veneto arrived at Malta without further molestation, and were then transferred to Egypt.
Some consideration was given to the idea of incorporating Italia and her sister into the USN or the RN. Italia technically became US war booty, while Vittorio Veneto was given to the United Kingdom. The ships certainly had the speed to operate with fast carrier groups in the Pacific, but there were several problems. Neither the USN nor the RN had the appropriate ammunition or spare part stores to operate the ships over a long period of time. Moreover, the short range of Italia would have proven a severe handicap in the Pacific. Had the war situation been more critical, the two ships might have been used nonetheless, but by 1944 the USN, the RN, and the Marine Nationale had overwhelming superiority in fast battleships over the IJN. Italia saw no further service, although she was physically returned to Italy after the war. Struck from the US list in 1948, she was scrapped in the 1950s.
(Images courtesy of regiamarina.net, which has some outstanding photos and data about the Italian Navy in World War II.)
Trivia: What three battleships were sunk by Italian frogmen?