In the years following WW I, following the Treaty of Washington, there was a period of so-called "naval holidays" during which not only the construction of new vessels was stopped, but also existing ones were scrapped. On the basis of this treaty, Italy demolished the four battleships of the Caracciolo class of which one had already been launched and three were laid down.

After this period of standstill, when construction started again, an interesting phenomenon took place; instead of building new ships, most navies remodeled more or less extensively all the units built after the period 1908-1910. Generally, these ships received new machinery, which altered the configuration of the funnels and often the number of propellers. On many ships, the principal armament was replaced, and on most the secondary armament completely replaced thus making it more adept at air defense and involving changes to the forecastle including the installation of new range finding apparatuses and catapults for reconnaissance airplanes.

R.N. Andrea Doria.

The Regia marina adapted itself to the trend set by the other navies, and in 1931-32 began studying the radical transformation of 4 battleships of the Conte di Cavour class, ships which were originally built with substantial help from British firms. These transformations were completed in two periods: 1933- 1937 for the Cavour and Cesare and 1937-1940 for Duilio and Doria. More than transformation, we should refer to this work as a reconstruction since of the original ships only the hull and the side armor plates were re-utilized. The hull itself was altered with the installation of a new bow, which increased the overall length, by 10.30 meters. Inside the hull, a new system of defense against torpedo attacks invented by General Pugliese was installed. This installation required the complete removal of all internal structures. The original power plan was replaced, reducing the number of propellers from 4 to 2. The primary and secondary armaments were completely replaced. The triple turret centrally located between the two funnels was also eliminated as were all the pillbox-installed 152 mm and 76mm guns.

The new armament was based on 10 320mm guns on two double and two triple turrets, 12 120mm guns in 6 small turrets and 8 100mm guns on 4 mounts plus minor armament. Three torpedo tubes originally installed under the waterline, were also eliminated. After reconstruction, these could have been considered new ships. During the reconstruction of the 4 old battleships, the Regia Marina began studies on new units based on the dictates of the Treaty of Washington which allowed up to 35,000 tons and guns of up to 406 mm which were rejected in favor of guns of 381 mm.

The project was directed by the General of Naval Constructions Umberto Pugliese, and around October 1934 the first two units, Littorio and Vittorio Veneto were contracted, and entered service in 1940. In 1938, two more units were contracted, Roma and Impero, but only the first was completed in June 1942, while the second one was abandoned during construction in September 1943 and never completed.

R.N. Vittorio Veneto.

The battleship of the Littorio class, which in 1943 was renamed Italia, were the only Italian battleships armed with triple turrets, two forward and one aft, configuration typical of those of other navies. These ships had a power plant capable of generating 140,000 HP distributed over 4 propellers, while the Cavour had only 93,000 HP over 2 propellers. These new units, both for their seagoing and fighting performances, were comparable to those of other navies. Unfortunately, they were not equipped with RADAR. While the protection of the Cavour class battleships was the original dating back to 1914-15, the new units had a more modern armor similar to the one adopted by other navies such as in the British battlecruiser H.M.S. Hood, the battleships H.M.S. Nelson and H.M.S. Rodney, the German Graf Spee, the French Richelieu, or the Japanese Yamato.

The armour was not built by vertical plates, like the Cavour, but by two layers of plates placed an at angle protruding on the high part and caving on the lower one. The external plate was 350mm thick and at about 600mm a second armor of about 36mm served as a shield against shrapnel. The horizontal armor was designed against the new aerial bombs and was organized over three bridges. This protection was inadequate against the new German rocket bombs, which were able to penetrate the vital parts of the battleship Roma and blow it apart.

Underwater defenses were particularly taken care of, on both the Cavour and Littorio class with the adoption of an "absorbent structure" invented by General Umberto Pugliese. This structure was made of a large cylinder of low resistance contained in a stronger structure filled with liquid and completely surrounding the inner cylinder. The explosion of a torpedo was to cause the external bulkhead to give way and the pressure generated by the explosion would be transferred by the liquid and absorbed by the internal cylinder thus preventing damage to the internal bulkhead.

Partially adapted and translated from the book "Guida alle navi d'Italia", by Gino Galuppini, published in 1982 by Arnoldo Mondadori Editore.