Planning for a large surface combatant to operate as a long-range raider was initiated by the Officine di Costruzione Navale (OCN) of the Royal Sicilian Navy as early as 1925. Planned to operate alongside Reichspakt naval forces from the German Empire and the Netherlands in the Indian Ocean from bases in Madagascar, the Dutch East Indies, and German Indochina, the idea was conceived at a time when a naval war against the Japanese Empire was still the most looming security threat to the Reichspakt alliance. Eventually, increased militarism from the French Commune and the Socialist Republic of Italy led the Sicilians to postpone such a project, and despite a temporary revival of interest in the concept by the Royal Italian Federation after that nation’s birth, the concept was finally shelved in the late 1930’s as resources were diverted to address more imminent threats far closer to home. Though it never came to fruition, the Concetto Incrociatore Allargato 1930 was unique in the history of Italian shipbuilding, a design conceived at a time when global commitments were the center of naval planning, but these grand visions were shortly dashed away when the threat next door came knocking. Nevertheless, the design proved interesting, and particulars were as follows:
-Displacement: 30,000 tons nominal
-Length: 235 meters (771 feet)
-Beam: 21.9 meters (72 feet)
-Draught: 15 meters (28 feet)
-Range: 8,300 nautical miles at 20 knots
As mentioned, the design was intended to function as a long-range raider, strangling Japanese commerce in the Indian Ocean and Southeast Asia by overcoming escorted convoys from Japanese bases and allies with its superior firepower, and fleeing from anything it couldn’t outgun. This was deemed the most affordable way to deal with the Japanese threat at sea, as it would force the Japanese to disperse their otherwise locally superior naval forces to engage Reichspakt raiders that would be scattered across the region at the outset of hostilities, freeing Reichspakt planners from having to dedicate significant naval resources to the theater when they were needed closer to home.
To accomplish the task of outgunning anything it couldn’t outrun, the design was to be armed with nine Cannone da 280/28 quick-firing guns in three triple turrets. Based on German designs of the same caliber, they were adapted to fit in locally-designed turrets and could fire a 660-pound AP shell at a velocity of 3,000 feet per second to a distance of ~43,000 yards. No less than eight guns were actually manufactured by the ordnance factory at Mongiana, though these never saw service at sea and went on to serve as railway artillery or coast defense guns. Secondary armament consisted of 16 x Cannone da 120/35 in eight twin semi-enclosed turrets. With a maximum elevation of 75 degrees and a rate of fire of 15-18 rounds per minute, they also were intended for use against aerial targets. Anti-aircraft armament was rounded out by a very modern and ambitious fit of seven quadruple 37-mm Cannone Mitragliera da 37/34 gas-operated magazine-fed automatic cannons with a practical sustained rate of fire of around 170 rounds per minute. Also included in the armament fit, and deemed mandatory for raiding duties, were a pair of quadruple 53.3cm (21.0 in) torpedo tubes in armored box launchers astern. Fire control for the secondary battery was somewhat hampered by the presence of only one director aft, as opposed to the pair forwards, which made directing the fire of the guns to both sides simultaneously practically impossible.
The hull design itself was very sleek, with an aggressively raked bow for operating in the open ocean, while two thin military pole masts and a pair of large funnels dominated the otherwise low and minimalistic silhouette. Boats were stored amidships, serviced by a large crane, while liferafts and smaller boats were to be fitted alongside the turrets and astern during regular service. A German-built catapult for a single Heinkel He 114 seaplane was also mounted astern.
Armor protection was relatively light, with the idea being that the quality of the German-made armor plate would make up for the sheer lack of thickness, and that speed would allow the vessel’s commander to break off and engage at his choosing, staying out of the range of enemy guns. Therefore, belt armor was maintained at a conservative 105mm (4.1in), deck armor at 45mm (1.8in), and turret armor at 140mm (5.5in.) Underwater protection was substantial, with the habitual excellent degree of internal compartmentalization and subdivision.
The intended design speed of 32 knots was to be achieved through a powerful plant of eight German-designed high-pressure oil-fired boilers license built at the Ferdinandea foundry supplying steam to four Brown-Boveri steam turbine sets to be imported from Switzerland via Austria-Hungary (the S.R.I. blocked any transfer of industrial or defense-related equipment to the Federation through its territory.) The engine plants were to have a rated output of 155,000shp on four shafts, each driving a three-bladed bronze propeller that was around 4.5 meters (15 feet) in diameter. Bunkerage capacity was to be sufficient for 8,300 nautical miles at 20 knots, which was believed sufficient to mount long-range raiding operations in the South Pacific and Indian Ocean, both of which featured a multitude of Reichspakt bases at which the vessels could refuel and rearm.
In the end, only one of the planned pair of ships was laid down, with only the keel being laid at Castellammare di Stabia in April 1934. No progress was made nor was a name even assigned to the vessel until the decision was made to scrap the keel and divert the material towards the navy’s destroyer program. The main battery guns were diverted to serve as coastal and railway artillery pieces, while the secondary battery guns were distributed to several units of the Capitani-class destroyers, who utilized the same armament. The decision to scrap the vessels was made following the outbreak of war between the S.R.I. and the R.I.F. in 1938, as resources were desperately needed to maintain the offensive against the socialists on land, and the navy was re-oriented for combat far closer to home.