The Regia Marina (Royal Italian Navy) explored various projects for adding one or more aircraft carriers to the fleet in the 1930s but took no action beyond developing a basic design for constructing a new vessel and identifying suitable candidate merchant ships for conversion. In mid-1940, as Italy prepared to enter the war as an ally of Germany, a design was prepared for a simple conversion of the fast liner Roma into an aircraft carrier, but again was deemed less of a priority than other construction and set aside in January 1941.
It took the shock of defeat at Cape Matapan (March 28, 1941), which the Italians largely attributed to effective British deployment of its carrier Formidable, to revive demands for a carrier as an urgent requirement. In July 1941 the Undersecretary of the Navy authorized the conversion of the Roma into a carrier, using the design studies of the previous year as a basis. In the event, the project became much more ambitious and required a major transformation of the relatively elderly liner into the carrier Aquila.
Displacement: 23,350 tons (standard), 27,800 tons (full load)
Dimensions: 759’2” (oa) x 96’6” x 24’0”
Flight deck: 700’0” x 83’0”
Machinery: Belluzzo geared turbines, 8 Thornycroft boilers,
4 shafts, 140,000 shp = 30 knots
Bunkerage: 2,800 tons = 4,000 nm @ 18 knots
Armament: 8 x 5.3”, 12 x 65mm AA, 22 x 6-barrel 20mm AA
The superstructure was razed completely and a large hangar 525 feet long and 59 feet wide was erected beneath the steel flight deck. The Roma’s original power plant was replaced completely with two sets of machinery originally intended for light cruisers of the Capitani Romani class, raising the carrier’s speed from 21 knots to 30 knots. The furnace uptakes were trunked to starboard into a very large stack that was incorporated into a substantial island structure. Two elevators connected the hangar and flight deck, which carried two catapults and full arresting gear. All armament was fitted on platforms sponsoned out from the ship’s side. Magazines and aviation fuel stowage were created and protected by 3-inch armor decks. To ensure stability and provide effective defense against torpedo attack, the hull was fitted with deep bulges on each side.
Design and construction
Work on converting Roma into an aircraft carrier began in earnest at Cantieri Ansaldo, Genoa, in November 1941. Since a battleship named Roma was already under construction, the ship's name was changed to Aquila.
The liner's interior was completely gutted to allow for replacement of the original machinery and the addition of a hangar deck and workshops. Deep bulges were added to either side of the hull to improve stability and provide a modest degree of torpedo defense. A layer of reinforced concrete—6–8 cm (2.4–3.1 in) thick—was applied inboard of the bulges for splinter protection. The hull was also lengthened to take advantage of the increased power of Aquila′s new machinery.
The designers worked in 3–8 cm (1.2–3.1 in) of armor over the magazines and aviation fuel tanks. The fuel tanks copied British practice and consisted of cylinders or coffer dams separated from the ship's hull by water-filled compartments. This was a safety measure intended to prevent fracturing of the fuel system and the inadvertent spread of volatile AvGas fumes due to severe vibration or "whip" from bomb hits, near misses and torpedo hits.
Aquila′s new propulsion system consisted of four sets of Belluzzo geared turbines taken from two canceled Capitani Romani-class light cruisers (Cornelio Silla and Paolo Emilio). They were capable of generating 151,000 shp (113,000 kW), and Aquila was expected to reach 30 kn (56 km/h; 35 mph) on trials and 29.5 kn (54.6 km/h; 33.9 mph) when fully laden.
Aquila had a single continuous 211.6 × 25.2 m (694 ft 3 in × 82 ft 8 in) flight deck. It was partially armored with 7.6 cm (3.0 in) plate over the gasoline bunkers and magazines. The flight deck ended short of the bows but overhung the stern, where it featured a pronounced round-down to improve air flow. Two 50 feet (15 m) octagonal lifts with a 5 short tons (4.5 t) capacity enabled transfer of aircraft between the hangar deck and flight deck. One was directly amidships and the second another 90 ft (27 m) forward, thus placing them far enough from the aft arrester wires that both could be used for striking down aircraft into the hangar immediately after a landing.
Two German-supplied Demag compressed air-driven catapults, each capable of launching one aircraft every 30 seconds, were installed parallel to each other at the forward end of the flight deck. These were originally intended for Germany's own "Carrier B", Graf Zeppelin′s incomplete—and eventually scrapped—sister ship. The Italians obtained them—along with five sets of arrester gear and other component plans—during a naval technical mission to Germany in October–November 1941.
A set of rails led aft from the catapults to the elevators and into the hangars. For catapult-assisted launches, aircraft would be hoisted in the hangar onto a portable collapsible catapult carriage, raised on the elevators to flight deck level and then trundled forward on the rails to the catapult starting positions, the same system as employed on Graf Zeppelin.
According to Edward L. Barker, Aquila′s engines and catapults were successfully tested in August 1943. However the arresting gear installed on the carrier, consisting of four cables, failed to work properly. This prevented aircraft, once launched, from landing back on board. It was therefore proposed that aircraft taking off from Aquila would, after performing their mission, fly back to the nearest land-based airfield or simply ditch in the sea, a serious and embarrassing limitation on her capabilities as a fleet carrier.
Aquila′s starboard-side island contained a single large vertical funnel for carrying exhaust gases clear of the flight deck. It also included a tall command tower and the fire control directors for the 135 mm (5.3 in) guns.
Six 6-barrelled 20 mm (0.79 in)/65 caliber (cal) anti-aircraft (AA) cannons were positioned just fore and aft on the island. In addition, Aquila carried eight 135 mm (5.3 in)/45 cal guns taken from one of the canceled Capitani Romani-class cruisers. Though not designed as dual purpose weapons, these guns had an elevation of 45° and were therefore capable of providing a useful barrage against attacking enemy aircraft (by comparison, Italy's best heavy AA gun—the 90 mm (3.5 in)/50 cal—had an elevation of 85°). It was intended to mount 12 newly-designed 65 mm (2.56 in) AA guns on sponsons just below flight deck level (six on either side of the hull). However, this gun—with an automatic feeder and 20 rpm rate of fire—never got beyond prototype stage. An additional 16 six-barrelled 20 mm cannons—also mounted below the flight deck—rounded out the ship's AA defense.
Throughout 1942 and 1943, trials were conducted at Perugia and Guidonia—the Regia Aeronautica′s equivalent to the German Luftwaffe′s test facility at Rechlin—to find aircraft suitable for conversion to carrier use. The Italians selected the SAIMAN 200, Fiat G.50 bis and Reggiane Re.2001 as potential candidates.
In March 1943, German engineers and instructors with experience on Graf Zeppelin arrived to advise on aircraft testing and to help train future carrier pilots culled from 160 Gruppo C.T. of the Regia Aeronautica. They brought with them examples of a Junkers Ju 87C Stuka dive bomber (a navalized version with folding wings, arrester hook and catapult attachment points) and an Arado Ar 96B single-engine trainer. After conducting comparative flight trials, the Italians eventually settled on the Re.2001 as their standard carrier fighter/fighter-bomber and even the Germans concluded it had better potential than their own counterpart, the Messerschmitt Bf 109T. All flight testing—including simulated braked deck landings—was land-based.
Aquila′s planned air complement was 51 non-folding Reggiane Re.2001 OR fighter-bombers: 41 stowed in the hangar deck (including 15 suspended from the deck head) and 10 on the flight deck in a permanent deck park. A folding-wing version of the Re.2001 was planned, which would have increased the size of Aquila′s air group to 66 aircraft, but this never materialized. Only 10 Re.2001s were fully converted for carrier use. They were given tail hooks, RTG naval radio equipment and bomb racks for carrying 650 kg (1,400 lb) of bombs. They were also armed with two 12.7 mm (0.5 in) Breda-SAFAT machine guns mounted above the engine cowling. At least one Re.2001G was under test at Perugia as a naval torpedo bomber and was given a lengthened tail wheel strut to accommodate the added height of a torpedo suspended below the fuselage.
When Italy surrendered on September 8, 1943, the Aquila was virtually complete. The Germans seized the ship but it was heavily damaged by United States Army Air Force bombing on June 16, 1944 and a human torpedo attack on April 19, 1945. On April 24, 1945, the ship was scuttled at Genoa. After World War II the ship was raised and taken to La Spezia in 1949. Initially the Italian Navy considered refitting the Aquila for service as a carrier but this plan was abandoned and the ship broken up in 1952.
In late 1942 the Regia Marina decided to add a second carrier to the fleet and began a simple conversion of the liner Augustus along the lines originally proposed for the Roma. When the ship, by then renamed the Sparviero, was seized by Germany after Italy surrendered only the superstructure had been razed. The hulk was scuttled on April 24, 1945, in an attempt to block the entrance to the harbor at Genoa. It was raised in 1947 and scrapped.