Andrea Doria-class battleship

Andrea Doria during World War I
Class overview
Operators:	Regia Marina  Marina Militare
Preceded by:	Conte di Cavour class
Succeeded by:	Francesco Caracciolo class (planned) Littorio class (actual)
Built:	1912–16
In service:	1915–53
Completed:	2
Scrapped:	2
General characteristics (as built)
Type:	Dreadnought battleship
Displacement:	24,729 long tons (25,126 t) (deep load)
Length:	176 m (577 ft 5 in) (o/a)
Beam:	28 m (91 ft 10 in)
Draft:	9.4 m (30 ft 10 in)
Installed power:	30,000 shp (22,000 kW) 20 × Yarrow boilers
Propulsion:	4 × shafts 4 × Parsons steam turbine sets
Speed:	21 knots (39 km/h; 24 mph)
Range:	4,800 nmi (8,900 km; 5,500 mi) at 10 knots (19 km/h; 12 mph)
Complement:	31 officers 969 enlisted men
Armament:	3 × triple, 2 × twin 305 mm (12 in) guns 16 × single 152 mm (6 in) guns 19 × single 76 mm (3 in) guns 3 × 450 mm (17.7 in) torpedo tubes
Armor:	Belt: 250 mm (9.8 in) Gun turrets: 280 mm (11.0 in) Casemates: 130 mm (5.1 in) Deck: 98 mm (3.9 in) Conning tower: 280 mm (11.0 in)
General characteristics (after reconstruction)
Displacement:	28,882–29,391 long tons (29,345–29,863 t) (deep load)
Length:	186.9 m (613 ft 2 in)
Beam:	28.03 m (92 ft 0 in)
Draft:	10.3 m (33 ft 10 in)
Installed power:	75,000 shp (56,000 kW) 8 × Yarrow boilers
Propulsion:	2 × shafts 2 × geared steam turbines
Speed:	26 knots (48 km/h; 30 mph)
Range:	4,000 nmi (7,400 km; 4,600 mi) at 18 knots (33 km/h; 21 mph)
Complement:	1,520
Armament:	2 × triple, 2 × twin 320 mm Model 1934 guns 4 × triple 135 mm /45 guns 10 × single 90 mm /50 AA guns 6 × twin, 3 × single 37 mm Breda AA guns 8 × twin, 20 mm Breda AA guns

The Andrea Doria class (usually called Caio Duilio class in Italian sources) was a pair of dreadnought battleships built for the Royal Italian Navy (Regia Marina) during the early 1910s. The two ships—Andrea Doria and Caio Duilio—were completed during World War I. The class was an incremental improvement over the preceding Conte di Cavour class. Like the earlier ships, Andrea Doria and Caio Duilio were armed with a main battery of thirteen 305-millimeter (12.0 in) guns.

The two ships were based in southern Italy during World War I to help ensure that the Austro-Hungarian Navy would stay bottled up in the Adriatic. Neither vessel saw any combat during the conflict. After the war, they cruised the Mediterranean and were involved in several international incidents, including at Corfu in 1923. In 1933, both ships were placed in reserve. In 1937 the ships began a lengthy reconstruction. The modifications included removing their center main battery turret and boring out the rest of the guns to 320 mm (12.6 in), strengthening their armor protection, installing new boilers and steam turbines, and lengthening their hulls. The reconstruction work lasted until 1940, by which time Italy was already engaged in World War II.

The two ships were moored in Taranto on the night of 11/12 November 1940 when the British launched a carrier strike on the Italian fleet. In the resulting Battle of Taranto, Caio Duilio was hit by a torpedo and forced to beach to avoid sinking. Andrea Doria was undamaged in the raid; repairs for Caio Duilio lasted until May 1941. Both ships escorted convoys to North Africa in late 1941, including Operation M42, where Andrea Doria saw action at the inconclusive First Battle of Sirte on 17 December. Fuel shortages curtailed further activity in 1942 and 1943, and both ships were interned at Malta following Italy's surrender in September 1943. Italy was permitted to retain both battleships after the war, and they alternated as fleet flagship until the early 1950s, when they were removed from active service. Both ships were scrapped after 1956.