The Pisa class consisted of three armored cruisers built in Italy in the first decade of the 20th century. Two of these were for the Royal Italian Navy (Regia Marina) and the third was sold to the Royal Hellenic Navy and named . This ship served as the Greek flagship for the bulk of her active career and participated in the Balkan Wars of 1912–1913, fighting in two battles against the Ottoman Navy. She played a minor role in World War II after escaping from Greece during the German invasion in early 1941. Influenced by communist agitators, her crew mutinied in 1944, but it was suppressed without any bloodshed. Georgios Averof returned to Greece after the German evacuation in late 1944 and became a museum ship in 1952. She is the only surviving armored cruiser in the world.
The two Italian ships participated in the Italo-Turkish War of 1911–1912 during which they supported ground forces in Libya with naval gunfire and helped to occupy towns in Libya and islands in the Dodecanese. They played a minor role in World War I after a submarine sank shortly after Italy joined the war in 1915. Her sister ship, , became a training ship after the war and was broken up for scrap in 1937.
Design and description
The Pisa class was designed in 1904 by Italian engineer Giuseppe Orlando, who attempted to replicate on a smaller scale the armament and armor of the s then entering the service of the Regia Marina. The Italians classified large armored cruisers like the Pisas as second-class battleships. For ships of their displacement, they were considered to have been heavily armed, but inferior to battlecruisers, a type introduced during their lengthy construction time.
The Pisa-class ships had a length between perpendiculars of and an overall length of . They had a beam of and a draft of . The ships displaced at normal load, and at deep load. The Pisa class had a complement of 32 officers and 652 to 655 enlisted men.
Propulsion
The ships were powered by two vertical triple-expansion steam engines, each driving one propeller shaft using steam supplied by 22 Belleville boilers. Designed for a maximum output of and a speed of , both ships handily exceeded this, reaching speeds of during their sea trials from . They had a cruising range of about at a speed of and at a speed of .
Armament
The main armament of the two Italian Pisa-class ships consisted of four Cannone da 254/45 V Modello 1906 guns in hydraulically powered, twin-gun turrets fore and aft of the superstructure. The gun fired armor-piercing (AP) projectiles at a muzzle velocity of . The Royal Hellenic Navy preferred smaller 234 mm (9.2 in) guns purchased from Britain for Georgios Averof, but the ship was otherwise armed nearly identically to her half-sisters. The shell of the Elswick Pattern 'H' gun was fired at a muzzle velocity of .
The Italian ships mounted eight Cannone da 190/45 V Modello 1906 in four hydraulically powered twin-gun turrets, two in each side amidships, as their secondary armament. These Vickers guns fired AP shells at . The Elswick Pattern 'B' 7.5-inch guns aboard Georgios Averof used AP shells which were fired at muzzle velocities of .
For defense against torpedo boats, all three ships mounted 16 Vickers quick-firing (QF) Cannone da 76/50 V Modello 1908 guns. This gun fired a projectile at a muzzle velocity of . The ships were also fitted with eight (Pisa and Amalfi) or four (Georgios Averof) QF Cannone da 47/40 V Modello 1908 guns. The two Italian ships were equipped with three submerged torpedo tubes while those of Georgios Averof were in diameter.
During World War I, Pisas 76 and 47 mm guns were replaced by twenty 76/40 guns; six of these were anti-aircraft (AA) guns while Georgios Averof received one additional 76 mm AA gun. During her 1925 refit, the latter ship had her light armament changed to four 76 mm low-angle guns, two 76 mm AA guns, four 47 mm low-angle guns and five 40 mm AA guns.
Protection
All three ships were protected by an armored belt that was thick amidships and reduced to at the bow and stern. The armored deck was thick. The conning tower armor was thick. The 254 mm gun turrets were protected by of armour while the 190 mm turrets had .