 San Marco underway, 18 August 1910 | |
| Class overview | |
|---|---|
| Name | San Giorgio |
| Builders | Regio Cantiere di Castellammare di Stabia,Castellammare di Stabia |
| Operators |  Regia Marina |
| Preceded by | Pisa class |
| Succeeded by | None |
| Built | 1905–1911 |
| In service | 1910–1943 |
| Completed | 2 |
| Lost | 1 |
| Scrapped | 1 |
| General characteristics | |
| Type | Armored cruiser |
| Displacement | 10,167–10,969 t (10,006–10,796 long tons) |
| Length | 140.89 m (462 ft 3 in) (o/a) |
| Beam | 21.03 m (69 ft 0 in) |
| Draft | 7.35–7.76 m (24 ft 1 in – 25 ft 6 in) |
| Installed power |
|
| Propulsion |
|
| Speed | 23knots (43 km/h; 26 mph) |
| Range | 4,800–6,270 nmi (8,890–11,610 km; 5,520–7,220 mi) at 10 knots (19 km/h; 12 mph) |
| Complement | 32 officers, 666–73 enlisted men |
| Armament |
|
| Armor |
|
TheSan Giorgio class consisted of twoarmored cruisers built for the Royal Italian Navy (Regia Marina) in the first decade of the 20th century. The second ship,San Marco, was used to evaluate recently inventedsteam turbines in a large ship and incorporated a number of other technological advances. The ships participated in theItalo-Turkish War of 1911–1912, althoughSan Giorgio was under repair for most of the war.San Marco supported ground forces inLibya withnaval gunfire and helped them to occupy towns in Libya and islands in theDodecanese. During World War I, the ships' activities were limited by the threat ofAustro-Hungarian submarines, although they didbombard Durazzo, Albania in 1918.
San Giorgio spent several years in the Far East and Italian Somaliland after the war and became atraining ship in 1931. After a brief deployment to Spain in 1936, she was reconstructed to better serve her role as a training ship. The ship'santi-aircraft armament was augmented when she was deployed toTobruk, Libya to reinforce the port's defenses after Italy declared war on Britain in May 1940.San Giorgio wasscuttled in early 1941 when Allied forces were poised to capture the port. Her wreck wassalvaged in 1952, but sank while under tow.San Marco was converted into atarget ship in the early 1930s and was found sunk at the end of the war. She wasscrapped in 1949.
TheSan Giorgio class was ordered almost immediately after the precedingPisa-class ships, and was an improved version of that design. Theforecastle was extended to improve seaworthiness,turret armor was increased, habitability was improved and the propulsion machinery was redistributed.San Marco was given the first steam turbines fitted in a large Italian ship for comparative purposes withSan Giorgio, which retained the traditionalvertical triple-expansion steam engines (VTE).San Marco was a very innovative ship as she was the first turbine-powered ship in any navy to have fourpropeller shafts, the first with agyroscopic compass, the first withantiroll tanks, and the first not to use wood in any way.[1]
TheSan Giorgio-class ships had alength between perpendiculars of 131.04 meters (429 ft 11 in) and anoverall length of 140.89 meters (462 ft 3 in). They had abeam of 21.03 meters (69 ft 0 in) and adraft of 7.35–7.76 meters (24 ft 1 in – 25 ft 6 in). The ships displaced 10,167–10,969 metric tons (10,006–10,796 long tons) at normal load, and 11,300–11,900 metric tons (11,100–11,700 long tons) atdeep load. The ships had a complement of 32 officers and 666 to 673 enlisted men.[2]
The machinery installation of this class was changed in comparison to that of thePisa class, with the enginesamidships with the 14 mixed-firingwater-tube boilers fore and aft of the engines. Their exhausts were trunked together into two widely spaced pairs offunnels. Designed for a maximum speed of 23knots (43 km/h; 26 mph),[3] the two ships were given different types of propulsion machinery for evaluation.San Giorgio's two shafts, pair of 19,500-indicated-horsepower (14,500 kW) VTE steam engines andBlechynden boilers differed only slightly from those used by thePisas. In contrast,San Marco's four shafts, each driven by a license-builtParsons steam turbine, was a first for theRegia Marina. The turbines used steam provided byBabcock & Wilcox boilers at a working pressure of 210 psi (1,448 kPa; 15 kgf/cm2)[4] to reach their designed output of 23,000 shp (17,000 kW). Both ships exceeded their designed speeds, withSan Giorgio reaching 23.2 knots (43.0 km/h; 26.7 mph) andSan Marco 23.75 knots (43.99 km/h; 27.33 mph) during theirsea trials. The biggest difference between the sisters was that the turbines ofSan Marco proved to be significantly less economical in service (a range of 4,800nautical miles (8,900 km; 5,500 mi) at a speed of 10 knots (19 km/h; 12 mph) and 2,480nautical miles (4,590 km; 2,850 mi) at 21.25 knots (39.36 km/h; 24.45 mph)) compared toSan Giorgio's VTE steam engines (6,270nautical miles (11,610 km; 7,220 mi) at 10 knots (19 km/h; 12 mph) and 2,640nautical miles (4,890 km; 3,040 mi) at 21.25 knots (39.36 km/h; 24.45 mph).[5]
The main armament of theSan Giorgio-class ships consisted of fourCannone da 254/45 A Modello 1907[Note 1] guns in electrically powered, twin-gun turrets fore and aft of thesuperstructure.[5] The turrets had anarc of fire of 260°.[4] The 254 mm (10.0 in) gun fired 204.1–226.8-kilogram (450–500 lb)armor-piercing (AP) projectiles at amuzzle velocity of 870 meters per second (2,850 ft/s). At maximum elevation of +25°, the guns had a range of about 25,000 meters (27,000 yd).[6] The ships mounted eightCannone da 190/45 A Modello 1908 in four electrically powered twin-gun turrets, two in each side amidships, as their secondary armament. Their arc of fire was 160°.[4] TheseArmstrong Whitworth 190 mm (7.5 in) guns fired90.9-kilogram (200 lb) AP shells at 864–892 m/s (2,835–2,927 ft/s). At maximum elevation of +25°, the guns had a range of about 22,000 meters (24,000 yd).[7]
For defense againsttorpedo boats, theSan Giorgios mounted 18quick-firing (QF) 40-caliber 76 mm (3.0 in) guns. Eight of these were mounted inembrasures in the sides of the hull and the rest in the superstructure.[5] The ships were also fitted with a pair of QF 40-caliber47 mm (1.9 in) guns. TheSan Giorgio-class ships were equipped with three submerged 450 mm (17.7 in)torpedo tubes. During World War I, eight of the 76 mm guns were replaced by six 76 mmanti-aircraft (AA) guns[5] and one torpedo tube was removed.[3]
The ships were protected by anarmored belt that was 200 mm (7.9 in) thick amidships and reduced to 80 mm (3.1 in) at the bow and stern.[3] The belt was 2.2 m (7 ft 3 in) high, of which 1.5 m (4 ft 11 in) was below thewaterline.[4] The armoreddeck was 50 mm (2.0 in) thick and theconning tower armor was 254 mm thick. The 254 mm gun turrets were protected by 200 mm of armour while the 190 mm turrets had 160 mm (6.3 in).[5]
| Name | Builder[2] | Laid down[5] | Launched[5] | Completed[5] | Fate |
|---|---|---|---|---|---|
| San Giorgio | Regio Cantieri di Castellammare di Stabia,Castellammare di Stabia | 4 July 1905 | 27 July 1908 | 1 July 1910 | Scuttled, 22 January 1941;salvaged, but sank under tow, 1952[8] |
| San Marco | 2 January 1907 | 20 December 1908 | 7 February 1911 | Sunk, 1945;scrapped, 1949[9] |
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San Giorgioran aground in August 1911 offNaples-Posillipo;[10] heavily damaged, she was under repair until June 1912, missing most of the Italo-Turkish War.San Marco supported the occupations ofBenghazi andDerna, Libya during the war and bombarded the fortifications defending the entrance to theDardanelles.[11] She also supported the forces occupying the island ofRhodes in May 1912. In February 1913,San Giorgio cruised theAegean Sea and made a port visit toSalonica, Greece, the next month.[12] She ran aground again on 21 November in theStrait of Messina, but was only slightly damaged.[8]
During World War I, the activities of the ships were restricted by the threat of submarine attack after the armored cruisersGiuseppe Garibaldi andAmalfi were sunk by submarines shortly after Italy joined the war in May 1915, although the ships did participate in the bombardment of Durazzo, Albania in late 1918.[13]
After the war,San Giorgio was deployed to theFar East[14] whileSan Marcos played a minor role in theCorfu incident in 1923.[15][16]San Giorgio, escorted bySan Marco, ferriedCrown PrinceUmberto to South America in July–September 1924,[17][18] and then supported operations inItalian Somaliland in 1925–1926.[14] The ship was disarmed and converted into a radio-controlled target ship in 1931–1935; her old boilers were replaced by four oil-burning ones which reduced her maximum speed to 18 knots (33 km/h; 21 mph). She was captured by the Germans when they occupiedLa Spezia on 9 September 1943;San Marcos was found at the end of the war half-sunk in the harbor there and was broken up in 1949.[9]
From 1930 to 1935,San Giorgio was based inPola as a training ship, and was sent to Spain after theSpanish Civil War began in 1936 to protect Italian interests.[14] In 1937–1938 she was reconstructed to serve as a dedicated training ship fornaval cadets at theArsenale di La Spezia: six boilers were removed and the remaining eight were converted to burn fuel oil which reduced her speed to 16–17 knots (30–31 km/h; 18–20 mph). Each pair of funnels was trunked together and her 76/40 guns were replaced by100 mm (4 in) / 47 caliber guns in four twin turrets abreast the funnels. Her torpedo tubes were also removed while she received a light AA suite for the first time, with the addition of six Breda37 mm (1.5 in) 54-cal. guns, a dozen 20 mm (0.79 in)Breda Model 35 autocannon and four 13.2 mm (0.52 in)Breda Model 31 machine guns in two twin mounts.[9][19]
Prior to her being sent to reinforce the defenses of Tobruk in early May 1940, a fifth 100/47 gun turret was added on the forecastle and five more twin13.2 mm (0.52 in) machine gun mounts were added to better suit her new role as a floating battery.[19] Two days after Italy declared war on Britain on 10 June, the Britishlight cruisersGloucester andSouthampton bombarded Tobruk and attackedSan Giorgio, which was not hit during the engagement.[20] A British submarine fired two torpedoes atSan Giorgio on 19 June, but these detonated before reaching the ship.[21] The ship's guns engagedAllied aircraft attacking Tobruk many times, destroying several. She was scuttled in shallow water on 22 January 1941 to prevent her capture during theBattle of Tobruk.[19]San Giorgio was awarded theGold Medal of Military Valour (Medaglia d'Oro al Valore Militare) for her performance at Tobruk.[22] Her wreck was refloated in 1952, but sank under tow en route to Italy.[19]
