USS California (ACR-6)

	USS San Diego (ACR-6), 28 January 1915, while serving as flagship of the Pacific Fleet. Note two-star rear admiral's flag flying from her mainmast top.
History
United States
Name	California (1907–1914); San Diego (1914–1918);
Namesake	State of California; City of San Diego, California;
Ordered	3 March 1899
Awarded	10 January 1901
Builder	Union Iron Works, San Francisco, California
Cost	$3,800,000 (contract price of hull and machinery)
Laid down	7 May 1902
Launched	28 April 1904
Sponsored by	Miss F. Pardee
Commissioned	1 August 1907
Renamed	San Diego, 1 September 1914
Identification	Hull symbol: ACR-6
Fate	Sunk 19 July 1918, by U-156
General characteristics
Class & type	Pennsylvania-class armored cruiser
Displacement	13,680 long tons (13,900 t) (standard); 15,138 long tons (15,381 t) (full load);
Length	503 ft 11 in (153.59 m) oa; 502 ft (153 m) pp;
Beam	69 ft 6 in (21.18 m)
Draft	24 ft 1 in (7.34 m) (mean)
Installed power	16 × Babcock & Wilcox boilers; 23,000 ihp (17,000 kW);
Propulsion	2 × vertical triple expansion reciprocating engines; 2 × screws;
Speed	22 kn (41 km/h; 25 mph); 22.20 kn (41.11 km/h; 25.55 mph) (Speed on Trials);
Complement	80 officers 745 enlisted 64 Marines
Armament	4 × 8 in (203 mm)/40 caliber Mark 5 breech-loading rifles (BL)(2×2); 14 × 6 in (152 mm)/50 cal Mark 6 BL rifles; 18 × 3 in (76 mm)/50 cal rapid-fire guns; 12 × 3-pounder (47 mm (1.9 in)) Driggs-Schroeder guns; 2 × 1-pounder (37 mm (1.5 in)) Driggs-Schroeder saluting guns; 2 × 18 inch (450 mm) torpedo tubes;
Armor	Belt: 6 in (152 mm) (top & waterline); 5 in (127 mm) (bottom); Deck: 1+1⁄2 in (38 mm) - 6 in (amidships); 4 in (102 mm) (forward & aft); Barbettes: 6 in; Turrets: 6 - 6+1⁄2 in (165 mm); Conning Tower: 9 in (229 mm);
General characteristics (Pre-1911 Refit)
Installed power	8 × Modified Niclausse boilers, 12 × Babcock & Wilcox boilers
Armament	4 × 8 in/45 cal Mark 6 BL rifles (2×2); 14 × 6 in/50 cal Mark 6 BL rifles; 18 × 3 in/50 cal rapid-fire guns; 4 × 3-pounder (47 mm) Driggs-Schroeder saluting guns; 2 × 18 in submerged torpedo tubes;
	USS SAN DIEGO (Armored Cruiser) Shipwreck Site
	U.S. National Register of Historic Places
Nearest city	Fire Island, New York
Area	27 acres (11 ha)
Built	1918
Built by	Union Iron Works
NRHP reference No.	98000071
Added to NRHP	17 February 1998

The second USS California (ACR-6), also referred to as "Armored Cruiser No. 6", and later renamed San Diego, was a United States Navy Pennsylvania-class armored cruiser.

California was launched on 28 April 1904 by Union Iron Works at San Francisco, California, sponsored by Miss Florence Pardee, daughter of California Governor George C. Pardee, and commissioned on 1 August 1907. It would later be the only major US warship lost during World War 1, sunk by a German mine after reaching Long Island, New York while en route from Portsmouth, New Hampshire to New York.