For other ships of the same name, see USS Alert.
Alert, serving as tender for the Third Submarine Division of the Pacific Fleet, lying alongside the wharf at Kuahua Island, U.S. Naval Station, Pearl Harbor, 22 August 1917. K-3 and K-4 are identifiable alongside; the unidentified "boat" is probably K-8.
|Builder:||John Roach & Sons|
|Launched:||18 September 1874|
|Commissioned:||27 May 1875|
|Decommissioned:||9 March 1922|
|Fate:||Sold 29 July 1922|
|Class & type:||Alert-class gunboat|
|Displacement:||1,020 long tons (1,040 t)|
|Length:||199 ft 9 in (60.88 m)|
|Beam:||32 ft (9.8 m)|
|Draft:||13 ft (4.0 m)|
|Speed:||10 kn (12 mph; 19 km/h)|
|Complement:||202 officers and enlisted|
|Armament:||1 × 11 in (280 mm) smoothbore, 2 × 9 in (230 mm) smoothbore, 1 × 60-pounder rifled, Spar torpedoes|
The third USS Alert was an iron-hulled screw steamer gunboat in the United States Navy. The lead ship in her class, Alert was destined for a long naval career, serving from 1875 to 1922, a period of 47 years, including service as a submarine tender in World War I. Toward the end of her career she received the designation AS-4.
Alert was laid down in 1873 by John Roach & Sons at Chester, Pennsylvania in 1873. Launched on 18 September 1874, Alert was commissioned for the first time on 27 May 1875, Commander William T. Sampson in command.