|Affiliation||United States Navy|
|Torpedo||4 tubes (forward)|
|REXP Gain Rate||10%|
|Upgraded From||Atlanta Class|
|Upgrades Into||S Class (USN)|
The United States Navy's sixteen O-class submarines were created out of the lessons learned from the L class. The O class were about 80 tons larger than the L class, with greater power and endurance for ocean patrols. Due to the American entry into World War I the O class were built much more rapidly than previous classes, and were all commissioned in 1918. O-1 through O-10 were group 1, designed byElectric Boat, O-11 through O-16 were group 2, designed by the Lake Torpedo Boat Company and sometimes considered a separate class. The group 2 boats entered service just before the end of World War I. Eight of the group 1 boats survived to serve in World War II as training boats when they were recommissioned in 1941.
The O class were built by five shipyards: O-1 by Portsmouth Navy Yard,Kittery, Maine, O-2 by Puget Sound Navy Yard, Bremerton, Washington,O-3 through O-10 by Fore River Shipyard, Quincy, Massachusetts, O-11 through O-13 by Lake Torpedo Boat Company, Bridgeport, Connecticut, and O-14 through O-16 by California Shipbuilding (formerly Craig Shipbuilding), Long Beach, California.