The US Navy bareboat chartered "Quirigua" through the Maritime Commission on 2 June 1941 under Public Law 101, 77th Congress and Executive Order 8771. Brewer's Drydock Co. of Staten Island, New York converted the ship for Navy service by adding one single 5"/38 caliber gun, four 3"/50 caliber guns for anti-aircraft (AA) and anti-submarine use and up to eight Oerlikon 20 mm cannon AA guns. She was renamed "Mizar" and commissioned into the US Navy on 14 June 1941, commanded by Cmdr E.D. Walbridge.