From: Dictionary of American Naval Fighting Ships, Vol.VI p 330
A precious stone of transparent rich blue corundum. Sapphire (SP--710) retained her mercantile name in United States Naval service.
The second Sapphire (PYc--2), a yacht built in 1929 as Buccaneer by George Lawley and Sons, Neponset, Mass., was acquired by the Navy from her owner, Mr. Leon Mandel, Quonset, Mass., on 1 November 1940; renamed Sapphire and designated PYc--2 ; converted for Navy use by her original builder ; and commissioned at Boston on 6 June 1941, Lt. A. N. Daniels, USNR, in command.
In August, Sapphire proceeded to Norfolk, Va., whence, in September, she moved north to her home port, New London, Conn. There, through World War II, she supported various Submarine School programs, but was primarily engaged in training prospective commanding officers in attack procedures and in testing sound equipment. With the end of the war, Sapphire was designated for inactivation. On 19 September 1945, she departed New London and proceeded to Charleston, S.C., where she was decommissioned on 29 October 1945. Struck from the Navy list on 13 November of the same year, she was transferred to the Maritime Commission for disposal through sale on 3 September 1946.