From: Dictionary of American Naval Fighting Ships, Vol.V p 281
A variant spelling of phenacite, a glassy mineral, either colored or colorless, which is used as a gem and may be mistaken for quartz.
Phenakite (PYc--25), a coastal patrol yacht, was built by Pusey and Jones Co., Wilmington, Del., in 1902; acquired by the Navy as Sechern from her owner, Mr. J. Martin of Brooklyn, N.Y., 17 February 1942; converted for Navy use by Robert Jacobs, Inc., City Island, N.Y.; renamed Phenakite 3 March 1942; and commissioned at Tompkinsville, N.Y., 1 July 1942, Lt. John D. Lannon in command.
After shakedown and training along the New England coast, Phenakite departed New York 16 October for duty with the Fleet Sonar School at Key West, Fla. Assigned to Service Squadron 9, she reached Florida waters 3 November. During the next two years she embarked student officers and sailors for daily at sea training cruises. As a sonar training ship, she ranged the submarine operating area off the Florida Keys while her students practiced sonar tactics and maneuvers. In addition, the patrol yacht served both as an escort between the operating area and Key West and as a night patrol ship in the approaches to Key West harbor.
Assigned to duty with the 3d Naval District 2 November 1944, Phenakite steamed to New York between 5 and 10 November. She decommissioned at Tompkinsville 17 November and was placed in service. On 29 November she was assigned to the Naval Reserve Midshipmen Training School, Flushing Bay, Long Island. During the remainder of World War II she cruised primarily in Long Island Sound with midshipmen crews embarked.
Phenakite discontinued her training exercises at the wars end and returned to Tompkinsville 20 August 1945. She was placed out of service 2 October 1945 and returned to the Maritime Commission 5 November. On 29 December she was returned as Sachem to Mr. J. Martin, her former owner. Her name was struck from the Naval Register 7 February 1946. She was subsequently sold to Circle Line, New York City and renamed Circle Line V.