Killarney, a 32 gross ton motor boat built in 1910 at Bay City, Michigan, was employed as a pleasure craft on the Great Lakes. The Navy purchased her in April 1917 for conversion to a patrol boat. Commissioned in the following June as USS Killarney (SP-219), she operated in the Saint Mary's River between Lakes Huron and Superior until the autumn of that year, then shifted to the Saint Clair River, near Detroit. She was transferred to the Detroit Naval Training Camp in March 1919 and apparently left active service in August. Killarney was sold in December 1919.