USS Manayunk (YN-100/AN-81) was a Cohoes-class net laying ship which was assigned to protect United States Navy ships and harbors during World War II with her anti-submarine nets.

The second ship to be so named by the Navy, Manayunk was laid down with the hull identification number YN-100 by the Commercial Iron Works, Portland, Oregon on 18 December 1944.

The ship redesignated AN-81 on 17 January 1945 and launched on 30 March 1945; sponsored by Mrs. Bryan Wallace Strong.

She operated in the Mariana Islands, primarily in the Saipan-Tinian area, laying and maintaining nets and moorings until the spring of 1946.

She continued to be listed as Navy-owned until formally turned over to the U.S. Maritime Administration in September 1962 at Olympia, Washington.