Originally designated LSM‑550, she was reclassified (ARS(D)‑2) on 24 April 1945, and was laid down on 25 August 1945 by Brown Shipbuilding Corporation, Houston, Texas.

Designed for salvage work, specifically emergency harbor clearance, Mender completed her shakedown training in the Norfolk, VA, area and got underway, 30 April 1946, for the Pacific.

Within three hours of the detonation she returned to the harbor to assist in recovering beached and damaged craft and in gathering scientific information on underwater effects of the blast.

She departed Hawaiian waters 2 February and sailed to Eniwetok where she replaced moorings before continuing on to Japan, arriving at Sasebo on 14 March.

On 12 April she headed for the Korean combat zone to salvage SS Park Benjamin, grounded with several compartments flooded near Pusan.

Then on 2 September she pointed her bow south for the Philippines and for the next month and a half conducted diving and demolition operations to rid Subic Bay of the hulk of the Japanese vessel Oroyoku Maru.