The second ship to be so named by the Navy, Catalpa (YN-5) was launched 22 February 1941 by Commercial Iron Works, Portland, Oregon; sponsored by Mrs. E. B. Colton; and on 20 June 1941 placed in service for duty in the 12th Naval District.

At Nandi, Suva, and during October and November 1942 at Funafuti in the Ellice Islands, Catalpa laid and cared for harbor entrance nets, protecting important South Pacific Ocean bases.

With the assault forces, she arrived off Peleliu on 15 September, and after standing by as the first troops smashed ashore, sailed on to mine-infested Kossol Passage to begin the work of preparing what would become a major fleet anchorage.

With the buildup of the fleet brought into effect upon the outbreak of hostilities in Korea, Catalpa was re-commissioned 7 August 1950 and reported to the net depot in San Francisco Bay for training and local duty.

On 1 February 1952, she sailed from San Diego, California, for the Far East, and through 1954 installed and tended nets in Tokyo Bay, except for a period in the fall of 1953 when she carried out similar duties at Guam.