The third ship to be so named by the U.S. Navy, Penobscot (ATA–188), an auxiliary ocean tug, was laid down as ATR–115 by Levingston Shipbuilding Company, Orange, Texas, 11 September 1944; launched 12 October; and placed in service 12 December.

Assigned homeyard at Pearl Harbor, she provided extensive advanced base towing services and called at numerous islands as events in the march towards victory in the Pacific reached a crescendo.

In addition to towing assignments, Penobscot conducted torpedo and naval mine recovery operations, and provided a wide range of services to ships of the Fleet.

One demonstration of her operational flexibility occurred in May 1967 when she assisted USNS Mission Capistrano in oceanographic research off Bermuda.

After overhaul at Coastal Shipyard and Drydock Company, Staten Island, New York, that autumn, Penobscot resumed her multifarious tasks, nearly every aspect of which involves the rendering of service to the Fleet.