(DD-691 : dp. 1. 376'6", b. 40'; dr. 17'9", 8. 37 k.; cpl. 336; a. 5 5", 10 20mm., 8 21" tt., 6 dcp.' 2 dct.; cl. Fletcher)

Mertz (DD-691) was laid down by Bath Iron Works Corp.,, Bath, Maine, 10 May 1943, launched 11 September 1943; sponsored by Mrs. Selma M. Allen, daughter of Rear Admiral Mertz; and commissioned at Charlestown, Mass., 19 November 1943, Comdr. William S. Estabrook, Jr., in command.

After shakedown off Bermuda Mertz departed Norfolk, 26 January 1944 for the central Pacific, via the Panama Canal and San Diego, arriving Pearl Harbor 5 March. On the 9th the destroyer got underway for the Marshalls as convoy escort, arriving Majuro Atoll 6 days later. Mertz sailed 22 March to join TO 58.2 on the 26th and act as escort back to Majuro. En route, on 31 March she caught a Japanese maw at 0600 in the glare of her searchlights. The enemy merchant ship maneuvered to get away, only to go down under the bail of 5-inch projectiles from Mertz. The task group reached Majuro 6 April. Five days later Mertz steamed for the New Hebrides as a screen for Barnes (CVE-20), arriving Espiritu Santo the 15th.

In mid-May the destroyer returned to Pearl Harbor to prepare for the Marianas campaign. She took fire support and patrol station close ashore to Saipan on 14 June, pounding gun emplacements in the daytime and at night maintaining illumination over the enemy lines until 22 June when she began screening convoys.

Mertz participated in the occupation of Pelelieu and Anguar in the Palau Islands, arriving 10 September. She retired to Manus, Admiralties, the 23d to prepare for the invasion of Leyte, Philippines.

On 20 October, D-Day for the Leyte landing forces Mertz escorted landing craft through air attacks to the beach and later in the day patrolled off Dinagat Island at the entrance to Leyte Gulf. Early in the morning of' 25 October as the Japanese Southern Force approached Leyte Gulf through the Mindanao Sea, Mertz and McNair (DD-679) patrolled between Desolation Point and Homonhon Island, lest the enemy fleet choose to steam north along the east coast of Dinagat Island to attack the Allied beachhead. When the Japanese entered Surigao Strait, Rear Adm. Jesse B. Oldendorf's force met and virtually destroyed the enemy armada in the classic "crossing-of-the-T" maneuver known as the Battle of Surigao Strait part of the overall Battle for Leyte Gulf. Later that same day Mertz splashed a "Zeke" at several hundred yards with heavy machinegun fire.

With the Leyte beachhead established, the destroyer got underway 26 October for Hollandia, New Guinea, anchoring in Humboldt Bay on the 30th to replenish. She got underway for Leyte again 9 November escorting a reinforcement convoy arriving 6 days later Mertz then continued on to Seeadler Harbor Manus, to Join a task unit staging for the daring expedition through the Sulu Sea controlled by the enemy since early 1942, to capture Mindoro The American ships had to contend with both a typhoon and heavy air attacks. Mertz splashed an "Oscar" 15 December and assisted in the destruction of several others. Departing San Pedro Bay 4 January 1945, she made another voyage through the Sulu Sea, to support the invasion of Luzon at Lingayen Gulf on the 9th before returning to San Pedro Bay on the 16th.

On 10 February Mertz steamed from Ulithi for 3 months at sea with the Fast Carrier Task Force. During this time she played a role in the airstrikes on the Tokyo area 16 February, the landings on Iwo Jima 19 February and the raids on Okinawa 1 March While screening the flattops off Kyushu, Japan, in March, she downed two more enemy planes. While operating off Okinawa Mertz helped sink two Japanese submarines: RO-46 on 9 April and I-56 on 18 April. The destroyer retired to Ulithi 14 May before returning to Okinawa the 24th. She next steamed to Okino Daito Jima which she bombarded 9 June.

The next day she got underway for Leyte Gulf, anchoring at San Pedro Bay 13 June.

As part of Adm. William F. Halsey's 3d Fleet she cleared San Pedro 1 July and 9 days later arrived at the launching area off the southeast coast of Tokyo for strike on the Japanese home islands. Beginning with the attacks on Tokyo 10 July, Mertz ranged up and down the coasts of Japan until she Joined an antishipping sweep in the Kuriles while en route to the Aleutians. The destroyer arrived Adak 14 August, the day of Japan's capitulation.

Mertz's first and only peacetime duty came 31 August when she departed Adak for Japan, arriving Ominato northern Honshu, 8 September to operate with the 3d Fleet during the occupation of the northern Honshu-Hokaido area. On the 15th the destroyer departed Ominato Harbor for the west coast, arriving San Francisco 30 September.

On 1 December Mertz steamed to San Diego, where she decommissioned 23 April 1946 and entered the Pacific Reserve Fleet. She was as reassigned to the Long Beach Calif., group 1 July 1951 and the Stockton, Calif., group 1 January 1959 to remain there into 1969.