In Roman mythology, a god of the sea, having jurisdiction over the ports and shores.
(AGP–4: dp. 3,960; l. 328’0”; b. 50’0”; dr. 13’6”; s. 12 k.; cpl. 283; a. 2 3”, 8 40mm., 8 20mm.; cl. Portunus.)
The first Portunus (AGP–4) was laid down as LST–330 by the Philadelphia Naval Shipyard, 12 November 1942; launched 11 February 1943 as Portunus (AGP–4); and commissioned at Baltimore, Md., 12 June 1943, Lt. Comdr. James R. Hanna in command.
After shakedown along the east coast, this motor torpedo boat tender departed the U.S. 23 July 1943 in TG 29.6 for the Panama Canal, whence she continued to Australia. At Cairns, 10 October, she loaded PT Base 4 gear for transport to Kana Kope, New Guinea. On the 20th she arrived at Buna, New Guinea, and until 4 July 1944 repaired and serviced U.S. and Australian naval units operating along the New Guinea coast.
Underway 4 July in convoy with Hilo and 8 units of MTB Squadron 25, Portunus arrived at Mios Woendi in the Schoutens 9 July. Through December, she underwent overhaul at Brisbane, and on 29 January 1945 returned to Mios Woendi and resumed repair work.
On 20 February she got underway for Leyte Island, whence she proceeded to Ilo Ilo, Panay, to support MTB Ron 33 during the assault there and to establish a patrol base after its success. The assault waves met no apparent opposition, the enemy having set fires and demolition charges and evacuated the city.
On 2 April Portunus got underway for Samar and Leyte. On 16 April she joined company with the remainder of TG 78.2 to land the 24th Infantry Division, U.S. Army and secure Parang, Mindanao. She steamed between various points on Mindanao and Samar, supplying MTB’s, until 16 July when she got underway in convoy for Okinawa. She anchored off Hagushi, 21 July and shifted to Togouchi Harbor the next day. She serviced and repaired MTB Ron 31 and 37 and various other units through 29 September when she prepared to get underway for California and inactivation.
Decommissioned at Mare Island 18 April 1946, she was struck from the Navy List 13 November 1946, transferred to the Maritime Commission 6 February 1948 and simultaneously delivered to the Kaiser Co., Oakland, for scrapping.
Portunus earned 3 battle stars for World War II service.