The second USS Tangier (AV-8) was a Maritime Commission type C-3 cargo ship, converted to a seaplane tender in the United States Navy during World War II. The ship, the first of the C-3s to be launched and significant in a revival of Pacific coast shipbuilding, was launched 15 September 1939 and delivered to the Maritime Commission as Sea Arrow. The ship was acquired by the U.S. Navy during completion before any commercial service, put back into the builder's yard, and converted to a seaplane tender during 1940. After spending over a year in conversion the ship was commissioned on 25 August 1941.

Tangier was present during the Attack on Pearl Harbor that drew the United States into World War II and saw service throughout the Pacific until the end of the war. The vessel was placed in reserve January 1947 at Philadelphia and remained in reserve until 1961 when sold for mercantile use. Renamed Detroit in 1962 and converted to a car carrier/container ship. In October 1974 the vessel was sold for scrap and broken up at Valencia, Spain.

Sea Arrow was the first C-3 type and first vessel with high pressure steam plant installation, fireproof construction, and over half the hull welded construction to be built on the Pacific coast. Successful construction of the first ship answered questions raised about whether Pacific coast shipyards could find enough skilled labor, particularly mechanics to install high pressure engineering plants, to compete. Moore was contracted to build four ships, yard hulls 195 through 198, Maritime Commission hulls 51–52 and then 136–137 with the intervening MC hulls being built in the east. The prospect of war caused rapid changes in the destiny of these vessels with name changes during construction that are confusing.

Sea Arrow was immediately acquired by the Navy and renamed with the other three hulls being designated after launch or still under construction for Moore-McCormack Lines. The second and third ships were christened Sea Star and Sea Panther but were renamed Mormacsea and Mormacstar with the fourth being named Mormacsun before launch. Ex Sea Star/Mormacsea became USS Elizabeth C. Stanton (AP-69). Mormacsun was also acquired by the Navy and became USS Florence Nightingale (AP-70). The Moore Dry Dock Sea Panther, renamed Mormacstar, got renamed again to Mormacsea. To truly confuse matters the Moore Dry Dock Sea Panther duplicated the name of MC hull 40 launched by Federal Shipbuilding of New Jersey that became USS Hamul (AD-20) with a later ship, MC hull 390 built in Mississippi, also being named Sea Panther.

Pacific coast interests had been pressing the Maritime Commission to begin awarding contracts for new shipbuilding programs to Pacific yards. The launch of Sea Arrow was seen as the beginning of a revival of the industry. As a result, the launch drew considerable attention and presence of business figures speaking and among the 680 invited guests.

The ship was laid down under a Maritime Commission contract (MC hull 51) as Sea Arrow on 18 March 1939 at Oakland, California by Moore Dry Dock Company; launched on 15 September 1939; sponsored by Mrs. Joseph R. Sheehan. The launch, six weeks ahead of schedule and a month before the first C-3 in an Atlantic coast yard, was the first of the C-3s launched. A feature of the launch was a painting of giant eyes around the plugged hawse pipes. The keel for the second C-3 was prefabricated and immediately placed on the ways.

Sea Arrow completed trials with almost no problems even though the geared turbines had been delayed with a rushed installation and had been the yard's first high pressure steam installation. Sea Arrow, renamed Tangier designated AV-8 on 3 June 1940, was delivered to the Maritime Commission 8 July 1940 and immediately purchased by the Navy, commissioned in ordinary, and put back into the Moore Dry Dock yard for the extensive modifications required for Navy purposes.

Tangier, under the command of Commander and future Vice Admiral Clifton A. F. Sprague, remained at Oakland for over a year undergoing conversion to a seaplane tender. Finally, on 25 August 1941, she went into full commission and put to sea on her shakedown cruise. At the completion of shakedown training, she was assigned as tender to Patrol Wing 2 (PatWing 2), based in Hawaii. Tangier arrived at Pearl Harbor on 3 November and moored at berth F-10 forward of the former battleship Utah directly astern at F-11. Utah was serving as an anti-aircraft training ship. There, she spent the last month of peacetime caring for her complement of seaplanes.