USS Tunny (SS/SSG/APSS/LPSS-282) was a which saw service in World War II and in the Vietnam War. Tunny received nine battle stars and two Presidential Unit Citations for her World War II service and five battle stars for her operations during the Vietnam War. Tunny was the first ship of the United States Navy to be named for the tunny, any of several oceanic fishes resembling the mackerel.
Construction Tunnys keel was laid down on 10 November 1941 at Vallejo, California, by the Mare Island Navy Yard. She was launched on 30 June 1942, sponsored by Mrs. Frederick G. Crisp, wife of Rear Admiral Frederick G. Crisp, manager of the Mare Island Navy Yard, and commissioned on 1 September 1942.
World War II service September 1942–January 1943 After commissioning, Tunny conducted shakedown training from California ports. On 29 November 1942, at a position in the Pacific Ocean off California which the armed tanker reported as but actually was in the vicinity of , Huguenot mistook Tunny for a Japanese submarine and opened gunfire on her.Hinman & Campbell, pp. 317–318. Tunny was under escort by the submarine chaser , which was about from Tunny on her starboard quarter at the time. Tunny pulled away from at high speed to a range of and avoided damage and casualties.
After completing shakedown, Tunny arrived in the Hawaiian Islands on 12 December 1942. She then engaged in an additional week of training, followed by two weeks repairs.
First war patrol (12 January – 20 February 1943) She got underway from Submarine Base, Pearl Harbor, on 12 January 1943 for her first war patrol. For nearly a week, rough seas hampered the progress of the submarine. Then, as she approached the Ryukyu Islands, sea traffic increased. Sightings of sampans became frequent, and Tunny often dove to avoid detection by suspicious-looking trawlers.
At 05:30 on 26 January, Tunny sighted masts and a stack over the horizon indicating a possible target. During the day, she lessened the distance between herself and her quarry; and, near dusk, she closed a 400-ton trawler. Finding the prey not worth a torpedo, the submarine surfaced and opened fire with her deck gun. Soon, darkness forced her to discontinue the attack, and she continued on her way.
On 29 January, she began patrolling off Formosa. An hour and a half before midnight on 31 January, her periscope at last disclosed a worthwhile target, a freighter approaching Takao Ko. Tunny fired two "fish" from her bow tubes, but the freighter made a radical change of course which enabled her to evade the torpedoes. When her target counterattacked and dropped two depth charges, Tunny broke off the attack and submerged.
On 1 February, Tunny set her course for the China coast, running on the surface. As darkness fell on 2 February, she was only hours from Hong Kong, expecting to make landfall on Tamkan Island by daybreak. At 2130, she made radar contact; and, through the night, drew closer to her as yet unseen quarry.
A light rain was falling and visibility was poor when, half an hour before morning twilight, Tunny began a radar approach. Rapidly shoaling water less than deep and land masses on two sides of the submarine limited her maneuverability. At , the extreme phosphorescence of the water illuminated her wake and betrayed her presence to the enemy ship, which began signaling the unidentified intruder with a blinker light. Despite her detection, Tunny continued the approach until she was only from the target and then launched three torpedoes. The Japanese ship, now discernible as a loaded tanker, began to maneuver radically and opened fire on the submarine. Undeterred, Tunny submerged and continued the attack, firing a second volley from her stern tubes. One of these torpedoes hit the side of the tanker with a thud, but without explosion, and a small column of water erupted just forward of the tanker's bridge. Duds and prematures were a problem for American submarines early in 1943, and verification that this torpedo had indeed hit the tanker, but failed to detonate, was forthcoming when members of the tanker's crew dashed to the spot in question and began examining the impact area with flashlights. Despite continuous fire from the ship and the proximity of land, Tunny managed to stay within firing range of her target by traveling at full speed. After the tanker successfully evaded Tunnys third salvo, the submarine fired a last torpedo from as the intended victim reached the passage into Hong Kong. Following this disappointing conclusion to her attack, Tunny dove in anticipation of search planes which appeared within two hours and continued their surveillance throughout the day.
After dark on 3 February, while patrolling Lema Channel, Tunny made radar contact with a sizable target. On this very dark night, visual identification was impossible; but, at 2005, the submarine approached to and made a three-torpedo attack. The sound of the target's screws ceased immediately, and Tunny claimed to have sunk this unidentified ship which had been seen only on radar. When the submarine surfaced at daybreak the following day, the submariners discovered an unexpected visitor on deck—a six-foot black and yellow striped snake.
On 4 February, Tunny set her course for Swatow, keeping to the shoreline in hopes of intercepting shipping. En route, she passed a large hospital ship well marked and brilliantly lighted. On 6 February and 7 February, Tunny patrolled off Swatow. Numerous junks plying the Formosa and Swatow banks at all hours added to the hazards imposed by shallow water, and an inoperable fathometer (depthmeter) made it impossible for Tunny to approach the shore closer than .
Early on the morning of 8 February, she went deep to avoid a plane revealed by radar. When she surfaced, she discovered a freighter off her beam. She shadowed the target during the day and, after sunset, made her approach and launched two torpedoes from a distance of . Due to bad runs, neither of these took effect, but they did alert the freighter, which opened fire on Tunny. The submarine fired two shots from her bow tubes, but one torpedo missed, and the other circled around to the right. Tunny then drew ahead for a surface approach and fired three more torpedoes. Two of these found the mark; but one put on an amazing show, veering sharply first to the left and then to the right, before hitting the target. The Kusayama Maru, a heavily laden, 5000-ton cargo ship, sank by the stern in 20 minutes; Tunny had scored her first confirmed kill. As she proceeded on towards Takao harbor, a searchlight suddenly pierced the dark not far ahead, and Tunny dove to avoid detection.
The next day, Tunny sighted a large transport. Undetected by two nearby patrol vessels and a plane, she made her approach and scored two hits on the transport with her remaining torpedoes. However, the ship did not sink and later left the area.
On 11 February, Tunny set her course for Midway Island. En route, she used a combination of 20 millimeter and five-inch (127 mm) gunfire to sink a 100-ton fishing trawler. On 20 February, she made contact with the harbor escort and proceeded to moor at Midway Island, completing her first aggressive and successful patrol. She later continued on to Hawaii, arriving at Pearl Harbor on 24 February 1943.
Second war patrol (24 March – 23 April 1943) After refitting by tender and three days of training, Tunny departed the Hawaiian Islands on 18 March, paused at Midway Island for replacement of her periscope, and got underway for Wake Island on 24 March. Later, Commander, Submarine Force, Pacific Fleet, would describe Tunnys second war patrol as belonging "in that exceptional category of one of the outstandingly aggressive patrols of the war."
On 27 March 1943, Tunny arrived off Wake Island and operated within a circle all day, flooding down the decks awash when within of the island. Before dawn the next morning, she closed to within of the Japanese-held island and watched as its awakening occupants turned on their lights. A motor torpedo boat and two patrol boats passed by less than from the submarine without detecting her presence. Trailing these vessels, Tunny came upon a cargo ship, Suwa Maru, and all hands scrambled to battle stations. Shortly after sunrise, the submarine launched her attack, firing two torpedoes from a range of . The first found its mark and blew the stern off the enemy ship, but the buoyancy of the lightly loaded vessel kept it afloat. Tunny was maneuvering at periscope depth to avoid depth charges dropped across her bow at a range of when the first of several aerial bombs fell close aboard. The submarine dove to . When she attempted to surface an hour later, Tunny was again driven down by an aerial adversary. Later in the morning, traveling submerged at , she set her course for her assigned patrol area.
On 31 March, she entered the patrol area in the Caroline Islands, and, on 1 April 1943, she conducted submerged patrols off North Pass Island, Truk, and later in the day on the Japanese naval base's western approaches. Failing to find any action in these areas, she surfaced late in the afternoon on 2 April and set her course for the channel between Puluwat Island and Pulap Island. Later that day, as she patrolled off Alet Island, Tunny made radar contact with a ship dead ahead. Heading in for a flank attack, she sighted a astern of her chosen target. Tunny launched three torpedoes from and noted a hit in the forward hold of the Japanese cargo ship before diving to to avoid the attention of the destroyer. Minutes later, a series of nine depth charges tumbled down in search of the submarine, but exploded at too shallow a depth to achieve their purpose. Some 15 minutes later, as Tunny started up to take a look, she was jolted by a deep-set depth charge which caught her at , but caused only minor damage—a small price to pay for the sinking of Toyo Maru Number 2. Before midnight, the destroyer gave up the search, and the submarine surfaced and set her course for the Namonuito group to the north.
Late on 4 April, Tunny headed west to intercept traffic reported north of McLaughlin Bank. On 7 April, while patrolling in that area, the submarine took advantage of a rain squall to approach within of a radar-tracked target. She then launched two torpedoes at the Kosei Maru, an 8000-ton passenger-cargo ship, scoring a hit amidships and one aft, and dove immediately to escape the inevitable wrath of the escorting Akatsuki-class destroyer which had been patrolling just ahead of the now-stricken transport. The ensuing depth charge counterattack continued until the destroyer lost contact with the submarine in a heavy rain squall. Having added a third cargo ship to her list of kills, Tunny retired from the scene of the attack.