1943 Departing Midway on 27 October, Tinosa headed for the Palau-Truk sea lanes. On 22 November, she sighted two cargo ships and two small escort craft steaming in convoy. The submarine fired six torpedoes, scoring hits on both cargo ships. The entire action took only five minutes and left her between two mortally stricken ships, her position clearly marked by torpedo wakes leading out ahead and astern—a perfect fix for the enemy escorts. Amid the sounds of the cargo vessels breaking up, Tinosa dove deep to avoid the certain counter-attack of the escort vessels. A short time later, four depth charges exploded close by the submarine, knocking out her planes, gyro, steering, internal communications, and other equipment. She made a wild climb to , then dove to , before her crew regained control. Tinosa then resumed evasive tactics which enabled her to elude the remnants of the convoy late in the afternoon. During an attack on a convoy on 26 November, Tinosa sank Japanese cargo ship Shini Maru and then dodged 34 depth charges, none of which caused her any damage. She emerged from this encounter with a torpedo stuck in her number 5 tube but managed to remedy the problem and headed for the Molucca Passage-Palau traffic lanes. On 3 December, she sighted a large passenger-cargo vessel, the Azuma Maru, protected by a single escort. At 18:20, Tinosa launched a torpedo attack, damaging the Japanese ship. At 21:01 while maneuvering on the surface as she sought to finish off the Azuma Maru, Tinosa came under fire from the burning vessel; and, minutes later, she narrowly avoided being rammed by the crippled enemy ship which circled out of control because of a damaged rudder. At 21:20, Tinosa fired three more torpedoes, and the Azuma Maru sank. She concluded this patrol at Fremantle, Australia, on 16 December 1943. Fifth patrol, January–March 1944 After sailing on 10 January 1944 for the South China Sea, Tinosa landed the Australian Z Special Unit intelligence team Python Two and its supplies at Labian Point, North Borneo, under cover of darkness on 20 January, before proceeding to the Flores Sea. Two days later, she sank Koshin Maru and Seinan Maru and damaged a third ship in a running attack on a convoy off Viper Shoal. In another action on the night of 15 February – 16 February, Tinosa drew gunfire from the ships of a convoy