Upon commissioning, I-45 was attached formally to the Yokosuka Naval District and was assigned to Submarine Squadron 11 for workups in the Iyo-nada in the Seto Inland Sea.[1] She called at the Tokuyama Fuel Depot from 22 to 23 February 1944 to refuel.[1]
First war patrol
On 25 March 1944, I-45 was reassigned to Submarine Division 15 in the 6th Fleet.[1] She departed Kure, Japan, that day to begin her first war patrol, assigned a patrol area in the Pacific Ocean east of the Marshall Islands.[1]
Although she survived the attack, I-45 had suffered heavy damage, forcing her to return to Japan.[1] She reached Yokosuka, Japan, on 15 April 1944[1] and in late April began repairs at Kure Naval Arsenal at Kure which lasted until late May 1944.[1]
Marianas campaign
On 12 June 1944, U.S. landings on Saipan began both the Battle of Saipan and the Marianas campaign, and on 13 June the commander-in-chief of the Combined Fleet, AdmiralSoemu Toyoda, activated Operation A-Go for the defense of the Mariana Islands.[1] On 28 June 1944, I-45 departed Yokosuka in company with the submarine I-55 bound for Tinian in the Marianas and carrying an Unkato cargo container[1] — a 135-foot (41.1m) submersible cargo container that could carry up to 377 tons of supplies, designed for a one-way trip in which the cargo's recipients released, recovered, and unloaded it[3] — loaded with weapons and ammunition.[1] Encountering heavy seas during her voyage,[1] she was redirected to Guam to pick up Imperial Japanese Navy Air Service pilots who were stranded there.[1] She attempted to contact Japanese forces ashore on Guam on both 14 and 16 July 1944 to deliver her Unkato and pick up the airmen, but failed on each occasion because of a communications mix-up.[1] After the second failure, she dumped the Unkato container overboard and headed back to Japan.[1] She arrived at Yokosuka on 27 July 1944, and later moved to Kure.[1]
Second war patrol
The commander-in-chief of the Combined Fleet, Admiral Soemu Toyoda, activated Operation Shō-Gō 1 for the defense of the Philippine Islands on 13 October 1944.[1]I-45 departed Kure on the same day to begin her second war patrol, assigned a patrol area in the Philippine Sea.[1] U.S. forces landed on Leyte in the Philippines on 20 October 1944, beginning both the Battle of Leyte and the Philippines campaign, and the Japanese naval reaction to the invasion resulted in the Battle of Leyte Gulf of 23–26 October 1944.[1] On 24 October 1944, the second day of the battle, I-45 and the submarines I-26, I-37, I-53, I-54, and I-56 were designated Submarine Group A under the direct command of the commander-in-chief of the 6th Fleet, Vice AdmiralShigeyoshi Miwa,[1] and I-45 received orders to move to patrol station "Re" off the northeast coast of Mindanao.[1]
At 03:25 a large underwater explosion occurred, apparently from the sunken Eversole, killing about 30 survivors in the water and injuring others.[1] The explosion alerted Richard S. Bull, which arrived on the scene and began a rescue operation while the destroyer escort USSWhitehurst, which had been detached from the screen of a passing fleet oiler unit, provided antisubmarine cover.[1] By 06:30, Richard S. Bull had pulled the last of 139 survivors from the water, three of whom later died.[1] Including them, Eversole′s crew suffered 77 dead in the sinking.[1]
Meanwhile, at 05:45 Whitehurst detected a submerged submarine — probably I-45 — on sonar 85 nautical miles (157km; 98mi) northeast of Siargao, about 50 nautical miles (93km; 58mi) from the site of Eversole′s sinking.[1] After Whitehurst made three unsuccessful Hedgehog attacks,[1] the submarine — which Whitehurst′s commanding officer later described as displaying "excellent evasive tactics and maneuverability,"[1] continually turning away from attacks and presenting her stern and wake to Whitehurst[1] — tried to escape at a depth of 225 feet (69m).[1] At 06:48, Whitehurst conducted a fourth Hedgehog attack, which this time resulted in five or six small explosions, followed by a large underwater explosion that disabled Whitehurst′s sound gear and heavy rumbling noises.[1]Whitehurst resumed her search for the submarine at 07:20 and noted a large amount of oil on the surface as well as wood and other debris, some of which her motorwhaleboat recovered.[1] She suspended her search at 12:15.[1] The explosions, oil, and debris marked the sinking of the submarine, presumably I-45, at 10°10′N127°28′E / 10.167°N 127.467°E / 10.167; 127.467 (I-45).[1]
The 6th Fleet issued orders to I-45 on 5 November 1944 to move to a new patrol area east of Lamon Bay, but she never acknowledged them.[1] On 2 December 1944, the Imperial Japanese Navy declared I-45 to be presumed lost off the Philippines with the loss of all 104 men aboard.[1] She was stricken from the Navy list on 10 March 1945.[1]
Japan
