They had a diving depth of 75 metres (246 ft)[1] For surface running, the submarines were powered by two 4,500-brake-horsepower (3,356 kW) diesel engines, each driving one propeller shaft.

[4] On 11 November 1941, the 6th Fleet's commander, Vice Admiral Mitsumi Shimizu, held a meeting with the commanding officers of the submarines of Submarine Squadron 3 aboard his flagship, the light cruiser Katori, and his chief of staff briefed them on plans for Operation Z, the upcoming surprise attack on Pearl Harbor in Hawaii.

[5] The attack would begin the Pacific campaign and bring Japan and the United States into World War II.

[4][5][13] Assigned to support Operation Z, I-74 got underway from Kwajalein on 23 November 1941 with the commander of Submarine Division 11 embarked and set course for the Hawaiian Islands.

[14][15][16] By the time two damaged Mitsubishi A6M2 Zero (Allied reporting name "Zeke") fighters — one each from the aircraft carriers Hiryū and Sōryū — arrived over Niihau on 7 December, however, I-74 already had received orders to conclude her lifeguard duties and had departed the area.

[4] While she was at sea, 16 United States Army Air Forces B-25 Mitchell bombers launched by the aircraft carrier USS Hornet (CV-8) struck targets on Honshu in the Doolittle Raid on 18 April 1942.

[5] In support of the raid, United States Navy F4F Wildcat fighters and SBD Dauntless dive bombers from the aircraft carrier USS Enterprise (CV-6) attacked Japanese vessels forming a picket line in the North Pacific Ocean in the approaches to Japan.

[10][13] The two submarines departed Kwajalein in company that day to participate in Operation MI, the planned Japanese invasion of Midway Atoll.

[5][13] Plans called for them first to support a preliminary phase of the Midway operation, Operation K-2, which called for the Japanese submarines I-121 and I-123 to refuel two Kawanishi H8K (Allied reporting name "Emily") flying boats at the French Frigate Shoals in the Northwestern Hawaiian Islands so that the two aircraft could conduct a reconnaissance flight over Pearl Harbor,[19] while I-174 patrolled south of Pearl Harbor to rescue the crews of the aircraft if they were shot down.

[4][5] I-174 set out from Kwajalein on her third war patrol on 9 July 1942, tasked with conducting a reconnaissance of the Port Moresby, New Guinea, area.

[4][5] Soon after she departed an oil leak developed, forcing her to abort the patrol and proceed to Rabaul on New Ireland in the Bismarck Archipelago for repairs.

[5] I-174 was 70 nautical miles (130 km; 81 mi) east of Brisbane, Australia, late on the morning of 1 June 1943 when she sighted what she identified as a 6,000-gross register ton merchant ship.

[5] In fact, the vessel was the 3,303- or 3,306-gross register ton (according to different sources) American cargo ship Point San Pedro,[5][21] which was nearing the end of a voyage from Balboa in the Panama Canal Zone to Brisbane.

[5] While submerged off Brisbane on 3 June 1943, I-174 sighted a northbound Allied convoy of at least six transports escorted by three destroyers at a range of 16,250 yards (14,860 m).

[5] I-174 was submerged off Cape Moreton at the northeastern tip of Moreton Island off South East Queensland, Australia, at 08:45 on 4 June 1943 when she sighted the 4,113-gross register ton United States Army Transport USAT Edward Chambers, which was on a voyage from Balboa, Panama Canal Zone, to Brisbane.

[5] Unable to close with Edward Chambers to achieve an attack position while submerged, I-174 surfaced and opened fire with her 120-millimeter (4.7 in) deck gun.

[5] At 10:25 on 5 June 1943, I-174 was 60 nautical miles (110 km; 69 mi) northeast of Coffs Harbour when she detected the propeller noises of Convoy PG53 at a range of 13,000 yards (11,900 m).

[5] Taking advantage of bad weather and poor visibility, she surfaced at 12:55 and closed to only 1,600 yards (1,500 m) behind the convoy's rearmost ships.

[5] She attempted to further close the range, but Allied patrol aircraft appeared twice, forcing her to submerge for 20 to 25 minutes each time before surfacing to resume her pursuit of the convoy.

[5] The Beaufort loitered in the area, and made another attack only moments after I-174 resurfaced, the bombs landing close aboard on her port side.

[5] After penetrating the escort screen, I-174 fired two torpedoes at two overlapping transports, which her commanding officer estimated as of 8,000 and 10,000 gross register tons.

[5] One torpedo struck the 5,000-displacement ton U.S. Navy tank landing ship USS LST-469 in her starboard side aft, killing 26 men and wrecking the vessel's steering gear.

[5] Moments later, lookouts aboard the 5,551-gross register ton U.S. Army Transport USAT Portmar, which was loaded with fuel and ammunition, sighted the second torpedo approaching.

[5] On 20 June 1943, I-174 received orders to terminate her patrol and return to Truk via a route that took her east of the Solomon Islands.

[4] With the new commanding officer of the Imperial Japanese Navy's 7th Base Unit, Rear Admiral Kunio Mori, aboard as a passenger, I-174 left Rabaul on her second supply run on 7 September 1943.

[5] When her oxygen supply was nearly exhausted, I-174 surfaced to fight it out with the destroyer, but found no Allied ships in sight and proceeded with her voyage.

[5] As she neared Rabaul, a United States Army Air Forces B-17 Flying Fortress attacked her on 12 September 1943, dropping several bombs which landed close aboard but inflicted no significant damage.

[5] In response, the commander of the 6th Fleet, Vice Admiral Takeo Takagi, ordered I-174, I-175, and the submarines I-19, I-21, I-35, I-39, I-40, I-169, and Ro-38 to attack the U.S. landing force.

I-174 was on the surface charging her batteries 30 nautical miles (56 km; 35 mi) east of Tarawa when her lookouts sighted an approaching U.S.

[5] When her battery became depleted and her oxygen supply was almost exhausted, I-174 surfaced to fight it out with the destroyer and managed to escape into a rain squall.