Japanese Submarine I-25: A Pacific War Pioneer

The Japanese Submarine I-25 was a pioneer in the Pacific War, playing a significant role in the early years of the conflict.

Commissioned in 1939, I-25 was one of the most advanced submarines of its time.

I-25 was designed to operate in the open ocean, with a range of over 14,000 nautical miles and a top speed of 23.5 knots.

The submarine was equipped with six 533mm torpedo tubes and carried 17 torpedoes.

I-25 was involved in several key battles, including the attack on Pearl Harbor and the Battle of Midway.

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I-25 departed Yokosuka on 21 November 1941, preparing for hostilities in World War II. It patrolled a line 222 km north of Oahu during the Japanese Attack on Pearl Harbor.

I-25 attacked SS Connecticut 16 km off the US coast, but the damaged tanker managed to escape and ran aground at the mouth of the Columbia River. The submarine then returned to Kwajalein to refuel and be refurbished.

I-25's next operational patrol took it to the south Pacific, where it reconnoitred the Australian harbours of Sydney, Melbourne, and Hobart, and the New Zealand harbours of Wellington and Auckland.

The I-25's First Patrol was a significant event in its history. It departed Yokosuka on 21 November 1941, under the command of Lieutenant Commander Akiji Tagami.

I-25 was accompanied by three other submarines, and together they patrolled a line 222 km (120 nmi; 138 mi) north of Oahu during the Japanese Attack on Pearl Harbor. This marked the beginning of the I-25's involvement in World War II.

After the Japanese aircraft carriers sailed west following the attack, I-25 and eight other submarines sailed eastwards to patrol the west coast of the United States. The I-25 specifically patrolled off the mouth of the Columbia River.

A scheduled shelling of American coastal cities on Christmas eve of 1941 was canceled due to the frequency of coastal air and surface patrols. This indicates that the I-25's crew was aware of the increased vigilance on the US coast.

The I-25 attacked SS Connecticut 16 km (9 nmi; 10 mi) off the US coast, damaging the tanker but allowing it to escape. The damaged ship later ran aground at the mouth of the Columbia River.

The I-25 returned to Kwajalein on 11 January 1942 to refuel and be refurbished, marking the end of its first patrol.

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The I-25's Second Patrol was a significant mission that took the submarine south to reconnoitre Australian and New Zealand harbours.

I-25 left Kwajalein atoll in the Marshall Islands on 5 February for its next operational patrol in the south Pacific.

The submarine travelled on the surface for nine days before approaching the Australian coastline, where it only travelled on the surface under the cover of night.

On 14 February, I-25 was within a few miles of the coast near Sydney, and the searchlights in Sydney could clearly be seen from the bridge.

A number of days of rough swell prevented an immediate launch of the "Glen" floatplane, which the crew had to wait for before they could proceed with their mission.

Finally, on 17 February, Warrant Flying Officer Nobuo Fujita took off in the "Glen" for a reconnaissance flight over Sydney Harbour to look at Sydney's airbase.

By 0730, Fujita had returned to I-25 and disassembled the "Glen" and stowed it in the watertight hangar, ready for the next leg of their journey.

I-25 then headed southwards on the surface at 26 km/h, and by midday on Wednesday 18 February, they were nearly 740 km south east of Sydney.

The crew's next mission was a similar flight over Melbourne, which they launched from Cape Wickham at the northern end of King Island on 26 February.

Fujita's reconnaissance flight was over Port Phillip Bay, providing valuable information for the Japanese military.

I-25 continued its patrol, eventually flying over Hobart on 1 March, Wellington on 8 March, Auckland on 13 March, and Fiji on 17 March.

After completing its reconnaissance missions, I-25 returned to its base at Kwajalein on 31 March and then proceeded to Yokosuka for refit.

The I-25's Attack on Fort Stevens was a pivotal moment in its patrol. On June 21, 1942, the submarine approached the Oregon coast, avoiding potential minefields by following fishing boats.

I-25's target was initially a suspected submarine base at Astoria, Oregon, but LtCdr Tagami selected Battery "Russell" at Fort Stevens instead. Fort Stevens housed a collection of large-calibre coastal defence guns, albeit most of them ancient and obsolete.

The attack began at midnight, with I-25 firing 17 rounds over 15 minutes. The shells landed harmlessly in swampy ground, with a few hitting the fort's baseball field.

A blackout was ordered at Fort Stevens, depriving the gunners of any reference points to aim at. This led to most of the rounds landing off-target.

The only meaningful damage was the severing of telephone lines, with no casualties or injuries to personnel. The fort's guns did not return fire, as they were out of range.

A USAAF A-29 Hudson patrol bomber spotted I-25 the following day and attacked, but the bombs fell wide of the mark.

Airborne reconnaissance was a crucial aspect of the Japanese submarine I-25's operations. The submarine was equipped with a floatplane that could be launched from the deck to gather intelligence and conduct reconnaissance missions.

The floatplane, a Type 0 reconnaissance seaplane, was designed to be lightweight and compact, allowing it to be easily stowed on the submarine's deck. It was a Nakajima E4N2, a Japanese biplane seaplane.

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The I-25's floatplane was used to conduct reconnaissance missions in the Indian Ocean, where the submarine was operating. The plane was able to gather valuable intelligence on enemy shipping and naval movements.

The floatplane was also used for search and rescue missions, as well as for communication with other Japanese forces.