''I-10'' was an

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrend ...

Type A1 submarine that served during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. Designed as a

submarine aircraft carrier A submarine aircraft carrier is a submarine equipped with aircraft for observation or attack missions. These submarines saw their most extensive use during World War II, although their operational significance remained rather small. The most fam ...

, she was commissioned in 1941 and supported the

attack on Pearl Harbor The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawaii ...

, operated in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

— including support for the 1942

midget submarine A midget submarine (also called a mini submarine) is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to six or nine, with little or no on-board living accommodation. They normally work with mother ships, ...

attack on Diego Suarez — and in the New Caledonia and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

areas, and took part in the Guadalcanal campaign and Marianas campaign before she was sunk in 1944 during her seventh war patrol.

Design and description

Type A1 submarines were versions of the preceding Type J3 with superior range and an improved aircraft installation, and they were fitted as

squadron Squadron may refer to: * Squadron (army), a military unit of cavalry, tanks, or equivalent subdivided into troops or tank companies * Squadron (aviation), a military unit that consists of three or four flights with a total of 12 to 24 aircraft, ...

flagships. They displaced on the surface and submerged. The submarines were long and had a beam of and a

draft Draft, The Draft, or Draught may refer to: Watercraft dimensions * Draft (hull), the distance from waterline to keel of a vessel * Draft (sail), degree of curvature in a sail * Air draft, distance from waterline to the highest point on a vesse ...

of . They had a diving depth of .Bagnasco, p. 188 For surface running, Type A1 submarines were powered by two

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...

s, each driving one

propeller shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect ...

. When submerged each propeller was driven by a

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate for ...

. They could reach on the surfaceChesneau, p. 200 and underwater. On the surface, the Type A1s had a range of at ; submerged, they had a range of at . Type A1 submarines were armed with four internal bow

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s and carried a total of 18

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, s ...

es. They were also armed with a single /40

deck gun A deck gun is a type of naval artillery mounted on the deck of a submarine. Most submarine deck guns were open, with or without a shield; however, a few larger submarines placed these guns in a turret. The main deck gun was a dual-purpose ...

and two twin Type 96 anti-aircraft guns.Carpenter & Dorr, p. 101 Unlike on the Type J3 submarines, the aircraft

hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...

was integrated into the conning tower and faced forward, and the

aircraft catapult An aircraft catapult is a device used to allow aircraft to take off from a very limited amount of space, such as the deck of a vessel, but can also be installed on land-based runways in rare cases. It is now most commonly used on aircraft carrier ...

was forward of the hangar, while the deck gun was aft of the conning tower. Reversing the locations of the deck gun and catapult allowed aircraft launching from a Type A1 submarine to use the forward motion of the submarine to supplement the speed imparted by the catapult.

Construction and commissioning

Built by Kawasaki at Kobe, Japan, ''I-10'' was

laid down Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one o ...

as ''Submarine No. 10'' on 7 June 1938. Later renamed ''I-10'', she was launched on 20 or 29 September 1939, according to different sources, and was completed and commissioned on 31 October 1941.

Service history

Pre-World War II

On the day of her commissioning, ''I-10'' was attached to the Sasebo Naval District and assigned to Submarine

Squadron Squadron may refer to: * Squadron (army), a military unit of cavalry, tanks, or equivalent subdivided into troops or tank companies * Squadron (aviation), a military unit that consists of three or four flights with a total of 12 to 24 aircraft, ...

2 in the 6th Fleet. By 10 November 1941, she was serving as the squadron's flagship. That day, the 6th Fleet commander, Vice Admiral

Mitsumi Shimizu was a vice admiral in the Imperial Japanese Navy in World War II. Biography Shimizu was a native of Nagano prefecture. He graduated 24th out of 191 cadets from the 36th class of the Imperial Japanese Naval Academy, in November 1908. His classmat ...

, held a meeting with the commanding officers of the submarines of Submarine Squadron 3 aboard his flagship, the

light cruiser A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to th ...

, and his chief of staff briefed them on plans for Operation Z, the upcoming surprise

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

. The attack would begin the Pacific campaign and bring Japan and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

into

. ''I-10'' and the submarine were assigned to the 6th Fleet Reconnaissance Unit. As Japanese military forces began to deploy for the opening Japanese offensive of the war, ''I-10'', with an embarked Watanabe E9W1 ( Allied reporting name "Slim") floatplane, departed

Yokosuka is a city in Kanagawa Prefecture, Japan. , the city has a population of 409,478, and a population density of . The total area is . Yokosuka is the 11th most populous city in the Greater Tokyo Area, and the 12th in the Kantō region. The city ...

, Japan, on 16 November 1941, with orders to conduct a reconnaissance of areas in the vicinity of Fiji and the

Samoan Islands The Samoan Islands ( sm, Motu o Sāmoa) are an archipelago covering in the central South Pacific, forming part of Polynesia and of the wider region of Oceania. Administratively, the archipelago comprises all of the Independent State of Samoa an ...

, including

Tutuila Tutuila is the main island of American Samoa (and its largest), and is part of the archipelago of Samoan Islands. It is the third largest island in the Samoan Islands chain of the Central Pacific. It is located roughly northeast of Brisbane, A ...

American Samoa American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of Samoa. Its location is centered on . It is east of the Internationa ...

. She arrived at Kwajalein Atoll in the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Intern ...

on 23 November 1941 to refuel, then proceeded to Fijian waters. Off

Viti Levu Viti Levu (pronounced ) is the largest island in the Republic of Fiji. It is the site of the nation's capital, Suva, and home to a large majority of Fiji's population. Geology Fiji lies in a tectonically complex area between the Australian ...

in the Fiji Islands on 30 November 1941, she launched her floatplane to reconnoiter Suva Bay off Suva.Prange, Gordon W., "At Dawn We Slept: The Untold Story of Pearl Harbor", Penguin Books, New York, New York, 1981, Library of Congress card number 82-5896, , page 431. The floatplane′s crew reported sighting no enemy ships at Suva Bay, but it never returned to ''I-10'', and after a fruitless three-day search for it and its crew under radio silence, ''I-10'' gave up the search and reported the loss of her plane and its crew to 6th Fleet headquarters. While ''I-10'' was at sea, she received the message "Climb

Mount Niitaka Yu Shan or Yushan, also known as Mount Jade, Jade Mountain, or , and known as Mount Niitaka during Taiwan under Japanese rule, Japanese rule, is the highest mountain in Taiwan at above sea level, giving Taiwan the List of islands by highes ...

1208" ( ja, Niitakayama nobore 1208) from the

Combined Fleet The was the main sea-going component of the Imperial Japanese Navy. Until 1933, the Combined Fleet was not a permanent organization, but a temporary force formed for the duration of a conflict or major naval maneuvers from various units norm ...

on 2 December 1941, indicating that war with the Allies would commence on 8 December 1941

Japan time , or , is the standard time zone in Japan, 9 hours ahead of UTC (UTC+09:00). Japan does not observe daylight saving time, though its introduction has been debated on several occasions. During World War II, the time zone was often referred to as ...

, which was on 7 December 1941 on the other side of the International Date Line in

. On 3 December 1941, she conducted a submerged reconnaissance of the harbor at

Pago Pago Pago Pago ( ; Samoan: )Harris, Ann G. and Esther Tuttle (2004). ''Geology of National Parks''. Kendall Hunt. Page 604. . is the territorial capital of American Samoa. It is in Maoputasi County on Tutuila, which is American Samoa's main island. ...

on Tutuila in American Samoa, sighting what she identified as a

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

" ''Astoria''-class"

heavy cruiser The heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 inches) in caliber, whose design parameters were dictated by the Washington Naval T ...

World War II

First war patrol

Heading toward Hawaii after leaving the waters around American Samoa, ''I-10'' arrived in a patrol area south of

Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O� ...

on 7 December 1941, the day the Japanese attacked Pearl Harbor. On 9 December, she received a report that the submarine had sighted the U.S. Navy aircraft carrier , along with orders to leave her patrol area and join the search for ''Lexington''. While southeast of Hawaii after dark that evening, she fired one

at the

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

nian 4,430- gross register ton

motor vessel A motor ship or motor vessel is a ship propelled by an internal combustion engine, usually a diesel engine. The names of motor ships are often prefixed with MS, M/S, MV or M/V. Engines for motorships were developed during the 1890s, and by th ...

, which was on a voyage from Suva to

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, with cargo of sugar and

pineapple The pineapple (''Ananas comosus'') is a tropical plant with an edible fruit; it is the most economically significant plant in the family Bromeliaceae. The pineapple is indigenous to South America, where it has been cultivated for many centuri ...

s.Edwards, p. 4. After the torpedo missed, she surfaced and attacked ''Donerail'' with gunfire, firing twenty rounds. As ''Donerail''′s crew abandoned ship, one shell struck her starboard

lifeboat Lifeboat may refer to: Rescue vessels * Lifeboat (shipboard), a small craft aboard a ship to allow for emergency escape * Lifeboat (rescue), a boat designed for sea rescues * Airborne lifeboat, an air-dropped boat used to save downed airmen ...

while it still hung in its davits, completely destroying it and killing everyone in it. ''Donerail'' sank two hours later at . Meanwhile, ''I-10''′s crew opened

machine gun A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) ar ...

fire on her survivors. Twenty-seven of ''Donerail''′s passengers and crew died in the sinking and subsequent massacre, leaving only 16 alive. Of the 42 people aboard ''Donerail'', only eight ultimately survived, reaching

Tarawa Tarawa is an atoll and the capital of the Republic of Kiribati,Kiribati
''

Gilbert Islands 38 days later. On 12 December 1941, ''I-10'' was reassigned to the Advance Force, and that day she received orders to proceed to the

United States West Coast The West Coast of the United States, also known as the Pacific Coast, Pacific states, and the western seaboard, is the coastline along which the Western United States meets the North Pacific Ocean. The term typically refers to the contiguous U.S. ...

and patrol in an area off

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United State ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. On 13 December 1941, Japanese Imperial General Headquarters ordered the submarines of the 6th Fleet to bombard the U.S. West Coast. On 14 December 1941, the 6th Fleet′s commander, Vice Admiral

, in turn ordered ''I-10'' and the submarines , ''I-15'', ''I-17'', , , , ''I-25'', and each to fire 30 rounds at targets on the U.S. West Coast on the evening of 25 December 1941, with the commander of Submarine

1, Rear Admiral Tsutomu Sato. aboard ''I-9'' in overall command of the bombardment. On 22 December 1941 the commander-in-chief of the

, Admiral

Isoroku Yamamoto was a Marshal Admiral of the Imperial Japanese Navy (IJN) and the commander-in-chief of the Combined Fleet during World War II until he was killed. Yamamoto held several important posts in the IJN, and undertook many of its changes and reor ...

, postponed the bombardment until 27 December. On 27 December 1941, Sato cancelled the bombardment because most of the submarines tasked with carrying it out were low on fuel. ''I-10''′s time off the U.S. West Coast otherwise passed quietly. On 9 January 1942 she was reassigned directly to 6th Fleet headquarters, and on 11 January 1942 she arrived at Kwajalein.

January–April 1942

After an overnight stay at Kwajalein, ''I-10'' departed on 12 January 1942 bound for Yokosuka, which she reached on 21 January 1942. While in Japan, she was reassigned to Submarine Squadron 8 on 10 March 1942. On 12 March, she got underway from Yokosuka to search for and attack the aircraft carriers of U.S. Navy

Task Force 17 Task Force 17 (TF17) was an aircraft carrier task force of the United States Navy during the Pacific Campaign of World War II. TF17 participated in several major carrier battles in the first year of the war. TF17 was initially centered around ...

, which had conducted the Lae-Salamaua Raid against Japanese forces landing on the northeast coast of

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...

on 10 March, but she had no success, and she returned to Japan, arriving at

Kure is a port and major shipbuilding city situated on the Seto Inland Sea in Hiroshima Prefecture, Japan. With a strong industrial and naval heritage, Kure hosts the second-oldest naval dockyard in Japan and remains an important base for the Japan ...

on 20 March 1942. During ''I-10''′s stay in Japan, the German naval staff in

Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...

formally requested on 27 March 1942 that Japan begin attacks on Allied

convoy A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used ...

s in the

. On 8 April 1942, the Japanese formally agreed to meet this request by dispatching submarines to operate off the coast of East Africa, and that day they withdrew Submarine Division 1 of

Submarine Squadron 8 A submarine squadron (SUBRON) is a naval formation or unit in such states such as the United Kingdom, United States, and Russia/Soviet Union. In France the equivalent unit is the ' (ESNA), part of the French submarine forces (and before the Second ...

from its base at Kwajalein to Japan. By 16 April 1942 they had created the "A" detachment within Submarine Squadron 8, consisting of ''I-10'' and the submarines , , , and , as well as

s and the

auxiliary cruiser An armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in ...

s and , which were to operate as supply ships for the submarines. That morning, the commander of the 6th Fleet, Vice Admiral

Teruhisa Komatsu Marquis was an admiral in the Imperial Japanese Navy in World War II. Born as HIH Kitashirakawa-no-miya Teruhisa, as the younger son of HIH Prince Kitashirakawa Yoshihisa, his title was devolved from royal status that that of the ''kazoku'' p ...

, the commander of Submarine Squadron 8, their staffs, and the midget submarine crews paid a courtesy call on Admiral Yamamoto aboard his flagship, the battleship , at Hashirajima anchorage. After the visit with Yamamoto, the detachment got underway at 11:00, bound for Penang in Japanese-occupied British Malaya. During the detachment′s voyage, 16

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

B-25 Mitchell

bomber A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped from an air ...

s launched by the aircraft carrier struck targets on

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island se ...

in the

Doolittle Raid The Doolittle Raid, also known as the Tokyo Raid, was an air raid on 18 April 1942 by the United States on the Japanese capital Tokyo and other places on Honshu during World War II. It was the first American air operation to strike the Japa ...

on 18 April 1942. The detachment received orders from the 6th Fleet that day to divert from its voyage and head northeast, passing north of the

Bonin Islands The Bonin Islands, also known as the , are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan and northwest of Guam. The name "Bonin Islands" comes from the Japanese word ''bunin'' (an archaic read ...

, to intercept the U.S. Navy task force that had launched the strike. The detachment failed to find the U.S. ships and soon resumed its voyage. ''I-30'' and ''Aikoku Maru'' called at Penang from 20 April to 22 April 1942 before heading into the Indian Ocean to conduct an advance reconnaissance of the "A" Detachment′s planned operating area. ''I-10'' made an overnight stop at

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

from 23 to 24 April, then proceeded to Penang. The

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

transport Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelin ...

''Urajio Maru'' mistakenly opened gunfire on her during her voyage, but she avoided damage and arrived at Penang safely on 25 April 1942. On 27 April, the rest of the "A" Detachment arrived at Penang, where the

seaplane carrier A seaplane tender is a boat or ship that supports the operation of seaplanes. Some of these vessels, known as seaplane carriers, could not only carry seaplanes but also provided all the facilities needed for their operation; these ships are rega ...

— which had undergone modifications allowing her to carry Type A midget submarines — rendezvoused with it. ''I-16'', ''I-18'', and ''I-20'' each embarked a midget submarine at Penang on 30 April 1942.

Indian Ocean operation

''I-10'' and the other "A" detachment units got underway from Penang on 30 April 1942, headed westward into the Indian Ocean with ''I-10'' serving as the detachment′s flagship. The submarines refueled at sea from ''Aikoku Maru'' and ''Hōkoku Maru'' on 5, 10, and 15 May 1942. ''I-10''′s

Yokosuka E14Y The Yokosuka E14Y ( Allied reporting name Glen) was an Imperial Japanese Navy reconnaissance seaplane transported aboard and launched from Japanese submarine aircraft carriers such as the during World War II. The Japanese Navy designation was ...

1 (Allied reporting name "Glen") floatplane began reconnaissance flights over ports in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

by reconnoitering

Durban Durban ( ) ( zu, eThekwini, from meaning 'the port' also called zu, eZibubulungwini for the mountain range that terminates in the area), nicknamed ''Durbs'',Ishani ChettyCity nicknames in SA and across the worldArticle on ''news24.com'' from ...

on 20 May 1942, where its crew found no targets of importance. Although challenged from the ground during the flight, the aircraft escaped after its radioman bought time by transmitting a false recognition signal in response. The plane made flights over East London, Port Elizabeth, and

Simon's Town Simon's Town ( af, Simonstad), sometimes spelled Simonstown, is a town in the Western Cape, South Africa and is home to Naval Base Simon's Town, the South African Navy's largest base. It is located on the shores of False Bay, on the eastern ...

over the next week, and by 24 May the "A" detachment submarines were encountering heavy Allied shipping traffic as they approached East Africa. On the night of 29 May, ''I-10''′s floatplane flew over

Diego-Suarez Antsiranana ( mg, Antsiran̈ana ), named Diego-Suárez prior to 1975, is a city in the far north of Madagascar. Antsiranana is the capital of Diana Region. It had an estimated population of 115,015 in 2013. History The bay and city originally u ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

, sighting the British battleship among the ships

anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄ� ...

ed there. The "A" detachment commander selected Diego-Suarez as the target for a midget submarine attack, scheduled for 30 May 1942. On 30 May 1942, ''I-18''′s midget submarine could not launch because of engine failure, but ''I-16'' and ''I-20'' both launched their midget submarines to attack the Allied warships at Diego Suarez.Rigge, Simon (1980). ''War in the Outposts''. Chicago, Time-Life Books, pp. 107–108, I-20′s midget submarine, ''M-20b'', managed to enter the harbor and was attacked with depth charges, but fired two torpedoes. One torpedo seriously damaged ''Ramillies'', while the second sank the 6,993-ton

oil tanker An oil tanker, also known as a petroleum tanker, is a ship designed for the bulk transport of oil or its products. There are two basic types of oil tankers: crude tankers and product tankers. Crude tankers move large quantities of unrefined cru ...

''British Loyalty''. ''Ramillies'' required repairs in South Africa and

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. Neither midget submarine returned, and on 31 May 1942, ''I-10''′s floatplane made a flight over Diego Suarez in the hope of locating any of the midget submarine crewmen who might have reached shore, without success. ''I-16''′s midget submarine disappeared at sea and the body of one of its crewman was found washed ashore on Madagascar on 31 May. The crew of ''M-20b'' beached their craft at Nosy Antalikely and moved inland towards a pre-arranged pick-up point near Cape Amber, but were both killed in a firefight with British Royal Marines on 2 June 1942; one Marine was killed in the action as well. After the midget submarine attack, the "A" detachment began anti-shipping operations in the Indian Ocean. ''I-10'' had her first success at 02:31 on 5 June 1942 when she sank the 2,639-gross register ton Panamanian steamer in the

Mozambique Channel The Mozambique Channel (french: Canal du Mozambique, mg, Lakandranon'i Mozambika, pt, Canal de Moçambique) is an arm of the Indian Ocean located between the Southeast African countries of Madagascar and Mozambique. The channel is about lon ...

east of Beira,

Portuguese East Africa Portuguese Mozambique ( pt, Moçambique) or Portuguese East Africa (''África Oriental Portuguesa'') were the common terms by which Mozambique was designated during the period in which it was a Portuguese colony. Portuguese Mozambique originally ...

, at . Later that day, she sank the American 4,999-gross register ton armed cargo ship at ; the British steamer rescued ''Melvin H. Baker''′s crew. Again in the Mozambique Channel east of Beira, she torpedoed the 5,224-gross register ton British steamer — which was on a voyage from

New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...

Bombay Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second-m ...

British India The provinces of India, earlier presidencies of British India and still earlier, presidency towns, were the administrative divisions of British governance on the Indian subcontinent. Collectively, they have been called British India. In one ...

with a stop at

Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...

, South Africa, carrying military personnel and government stores — at 09:53 on 8 June 1942; ''King Lud'' sank at , with no survivors. ''Aikoku Maru'' and ''Hōkoku Maru'' refueled and replenished ''I-10'' on 17 June 1942. Returning to action, she torpedoed the 4,957-gross register ton British

— which was on a voyage from the River Tyne in

to Aden with a cargo of military stores — in the Mozambique Channel south of Beira on 28 June 1942; ''Queen Victoria'' sank at , with no survivors. Still in the Mozambique Channel south of Beira on 30 June, she torpedoed the American 6,737-gross register ton armed steamer , which was on a voyage from Bombay to Cape Town with a cargo of

manganese ore Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

, jute, and

leather Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hog ...

. Two torpedoes hit ''Express'' on her starboard side and she sank by the stern at . Eleven members of ''Express''′s crew and two personnel of her

United States Navy Armed Guard United States Navy Armed Guard units were established during World War II and headquartered in New Orleans.World War II U.S. Navy Armed Guard and World War II U.S. Merchant Marine, 2007-2014 Project Liberty Ship, Project Liberty Ship, P.O. Box 2 ...

drowned after abandoning ship when their boat was swamped in heavy seas. ''I-10''′s success against Allied shipping in the Indian Ocean continued in July. At 16:15 on 6 July 1942, she torpedoed and sank the Greek 4,504-gross register ton merchant ship ''Nymphe'' at . At 07:48 on 8 July, she torpedoed the British 5,498-gross register ton armed steamer — which was making a voyage from

Philadelphia Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

, to

Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandri ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...

, via

Lourenço Marques Maputo (), formerly named Lourenço Marques until 1976, is the capital, and largest city of Mozambique. Located near the southern end of the country, it is within of the borders with Eswatini and South Africa. The city has a population of 1,088 ...

, Portuguese East Africa, carrying 8,000 tons of general cargo — in the Mozambique Channel. One torpedo hit ''Hartismere'' in the vicinity of her No. 1

hold Hold may refer to: Physical spaces * Hold (ship), interior cargo space * Baggage hold, cargo space on an airplane * Stronghold, a castle or other fortified place Arts, entertainment, and media * Hold (musical term), a pause, also called a Ferm ...

, triggering a violent explosion which started a fire and prompted her crew to abandon ship. ''I-10'' surfaced and sank ''Hartismere'' with gunfire at , and ''Hartismere''′s crew and gunners made it to shore in her lifeboats at Caldera Point on the coast of Portuguese East Africa. ''I-10''′s final victim of the Indian Ocean operation was the 4,427-ton Dutch armed merchant ship ''Alchiba'', which was on a voyage from Durban, South Africa, to

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

via Aden with a cargo of 4,000 tons of ammunition. ''I-10'' torpedoed ''Alchiba'' at 17:55 on 8 July, hitting her in her

engine room On a ship, the engine room (ER) is the compartment where the machinery for marine propulsion is located. To increase a vessel's safety and chances of surviving damage, the machinery necessary for the ship's operation may be segregated into var ...

on the

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

side. The torpedo hit killed five

firemen A firefighter is a first responder and rescuer extensively trained in firefighting, primarily to extinguish hazardous fires that threaten life, property, and the environment as well as to rescue people and in some cases or jurisdictions also ...

, destroyed two lifeboats, and knocked out all of ''Alchiba''′s lights. Her surviving crew abandoned ship, after which ''I-10'' surfaced and fired nine rounds at ''Alchiba''. ''Alchiba'' broke in two and sank at . Some of her survivors mistakenly claimed that two submarines had attacked her. ''I-10'' returned to Penang on 30 July 1942.

August–October 1942

''I-10'' departed Penang on 1 August 1942 bound for Yokosuka, which she reached on 12 August. She remained in Japan until 21 October 1942, when she departed Yokosuka heading for

Truk Atoll Chuuk Lagoon, previously Truk Atoll, is an atoll in the central Pacific. It lies about northeast of New Guinea, and is part of Chuuk State within the Federated States of Micronesia (FSM). A protective reef, around, encloses a natural harbo ...

. She arrived at Truk on 27 October 1942.

Guadalcanal campaign

The Guadalcanal campaign had begun with

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

landings on Guadalcanal in the southeastern

Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...

on 7 August 1942. While ''I-10'' was at Truk, she was reassigned to the "C" Patrol Unit on 31 October 1942. On 24 November 1942 she got underway from Truk to patrol off San Cristobal in support of a midget submarine attack against Allied shipping in Lungga Roads off the north coast of Guadalcanal.I-10 ijnsubsite.com 10 July 2018 Accessed 20 February 2022
/ref> She returned to Truk on 18 December 1942.

Third war patrol

With a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane aboard, ''I-10'' departed Truk on 5 January 1943, ordered to attack Allied shipping south of the Solomon Islands and conduct a reconnaissance of

Nouméa Nouméa () is the capital and largest city of the French special collectivity of New Caledonia and is also the largest francophone city in Oceania. It is situated on a peninsula in the south of New Caledonia's main island, Grande Terre, and ...

on Grande Terre in New Caledonia, of

waters, and of the

Torres Strait The Torres Strait (), also known as Zenadh Kes, is a strait between Australia and the Melanesian island of New Guinea. It is wide at its narrowest extent. To the south is Cape York Peninsula, the northernmost extremity of the Australian mai ...

. She passed east of the Solomons on 10 January. She sighted what she identified as an aircraft carrier escorted by two destroyers on 16 January south-southeast of Nouméa and attempted a pursuit and attack, but she failed to achieve a good attack position and all of her torpedoes missed. At 00:15 on 20 January 1943 she sighted what she identified as an unescorted

south of Nouméa, and at 00:20 on 23 January she sighted two destroyers east of Nouméa. After dark on 24 January, she launched her floatplane for a reconnaissance flight over the Nouméa area — at a time when

United States Secretary of the Navy The secretary of the Navy (or SECNAV) is a statutory officer () and the head (chief executive officer) of the Department of the Navy, a military department (component organization) within the United States Department of Defense. By law, the se ...

Frank Knox William Franklin Knox (January 1, 1874 – April 28, 1944) was an American politician, newspaper editor and publisher. He was also the Republican vice presidential candidate in 1936, and Secretary of the Navy under Franklin D. Roosevelt durin ...

and the Commander-in-Chief of the United States Pacific Fleet, Chester W. Nimitz, were in Nouméa for a Commander,

South Pacific Area The South Pacific Area (SOPAC) was a multinational U.S.-led military command active during World War II. It was a part of the U.S. Pacific Ocean Areas under Admiral Chester Nimitz. The delineation and establishment of the Pacific Ocean Areas was ...

conference — and at 01:00 on 25 January its crew reported seeing several battleships, cruisers, destroyers, and transports in the harbor. On 30 January 1943, ''I-10'' was in the Coral Sea south of the Amédée Lighthouse on Amédée Island in New Caledonia when she hit the American 7,176- gross register ton

Liberty ship Liberty ships were a class of cargo ship built in the United States during World War II under the Emergency Shipbuilding Program. Though British in concept, the design was adopted by the United States for its simple, low-cost construction. Ma ...

with a single torpedo in the stern at 04:49. ''Samuel Gompers'', which was on a voyage from Nouméa to

Newcastle Newcastle usually refers to: *Newcastle upon Tyne, a city and metropolitan borough in Tyne and Wear, England *Newcastle-under-Lyme, a town in Staffordshire, England *Newcastle, New South Wales, a metropolitan area in Australia, named after Newcastle ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, Australia, suffered an explosion and sank at 04:54 at . At about 14:00 on 9 February 1943, ''I-10'' fired torpedoes at what she identified as an unescorted transport, but the torpedoes passed under the ship without exploding. At 05:42 on 10 February, she attacked another transport in the area, but failed to gain a good firing position and all her torpedoes missed. ''I-10'' arrived off

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The most populous urban area in the country and the fifth largest city in Oceania, Auckland has an urban population of about ...

, New Zealand, on 14 February 1943 and off

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by metr ...

, New Zealand, on 16 February. On 22 February, Allied signals intelligence intercepted several of ''I-10''′s transmissions and, based on them, estimated that ''I-10'' was about to pass through the

Cook Strait Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A ...

, not realizing that she had already transited the strait over a week earlier. A Royal New Zealand Air Force search for ''I-10'' in the Cook Strait area found nothing. ''I-10'' attacked a transport at 10:50 on 27 February 1943, but her torpedoes missed. On 1 March 1943, however, she succeeded in torpedoing the American 7,141-gross register ton tanker in the

New Hebrides New Hebrides, officially the New Hebrides Condominium (french: link=no, Condominium des Nouvelles-Hébrides, "Condominium of the New Hebrides") and named after the Hebrides Scottish archipelago, was the colonial name for the island group ...

at . ''Gulfwave''′s crew and

detachment suffered no casualties, and the tanker made port at Suva in the Fiji Islands under her own power.
A WWII history
A WWII history After reconnoitering the Torres Strait on 5 March, ''I-10'' headed back to Truk, which she reached on 10 March 1943.

March–June 1943

''I-10'' got underway from Truk on 15 March 1943 and set course for

Sasebo is a core city located in Nagasaki Prefecture, Japan. It is also the second largest city in Nagasaki Prefecture, after its capital, Nagasaki. On 1 June 2019, the city had an estimated population of 247,739 and a population density of 581 persons p ...

, Japan, where she arrived on 21 March to undergo repairs. With them complete, she departed Sasebo on 17 May 1943 and made for the Seto Inland Sea for workups and where from 17 to 19 May she engaged in refueling exercises in the Iyo-nada with the submarine , which had been selected to carry out a ''Yanagi'' mission, a round-trip voyage between Japan and

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

occupied France The Military Administration in France (german: Militärverwaltung in Frankreich; french: Occupation de la France par l'Allemagne) was an interim occupation authority established by Nazi Germany during World War II to administer the occupied zo ...

''I-10'' arrived at Kure on 26 May 1943. On 1 June 1943,''I-10'' departed Kure in company with ''I-8'' and the submarine tender . The three vessels proceeded to Saeki Gulf, then departed Saeki Gulf on 2 June and made for Penang, where ''I-10'' arrived on 12 June 1943 and was made flagship of Submarine Squadron 8.

Fourth war patrol

On 27 June 1943, ''I-10'' departed Penang with the commander of Submarine Squadron 8, Rear Admiral Noboru Ishizaki, aboard to begin her fourth war patrol in company with ''I-8'', which was beginning the next leg of her ''Yanagi''-mission voyage to France. ''I-10'' refueled ''I-8'' at on 1 July and again at on 6 July 1943 before the two submarines separated, ''I-8'' proceeding on her voyage to France and ''I-10'' beginning anti-shipping operations in the Indian Ocean. In the Gulf of Aden, ''I-10'' hit the 7,634-gross register ton Norwegian tanker ''Alcides'' with two torpedoes on 22 July 1943. ''Alcides'', which was on a voyage from Abadan,

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

, to Fremantle, Australia, sank at . ''I-10'' took ''Alcides''′s

master Master or masters may refer to: Ranks or titles * Ascended master, a term used in the Theosophical religious tradition to refer to spiritually enlightened beings who in past incarnations were ordinary humans *Grandmaster (chess), National Master ...

, radio officer, and second mate aboard, and they remained prisoners of war in Japan until freed by American forces on 29 August 1945. ''I-10'' returned to Penang on .

Fifth war patrol

With a five-man film crew embarked to capture footage for the propaganda film ''Gochin!'' ("''Sunk!''") and a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane aboard, ''I-10'' departed Penang at 16:00 on 2 September 1943 and headed back into the Indian Ocean to begin her fifth war patrol, assigned a patrol area in the Gulf of Aden. On 14 September, she torpedoed and sank the 6,361-gross register ton Norwegian tanker ''Bramora'' — which was carrying oil from

Bandar Abbas Bandar Abbas or Bandar-e ‘Abbās ( fa, , , ), is a port city and capital of Hormozgān Province on the southern coast of Iran, on the Persian Gulf. The city occupies a strategic position on the narrow Strait of Hormuz (just across from Musand ...

, Iran, to

Melbourne Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...

, Australia — southwest of the

Chagos Archipelago The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives arch ...

at . At dawn on 20 September 1943, her floatplane flew a reconnaissance mission over Perim Island in the

Bab-el-Mandeb The Bab-el-Mandeb ( Arabic: , , ) is a strait between Yemen on the Arabian Peninsula, and Djibouti and Eritrea in the Horn of Africa. It connects the Red Sea to the Gulf of Aden. Name The strait derives its name from the dangers a ...

to investigate a report that the Allies had constructed an airfield there, but its crew found no airfield on the island. ''I-10'' returned to the Gulf of Aden, where at about 02:00 on 24 September 1943 she sighted the American 7,634-gross register ton Liberty ship southeast of Aden. She fired two torpedoes at 03:12, one of which struck ''Elias Howe'', killing two men in her

and starting a large fire. ''Elias Howe'' transmitted an SOS. ''I-10'' surfaced and hit ''Elias Howe'' with another torpedo, and 15 minutes after the second hit explosives aboard ''Elias Howe'' detonated. ''Elias Howe'' sank by the stern at . The

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...

armed trawler Naval trawlers are vessels built along the lines of a fishing trawler but fitted out for naval purposes; they were widely used during the First and Second World Wars. Some—known in the Royal Navy as "Admiralty trawlers"— were purpose-built t ...

and a

seaplane A seaplane is a powered fixed-wing aircraft capable of taking off and landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their technological characteri ...

rescued ''Elias Howe''′s survivors. At about 16:30 on 1 October 1943, ''I-10'' sighted an Allied

in the Gulf of Aden heading west at and set out in pursuit. She fired three torpedoes at the 4,836-gross register ton Norwegian armed merchant ship , which was carrying a cargo of

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...

from

Mombasa Mombasa ( ; ) is a coastal city in southeastern Kenya along the Indian Ocean. It was the first capital of the British East Africa, before Nairobi was elevated to capital city status. It now serves as the capital of Mombasa County. The town is ...

British East Africa East Africa Protectorate (also known as British East Africa) was an area in the African Great Lakes occupying roughly the same terrain as present-day Kenya from the Indian Ocean inland to the border with Uganda in the west. Controlled by Bri ...

to Aden. Two torpedoes hit ''Storviken'' on her starboard side, and she sank by the stern at . ''I-10'' took two members of her crew prisoner. At around 16:10 on 4 October 1943, ''I-10'' detected the sound of multiple propellers while submerged in the Gulf of Aden, and soon sighted Convoy AP-47, consisting nine merchant ships bound from Aden to Abadan escorted by two destroyers. ''I-10'' pursued the convoy, surfacing after sunset. When northwest of

Cape Guardafui Cape Guardafui ( so, Gees Gardafuul, or Raas Caseyr, or Ras Asir, it, Capo Guardafui) is a headland in the autonomous Puntland region in Somalia. Coextensive with Puntland's Gardafuul administrative province, it forms the geographical apex of th ...

, the northernmost tip of British Somaliland, at 05;10 on 5 October, she fired three torpedoes at overlapping targets at a range of , then dived to . One torpedo struck the 9,057-gross register ton Norwegian armed tanker on her starboard bow at . As major flooding progressed, her master ordered her crew to abandon ship, but the crew returned to ''Anna Knudsen'' when the flooding abated. ''I-10''′s crew, meanwhile, reported hearing three loud explosions followed by breaking-up noises indicating the sinking of one or more ships, and claimed three merchant ships sunk. ''I-10'' suffered minor damage to her engine room during a brief depth-charging by the convoy′s escorts. In the Indian Ocean near Addu Atoll on 24 October 1943 at 11:25, ''I-10'' fired two torpedoes at the British 4,533-gross register ton armed motor vessel , which was on a voyage from

Calcutta Kolkata (, or , ; also known as Calcutta , List of renamed places in India#West Bengal, the official name until 2001) is the Capital city, capital of the Indian States and union territories of India, state of West Bengal, on the eastern ba ...

to Durban, South Africa, carrying 8,700 tons of general cargo. Both torpedoes missed, so ''I-10'' surfaced and opened gunfire, starting a fire aboard ''Congella''. ''Congella''′s crew abandoned ship, and she sank at . ''I-10'' took her radio operator prisoner. The British

whaling ship A whaler or whaling ship is a specialized vessel, designed or adapted for whaling: the catching or processing of whales. Terminology The term ''whaler'' is mostly historic. A handful of nations continue with industrial whaling, and one, Jap ...

''Okapi'' and two

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...

Catalina Catalina may refer to: Arts and media * ''The Catalina'', a 2012 American reality television show * ''Catalina'' (novel), a 1948 novel by W. Somerset Maugham * Catalina (''My Name Is Earl''), character from the NBC sitcom ''My Name Is Earl'' ...

flying boats rescued her other 37 survivors. Three gunners and 25 crew died in her sinking. ''I-10'' concluded her patrol with her return to Penang on 30 October 1943.

November 1943–February 1944

''I-10'' departed Penang on 5 November 1943, called at Singapore from 7 November to 7 December 1943, and then proceeded to Sasebo, which she reached on 16 December 1943. She underwent repairs and an overhaul at Sasebo, during which she was attached directly to 6th Fleet headquarters on 1 January 1944. When her repairs were complete, ''I-10'' departed Sasebo on 3 February 1944 bound for Truk. On 9 February 1944, Fleet Radio Unit, Melbourne (FRUMEL), an Allied signals intelligence unit in Melbourne, Australia, decrypted a Japanese message reporting that ''I-10'' would arrive at Truk via the North Channel on 10 February 1944, but she arrived safely at Truk on 10 February despite the Allied knowledge of her schedule.

Operation Hailstone

During ''I-10''′s stay at Truk, U.S. Navy

Task Force 58 The Fast Carrier Task Force (TF 38 when assigned to Third Fleet, TF 58 when assigned to Fifth Fleet), was the main striking force of the United States Navy in the Pacific War from January 1944 through the end of the war in August 1945. The task ...

conducted

Operation Hailstone Operation Hailstone ( ja, トラック島空襲, Torakku-tō Kūshū, lit=airstrike on Truk Island), 17–18 February 1944, was a massive United States Navy air and surface attack on Truk Lagoon conducted as part of the American offensive drive ...

, a major attack on Truk by carrier aircraft supported by anti-shipping sweeps around the

atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can gr ...

by surface warships, on 17 and 18 February 1944. ''I-10'' suffered three killed and two wounded and sustained minor damage during the first day of the raid, but she and the submarines and put to sea on 17 February in an attempt to intercept the attacking ships. ''I-10'' searched for them east of

Dublon Tonowas (or Tonoas), also known by its Spanish name of Dublon, is an island in the Chuuk (formerly Truk) lagoon, Federated States of Micronesia. It has an area of 8.8 km2 and the population was 3,200 at the time of the last census (1980). A na ...

(known to the Japanese as Natsushima) without success and returned to Truk.

Sixth war patrol

''I-10'' departed Truk for her sixth war patrol on 25 February 1944, intending to operate off the U.S. West Coast. On 4 March 1944, however, she suffered damage in a depth-charge attack in the Pacific Ocean east of

Mili Atoll Mili Atoll ( Marshallese: , ) is a coral atoll of 92 islands in the Pacific Ocean, and forms a legislative district of the Ratak Chain of the Marshall Islands. It is located approximately southeast of Arno. Its total land area is making it the s ...

and was forced to abort her patrol. She arrived at Yokosuka on 20 March 1944 for repairs. While she was under repair, workers probably installed an E27 Type 3

radar detector A radar detector is an electronic device used by motorists to detect if their speed is being monitored by police or law enforcement using a radar gun. Most radar detectors are used so the driver can reduce the car's speed before being ticketed ...

and a Type 3

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on o ...

aboard her.

Seventh war patrol

With her repairs complete, ''I-10'' left Yokosuka on 4 May 1944 with a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane embarked to begin her seventh war patrol, assigned a patrol area in the Pacific Ocean east of the

. After dark on 12 June 1944, her floatplane reconnoitered the American fleet anchorage at

Majuro Atoll Majuro (; Marshallese: ' ) is the capital and largest city of the Marshall Islands. It is also a large coral atoll of 64 islands in the Pacific Ocean. It forms a legislative district of the Ratak (Sunrise) Chain of the Marshall Islands. The ato ...

, but an American expeditionary force had departed Majuro six days earlier, and the plane's crew found no ships there.Morison, Samuel Eliot, "History of United States Naval Operations in World War II: Vollume Eight - New Guinea and the Marianas March 12944 - August 1944," Little, Brown and Company, Boston, 1953, 1989, Library of Congress card number 53-7298, page 229. Upon returning to ''I-10'', the floatplane

capsize Capsizing or keeling over occurs when a boat or ship is rolled on its side or further by wave action, instability or wind force beyond the angle of positive static stability or it is upside down in the water. The act of recovering a vessel fro ...

d and was lost, although ''I-10'' recovered its crew. On 13 June 1944, the commander-in-chief of the Combined Fleet, Admiral

Soemu Toyoda was an admiral in the Imperial Japanese Navy in World War II. Biography Early career Toyoda was born in what is now part Kitsuki city, Ōita Prefecture. He graduated from the 33rd class of the Imperial Japanese Navy Academy in 1905, ranked 26 ...

, activated Operation A-Go for the defense of the Mariana Islands and ordered the commander-in-chief of the 6th Fleet, Vice Admiral

Takeo Takagi was an admiral in the Imperial Japanese Navy during World War II. Biography Takagi was a native of Iwaki city, Fukushima prefecture. He was a graduate of the 39th class of the Imperial Japanese Naval Academy, ranking 17th of 148 cadets in 1911. ...

on Saipan, to redeploy all 6th Fleet submarines to the Marianas. Takagi, in turn, ordered all 18 available submarines, including , to deploy east of the Marianas. The Marianas campaign began on 15 June 1944 with U.S. landings on Saipan, beginning the

Battle of Saipan The Battle of Saipan was a battle of the Pacific campaign of World War II, fought on the island of Saipan in the Mariana Islands from 15 June to 9 July 1944 as part of Operation Forager. It has been referred to as the "Pacific D-Day" with the ...

and disrupting communications with Takagi, so the commander of Submarine Squadron 7, Rear Admiral Noboru Owada, took temporary command of the 6th Fleet and ordered all but six of the submarines to withdraw from the Marianas. was among the six ordered to remain. On 24 June 1944, the Combined Fleet ordered Owada to evacuate Takagi and his staff from their headquarters on the eastern coast of Saipan. was operating east of Saipan at the time, so Owada ordered her to conduct the evacuation. At 12:00

Japan Standard Time , or , is the standard time zone in Japan, 9 hours ahead of UTC ( UTC+09:00). Japan does not observe daylight saving time, though its introduction has been debated on several occasions. During World War II, the time zone was often referred to ...

on 28 June 1944, reported that she was northeast of Saipan and had not found it possible to break through the cordon of American ships off Saipan to reach Takagi and his staff. The Japanese never heard from her again, and on 2 July 1944 declared her to be presumed lost off Saipan with all 103 hands.

Loss

In fact, ''I-10'' had not yet been lost on 2 July, but she did not survive much longer. At 17:02 on 4 July 1944, U.S. Navy Task Group 50.17, with six tankers and the escort carrier , was refueling at sea northeast of Saipan when the

destroyer escort Destroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships. Development of the destroyer escort was promoted by th ...

gained sound contact on a submerged submarine bearing 250 degrees at a range of . While the task group made an emergency turn to port, ''Riddle'' quickly dropped five depth charges. ''Riddle'' then began an approach for another attack but the submarine turned into the wakes of the ships of the retiring task group, and ''Riddle'' lost contact in the turbulence. After 18 minutes, ''Riddle'' regained contact at a range of . She fired three patterns of

Hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introductio ...

projectiles, but the submarine dived deeper and maneuvered aggressively, avoiding the projectiles. At 18:12, ''Riddle'' made another attack with a full pattern of depth charges set to explode deep, but without result. ''Riddle'' passed the estimated range, bearing, and course of the submarine to the destroyer , which established contact on the submarine at 18:22. ''David W. Taylor'' dropped 11 depth charges set to explode at medium depth. ''Riddle'' was about to begin another attack when a heavy underwater explosion occurred directly ahead of her at 18:28. Neither ship obtained any more contacts, and by sunset oil and debris had reached the surface at . It marked the demise of ''I-10''.Boyd & Yoshida, p. 209 On 5 July 1944, an oil slick extended downwind from the point of attack. The Japanese removed ''I-10'' from the

Navy list A Navy Directory, formerly the Navy List or Naval Register is an official list of naval officers, their ranks and seniority, the ships which they command or to which they are appointed, etc., that is published by the government or naval autho ...

on 10 October 1944.

Notes

References

* * * * * * * * {{DEFAULTSORT:I-010 Type A1 submarines 1939 ships World War II submarines of Japan Friendly fire incidents of World War II Japanese submarines lost during World War II Japanese war crimes Maritime incidents in December 1941 Maritime incidents in July 1944 World War II shipwrecks in the Pacific Ocean Ships built by Kawasaki Heavy Industries Submarines sunk by United States warships Warships lost in combat with all hands Submarines lost with all hands