Prior to World War II, the Indian Ocean was an important maritime trade route between European nations and their colonial territories in East Africa, the Arabian Peninsula, British India, Indochina, the East Indies (Indonesia), and Australia for a long time. Naval presence was dominated by the Royal Navy Eastern Fleet and the Royal Australian Navy as World War II began, with a major portion of the Royal Netherlands Navy operating in the Dutch East Indies and the Red Sea Flotilla of the Italian Regia Marina operating from Massawa.
World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.
The Indian Ocean is the third largest of the world's oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi). It is bounded by Asia on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean or, depending on definition, by Antarctica.
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west and the Mediterranean Sea to the south. It comprises the westernmost part of Eurasia.
Axis naval forces gave a high priority to disrupting Allied trade in the Indian Ocean. Initial anti-shipping measures of unrestricted submarine warfare and covert raiding ships expanded to include airstrikes by aircraft carriers and raids by cruisers of the Imperial Japanese Navy. A Kriegsmarine Monsun Gruppe of U-boats operated from the eastern Indian Ocean after the Persian Corridor became an important military supply route to the Soviet Union.
The Axis powers, also known as "Rome–Berlin–Tokyo Axis", were the nations that fought in World War II against the Allies. The Axis powers agreed on their opposition to the Allies, but did not completely coordinate their activity.
The Allies of World War II, called the "United Nations" from the 1 January 1942 declaration, were the countries that together opposed the Axis powers during the Second World War (1939–1945). The Allies promoted the alliance as a means to control German, Japanese and Italian aggression.
Unrestricted submarine warfare is a type of naval warfare in which submarines sink vessels such as freighters and tankers without warning, as opposed to attacks per prize rules. Prize rules call for submarines to surface and search merchantmen and place crews in "a place of safety" before sinking them, unless the ship showed "persistent refusal to stop ... or active resistance to visit or search". During the First World War, the British introduced Q-ships with concealed deck guns, and armed many merchantmen, leading the Germans to ignore the prize rules; in the most dramatic episode they sank Lusitania in 1915 in a few minutes because she was carrying war munitions. The U.S. demanded it stop, and Germany did so. Admiral Henning von Holtzendorff, chief of the Admiralty staff, argued successfully in early 1917 to resume the attacks and thus starve the British. The German high command realized the resumption of unrestricted submarine warfare meant war with the United States but calculated that American mobilization would be too slow to stop a German victory on the Western Front.
Admiral Graf Spee was a Deutschland-class "Panzerschiff", nicknamed a "pocket battleship" by the British, which served with the Kriegsmarine of Nazi Germany during World War II. The two sister-ships of her class, Deutschland and Admiral Scheer, were reclassified as heavy cruisers in 1940. The vessel was named after Admiral Maximilian von Spee, commander of the East Asia Squadron that fought the battles of Coronel and the Falkland Islands, where he was killed in action, in World War I. She was laid down at the Reichsmarinewerft shipyard in Wilhelmshaven in October 1932 and completed by January 1936. The ship was nominally under the 10,000 long tons (10,000 t) limitation on warship size imposed by the Treaty of Versailles, though with a full load displacement of 16,020 long tons (16,280 t), she significantly exceeded it. Armed with six 28 cm (11 in) guns in two triple gun turrets, Admiral Graf Spee and her sisters were designed to outgun any cruiser fast enough to catch them. Their top speed of 28 knots left only the few battlecruisers in the Anglo-French navies fast enough and powerful enough to sink them.
Madagascar, officially the Republic of Madagascar, and previously known as the Malagasy Republic, is an island country in the Indian Ocean, approximately 400 kilometres off the coast of East Africa. The nation comprises the island of Madagascar and numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 88 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of its wildlife is found nowhere else on Earth. The island's diverse ecosystems and unique wildlife are threatened by the encroachment of the rapidly growing human population and other environmental threats.
The Regia Marina Red Sea Flotilla based at Massawa provided a focal point for Indian Ocean naval activity following Italian declaration of war on 10 June 1940; although Indian Ocean patrols of Kriegsmarine merchant raiders required defensive dispersion of Allied cruisers after May.
The Regia Marina was the navy of the Kingdom of Italy from 1861 to 1946. In 1946, with the birth of the Italian Republic, the Regia Marina changed its name to Marina Militare.
The Red Sea Flotilla was part of the Regia Marina Italia based at Massawa in the colony of Italian Eritrea, part of Italian East Africa. In World War II, the Red Sea Flotilla was active against the East Indies Station of the Royal Navy, from the Italian declaration of war on 10 June 1940 until the fall of Massawa on 8 April 1941.
Massawa is a city on the Red Sea coast of Eritrea located at the northern end of the Gulf of Zula beside the Dahlak Archipelago. As a historical and important port for many centuries, it was ruled by a succession of polities, including the Axumite Empire, Medri Bahri Kingdom, the Umayyad Caliphate, various Beja sultanates, the Ottoman Empire, the Khedivate of Egypt, Italy, Britain, and Ethiopia, until Eritrea's independence in 1991. Massawa was the capital of the Italian Colony of Eritrea until it was moved to Asmara in 1897.
In naval terminology, a destroyer is a fast, maneuverable long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller powerful short-range attackers. They were originally developed in the late 19th century by Fernando Villaamil for the Spanish Navy as a defense against torpedo boats, and by the time of the Russo-Japanese War in 1904, these "torpedo boat destroyers" (TBDs) were "large, swift, and powerfully armed torpedo boats designed to destroy other torpedo boats". Although the term "destroyer" had been used interchangeably with "TBD" and "torpedo boat destroyer" by navies since 1892, the term "torpedo boat destroyer" had been generally shortened to simply "destroyer" by nearly all navies by the First World War.
A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub.
The German auxiliary cruiser Atlantis, known to the Kriegsmarine as Schiff 16 and to the Royal Navy as Raider-C, was a converted German Hilfskreuzer, or merchant or commerce raider of the Kriegsmarine, which, in World War II, travelled more than 161,000 km (100,000 mi) in 602 days, and sank or captured 22 ships with a combined tonnage of 144,384. Atlantis was commanded by Kapitän zur See Bernhard Rogge, who received the Oak Leaves to the Knight's Cross of the Iron Cross. She was sunk on 22 November 1941 by the British cruiser HMS Devonshire.
Early focus was Allied neutralisation and capture of Regia Marina African naval bases, followed by invasions of Iraq in April and Iran in August, to displace governments friendly to the Axis powers. Later Allied focus was on destruction of Kriegsmarine commerce raiders and moving troops to defend against anticipated Japanese expansion into south-east Asia.
Iraq, officially the Republic of Iraq, is a country in Western Asia, bordered by Turkey to the north, Iran to the east, Kuwait to the southeast, Saudi Arabia to the south, Jordan to the southwest and Syria to the west. The capital, and largest city, is Baghdad. Iraq is home to diverse ethnic groups including Arabs, Kurds, Assyrians, Turkmen, Shabakis, Yazidis, Armenians, Mandeans, Circassians and Kawliya. Around 95% of the country's 37 million citizens are Muslims, with Christianity, Yarsan, Yezidism and Mandeanism also present. The official languages of Iraq are Arabic and Kurdish.
Iran, also called Persia, and officially the Islamic Republic of Iran, is a country in Western Asia. With over 81 million inhabitants, Iran is the world's 18th most populous country. Comprising a land area of 1,648,195 km2 (636,372 sq mi), it is the second largest country in the Middle East and the 17th largest in the world. Iran is bordered to the northwest by Armenia and the Republic of Azerbaijan, to the north by the Caspian Sea, to the northeast by Turkmenistan, to the east by Afghanistan and Pakistan, to the south by the Persian Gulf and the Gulf of Oman, and to the west by Turkey and Iraq. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, give it geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic and cultural center.
The Kriegsmarine was the navy of Nazi Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic. The Kriegsmarine was one of three official branches, along with the Heer (Army) and the Luftwaffe of the Wehrmacht, the German armed forces from 1933 to 1945.
Japanese submarine cruisers began patrolling the Indian Ocean during the Dutch East Indies campaign. Following the attack on Pearl Harbor, the Kido Butai fast carrier task force raided Darwin, Australia to cover the invasion of Timor and raided Ceylon to cover transport of Japanese troops to Rangoon. Kriegsmarine merchant raiders were less able to avoid Allied patrols; but the battle of the Atlantic spilled over into the Indian Ocean around Cape Agulhas as German Type IX submarines began patrolling the east coast of Africa.
Axis submarine patrols of Indian Ocean trade routes were expanded with establishment of a Kriegsmarine base in Penang as Allied anti-submarine patrols became increasingly effective in the Atlantic. Allied submarines and aircraft began patrolling the Strait of Malacca and Andaman Sea to intercept shipping supporting Japanese forces in Burma.
Use of Ultra intelligence information increased successful interceptions by Allied submarines and reduced Axis resupply opportunities in the Indian Ocean. Surrender of the Regia Marina and destruction of Kriegsmarine battleships made Royal Navy aircraft carriers available for raids of the Andaman Sea.
Allied focus was on amphibious operations along the Burma coast of the Andaman Sea. Axis submarine operations were restricted by fuel shortage and maintenance difficulties.
HMS Antelope was a British A-class destroyer, which was completed for the Royal Navy in 1930. Antelope served throughout the Second World War, taking part in the sinking of three enemy submarines and in Operation Torch, the Allied invasion of French North Africa.
USS Pogy (SS-266), a Gato-class submarine, was the first ship of the United States Navy to be named for the pogy, or menhaden.
USS Puffer (SS-268), a Gato-class submarine, was the first ship of the United States Navy to be named for the puffer.
This is a timeline for the Battle of the Atlantic (1939–1945) in World War II.
Albrecht Brandi was a German U-boat commander in Nazi Germany's Kriegsmarine during World War II. Together with Wolfgang Lüth, he was the only Kriegsmarine sailor who was awarded with the Knight's Cross of the Iron Cross with Oak Leaves, Swords and Diamonds. The Knight's Cross, and its variants were the highest awards in the military and paramilitary forces of Nazi Germany during World War II. Brandi is credited with the sinking of eight merchant ships for a total of 25,879 gross register tons (GRT), one auxiliary warship of 810 GRT, and three warships of 5,000 long tons.
HMS Saracen was a third-batch S-class submarine built for the Royal Navy during the Second World War. Completed in 1942, Saracen conducted a patrol in the North Sea where she sank a German U-boat. She was then assigned to the 10th Submarine Flotilla in Malta, from where she made three patrols; on her second, she sank an Italian submarine. Saracen was then reassigned to the 8th Submarine Flotilla, based in Algiers, French North Africa.
HMS Sportsman was a third-batch S-class submarine built for the Royal Navy during World War II. Completed in 1942, she spent most of the war serving in the Mediterranean Sea. After an initial patrol off Norway, she sank the heavy transport Général Bonaparte in the Mediterranean in 1943 and missed a French oil tanker. She was heavily damaged after an mistaken attack by an Allied bomber, and was sent east after repairs to participate in operations in the Black Sea. After the operation was cancelled, Sportsman patrolled the Aegean Sea, sending several Greek and German ships to the bottom. She sank the German transport SS Petrella in early 1944 despite it being clearly marked as a prisoner-of-war ship, killing 2,670 out of 3,173 Italians aboard. Sportsman sank several more ships, and suffered minor damage when she was detected and sighted while attempting to attack a convoy.
HMS Tigris was a T-class submarine of the Royal Navy. She was laid down at Chatham Dockyard and launched in October 1939.
HMS Marigold was a Flower-class corvette of the Royal Navy.
Convoy SL 125 was the 125th of the numbered series of World War II SL convoys of merchant ships from Sierra Leone to Liverpool. Ships carrying commodities bound to the British Isles from South America, Africa, and the Indian Ocean travelled independently to Freetown, Sierra Leone to be convoyed for the last leg of their voyage. Thirty-seven merchant ships departed Freetown on 16 October 1942 and were joined at sea by five more.
The Gruppe Monsun or Monsoon Group was a force of German U-boats (submarines) that operated in the Pacific and Indian Oceans during World War II. Although similar naming conventions were used for temporary groupings of submarines in the Atlantic, the longer duration of Indian Ocean patrols caused the name to be permanently associated with the relatively small number of U-boats operating out of Penang. After 1944, the U-boats of the Monsun Gruppe were operationally placed under the authority of the Southeast Asia U-boat Region.
Western Local Escort Force (WLEF) referred to the organization of anti-submarine escorts for World War II trade convoys from North American port cities to the Western Ocean Meeting Point near Newfoundland where ships of the Mid-Ocean Escort Force (MOEF) assumed responsibility for safely delivering the convoys to the British Isles.
The UG convoys were a series of east-bound trans-Atlantic convoys from the United States to Gibraltar carrying food, ammunition, and military hardware to the United States Army in North Africa and southern Europe during World War II. These convoys assembled in Hampton Roads near the mouth of Chesapeake Bay and terminated in various North African locations as Axis forces retreated from 1942 through 1945.
The CU convoys were a World War II series of fast trans-Atlantic convoys to the British Isles. The earliest convoys of the series were tankers sailing directly from petroleum refineries at Curaçao to the United Kingdom. Most convoys of the series assembled in New York City and included fast freighters and troopships, with tankers arriving from Aruba via TAG convoys to Guantánamo Bay and GN convoys from Guantánamo to New York.
HMS Tynedale was a Hunt-class destroyer of the first subgroup which served during the Second World War. She was sunk by the U-593 on 12 December 1943.
The Arctic Circle defining the "midnight sun" encompasses the Atlantic Ocean from the northern edge of Iceland to the Bering Strait. The area is often considered part of the Battle of the Atlantic or the European Theatre of World War II. Pre-war navigation focused on fishing and the international ore trade from Narvik and Petsamo. Soviet settlements along the coast and rivers of the Barents Sea and Kara Sea relied upon summer coastal shipping for supplies from railheads at Arkhangelsk and Murmansk. The Soviet Union extended the Northern Sea Route past the Taymyr Peninsula to the Bering Strait in 1935.
Aikoku Maru (愛国丸) was an armed merchant cruiser of the Imperial Japanese Navy in World War II. The ship entered service in 1940, the ship was later converted to an ammunition ship. She was destroyed in February 1944.
K XII was a K XI class patrol submarines of the Royal Netherlands Navy. The ship was built by Fijenoord shipyard in Rotterdam.
The 8th Submarine Squadron of the Imperial Japanese Navy was based at Swettenham Pier, Penang, Malaya, until late 1944 during World War II. Its mission was to disrupt Allied supply lines in aid of Nazi Germany.
Convoy HG 53 was the 53rd of the numbered series of World War II HG convoys of Homeward bound merchant ships from Gibraltar to Liverpool. Convoy HG 53 lost nine ships during a coordinated attack in February 1941. HG 53 was one of the few Atlantic convoys to have ships sunk by submarines, by aircraft, and by surface ships.