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 It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic.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 and the Luftwaffe, of the Wehrmacht, the German armed forces from 1935 to 1945.
The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.
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.
Merchant raiders are armed commerce raiding ships that disguise themselves as non-combatant merchant vessels.
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 long distance and high value trade.
A warship or combatant ship is a ship that is built and primarily intended for naval warfare. Usually they belong to the armed forces of a nation. As well as being armed, warships are designed to withstand damage and are typically faster and more maneuverable than merchant ships. Unlike a merchant ship, which carries cargo, a warship typically carries only weapons, ammunition and supplies for its crew. Warships usually belong to a navy, though they have also been operated by individuals, cooperatives and corporations.
Submarine warfare is one of the four divisions of underwater warfare, the others being anti-submarine warfare, mine warfare and mine countermeasures.
A tonnage war is a military strategy aimed at merchant shipping. The premise is that the enemy has a finite number of ships and a finite capacity to build replacements. The concept was made famous by German Grand Admiral Karl Dönitz, who wrote:
"The shipping of the enemy powers is one great whole. It is therefore in this connection immaterial where a ship is sunk—it must still in the final analysis be replaced by a new ship".
Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchant ships such as freighters and tankers without warning, as opposed to attacks per prize rules that call for warships to search merchantmen and place crews in "a place of safety" before sinking them, unless the ship shows "persistent refusal to stop ... or active resistance to visit or search". To follow the rules a submarine must surface, defeating the purpose of submarines and putting itself in danger of attack.
Naval warfare in World War I was mainly characterised by blockade. The Allied Powers, with their larger fleets and surrounding position, largely succeeded in their blockade of Germany and the other Central Powers, whilst the efforts of the Central Powers to break that blockade, or to establish an effective counter blockade with submarines and commerce raiders, were eventually unsuccessful. Major fleet actions were extremely rare and proved less decisive.
There was considerable Axis naval activity in Australian waters during the Second World War, despite Australia being remote from the main battlefronts. German and Japanese warships and submarines entered Australian waters between 1940 and 1945 and attacked ships, ports and other targets. Among the best-known attacks are the sinking of HMAS Sydney by a German raider in November 1941, the bombing of Darwin by Japanese naval aircraft in February 1942, and the Japanese midget submarine attack on Sydney Harbour in May 1942. About 40 Allied merchant ships were damaged or sunk off the Australian coast by surface raiders, submarines and mines. Japanese submarines also shelled three Australian ports and submarine-based aircraft flew over several Australian capital cities.
The Japanese raiders in the Indian Ocean were those vessels used by the Imperial Japanese Navy (IJN) during the Second World War to pursue its war on Allied commerce in that theatre. Possessing a powerful fleet of warships, prior to the start of World War II, the IJN had strategically planned to fight a war of fleet actions, and as a consequence delegated few resources to raiding merchant vessels. Nevertheless, in 1940, two passenger-cargo vessels – Aikoku Maru and Hōkoku Maru – of the Osaka Shipping Line were requisitioned for conversion to armed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. These vessels were subsequently used as merchant raiders attacking Allied commercial shipping along vital sea lanes of communication between Australia and the Middle East. Using their comprehensive armament and speed to their advantage, the raiders experienced a brief period of success. Japanese raiding in the Indian Ocean largely ceased by the end of 1942 after an action with a Dutch vessel, the Ondina and a Royal Indian Navy corvette, HMIS Bengal in which the Hōkoku Maru was sunk.
Naval strategy is the planning and conduct of war at sea, the naval equivalent of military strategy on land.
Naval boarding action is an offensive tactic used in naval warfare to come up against an enemy marine vessel and attack by inserting combatants aboard that vessel. The goal of boarding is to invade and overrun the enemy personnel on board in order to capture, sabotage, or destroy the enemy vessel. While boarding attacks were originally carried out by ordinary sailors who are proficient in hand-to-hand combat, larger warships often deploy specially trained and equipped regular troops such as marines and special forces as boarders. Boarding and close quarters combat had been a primary means to conclude a naval battle since antiquity, until the early modern period when heavy naval guns gained tactical primacy at sea.
Allied submarines were used extensively during the Pacific War and were a key contributor to the defeat of the Empire of Japan.
The U-boat campaign from 1914 to 1918 was the World War I naval campaign fought by German U-boats against the trade routes of the Allies. It took place largely in the seas around the British Isles and in the Mediterranean. The German Empire relied on imports for food and domestic food production and the United Kingdom relied heavily on imports to feed its population, and both required raw materials to supply their war industry; the powers aimed, therefore, to blockade one another. The British had the Royal Navy which was superior in numbers and could operate on most of the world's oceans because of the British Empire, whereas the Imperial German Navy surface fleet was mainly restricted to the German Bight, and used commerce raiders and unrestricted submarine warfare to operate elsewhere.
The convoy—a group of merchantmen or troopships traveling together with a naval escort—was revived during World War I (1914–18), after having been discarded at the start of the Age of Steam. Although convoys were used by the Royal Navy in 1914 to escort troopships from the Dominions, and in 1915 by both it and the French Navy to cover their own troop movements for overseas service, they were not systematically employed by any belligerent navy until 1916. The Royal Navy was the major user and developer of the modern convoy system, and regular transoceanic convoying began in June 1917. They made heavy use of aircraft for escorts, especially in coastal waters, an obvious departure from the convoy practices of the Age of Sail.
At the beginning of World War II, the Royal Navy was the strongest navy in the world, with the largest number of warships built and with naval bases across the globe. It had over 15 battleships and battlecruisers, 7 aircraft carriers, 66 cruisers, 164 destroyers and 66 submarines. With a massive merchant navy, about a third of the world total, it also dominated shipping. The Royal Navy fought in every theatre from the Atlantic, Mediterranean, freezing Northern routes to Russia and the Pacific ocean.
The German commerce raiders of World War I were surface vessels used by the Imperial German Navy for its Handelskrieg, a campaign against Allied seaborne trade. The ships comprised warships, principally cruisers, stationed in the German colonial empire before the war began, express liners commissioned as auxiliary cruisers and later, freighters outfitted as merchant raiders. These vessels had a number of successes and had a significant effect on Allied naval strategy, particularly in the early months of the war.
