Torpedo boat in the context of "Dogger Bank incident"

A PT boat (short for patrol torpedo boat) is a motor torpedo boat used by the United States Navy in World War II. These vessels were small, fast, and inexpensive to build, and were valued for their maneuverability and speed. However, PT boats were hampered at the beginning of the war by ineffective torpedoes, limited armament, and comparatively fragile construction that limited some of the variants to coastal waters. In the US Navy they were organized in Motor Torpedo Boat Squadrons (MTBRONs).

PT boats were very different from the first generation of torpedo boats, which had been developed at the end of the 19th century and featured a displacement hull form. These first generation torpedo boats rode low in the water, displaced up to 300 tons, and had a top speed of 25 to 27 kn (46 to 50 km/h). During World War I Italy, the US, and UK developed the first high-performance, gasoline-powered motor torpedo boats (often with top speeds over 40 kn (74 km/h)) and corresponding torpedo tactics, but these projects were all quickly disbanded after the Armistice. Design of World War II PT boats continued to exploit some of the advances in planing hull design borrowed from offshore powerboat racing and used multiple lightweight but more powerful marinized aircraft-derived V-12 engines, and thus were able to advance in both size and speed.

In naval terminology, a destroyer is a fast, maneuverable, long-endurance warship intended to escortlarger vessels in a fleet, convoy, or carrier battle group and defend them against a wide range of general threats. They were conceived in the late 19th century 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.

Before World War II, destroyers were light vessels with little endurance for unattended ocean operations; typically, a number of destroyers and a single destroyer tender operated together. After the war, destroyers grew in size. The American Allen M. Sumner-class destroyers had a displacement of 2,200 tons, while the Arleigh Burke class has a displacement of up to 9,600 tons, a difference of nearly 340%. Moreover, the advent of guided missiles allowed destroyers to take on the surface-combatant roles previously filled by battleships and cruisers. This resulted in larger and more powerful guided missile destroyers more capable of independent operation.

The Battle of Tsushima (Russian: Цусимское сражение, Tsusimskoye srazheniye, Japanese: 日本海海戦, Nihonkai kaisen) was the final naval battle of the Russo-Japanese War, fought on 27–28 May 1905 in the Tsushima Strait. A devastating defeat for the Imperial Russian Navy, the battle was the only decisive engagement ever fought between modern steel battleship fleets and the first in which wireless telegraphy (radio) played a critically important role. The battle was described by contemporary Sir George Clarke as "by far the greatest and the most important naval event since Trafalgar". The battle is also known in Japan as the Battle of the Sea of Japan.

The battle involved the Japanese Combined Fleet under Admiral Tōgō Heihachirō and the Russian Second Pacific Squadron under Admiral Zinovy Rozhestvensky, which had sailed over seven months and 18,000 nautical miles (33,000 km) from the Baltic Sea. The Russians hoped to reach Vladivostok and establish naval control of the Far East in order to relieve the Imperial Russian Army in Manchuria. The Russian fleet had a large advantage in the number of battleships, but was overall older and slower than the Japanese fleet, and outnumbered nearly three to one in total hulls. The Russians were sighted in the early morning on 27 May, and the battle began in the afternoon. Rozhestvensky was wounded and knocked unconscious in the initial action, and four of his battleships were sunk by sunset. At night, Japanese destroyers and torpedo boats attacked the remaining ships, and Admiral Nikolai Nebogatov surrendered in the morning of 28 May.

A motor torpedo boat is a fast torpedo boat, especially of the mid 20th century. The motor in the designation originally referred to their use of petrol engines, typically marinised aircraft engines or their derivatives, which distinguished them from other naval craft of the era, including other torpedo boats, that used steam turbines or reciprocating steam engines. Later, diesel-powered torpedo boats appeared, in turn or retroactively referred to as "motor torpedo boats" for their internal combustion engines, as distinct from steam powered reciprocating or turbine propulsion.

Though other navies built similar petrol-powered craft, the specific designation "motor torpedo boat", abbreviated to "MTB", is generally used for craft of the Royal Navy (RN) and Royal Canadian Navy boats.

Arctic naval operations of World War II were the World War II naval operations that took place in the Arctic Ocean, and can be considered part of the Battle of the Atlantic and/or of the European Theatre of World War II.

Pre-war navigation in the region 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. The Winter War of 1939-1940 between Finland and the Soviet Union opened the northern flank of the Eastern Front of World War II. The Arctic was initially dominated by the Soviet Northern Fleet of a few destroyers, with larger numbers of submarines, minesweepers, and torpedo cutters supported by icebreakers. The success of the 1940 German invasion of Norway provided the Kriegsmarine with naval bases from which capital ships might challenge units of the British Royal Navy Home Fleet. Luftwaffe anti-shipping aircraft of Kampfgeschwader 26 (KG 26) and Kampfgeschwader 30 (KG 30) operated intermittently from Norwegian airfields, while Küstenfliegergruppen aircraft including Heinkel He 115s and Blohm & Voss BV 138s undertook routine reconnaissance. Following the 1941 Axis invasion of the Soviet Union, the Allies initiated a series of Arctic convoys to bring military supplies to the Soviet Union in formations of freighters screened by destroyers, corvettes and minesweepers. Escorting cruisers typically maneuvered outside the formations, while a larger covering force including battleships and aircraft carriers often steamed nearby to engage Kriegsmarine capital ships or to raid the German naval bases in Norway.