Japanese destroyer Akizuki (1941)

A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use high explosive charges and a fuze set to detonate the charge, typically at a specific depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters.

Length overall is the maximum length of a vessel's hull measured parallel to the waterline. This length is important while docking the ship. It is the most commonly used way of expressing the size of a ship, and is also used for calculating the cost of a marina berth.

The beam of a ship is its width at its widest point. The maximum beam (BMAX) is the distance between planes passing through the outer extremities of the ship, beam of the hull (BH) only includes permanently fixed parts of the hull, and beam at waterline (BWL) is the maximum width where the hull intersects the surface of the water.

A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turbine involves advanced metalwork to form high-grade steel alloys into precision parts using technologies that first became available in the 20th century; continued advances in durability and efficiency of steam turbines remains central to the energy economics of the 21st century.

The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.

Fuel oil is any of various fractions obtained from the distillation of petroleum. Such oils include distillates and residues. Fuel oils include heavy fuel oil, marine fuel oil (MFO), bunker fuel, furnace oil (FO), gas oil (gasoil), heating oils, diesel fuel and others.

The 10 cm/65 Type 98 naval gun (六五口径九八式一〇糎高角砲), also known as the long 10cm high-angle gun (長10センチ高角砲), was a light caliber naval gun of the Imperial Japanese Navy used during World War II, employed on the aircraft carrier Taihō, the light cruiser Ōyodo, and Akizuki-class destroyers. The gun was considered by the Japanese to be their finest anti-aircraft artillery weapon. After the end of World War II, the gun remained in service on the two Japanese destroyers ceded to the Soviet Union and the Republic of China as war reparations.

A gun turret is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in some degree of azimuth and elevation.

Superfiring armament is a naval military building technique in which two turrets are located in a line, one behind the other, with the second turret located above ("super") the one in front so that the second turret can fire over the first. This configuration meant that both forward or aft turrets could fire at any target within their sector, even when the target was in the same vertical plane as the turrets.

A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships.

The naval Battle of the Eastern Solomons took place on 24–25 August 1942 and was the third carrier battle of the Pacific campaign of World War II and the second major engagement fought between the United States Navy and the Imperial Japanese Navy (IJN) during the Guadalcanal campaign. As at the Battle of the Coral Sea and the Battle of Midway, the ships of the two adversaries were never within sight of each other. Instead, all attacks were carried out by carrier-based or land-based aircraft.

Akashi was a Japanese repair ship, serving during World War II. She was the only specifically designed repair ship operated by the Imperial Japanese Navy. The navy based her design on the US Navy's USS Medusa.

Shimotsuki (霜月) was an Akizuki-class destroyer of the Imperial Japanese Navy. Her name means "November".

The Battle of the Philippine Sea was a major naval battle of World War II that eliminated the Imperial Japanese Navy's ability to conduct large-scale carrier actions. It took place during the United States' amphibious invasion of the Mariana Islands during the Pacific War. The battle was the last of five major "carrier-versus-carrier" engagements between American and Japanese naval forces, and pitted elements of the United States Navy's Fifth Fleet against ships and aircraft of the Imperial Japanese Navy's Mobile Fleet and nearby island garrisons. This was the largest carrier-to-carrier battle in history, involving 24 aircraft carriers, deploying roughly 1,350 carrier-based aircraft.

Zuikaku was the second and last Shōkaku-class aircraft carrier built for the Imperial Japanese Navy (IJN) shortly before the beginning of the Pacific War. Her aircraft took part in the attack on Pearl Harbor that formally brought the United States into the war, and she fought in several of the most important naval battles of the war, before being sunk during the Battle of Leyte Gulf.

The Battle of Leyte Gulf was the largest naval battle of World War II and by some criteria the largest naval battle in history, with over 200,000 naval personnel involved. It was fought in waters near the Philippine islands of Leyte, Samar, and Luzon from 23 to 26 October 1944 between combined American and Australian forces and the Imperial Japanese Navy (IJN), as part of the invasion of Leyte, which aimed to isolate Japan from the colonies that it had occupied in Southeast Asia, a vital source of industrial and oil supplies.

The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during the Second World War (1939–1945) to oppose the Axis powers, led by Nazi Germany, Imperial Japan, and Fascist Italy. Its principal members by the end of 1941 were the United Kingdom, United States, Soviet Union, and China.

The Battle of Leyte in the Pacific campaign of World War II was the amphibious invasion of the island of Leyte in the Philippines by American forces and Filipino guerrillas under the overall command of General Douglas MacArthur, who fought against the Imperial Japanese Army in the Philippines led by General Tomoyuki Yamashita. The operation, codenamed King Two, launched the Philippines campaign of 1944–45 for the recapture and liberation of the entire Philippine Archipelago and to end almost three years of Japanese occupation.

Cape Engaño is a cape and northern point of Palaui Island, an island off the northeasternmost point of the island of Luzon in the Philippines. It is administratively part of the municipality of Santa Ana in Cagayan province and is known for its lush green landscape, white sand beach and the Cape Engaño Lighthouse.

The geographic coordinate system (GCS) is a spherical or ellipsoidal coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface.

USS Halibut (SS-232), a Gato-class submarine, was the first ship of the United States Navy to be named for the halibut, a large species of flatfish.