HMS Peterhead (J59)

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 displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into weight. Traditionally, various measurement rules have been in use, giving various measures in long tons. Today, tonnes are more commonly used.

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.

The draft or draught of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel). The draught of the vessel is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if deployed. Draft determines the minimum depth of water a ship or boat can safely navigate. The related term air draft is the maximum height of any part of the vessel above the water.

In a navy, a rate, rating or bluejacket is a junior enlisted sailor who is not a warrant officer or commissioned officer. Depending on the country and navy that uses it, the exact term and the range of ranks that it refers to may vary.

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 2-pounder gun, officially the QF 2-pounder and universally known as the pom-pom, was a 40 mm (1.6 in) British autocannon, used as an anti-aircraft gun by the Royal Navy. The name came from the sound that the original models make when firing. This QF 2-pounder was not the same gun as the Ordnance QF 2-pounder, used by the British Army as an anti-tank gun and a tank gun, although they both fired 2 lb (0.91 kg), 40 mm (1.6 in) projectiles.

The Oerlikon 20 mm cannon is a series of autocannons, based on an original German Becker Type M2 20 mm cannon design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II. Many versions of the cannon are still used today.

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.

The Bay of Biscay, known in Spain as the Gulf of Biscay, and in France and some border regions as the Gulf of Gascony, is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and the northern coast of Spain west to Cape Ortegal. The south area of the Bay of Biscay that washes over the northern coast of Spain is known locally as the Cantabrian Sea.

The Blyth Shipbuilding & Dry Docks Company Ltd. was a British shipyard located in Blyth, Northumberland, England.

Blyth is a town and civil parish in southeast Northumberland, England. It lies on the coast, to the south of the River Blyth and is approximately 13 miles (21 km) northeast of Newcastle upon Tyne. It had a population of 37,339 in the 2011 Census.

Northumberland is a county in North East England, one of two counties in England which border with Scotland. Notable landmarks in the county include Alnwick Castle, Bamburgh Castle, Hadrian's Wall and Hexham Abbey.

Scotland is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a 96-mile (154-kilometre) border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the north and west, the North Sea to the northeast and east, and the Irish Sea to the south. It also contains more than 790 islands, principally in the archipelagos of the Hebrides and the Northern Isles. Most of the population, including the capital Edinburgh, is concentrated in the Central Belt—the plain between the Scottish Highlands and the Southern Uplands—in the Scottish Lowlands.

Peterhead is a town in Aberdeenshire, Scotland. It is Aberdeenshire's biggest settlement, with a population of 18,537 at the 2011 Census. It is the biggest fishing port in the United Kingdom for total landings by UK vessels, according to a 2019 survey.

Utah, commonly known as Utah Beach, was the code name for one of the five sectors of the Allied invasion of German-occupied France in the Normandy landings on June 6, 1944 (D-Day), during World War II. The westernmost of the five code-named landing beaches in Normandy, Utah is on the Cotentin Peninsula, west of the mouths of the Douve and Vire rivers. Amphibious landings at Utah were undertaken by United States Army troops, with sea transport, mine sweeping, and a naval bombardment force provided by the United States Navy and Coast Guard as well as elements from the British, Dutch and other Allied navies.

The Distinguished Service Cross (DSC) is a third-level military decoration awarded to officers; and, since 1993, ratings and other ranks of the British Armed Forces, Royal Fleet Auxiliary and the British Merchant Navy have been included. Additionally, the award was formerly awarded to members of other Commonwealth countries.

Pembroke Dock is a town and a community in Pembrokeshire, South West Wales, 3 miles (4.8 km) northwest of Pembroke on the banks of the River Cleddau. Originally Paterchurch, a small fishing village, Pembroke Dock town expanded rapidly following the construction of the Royal Navy Dockyard in 1814. The Cleddau Bridge links Pembroke Dock with Neyland.