German submarine U-993

Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship.

Hamburg, officially the Free and Hanseatic City of Hamburg, is the second-largest city in Germany after Berlin, as well as the overall 7th largest city and largest non-capital city in the European Union with a population of over 1.85 million. Hamburg is 941 km2 in area. Hamburg's urban area has a population of around 2.5 million and is part of the Hamburg Metropolitan Region, which has a population of over 5.1 million people in total. The city lies on the River Elbe and two of its tributaries, the River Alster and the River Bille. One of Germany's 16 federated states, Hamburg is surrounded by Schleswig-Holstein to the north and Lower Saxony to the south.

Ceremonial ship launching involves the performance of ceremonies associated with the process of transferring a vessel to the water. It is a nautical tradition in many cultures, dating back thousands of years, to accompany the physical process with ceremonies which have been observed as public celebration and a solemn blessing, usually but not always, in association with the launch itself.

Clover or trefoil are common names for plants of the genus Trifolium, consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with highest diversity in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics. They are small annual, biennial, or short-lived perennial herbaceous plants, typically growing up to 30 cm tall. The leaves are trifoliate, monofoil, bifoil, cinquefoil, hexafoil, septfoil, etcetera, with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx. Other closely related genera often called clovers include Melilotus and Medicago.

The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.

Brown, Boveri & Cie. was a Swiss group of electrical engineering companies. It was founded in Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1970 BBC took over the Maschinenfabrik Oerlikon. In 1988 it merged with ASEA to form ABB.

A motor–generator is a device for converting electrical power to another form. Motor–generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line. Large motor–generators were widely used to convert industrial amounts of power while smaller motor–generators were used to convert battery power to higher DC voltages.

A propeller is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft with an approximately horizontal axis.

The 8.8 cm SK L/45 was a German naval gun that was used in World War I and World War II on a variety of mounts.

The 5th U-boat Flotilla, also known as Emsmann Flotilla, was a U-boat flotilla of Nazi Germany's Kriegsmarine during World War II.

The 3rd U-boat Flotilla, also known as Lohs Flotilla, was the third operational U-boat unit in Nazi Germany's Kriegsmarine. Founded on 4 October 1937 under the command of Kapitänleutnant Hans Eckermann, it was named in honour of Oberleutnant zur See Johannes Lohs. Lohs, a U-boat commander during World War I, died on 14 August 1918 after his submarine UB-57 was sunk by a mine.

Marviken is a lake in Södermanland, Sweden.

Cape Finisterre is a rock-bound peninsula on the west coast of Galicia, Spain.

Lorient is a town (commune) and seaport in the Morbihan department of Brittany in western France.

Brest is a port city in the Finistère department, Brittany. Located in a sheltered bay not far from the western tip of the peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon. The city is located on the western edge of continental France. With 142,722 inhabitants in a 2007 census, Brest forms Western Brittany's largest metropolitan area, ranking third behind only Nantes and Rennes in the whole of historic Brittany, and the 19th most populous city in France; moreover, Brest provides services to the one million inhabitants of Western Brittany. Although Brest is by far the largest city in Finistère, the préfecture of the department is the much smaller Quimper.

The Faroe Islands, or simply the Faroes, are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark.

Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme metabolism, liver dysfunction, or biliary-tract obstruction. The prevalence of jaundice in adults is rare, while jaundice in babies is common, with an estimated 80% affected during their first week of life. The most commonly associated symptoms of jaundice are itchiness, pale feces, and dark urine.

Bergen, historically Bjørgvin, is a city and municipality in Vestland county on the west coast of Norway. As of 2021, its population is roughly 285,900. Bergen is the second-largest city in Norway. The municipality covers 465 square kilometres (180 sq mi) and is on the peninsula of Bergenshalvøyen. The city centre and northern neighbourhoods are on Byfjorden, 'the city fjord', and the city is surrounded by mountains; Bergen is known as the "city of seven mountains". Many of the extra-municipal suburbs are on islands. Bergen is the administrative centre of Vestland county. The city consists of eight boroughs: Arna, Bergenhus, Fana, Fyllingsdalen, Laksevåg, Ytrebygda, Årstad, and Åsane.

Bergen, historically Bjørgvin, is a city and municipality in Vestland county on the west coast of Norway. As of 2021, its population is roughly 285,900. Bergen is the second-largest city in Norway. The municipality covers 465 square kilometres (180 sq mi) and is on the peninsula of Bergenshalvøyen. The city centre and northern neighbourhoods are on Byfjorden, 'the city fjord', and the city is surrounded by mountains; Bergen is known as the "city of seven mountains". Many of the extra-municipal suburbs are on islands. Bergen is the administrative centre of Vestland county. The city consists of eight boroughs: Arna, Bergenhus, Fana, Fyllingsdalen, Laksevåg, Ytrebygda, Årstad, and Åsane.