A propeller is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral, that when rotated performs an action which is similar to Archimedes' screw. It transforms rotational power into linear thrust by acting upon a working fluid such as water or air. The rotational motion of the blades is converted into thrust by creating a pressure difference between the two surfaces. A given mass of working fluid is accelerated in one direction and the craft moves in the opposite direction. Propeller dynamics, like those of aircraft wings, can be modelled by Bernoulli's principle and Newton's third law. Most marine propellers are screw propellers with helical blades rotating around an approximately horizontal axis or propeller shaft.
A ship of the line was a type of naval warship constructed from the 17th century to the mid-19th century. The ship of the line was designed for the naval tactic known as the line of battle, which depended on the two columns of opposing warships maneuvering to fire with the cannons along their broadsides. In conflicts where opposing ships were both able to fire from their broadsides, the opponent with more cannons—and therefore more firepower—typically had an advantage. Since these engagements were almost invariably won by the heaviest ships carrying the most powerful guns, the natural progression was to build sailing vessels that were the largest and most powerful of their time.
A tugboat or tug is a type of vessel that maneuvers other vessels by pushing or pulling them either by direct contact or by means of a tow line. Tugs typically move vessels that either are restricted in their ability to maneuver on their own, such as ships in a crowded harbor or a narrow canal, or those that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms. Tugboats are powerful for their size and strongly built, and some are ocean-going. Some tugboats serve as icebreakers or salvage boats. Early tugboats had steam engines, but today most have diesel engines. Many tugboats have firefighting monitors, allowing them to assist in firefighting, especially in harbors.
The Second Battle of Copenhagen was a British bombardment of the Danish capital, Copenhagen in order to capture or destroy the Dano-Norwegian fleet, during the Napoleonic Wars. The incident led to the outbreak of the Anglo-Russian War of 1807, which ended with the Treaty of Örebro in 1812.
The action of 16 May 1797 was a naval battle that took place near Tripoli in Ottoman Tripolitania. The Danish squadron was victorious over a Tripolitan squadron that outnumbered them in terms of the number of vessels. The result was a peace treaty between the Bey of Tripoli and Denmark.
ICGV Týr is an Ægir-class offshore patrol vessel and the flagship of the Icelandic Coast Guard. The ship was built by Dannebrog Værft in Denmark in 1974–1975 and entered service in 1975. Týr is the second largest ship in the Icelandic Coast Guard and participated in the Third Cod War. The ship conducts patrols, search and rescue, fishery inspections, general law enforcement and counter-terrorism operations in the Icelandic exclusive economic zone and the waters of the surrounding territories, such as Greenland and Jan Mayen.
ICGV Ægir is an offshore patrol vessel of the Icelandic Coast Guard built by Aalborg Værft, in Denmark. She is the lead ship of the Ægir class and has one sister ship of an improved design, ICGV Týr. The ship entered service in 1968 and participated in the two last Cod Wars against the United Kingdom. Ægir primarily conducts patrols, search and rescue, fishery inspections, general law enforcement and counter-terrorism operations in the Icelandic exclusive economic zone.
The Landing Craft Infantry (LCI) were several classes of seagoing amphibious assault ships of the Second World War used to land large numbers of infantry directly onto beaches. They were developed in response to a British request for a vessel capable of carrying and landing substantially more troops than their smaller Landing Craft Assault (LCA). The result was a small steel ship that could land 200 men, traveling from rear bases on its own bottom at a speed of up to 15 knots.
The Action of 3 June 2007 occurred after a United States Navy dock landing ship attacked pirates hijacking a freighter.
The Dano-Swedish War of 1658–1660 was a war between Denmark–Norway and Sweden. It was a continuation of an earlier conflict between the two belligerents which had ended just months earlier, after Sweden and Denmark brokered a peace agreement in Roskilde in 1658. In the aftermath of that conflict, the Swedish king Charles X Gustav desired to add the province of Royal Prussia in Poland to the Swedish realm, but his position in the region was not strong enough with the opposition of Brandenburg and Austria. However, the Danes stalled and prolonged the fulfillment of some provisions of the earlier peace; the Swedish king decided to use this as a pretext to attack with an ambitious goal: to vanquish Denmark as a sovereign state and raze the capital of Copenhagen. A quick and decisive defeat of Denmark was however only seen as a means to a greater end. The long-term goal was to wage war in Europe without fearing Danish interference.
The Ægir-class offshore patrol vessel is a class of two offshore patrol vessels serving in the Icelandic Coast Guard (ICG). They participated in the two latter Cod Wars. The vessels conduct patrols, search and rescue, fishery inspections, general law enforcement and counter-terrorism operations in the Icelandic exclusive economic zone and the waters of the surrounding territories, such as Greenland and Jan Mayen.
French weapons in the American Civil War had a key role in the conflict and encompassed most of the sectors of weaponry of the American Civil War (1861–1865), from artillery to firearms, submarines and ironclad warships. The effect of French weapons was especially significant in field artillery and infantry. These weapons were either American productions based on French designs, or sometimes directly imported from France.
The Kawasaki Ki-88 was a proposed Japanese World War II fighter aircraft intended for use by the Imperial Japanese Army Air Force. Its anticipated performance was disappointing, and only a mock-up was completed.
SMS Cyclop was a Camäleon-class gunboat of the Prussian Navy that was launched in 1860. A small vessel, armed with only three light guns, Cyclop served during the three wars of German unification; during the first, the Second Schleswig War on 1864, she guarded the Prussian coastline but saw no action. She supported the army's campaign against the Kingdom of Hanover during the Austro-Prussian War of 1866, and she defended the Elbe for the duration of the Franco-Prussian War of 1870–1871, but again took part in no battles. Badly deteriorated by 1872, she was stricken from the naval register in March that year and broken up for scrap.
The Lindormen class is a class of minelayers built for the Danish Navy. The Lindormen class is currently in service with the Estonian Navy.
HDMS Diana was a frigate of the Royal Danish Navy. She was seized by Spain on 26 September 1809.
Underwater work is work done underwater, generally by divers during diving operations, but includes work done underwater by remotely operated vehicles and manned submersibles.
HDMS Hauch was a Danish gunboat, launched in 1862 and under command the following year. It was named after the naval officer Jens Erik Hauch, who died during the Battle of Copenhagen, while bravely defending the decommissioned frigate Kronborg against three Royal Navy ships of the line. Hauch can be viewed as a scaled-down version of the preceding six gunboats of the Thura class. Hauch was built entirely in iron and the smaller size meant that it could only accommodate a single cannon. The 30 lb smoothbore cannon was not very accurate and was replaced by a smaller, but rifled 18 lb cannon in 1864. Towards the end of her career the armament consisted of two small smoothbore cannons (falconets), used for warning shots during fisheries inspection duties. The steam engine was reused from the scrapped gunboat Støren. This engine lasted until 1886, when it was replaced by a new Burmeister & Wain 200 HP steam engine.
Frantz Christopher Henrik Hohlenberg was a Danish naval officer who specialised in ship design and had little seagoing experience.
HDMS Ingolf was a Danish schooner-rigged steam gunboat build in iron and launched in 1876. Ingolf marks a transition between the traditional gunships with muzzle-loading cannons placed along the sides of the ship and modern breechloading and turning guns placed in the centerline of the ship. The guns on Ingolf were breechloading guns from Krupp in Germany. The steam engine was British and could deliver 650 HP. The propeller could be hoisted up into a well on the underside of the ship, so as not to slow down the ship when she went for sails. Ingolf undertook a large number of voyages, often in the North Atlantic in summer and the Danish West Indies in winter. From 1897 Ingolf also served as training ship for non-commissioned officers and cadets. During World War I Ingolf was part of the Danish alerted fleet. The last voyage as a training ship was in 1922 and went to the Mediterranean. Decommissioned in 1926 and sold for scrap.
