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HMS President (1918)
HMS ''President'' (formerly HMS ''Saxifrage'') is a retired Flower-class Q-ship that was launched in 1918. She was renamed HMS ''President'' in 1922 and moored permanently on the Thames as a Royal Navy Reserve drill ship. In 1982 she was sold to private owners and, having changed hands twice, served as a venue for conferences and functions as well as the offices for a number of media companies. She has been moved to Chatham on the Medway in Kent since 2016, but is due to return to the capital. She had the suffix "(1918)" added to her name in order to distinguish her from HMS ''President'', the Royal Naval Reserve base in St Katharine Docks. She is one of the last three surviving Royal Navy warships of the First World War.The other two are in Belfast, and the 1915 monitor in Portsmouth dockyard She is also the sole representative of the first type of purpose built anti-submarine vessels, and is the ancestor of World War II convoy escort sloops, which evolved into modern anti-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
20040918-027-thames-ship
4 (four) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is tetraphobia, considered unlucky in many East Asian cultures. In mathematics Four is the smallest composite number, its proper divisors being and . Four is the sum and product of two with itself: 2 + 2 = 4 = 2 x 2, the only number b such that a + a = b = a x a, which also makes four the smallest squared prime number p^. In Knuth's up-arrow notation, , and so forth, for any number of up arrows. By consequence, four is the only square one more than a prime number, specifically 3, three. The sum of the first four prime numbers 2, two + 3, three + 5, five + 7, seven is the only sum of four consecutive prime numbers that yields an Parity (mathematics), odd prime number, 17 (number), seventeen, which is the fourth super-prime. Four lies between the first proper pair of twin primes, 3, three and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service. From the middle decades of the 17th century, and through the 18th century, the Royal Navy vied with the Dutch Navy and later with the French Navy for maritime supremacy. From the mid 18th century, it was the world's most powerful navy until the Second World War. The Royal Navy played a key part in establishing and defending the British Empire, and four Imperial fortress colonies and a string of imperial bases and coaling stations secured the Royal Navy's ability to assert naval superiority globally. Owing to this historical prominence, it is common, even among non-Britons, to ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanced Rudder
Balanced rudders are used by both ships and aircraft. Both may indicate a portion of the rudder surface ahead of the hinge, placed to lower the control loads needed to turn the rudder. For aircraft the method can also be applied to elevators and ailerons; all three aircraft control surfaces may also be mass balanced, chiefly to avoid aerodynamic flutter. Ships A balanced rudder is a rudder in which the axis of rotation of the rudder is behind its front edge. This means that when the rudder is turned, the pressure of water caused by the ship's movement through the water acts upon the forward part to exert a force which increases the angle of deflection, so counteracting the pressure acting on the after part, which acts to reduce the angle of deflection. A degree of semi-balance is normal to avoid rudder instability i.e. the area in front of the pivot is less than that behind. This allows the rudder to be moved with less effort than is necessary with an unbalanced rudder. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rudder
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the hull (watercraft), hull or fuselage, thus imparting a turning or yaw (rotation), yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern, tail, or after end. Often rudders are shaped so as to minimize Drag (physics), hydrodynamic or aerodynamic drag. On simple watercraft, a tiller—essentially, a stick or pole acting as a lever arm—may be attached to the top of the rudder to allow it to be turned by a helmsman. In larger vessels, cables, pushrods, or hydraulics may be used to link rudders to steering wheels. In typical air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unrestricted Submarine Warfare
Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchant ships such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules") that call for warships to search merchantmen and place crews in "a place of safety" (for which lifeboats do not qualify, except under particular circumstances) before sinking them, unless the ship shows "persistent refusal to stop ... or active resistance to visit or search". To follow the rules a submarine must surface, defeating the purpose of submarines and putting itself in danger of attack. History Limitations on warfare at sea date back to the 1899 Hague Convention. During the First World War, the United Kingdom introduced Q-ships with concealed deck guns and many armed merchantmen, leading Germany to ignore the prize rules. In the most dramatic episode they sank in 1915 in a few minutes because she was carrying war munitions. The U.S. demanded it stop, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-boat
U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role (commerce raiding) and enforcing a naval blockade against enemy shipping. The primary targets of the U-boat campaigns in both wars were the merchant convoys bringing supplies from Canada and other parts of the British Empire, and from the United States, to the United Kingdom and (during the Second World War) to the Soviet Union and the Allied territories in the Mediterranean. German submarines also destroyed Brazilian merchant ships during World War II, causing Brazil to declare war on both Germany and Italy on 22 August 1942. The term is an anglicised version of the German word ''U-Boot'' , a shortening of ''Unterseeboot'' ('under-sea-boat'), though the German term refers to any submarine. Austro-Hungarian Navy submarines were also kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QF 12 Pounder 12 Cwt Naval Gun
The QF 12-pounder 12-cwt gun (abbreviated as Q.F. 12-pdr. (12-cwt.)Gun drill for Q.F. 12-pdr. (12-cwt.) gun (Land service) 1925 the War Office, 1925) was a common, versatile caliber, calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick Ordnance Company, Elswick and used on Royal Navy warships, exported to allied countries, and used for land service. In British service "12-pounder" was the rounded value of the projectile weight, and "12 cwt (hundredweight)" was the weight of the barrel and breech, to differentiate it from other "12-pounder" guns. As the Type 41 3-inch (7.62 cm)/40 it was used on most early battleships and cruisers of the Imperial Japanese Navy, though it was commonly referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QF 4-inch Mk V Naval Gun
The QF 4 inch Mk V gunMk V = Mark 5. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. Mark V indicates this was the fifth model of QF 4-inch gun. was a Royal Navy gun of World War I which was adapted on HA (i.e. high-angle) mountings to the heavy anti-aircraft role both at sea and on land, and was also used as a coast defence gun. Service Naval service This QF gun was introduced to provide a higher rate of fire than the BL 4 inch Mk VII. It first appeared in 1914 as secondary armament on s, was soon adapted to a high-angle anti-aircraft role. It was typically used on cruisers and heavier ships, although s of 1917 also mounted the gun. Mk V was superseded by the QF 4 inch Mk XVI as the HA (i.e. anti-aircraft) gun on new warships in the 1930s, but it continued to serve on many ships such as destroyers, light and heavy cruisers in World War II. Army anti-aircraft gun Early in World War I several guns were supplied by the Navy for e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchusa-class Sloop
The twenty-eight ''Anchusa''-class sloops were built under the Emergency War Programme for the Royal Navy in World War I as the final part of the larger "Flower class", which were also referred to as the "Cabbage class", or "Herbaceous Borders". They were single screw fleet sweeping vessels (sloops) with triple hulls at the bow to give extra protection against loss when working. The ''Anchusa'' class of corvettes or convoy sloops were completed in 1917 and 1918. They were a small class of convoy protection ships built to look like merchant ships for use as Q-ships in World War I. Two members of the ''Anchusa'' group, and (renamed in 1922), survived to be moored on the River Thames for use as Drill Ships by the RNVR until 1988, a total of seventy years in RN service. was sold and preserved, and is now one of the last three surviving warships of the Royal Navy built during the First World War, (along with the 1914 Light cruiser in Belfast, and the 1915 Monitor in Por ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frigates
A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and maneuverability, intended to be used in scouting, escort and patrol roles. The term was applied loosely to ships varying greatly in design. In the second quarter of the 18th century, the 'true frigate' was developed in France. This type of vessel was characterised by possessing only one armed deck, with an unarmed deck below it used for berthing the crew. Late in the 19th century (British and French prototypes were constructed in 1858), armoured frigates were developed as powerful ironclad warships, the term frigate was used because of their single gun deck. Later developments in ironclad ships rendered the frigate designation obsolete and the term fell out of favour. During the Second World War the name 'frigate' was reintroduced to des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convoy
A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used in a non-military sense, for example when driving through remote areas. Naval convoys Age of Sail Naval convoys have been in use for centuries, with examples of merchant ships traveling under naval protection dating to the 12th century. The use of organized naval convoys dates from when ships began to be separated into specialist classes and national navies were established. By the French Revolutionary Wars of the late 18th century, effective naval convoy tactics had been developed to ward off pirates and privateers. Some convoys contained several hundred merchant ships. The most enduring system of convoys were the Spanish treasure fleets, that sailed from the 1520s until 1790. When merchant ships sailed independently, a privateer cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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