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Azalea-class Sloop
The ''Azalea'' class of twelve minesweeping sloops were built under the Emergency War Programme for the Royal Navy in World War I as part of the larger , which were also referred to as the Cabbage class, or "Herbaceous Borders". The third batch of twelve ships to be ordered in May 1915, they differed from the preceding only in mounting a heavier armament. One ship, converted to a Q-ship was lost during the war, another during the Allied intervention in the Russian Civil War in 1919. With the exception of two others, the rest were scrapped. One entered mercantile service, while the other was transferred to the Belgian Navy. Both were captured by the Germans during World War II and put into German service. One was lost with the final ship being scrapped in 1952 Design and description The ''Azalea''s were a series of twelve minesweeping sloops that were designed to operate as minesweepers with the fleet at the beginning of World War I. A shortage of this type required the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloop-of-war
In the 18th century and most of the 19th, a sloop-of-war in the Royal Navy was a warship with a single gun deck that carried up to eighteen guns. The rating system covered all vessels with 20 guns and above; thus, the term ''sloop-of-war'' encompassed all the unrated combat vessels, including the very small gun-brigs and cutters. In technical terms, even the more specialised bomb vessels and fireships were classed as sloops-of-war, and in practice these were employed in the sloop role when not carrying out their specialised functions. In World War I and World War II, the Royal Navy reused the term "sloop" for specialised convoy-defence vessels, including the of World War I and the highly successful of World War II, with anti-aircraft and anti-submarine capability. They performed similar duties to the American destroyer escort class ships, and also performed similar duties to the smaller corvettes of the Royal Navy. Rigging A sloop-of-war was quite different from a civilian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sheer (ship)
The sheer is a measure of longitudinal main deck curvature, in naval architecture. The sheer forward is usually twice that of sheer aft. Increases in the rise of the sheer forward and aft build volume into the hull, and in turn increase its buoyancy forward and aft, thereby keeping the ends from diving into an oncoming wave and slowing the ship. In the early days of sail, one discussed a hull's sheer in terms of how much "hang" it had. William Sutherland's ''The Ship-builders Assistant'' (1711) covers this information in more detail. The practice of building sheer into a ship dates back to the era of small sailing ships. These vessels were built with the decks curving upwards at the bow and stern in order to increase stability by preventing the ship from pitching up and down. Sheer on exposed decks also makes a ship more seaworthy by raising the deck at fore and aft ends further from the water and by reducing the volume of water coming on deck. See also *Camber (ship) The camb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Displacement (ship)
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. Ship displacement varies by a vessel's degree of load, from its empty weight as designed (known as "lightweight tonnage") to its maximum load. Numerous specific terms are used to describe varying levels of load and trim, detailed below. Ship displacement should not be confused with measurements of volume or capacity typically used for commercial vessels and measured by tonnage: net tonnage and gross tonnage. Calculation The process of determining a vessel's displacement begins with measuring its draft.George, 2005. p.5. This is accomplished by means of its "draft marks" (or "load lines"). A mer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (hull)
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. The more heavily a vessel is loaded, the deeper it sinks into the water, and the greater its draft. After construction, the shipyard creates a table showing how much water the vessel displaces based on its draft and the density of the water (salt or fresh). The draft can also be used to determine the weight of cargo on board by calculating the total displacement of water, accounting for the content of the ship's bunkers, and using Archimedes' principle. The closely related term "trim" is defined as the difference between the forward and aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam (nautical)
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. Generally speaking, the wider the beam of a ship (or boat), the more initial stability it has, at the expense of secondary stability in the event of a capsize, where more energy is required to right the vessel from its inverted position. A ship that heels on her ''beam ends'' has her deck beams nearly vertical. Typical values Typical length-to-beam ratios ( aspect ratios) for small sailboats are from 2:1 (dinghies to trailerable sailboats around ) to 5:1 (racing sailboats over ). Large ships have widely varying beam ratios, some as large as 20:1. Rowing shells designed for flatwater racing may have length to beam ratios as high as 30:1, while a cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Overall
__NOTOC__ Length overall (LOA, o/a, o.a. or oa) 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 (for example, £2.50 per metre LOA). LOA is usually measured on the hull alone. For sailing ships, this may ''exclude'' the bowsprit and other fittings added to the hull. This is how some racing boats and tall ships use the term LOA. However, other sources may include bowsprits in LOA. Confusingly, LOA has different meanings. "Sparred length", "Total length including bowsprit", "Mooring length" and "LOA including bowsprit" are other expressions that might indicate the full length of a sailing ship. LOD Often used to distinguish between the length of a vessel including projections (e.g. bow sprits, etc.) from the length of the hull itself, the Length on Deck or LOD is often repor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Between Perpendiculars
Length between perpendiculars (often abbreviated as p/p, p.p., pp, LPP, LBP or Length BPP) is the length of a ship along the summer load line from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. When there is no sternpost, the centerline axis of the rudder stock is used as the aft end of the length between perpendiculars. Measuring to the stern post or rudder stock was believed to give a reasonable idea of the ship's carrying capacity, as it excluded the small, often unusable volume contained in her overhanging ends. On some types of vessels this is, for all practical purposes, a waterline measurement. In a ship with raked stems, naturally that length changes as the draught of the ship changes, therefore it is measured from a defined loaded condition. See also * Length overall __NOTOC__ Length overall (LOA, o/a, o.a. or oa) is the maximum length of a vessel's hull measured para ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-submarine Warfare
Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typically carried out to protect friendly shipping and coastal facilities from submarine attacks and to overcome blockades. Successful ASW operations typically involved a combination of sensor and weapon technologies, along with effective deployment strategies and sufficiently trained personnel. Typically, sophisticated sonar equipment is used for first detecting, then classifying, locating, and tracking a target submarine. Sensors are therefore a key element of ASW. Common weapons for attacking submarines include torpedoes and naval mines, which can both be launched from an array of air, surface, and underwater platforms. ASW capabilities are often considered of significant strategic importance, particularly following provocative instan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and Autonomous underwater vehicle, robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as ''boats'' rather than ''ships'' irrespective of their size. Although experimental submarines had been built earlier, submarine design took off during the 19th century, and they were adopted by several navies. They were first widely used during World War I (1914–1918), and are now used in many navy, navies, large and small. Military uses include attacking enemy surface ships (merchant and military) or other submarines, and for aircraft carrier protection, Blockade runner, blockade running, Ballistic missile submarine, nuclear deterrence, reconnaissance, conventio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dispatch Vessel
Dispatch boats were small boats, and sometimes large ships, tasked to carry military dispatches from ship to ship or from ship to shore or, in some cases from shore to shore. Dispatch boats were employed when other means of transmitting a message was not possible or safe or as quick. Dispatch boats, which performed their dispatch-carrying duties only on a temporary basis, should not be confused with packet ships—sometimes called packet boats or paquetbots—which were cargo ships which also routinely carried the mail from port to port. Generally, dispatch boats served the military, and paquetbots served commerce. Use of term by the U.S. Navy ''Dispatch boat'' was a term used by the United States Navy in its journal accounts to describe boats which carried messages, or mail—otherwise termed dispatches—between high-ranking military officials aboard other ships or to land-based destinations. Dispatch boats during the American Revolution In 1776 the Continental Navy ship ''L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Funnel (ship)
A funnel is the smokestack or chimney on a ship used to expel boiler steam and smoke or engine exhaust. They are also commonly referred to as stacks. Purpose The primary purpose of a ship's funnel(s) is to lift the exhaust gases clear of the deck, in order not to foul the ship's structure or decks, and to avoid impairing the ability of the crew to carry out their duties. In steam ships the funnels also served to help induce a convection draught through the boilers. Design Since the introduction of steam-power to ships in the 19th century, the funnel has been a distinctive feature of the silhouette of a vessel, and used for recognition purposes. Funnel area The required funnel cross-sectional area is determined by the volume of exhaust gases produced by the propulsion plant. Often this area is too great for a single funnel. Early steam vessels needed multiple funnels ( had 5 when launched), but as efficiency increased new machinery needed fewer funnels. Merchant ships ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge (nautical)
The interior of the bridge of the Sikuliaq'', docked in Ketchikan, Alaska">RV_Sikuliaq.html" ;"title="Research Vessel ''RV Sikuliaq">Sikuliaq'', docked in Ketchikan, Alaska file:Wheelhouse of Leao Dos Mares.jpg, Wheelhouse on a tugboat, topped with a flying bridge The bridge, also known as the pilothouse or wheelhouse, is a room or platform of a ship from which the ship can be commanded. When a ship is under way, the bridge is manned by an officer of the watch aided usually by an able seaman acting as a lookout. During critical maneuvers the captain will be on the bridge, often supported by an officer of the watch, an able seaman on the wheel and sometimes a pilot, if required. History and etymology The compass platform of a British destroyer in the Battle of the Atlantic during the Second World War with central binnacle">Second_World_War.html" ;"title="Battle of the Atlantic during the Second World War">Battle of the Atlantic during the Second World War with central bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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