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Currituck-class Seaplane Tender
The ''Currituck''-class seaplane tenders were four ships built for the United States Navy during World War II. The role of a seaplane tender was to provide base facilities for squadrons of seaplanes in a similar way that an aircraft carrier does for its squadrons. While three members of the class were removed from active service in the 1960s, ''Norton Sound'' was modified to serve as a testbed for advanced radar and combat management systems, such as the Aegis Combat System. Design and description In the interwar period, the United States Navy sought to find a cheaper alternative to the construction of airstrips on land for its air fleet. The distances required for air support, primarily in the Pacific Theater, were long and interwar naval treaties limited the size of aircraft carriers. The seaplane carrier was developed during interwar planning, with two versions being designed for use. The first design, designated AV, operated two full squadrons of patrol aircraft, prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia Naval Shipyard
The Philadelphia Naval Shipyard was an important naval shipyard of the United States for almost two centuries. Philadelphia's original navy yard, begun in 1776 on Front Street and Federal Street in what is now the Pennsport section of the city, was the first naval shipyard of the United States. It was replaced by a new, much larger yard developed around facilities begun in 1871 on League Island, at the confluence of the Delaware and Schuylkill rivers. The Navy Yard expansion stimulated the development over time of residential and businesses in South Philadelphia, where many shipyard workers lived. During World War II, some 40,000 workers operated on shifts around the clock to produce and repair ships at the yard for the war effort. The United States Navy ended most of its activities there in the 1990s, closing its base after recommendations by the Base Realignment and Closure commission. In 2000, the Philadelphia Industrial Development Corporation, on behalf of the city of Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asiatic-Pacific Theater
The Asiatic-Pacific Theater was the theater of operations of U.S. forces during World War II in the Pacific War during 1941–1945. From mid-1942 until the end of the war in 1945, two U.S. operational commands were in the Pacific. The Pacific Ocean Areas (POA), divided into the Central Pacific Area, the North Pacific Area and the South Pacific Area, were commanded by Fleet Admiral Chester W. Nimitz, Commander-in-Chief Pacific Ocean Areas. The South West Pacific Area (SWPA) was commanded by General of the Army Douglas MacArthur, Supreme Allied Commander South West Pacific Area. During 1945, the United States added the United States Strategic Air Forces in the Pacific, commanded by General Carl A. Spaatz. Because of the complementary roles of the United States Army and the United States Navy in conducting war, the Pacific Theater had no single Allied or U.S. commander (comparable to General of the Army Dwight D. Eisenhower in the European Theater of Operations). No actual comma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) 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 specially 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 (ship), propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geared Turbine
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 steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process. Because the turbine generates rotary motion, it can be coupled to a generator to harness its motion into electricity. Such turbogenerators are the core of thermal power stations which can be fueled by fossil-fuels, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Ship
The lead ship, name ship, or class leader is the first of a series or class of ships all constructed according to the same general design. The term is applicable to naval ships and large civilian vessels. Large ships are very complex and may take as many as five to ten years to build. Improvements based on experience with building and operating the lead ship are likely to be incorporated into the design or construction of later ships in the class, so it is rare to have vessels that are identical. The second and later ships are often started before the first one is completed, launched and tested. Nevertheless, building copies is still more efficient and cost-effective than building prototypes, and the lead ship will usually be followed by copies with some improvements rather than radically different versions. The improvements will sometimes be retrofitted to the lead ship. Occasionally, the lead ship will be launched and commissioned for shakedown testing before following ship ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Displacement
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 merc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Load Displacement
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] |
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] |
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] |
Waterline Length
A vessel's length at the waterline (abbreviated to L.W.L)Note: originally Load Waterline Length is the length of a ship or boat at the level where it sits in the water (the ''waterline''). The LWL will be shorter than the length of the boat overall (''length overall'' or LOA) as most boats have bows and stern protrusions that make the LOA greater than the LWL. As a ship becomes more loaded, it will sit lower in the water and its ambient waterline length may change; but the registered L.W.L it is measured from a default load condition. This measure is significant in determining several of a vessel's properties, such as how much water it displaces, where the bow and stern waves occur, hull speed, amount of bottom-paint needed, etc. Traditionally, a stripe called the "boot top" is painted around the hull just above the waterline. In sailing boats, longer waterline length will usually enable a greater maximum speed, because it allows greater sail area, without increasing beam or d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escort Carrier
The escort carrier or escort aircraft carrier (U.S. hull classification symbol CVE), also called a "jeep carrier" or "baby flattop" in the United States Navy (USN) or "Woolworth Carrier" by the Royal Navy, was a small and slow type of aircraft carrier used by the Royal Navy, the United States Navy, the Imperial Japanese Navy and Imperial Japanese Army Air Force in World War II. They were typically half the length and a third the displacement of larger fleet carriers, slower, more-lightly armed and armored, and carried fewer planes. Escort carriers were most often built upon a commercial ship hull, so they were cheaper and could be built quickly. This was their principal advantage as they could be completed in greater numbers as a stop-gap when fleet carriers were scarce. However, the lack of protection made escort carriers particularly vulnerable, and several were sunk with great loss of life. The light carrier (U.S. hull classification symbol CVL) was a similar concept to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target simplifies the bomb's trajectory and allows the pilot to keep visual contact throughout the bomb run. This allows attacks on point targets and ships, which were difficult to attack with conventional level bombers, even ''en masse''. After World War II, the rise of precision-guided munitions and improved anti-aircraft defences—both fixed gunnery positions and fighter interception—led to a fundamental change in dive bombing. New weapons, such as rockets, allowed for better accuracy from smaller dive angles and from greater distances. They could be fitted to almost any aircraft, including fighters, improving their effectiveness without the inherent vulnerabilities of dive bombers, which needed air superiority to operate effectively. Method A dive bomber dives at a steep angle, normally between 45 and 60 degrees or ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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