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USS Narwhal (SSN-671)
USS ''Narwhal'' (SSN-671), a unique submarine, was the third vessel of the United States Navy to be named for the narwhal, a gray and white arctic whale with a unicorn-like, ivory tusk. Her keel was laid down on 17 January 1966 by the Electric Boat Division of General Dynamics Corporation, in Groton, Connecticut. She was launched on 9 September 1967 sponsored by Vice admiral Glynn R. Donaho (ret.), and commissioned on 12 July 1969. Design A unique design under project SCB 245,Friedman, ''U.S. Submarines since 1945'', pp. 149-151 ''Narwhal'' was her own class. Forward of the reactor compartment she was broadly similar to the contemporary submarines, but with a slightly larger diameter and the relocation of the auxiliary diesel generator from the bow compartment to the auxiliary machine room in the operations compartment. Her reactor compartment and engine room were unlike those of previous classes due to her unique natural circulation S5G reactor and direct-drive turbine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USS Narwhal (SS-167)
USS ''Narwhal'' (SS-167), the lead ship of her class of submarine and one of the "V-boats", was the second ship of the United States Navy to be named for the narwhal. She was named ''V-5'' (SC-1) when her keel was laid down on 10 May 1927 by the Portsmouth Navy Yard in Kittery, Maine. Design ''V-5'' was generally similar to the preceding submarine minelayer ''V-4'', although slightly smaller and lacking a minelaying system. The configuration of ''V-4'', ''V-5'', and ''V-6'' resulted from an evolving strategic concept that increasingly emphasized the possibility of a naval war with Japan in the far western Pacific. This factor, and the implications of the 1922 Washington Naval Treaty, suggested the need for long-range submarine "cruisers", or "strategic scouts", as well as long-range minelayers, for which long endurance, not high speed, was most important. The design was possibly influenced by the German "U-cruisers" of the Type U-139 and Type U-151 U-boat classes, althou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating electrical power when combined with a generator.Munson, Bruce Roy, T. H. Okiishi, and Wade W. Huebsch. "Turbomachines." Fundamentals of Fluid Mechanics. 6th ed. Hoboken, NJ: J. Wiley & Sons, 2009. Print. A turbine is a turbomachine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor. Early turbine examples are windmills and waterwheels. Gas, steam, and water turbines have a casing around the blades that contains and controls the working fluid. Credit for invention of the steam turbine is given both to Anglo-Irish engineer Sir Charles Parsons (1854–1931) for invention of the reaction turbine, and to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Propulsion
Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems. Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfares. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct-drive Mechanism
A direct-drive mechanism is a mechanism design where the force or torque from a prime mover is transmitted directly to the effector device (such as the drive wheels of a vehicle) without involving any intermediate couplings such as a gear train or a belt.Asada, H., & Kanade, T. (1983) Design of direct-drive mechanical arms' in ''Journal of Vibration, Acoustics, Stress, and Reliability in Design'', Volume 105, Issue 3, pp.312-316 History In the late 19th century and early 20th century, some of the earliest locomotives and cars used direct drive transmissions at higher speeds. Direct-drive mechanisms for industrial arms began to be possible in the 1980s, with the use of rare-earth magnetic materials. The first direct-drive arm was built in 1981 at Carnegie Mellon University. Today the most commonly used magnets are neodymium magnets. Design Direct-drive systems are characterized by smooth torque transmission, and nearly-zero backlash.Bruno Siciliano, Oussama Khatib (Eds., 2008) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Circulation
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow. Convective flow may be transient (such as when a multiphase mixture of oil and water separates) or steady state (see Convection cell). The convection may be due to gravitational, electromagnetic or fictitious body forces. Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be identified by clouds, with stronger convection resulting in thunderstorms. Natural convection also plays a role in stellar physics. Convection is often categorised or des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Characteristics Board
The Ship Characteristics Board was a unit of the United States Navy. The purpose of the Ship Characteristics Board was to coordinate the creation of 'ship characteristics' that are essential to the design of naval combatants and auxiliaries. Coordination was required because the operators and the designers of ships had different interests, perceptions, and concepts: as summarized by the naval historian Norman Friedman, "How to achieve the best possible compromise among competing bureaus has been one of the great dilemmas of 20th-century U.S. naval administration." This list of SCB projects is a useful exposition of the U.S. Navy's shipbuilding priorities in the first half of the Cold War. History The Ship Characteristics Board was founded in 1945 under the Office of the Chief of Naval Operations / OpNav. It was created after the body previously responsible for coordinating ships characteristics, the General Board, had been seen as ineffective in a series of earlier Navy bureau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Commissioning
Ship commissioning is the act or ceremony of placing a ship in active service and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to placing a warship in active duty with its country's military forces. The ceremonies involved are often rooted in centuries-old naval tradition. Ship naming and launching endow a ship hull with her identity, but many milestones remain before she is completed and considered ready to be designated a commissioned ship. The engineering plant, weapon and electronic systems, galley, and other equipment required to transform the new hull into an operating and habitable warship are installed and tested. The prospective commanding officer, ship's officers, the petty officers, and seamen who will form the crew report for training and familiarization with their new ship. Before commissioning, the new ship undergoes sea trials to identify any deficiencies needing corre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Naming And Launching
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. Ship launching imposes stresses on the ship not met during normal operation and, in addition to the size and weight of the vessel, represents a considerable engineering challenge as well as a public spectacle. The process also involves many traditions intended to invite good luck, such as christening by breaking a sacrificial bottle of champagne over the bow as the ship is named aloud and launched. Methods There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching". The oldest, most familiar, and most widely used is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Dynamics
General Dynamics Corporation (GD) is an American publicly traded, aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth-largest defense contractor in the world by arms sales, and 5th largest in the United States by total sales. The company is a Fortune 100 company, and was ranked No. 94 in 2022. Formed in 1954 with the merger of submarine manufacturer Electric Boat and aircraft manufacturer Canadair, the corporation today consists of ten subsidiary companies with operations in 45 countries. The company's products include Gulfstream business jets, Virginia- and Columbia-class nuclear-powered submarines, Arleigh Burke-class guided-missile destroyers, M1 Abrams tanks and Stryker armored fighting vehicles. In 2021, General Dynamics had worldwide sales of $38.85 billion and a workforce of approximately 103,000 full-time employees. The current chairman and chief executive officer (CEO) is Phebe Novakovic. History Electric Boat Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Boat
An electric boat is a powered watercraft driven by electric motors, which are powered by either on-board battery packs, solar panels or generators. While a significant majority of water vessels are powered by diesel engines, with sail power and gasoline engines also popular, boats powered by electricity have been used for over 120 years. Electric boats were very popular from the 1880s until the 1920s, when the internal combustion engine became dominant. Since the energy crises of the 1970s, interest in this quiet and potentially renewable marine energy source has been increasing steadily, especially as more efficient solar cells have become available, for the first time making possible motorboats with a theoretically infinite cruise range like sailboats. The first practical solar boat was probably constructed in 1975 in England. The first electric sailboat to complete a round-the-world tour (including a transit of the Panama Canal) using only green technologies is EcoSail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale). Odontocetes include the Monodontidae (beluga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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