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Allende-class Frigate
The ''Allende'' class is a series of anti-submarine frigates used by the Mexican Navy. ''Allende''-class frigates are former United States Navy -ships which were acquired beginning in 1997. They form the Mexican Gulf Fleet of the Mexican Navy. They are used for anti-submarine and offshore patrol duties. Description The ''Allende''-class frigates are former United States Navy s. They have a standard displacement of and at full load. The vessels measure long with a beam of and a maximum draught of . The ships are propelled by a Westinghouse steam turbine rated at turning one shaft using steam provided by two Combustion Engineering/Babcock & Wilcox boilers at a working pressure of and a temperature of . This gives the frigates a maximum speed of and a range of at on one boiler. The ships have a complement of 288 including 20 officers. The frigates are armed with a reduced version of their American layouts. They mount a single FMC /54 caliber Mk 42 dual purpose gun mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Todd Shipyard
Vigor Shipyards is the current entity operating the former Todd Shipyards after its acquisition in 2011. Todd Shipyards was founded in 1916, which owned and operated shipyards on the West Coast of the United States, East Coast of the United States and the Gulf. Todd Shipyards were a major part of the Emergency Shipbuilding Program for World War II. Vigor Shipyards In February 2011, Vigor Industrial purchased Todd for US$130 million. This included the Seattle, Everett and Bremerton operations. Today, Vigor Shipyards is a government repair subsidiary of Vigor Industrial. Originally, the Coast Guard wanted to acquire 25 Offshore Patrol Cutters (OPC) and spend about $8 billion for them. In April 2013, it was reported that Vigor proposed an Ulstein X-bow hull in the design competition for the OPC vessels. If successful in landing the contract, Vigor would have assembled the vessels at its Portland, Ore., shipyard. However, in February 2014, the USCG announced that Bollinger Sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual Purpose Gun
A dual-purpose gun is a naval artillery mounting designed to engage both surface and air targets. Description Second World War-era capital ships had four classes of artillery: the heavy main battery, intended to engage opposing battleships and cruisers of 305 mm to 457 mm (12 inch to 18 inch); a secondary battery for use against enemy destroyers of 152 mm to 203 mm (6 inch to 8 inch); heavy anti-aircraft guns of 76 mm to 127 mm (3 inch to 5 inch), which could create barrages to knock out airplanes at a distance; finally, light rapid-fire anti-aircraft batteries (A/A) to track and bring down aircraft at close range. The light A/A was dispersed throughout the ship and included both automatic cannons of 20 mm to 40 mm (.787 inch to 1.57 inch) and heavy machine guns of 12.7 mm to 14.5 mm (.50 inch to .58 inch). During World War II, the US Navy, Royal Navy, the French Navy, and the Imperial Japanese Navy combined the secondary battery with the heavy anti-aircraft guns, creating a d ... [...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] |
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] |
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] |
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage (4,635,628 tonnes as of 2019) and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft . The United States Navy traces its origins to the Continental Navy, which was established during the American Revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexican Navy
The Mexican Navy is one of the two independent armed forces of Mexico. The actual naval forces are called the ''Armada de México''. The ''Secretaría de Marina'' (''SEMAR'') (English: Naval Secretariat) includes both the ''Armada'' itself and the attached ministerial and civil service. The commander of the Navy is the Secretary of the Navy, who is both a cabinet minister and a career naval officer. The Mexican Navy's stated mission is "to use the naval force of the federation for external defense, and to help with internal order". As of 2020, the Navy consists of about 68,200 men and women plus reserves, over 189 ships, and about 130 aircraft. Rendición de cuentas SEMAR 2006 página 40 The Navy attempts to maintain a constant modernization program to upgrade its response capability. Given Mexico's large area of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frigate
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] |
Knox-class Frigate
The 46 ''Knox''-class frigates were the largest, last, and most numerous of the US Navy's second-generation anti-submarine warfare (ASW) escorts. Originally laid down as ocean escorts (formerly called destroyer escorts), they were all redesignated as frigates on 30 June 1975, in the 1975 ship reclassification plan and their hull designation changed from 'DE' to 'FF'. The ''Knox'' class was the Navy's last destroyer-type design with a steam turbine powerplant. Due to their unequal comparison to destroyers then in service (larger size with lower speed and only a single screw and 5-inch gun), they became known to a generation of destroyermen as "McNamara's Folly." These ships were retired from the US Navy at the end of the Cold War due to their relatively high running costs, a declining defense budget, and the need for ships with a more advanced anti-submarine capability. None of the ships served more than 23 years in the US Navy, and by 1994, all of the class had been retired, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helipad
A helipad is a landing area or platform for helicopters and powered lift aircraft. While helicopters and powered lift aircraft are able to operate on a variety of relatively flat surfaces, a fabricated helipad provides a clearly marked hard surface away from obstacles where such aircraft can land safely. Larger helipads, intended for use by helicopters and other vertical take-off and landing aircraft (VTOL), may be called ''vertiports.'' An example is Vertiport Chicago, which opened in 2015. Usage Helipads may be located at a heliport or airport where fuel, air traffic control and service facilities for aircraft are available. Most helipads are located remote from populated areas due to sounds, winds, space and cost constraints. However, some skyscrapers maintain a helipad on their roofs in order to accommodate air taxi services. Some basic helipads are built on top of highrise buildings for evacuation in case of a major fire outbreak. Major police departments may use a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hangar
A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish *''haimgard'' ("home-enclosure", "fence around a group of houses"), from *''haim'' ("home, village, hamlet") and ''gard'' ("yard"). The term, ''gard'', comes from the Old Norse ''garðr'' ("enclosure, garden"). Hangars are used for protection from the weather, direct sunlight and for maintenance, repair, manufacture, assembly and storage of aircraft. History The Wright brothers stored and repaired their aircraft in a wooden hangar constructed in 1902 at Kill Devil Hills in North Carolina for their glider. After completing design and construction of the ''Wright Flyer'' in Ohio, the brothers returned to Kill Devil Hills only to find their hangar damaged. They repaired the structure and constructed a new workshop while they waited for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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