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Keeper-class Cutter
The Keeper class of coastal buoy tenders consists of fourteen ships built for and operated by the United States Coast Guard. The ships were launched between 1995 and 1999 and all remain in active service. Their primary mission is to maintain thousands of Navigational aid, aids to navigation, both buoys and land-based. Their secondary missions include U.S. Coast Guard environmental protection, marine environmental protection, search and rescue, law enforcement, and light Icebreaker, ice-breaking. The Keeper-class ships play a specific role in the Coast Guard's buoy tender fleet. They are primarily deployed to coastal areas such as New York Harbor, Chesapeake Bay, and Puget Sound, while the seagoing tenders of the USCG seagoing buoy tender, ''Juniper'' class handle more off-shore areas, and inland tenders are assigned to the nation's large river systems. Origins and procurement In 1991, the average age of the twelve Coast Guard coastal buoy tenders approached 40 years, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red-class Cutter
The Red class consisted of five coastal USCG seagoing buoy tender, buoy tenders designed, built, owned, and operated by the United States Coast Guard. This was the first new class of buoy tenders built after World War II. It was designed to work in coastal waterways and the major rivers which fed them such as New York Harbor, Chesapeake Bay, and San Francisco Bay. Their primary mission was maintaining aids to navigation, with secondary missions of search and rescue, light icebreaking, law enforcement, and U.S. Coast Guard environmental protection, marine environmental protection. At the end of their Coast Guard careers, two of the ships were sunk off the New Jersey coast as part of artificial reefs. The three others were transferred to the Argentine Navy, where they remain in service. Origin and acquisition Of the 26 coastal buoy tenders in the Coast Guard fleet in 1964, 11 of them were judged to be obsolete. Nonetheless, United States Congress, Congress only a ... [...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 sides 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 cora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow Thruster
Manoeuvering thrusters (bow thrusters and stern thrusters) are transversal propulsion devices built into or mounted to either the Bow (watercraft), bow or stern (front or back, respectively) of a ship or boat to make it more manoeuvrable. Bow thrusters make docking easier, since they allow the captain to turn the vessel to port (nautical), port or starboard side, without using the main propulsion mechanism which requires some Steering#Watercraft, forward motion for turning; The effectiveness of a thruster is curtailed by any forward motion due to the Coandă effect#Problems caused, Coandă effect. A stern thruster is of the same principle, fitted at the stern. Sufficiently large vessels often have multiple bow thrusters and stern thrusters. Tunnel thrusters Large vessels usually have one or more tunnel thrusters built into the bow, below the waterline. An impeller in the tunnel can create thrust in either direction that makes the ship turn. Most tunnel thrusters are driven by e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ducted Propeller
A ducted propeller, also known as a Kort nozzle, is a marine propeller shrouded with a non-rotating nozzle. It is used to improve the efficiency of the propeller and is especially used on heavily loaded propellers or propellers with limited diameter. It was developed first by Luigi Stipa (1931) and later by Ludwig Kort (1934). The cross-section of the shroud has the form of a foil, and the shroud can offer hydrodynamic advantages over bare propellers, under certain conditions. Advantages are increased efficiency at lower speeds (10 knots), course stability when sailing astern, and increase of cavitation. Ducted propellers are also used to replace rudders. History Luigi Stipa in 1931 and later Ludwig Kort (1934) demonstrated that an increase in propulsive efficiency could be achieved by surrounding the propeller with a foil-shaped shroud in the case of heavily loaded propellers. A "Kort Nozzle" is referred to as an accelerating nozzle and is generally a MARIN 19A profile o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulstein Group
Ulstein Group is a group of companies focusing on various marine-related industries, but is mainly known for its shipbuilding and ship design activities. The largest unit is ''Ulstein Verft AS''. The company's head office and primary operations are located in the town of Ulsteinvik in Ulstein Municipality in Møre og Romsdal county, Norway, an important area for the Norwegian maritime cluster, and with subsidiaries in several other countries. The group also includes companies working with power & control systems, engineering, site follow-up and aftermarket services. The company has also been engaged in shipping. History The original company, ''Ulstein Mekaniske Verksted'', was established in 1917 by Martin Ulstein and his brother-in-law Andreas Flø. At age 23, Martin and Andreas founded the company to modify local fishing boats, which were undergoing a global transition from sail-power to motorization. Martin Ulstein borrowed money from Ulstein Sparebank, with his father actin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diesel Engine
The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compression (physics), compression; thus, the diesel engine is called a compression-ignition engine (CI engine). This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine (gasoline engine) or a gas engine (using a gaseous fuel like natural gas or liquefied petroleum gas). Introduction Diesel engines work by compressing only air, or air combined with residual combustion gases from the exhaust (known as exhaust gas recirculation, "EGR"). Air is inducted into the chamber during the intake stroke, and compressed during the compression stroke. This increases air temperature inside the Cylinder (engine), cylinder so that atomised diesel fuel injected into the combustion chamber ignites. The torque a dies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intercooler
An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines. Internal combustion engines Most commonly used with turbocharged engines, an intercooler is used to counteract the heat of compression and heat soak in the pressurised intake air. By reducing the temperature of the intake air, the air becomes denser (allowing more fuel to be injected, resulting in increased power) and less likely to suffer from pre-ignition or knocking. Additional cooling can be provided by externally spraying a fine mist onto the intercooler surface, or even into the intake air itself, to further reduce intake charge temperature through evaporative cooling. Intercoolers can vary dramatically in size, shape and design, depending on the performance and space requirements of the system. Many passenger cars use either front-mounted intercoolers locat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbocharger
In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the engine in order to produce more power for a given displacement. Turbochargers are distinguished from superchargers in that a turbocharger is powered by the kinetic energy of the exhaust gases, whereas a is mechanically powered (usually by a belt from the engine's crankshaft). However, up until the mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. History Prior to the inv ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Injection
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of a fuel injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All compression-ignition engines (e.g. diesel engines), and many spark-ignition engines (i.e. petrol (gasoline) engines, such as Otto or Wankel), use fuel injection of one kind or another. Mass-produced diesel engines for passenger cars (such as the Mercedes-Benz OM 138) became available in the late 1930s and early 1940s, being the first fuel-injected engines for passenger car use. In passenger car petrol engines, fuel injection was introduced in the early 1950s and gradually gained prevalence until it had largely replaced carburetors by the early 1990s. The primary difference between carburetion and fuel injection is that fuel injection atomizes the fuel through a small nozzle under high pressure, while carburetion relies on suction crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caterpillar Inc
Caterpillar Inc., also known as Cat, is an American construction, mining and other engineering equipment manufacturer. The company is the world's largest manufacturer of construction equipment. In 2018, Caterpillar was ranked number 73 on the ''Fortune'' 500 list and number 265 on the Global ''Fortune'' 500 list. Caterpillar stock is a component of the Dow Jones Industrial Average. Caterpillar Inc. traces its origins to the 1925 merger of the Holt Manufacturing Company and the C. L. Best Tractor Company, creating a new entity, California-based Caterpillar Tractor Company. In 1986, the company reorganized itself as a Delaware corporation under the current name, Caterpillar Inc. It announced in January 2017 that over the course of that year, it would relocate its headquarters from Peoria, Illinois, to Deerfield, Illinois, scrapping plans from 2015 of building an $800 million new headquarters complex in downtown Peoria. Its headquarters are located in Irving, Texas, since 2022 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z-drives On Keeper-class Buoy Tender
A Z-drive is a type of marine propulsion unit. Specifically, it is an azimuth thruster. The pod can rotate 360 degrees allowing for rapid changes in thrust direction and thus vessel direction. This eliminates the need for a conventional rudder. The Z-drive is so named because of the appearance (in Cross section (geometry), cross section) of the mechanical driveshaft or transmission (mechanics), transmission configuration used to connect the mechanically supplied driving energy to the Z-drive azimuth thruster device. This form of power transmission is called a Z-drive because the rotary motion has to make two right angle turns, thus resembling the letter "Z". This name is used to differentiate the arrangement of drive to that of the L-drive. It does not refer to an electric motor in a rotating pod. The device differs from a cyclorotor, which can also quickly change the direction of thrust, as the Z-drive uses a shrouded conventional screw that pivots or rotates the propeller, unl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Net Tonnage
Net tonnage (NT, N.T. or nt) is a dimensionless index calculated from the total moulded volume of the ship's cargo spaces by using a mathematical formula. Defined in ''The International Convention on Tonnage Measurement of Ships'' that was adopted by the International Maritime Organization in 1969, the net tonnage replaced the earlier net register tonnage (NRT) which denoted the volume of the ship's revenue-earning spaces in "register tons", units of volume equal to . Net tonnage is used to calculate the port duties and should not be taken as less than 30 per cent of the ship's gross tonnage.International Convention on Tonnage Measurement of Ships . International Maritime Organization (IMO). Net tonnage is not a measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
