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USCGC Marcus Hanna
USCGC ''Marcus Hanna'' (WLM-554) is a Keeper-class coastal buoy tender of the United States Coast Guard. Launched in 1997, she is home-ported in South Portland, Maine. Her primary mission is maintaining 376 aids to navigation from Boston to St. John's Bay, Maine. Secondary missions include marine environmental protection, light icebreaking, search and rescue, and security. She is assigned to the First Coast Guard District. Construction and characteristics On 22 June 1993 the Coast Guard awarded the contract for the Keeper-class vessels to Marinette Marine Corporation in the form of a firm order for the lead ship and options for thirteen more. The Coast Guard exercised options for three additional ships, including ''Marcus Hanna'' on 7 February 1996. The ship was launched on 23 August 1997 into the Menominee River. The keynote speaker at the launch ceremony was Assistant Secretary of the Department of Transportation Melissa J. Spillenkothen. Also in attendance was U.S. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maritime Call Sign
Maritime call signs are call signs assigned as unique identifiers to ships and boats. All radio transmissions must be individually identified by the call sign. Merchant and naval vessels are assigned call signs by their national licensing authorities. History One of the earliest applications of radiotelegraph operation, long predating broadcast radio, were marine radio stations installed aboard ships at sea. In the absence of international standards, early transmitters constructed after Guglielmo Marconi's first trans- Atlantic message in 1901 were issued arbitrary two-letter calls by radio companies, alone or later preceded by a one-letter company identifier. These mimicked an earlier railroad telegraph convention where short, two-letter identifiers served as Morse code Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse c ... [...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) of the mechanical driveshaft or 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 is different from the Voith-Schneider marine propulsion system (also mechanically linked), which can also quickly change the direction of thrust, as the ''Z-drive'' uses a shrouded conventional screw that pivots or rotate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Davit
Boat suspended from radial davits; the boat is mechanically lowered Gravity multi-pivot on Scandinavia'' file:Bossoir a gravité.jpg, Gravity Roller Davit file:Davits-starbrd.png, Gravity multi-pivot davit holding rescue vessel on North Sea ferry file:Freefall lifeboat.JPG, Freefall lifeboat on the ''Spring Aeolian'' file:Frapping line.jpg, Frapping line Labeled Tricing Gripe Steps to launch davit Roller Gravity Davit A davit (pronounced "dayvit" or see Wiktionary) is any of various crane-like devices used on a ship for supporting, raising, and lowering equipment such as boats and anchors. Davit systems are most often used to lower an emergency lifeboat to the embarkation level to be boarded. The lifeboat davit has falls (now made of wire, historically of manila rope) that are used to lower the lifeboat into the water. Davits can also be used as man-overboard safety devices to retrieve personnel from the water. The maintaining and operation of davits is all under jurisd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USCGC Marcus Hanna Ice Breaking Near Boston
United States Coast Guard Cutter is the term used by the U.S. Coast Guard for its commissioned vessels. They are or greater in length and have a permanently assigned crew with accommodations aboard. They carry the ship prefix USCGC. History of the USCG cutters The Revenue Marine and the Revenue Cutter Service, as it was known variously throughout the late 18th and the 19th centuries, referred to its ships as cutters. The term is English in origin and refers to a specific type of vessel, namely, "a small, decked ship with one mast and bowsprit, with a gaff mainsail on a boom, a square yard and topsail, and two jibs or a jib and a staysail." With general usage, that term came to define any vessel of the United Kingdom's HM Customs and Excise and the term was adopted by the U.S. Treasury Department at the creation of what would become the Revenue Marine. Since that time, no matter what the vessel type, the service has referred to its vessels with permanently assigned crews a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chief Warrant Officer
Chief warrant officer is a military rank used by the United States Armed Forces, the Canadian Armed Forces, the Pakistan Air Force, the Israel Defense Forces, the South African National Defence Force, the Lebanese Armed Forces and, since 2012, the Singapore Armed Forces. In the United States Armed Forces, chief warrant officers are commissioned officers, not non-commissioned officers (NCOs) like in other NATO forces. Canadian Armed Forces In the Canadian Armed Forces, a chief warrant officer or CWO is the most senior non-commissioned member (NCM) rank for army and air force personnel. Its equivalent rank for navy personnel is chief petty officer 1st class (CPO1). The French language form of chief warrant officer is . A CWO is senior to the rank of master warrant officer (MWO) and its navy equivalent of chief petty officer 2nd class (CPO2). Cadets Canada uses the ranks of chief petty officer 1st class (Royal Canadian Sea Cadets), chief warrant officer (Royal Canadian Arm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballast Tank
A ballast tank is a compartment within a boat, ship or other floating structure that holds water, which is used as ballast to provide hydrostatic stability for a vessel, to reduce or control buoyancy, as in a submarine, to correct trim or list, to provide a more even load distribution along the hull to reduce structural hogging or sagging stresses, or to increase draft, as in a semi-submersible vessel or platform, or a SWATH, to improve seakeeping. Using water in a tank provides easier weight adjustment than the stone or iron ballast used in older vessels, and makes it easy for the crew to reduce a vessel's draft when it enters shallower water, by temporarily pumping out ballast. Airships use ballast tanks mainly to control buoyancy and correct trim. History The basic concept behind the ballast tank can be seen in many forms of aquatic life, such as the blowfish or argonaut octopus. The concept has been invented and reinvented many times by humans to serve a variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships. The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ducted Propeller
A ducted propeller, also known as a Kort nozzle, is a marine propeller fitted 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 Kort nozzle is a shrouded propeller assembly for marine propulsion. 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 referre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulstein Group
Ulstein Group is a group of companies that focus 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 the municipality of Ulstein 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 and solutions, 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 Spareb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horsepower
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 watts. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied among geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on 1 January 2010, the use of horsepower in the EU is permitted only as a supplementary unit. History The development of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diesel Engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called 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). Diesel engines work by compressing only air, or air plus 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 the air temperature inside the cylinder to such a high degree that atomised diesel fuel injected into the combustion chamber ignites. With the fuel being injected into the air just before combustion, the dispersion of the fuel is ... [...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'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
