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Etna-class Cruiser
The ''Etna'' class was a series of protected cruisers that were built in the late 1880s for the Regia Marina (the Royal Italian Navy). The four ships built were slightly enlarged copies of the Elswick Works' design for the protected cruiser . ''Etna'', the lead ship of the class, was the only ship still in service when World War I began, although she served as a stationary headquarters ship for the Navy Commander-in-Chief in Taranto for the duration of the war. The three later ships all participated in putting down the Boxer Rebellion as part of the Eight-Nation Alliance. The three were struck from the Navy List before 1912, but ''Etna'' was not sold for scrap until 1921. Design and description The design of the ''Etna''-class protected cruisers was based on that of Sir W G Armstrong Mitchell & Co.'s Elswick Works' earlier ''Giovanni Bausan'', which was the first modern protected cruiser constructed for the Italian Navy. She proved successful enough that the Italians negoti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hudson–Fulton Celebration
The Hudson–Fulton Celebration from September 25 to October 9, 1909 in New York and New Jersey was an elaborate commemoration of the 300th anniversary of Henry Hudson’s discovery of the Hudson River and the 100th anniversary of Robert Fulton's first successful commercial application of the paddle steamer." 1909 Hudson–Fulton Celebration of the Discovery of the Hudson River and the First Successful Application of Steam to Navigation" Hudson River Maritime Museum. The image above of the Celebration program shows the event closing on Saturday, October 9, 1909. A report to the New York state legislature in 1910 by the official celebration Commission, as shown on the website of this reference, lists the celebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eight-Nation Alliance
The Eight-Nation Alliance was a multinational military coalition that invaded northern China in 1900 with the stated aim of relieving the foreign legations in Beijing, then besieged by the popular Boxer militia, who were determined to remove foreign imperialism in China. The Allied forces consisted of about 45,000 troops from what have, in popular tradition, been called eight 'nations' but included several empires, so thus actually far more than 8 nations in our contemporary 21st century terms, comprising: the German Empire, the Empire of Japan, the Russian Empire, the British Empire, particularly including forces from its full and sub-continent domains of Australia which was not a discrete official alliance signatory and the Empire of India, France which continued with overseas possessions, the United States which as democracy has historically demurred its global reach as 'empire', Italy, a kingdom in this peirod, and the Empire of Austria-Hungary. Neither the Chinese nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sponson
Sponsons are projections extending from the sides of land vehicles, aircraft or watercraft to provide protection, stability, storage locations, mounting points for weapons or other devices, or equipment housing. Watercraft On watercraft, a sponson is a projection that extends outward (usually from the hull, but sometimes other parts of the vessel) to improve stability while floating, or to act as a securing point for other equipment. Vessels with unstable body shapes or unevenly distributed weight are likely to feature sponsons to help prevent capsizing or other instabilities. On many vessels, these projections from the main body of the vessel can be attached and removed quickly and fairly easily. Canoes and kayaks sometimes feature sponson attachments as well, for stability in rough waters. These differ from outriggers, which extend a significant distance away from the body of the craft, and are employed on craft designed for open waters. A sponson's terminus is close to the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muzzle Velocity
Muzzle velocity is the speed of a projectile (bullet, pellet, slug, ball/ shots or shell) with respect to the muzzle at the moment it leaves the end of a gun's barrel (i.e. the muzzle). Firearm muzzle velocities range from approximately to in black powder muskets, to more than in modern rifles with high-velocity cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns firing kinetic energy penetrator ammunition. To simulate orbital debris impacts on spacecraft, NASA launches projectiles through light-gas guns at speeds up to . Projectile velocity For projectiles in unpowered flight, its velocity is highest at leaving the muzzle and drops off steadily because of air resistance. Projectiles traveling less than the speed of sound (about in dry air at sea level) are ''subsonic'', while those traveling faster are ''supersonic'' and thus can travel a substantial distance and even hit a target before a nearby observer hears the "bang" of the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbette
Barbettes are several types of gun emplacement in terrestrial fortifications or on naval ships. In recent naval usage, a barbette is a protective circular armour support for a heavy gun turret. This evolved from earlier forms of gun protection that eventually led to the pre-dreadnought. The name ''barbette'' ultimately comes from fortification - it originally meant a raised platform or mound, as in the French phrase ''en barbette'', which refers to the practice of firing a cannon over a parapet rather than through an embrasure in a fortification's casemate. The former gives better angles of fire but less protection than the latter. The disappearing gun was a variation on the barbette gun; it consisted of a heavy gun on a carriage that would retract behind a parapet or into a gunpit for reloading. Barbettes were primarily used in coastal defences, but saw some use in a handful of warships, and some inland fortifications. The term is also used for certain aircraft gun mounts. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breech-loading Weapon
A breechloader is a firearm in which the user loads the ammunition ( cartridge or shell) via the rear (breech) end of its barrel, as opposed to a muzzleloader, which loads ammunition via the front ( muzzle). Modern firearms are generally breech-loading – except for replicas of vintage weapons. Early firearms before the mid-19th century were almost entirely muzzle-loading. Mortars and the Russian GP-25 grenade launcher are the only muzzleloaders remaining in frequent modern usage. However, referring to a weapon specifically as breech loading is mostly limited to single-shot or otherwise non-repeating firearms, such as double-barreled shotguns. Breech-loading provides the advantage of reduced reloading time, because it is far quicker to load the projectile and propellant into the chamber of a gun/cannon than to reach all the way over to the front end to load ammunition and then push them back down a long tube – especially when the projectile fits tightly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or - by extension - a relative measure of the barrel length. Rifled barrels Rifled barrels introduce ambiguity to measurement of caliber. A rifled bore consists of alternating grooves and lands. The distance across the bore from groove to groove is greater than the distance from land to land. Projectiles fired from rifled barrels must be of the full groove to groove diameter to be effectively rotated by the rifling, but the caliber has sometimes been specified as the land to land diameter before rifling grooves were cut. The depth of rifling grooves (and the consequent ambiguity) increases in larger calibers. Steel artillery projectiles may have a forward bourrelet section machined to a diameter slightly smaller than the original land to land dimension of the barrel and a copper driving band somewhat larger than the groove to groove diameter t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Trial
A sea trial is the testing phase of a watercraft (including boats, ships, and submarines). It is also referred to as a " shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and it can last from a few hours to many days. Sea trials are conducted to measure a vessel's performance and general seaworthiness. Testing of a vessel's speed, maneuverability, equipment and safety features are usually conducted. Usually in attendance are technical representatives from the builder (and from builders of major systems), governing and certification officials, and representatives of the owners. Successful sea trials subsequently lead to a vessel's certification for commissioning and acceptance by its owner. Although sea trials are commonly thought to be conducted only on new-built vessels (referred by shipbuilders as 'builders trials'), they are regularly conducted on commissioned vessels as well. In new vessels, they are us ... [...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 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 blade to the water at t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (ship)
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 ... [...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 In watercraft, a racing shell (also referred to as just a ''fine boat'' (UK) or just ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Between Perpendiculars
Length between perpendiculars (often abbreviated as p/p, p.p., pp, LPP, LBP or Length BPP) is the length of a ship along the summer load line from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost A sternpost is the upright structural member or post at the stern of a (generally wooden) ship or a boat, to which are attached the transoms and the rearmost left corner part of the stern. The sternpost may either be completely vertical or m ..., or main stern perpendicular member. When there is no sternpost, the centerline axis of the rudder stock is used as the aft end of the length between perpendiculars. Measuring to the stern post or rudder stock was believed to give a reasonable idea of the ship's carrying capacity, as it excluded the small, often unusable volume contained in her overhanging ends. On some types of vessels this is, for all practical purposes, a waterline measurement. In a ship with raked stems, natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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