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HMS Isis (1896)
HMS ''Isis'' was an protected cruiser built for the Royal Navy in the mid-1890s. Technical details Eclipse-class second-class protected cruisers were preceded by the shorter Astraea-class cruisers. ''Isis'' had a displacement of when at normal load. It had a total length of , a beam of , a metacentric height of around , and a draught of . It was powered by two inverted triple-expansion steam engines which used steam from eight cylindrical boilers. Using normal draught, the boilers were intended to provide the engines with enough steam to generate and to reach a speed of ; using forced draft, the equivalent figures were and a speed of . Eclipse-class cruisers carried a maximum of of coal and achieved maximum speed of in sea trials. It carried five 40-calibre quick-firing (QF) guns in single mounts protected by gun shields. One gun was mounted on the forecastle, two on the quarterdeck and one pair was abreast the bridge. They fired shells at a muzzle velocity of . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Ship
A sister ship is a ship of the same class or of virtually identical design to another ship. Such vessels share a nearly identical hull and superstructure layout, similar size, and roughly comparable features and equipment. They often share a common naming theme, either being named after the same type of thing or person (places, constellations, heads of state) or with some kind of alliteration. Typically the ship class is named for the first ship of that class. Often, sisters become more differentiated during their service as their equipment (in the case of naval vessels, their armament) are separately altered. For instance, the U.S. warships , , , and are all sister ships, each being an . Perhaps the most famous sister ships were the White Star Line's s, consisting of , and . As with some other liners, the sisters worked as running mates. Other sister ships include the Royal Caribbean International's and . ''Half-sister'' refers to a ship of the same class but with some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service. From the middle decades of the 17th century, and through the 18th century, the Royal Navy vied with the Dutch Navy and later with the French Navy for maritime supremacy. From the mid 18th century, it was the world's most powerful navy until the Second World War. The Royal Navy played a key part in establishing and defending the British Empire, and four Imperial fortress colonies and a string of imperial bases and coaling stations secured the Royal Navy's ability to assert naval superiority globally. Owing to this historical prominence, it is common, even among non-Britons, to ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadside (naval)
A broadside is the side of a ship, or more specifically the battery of cannon on one side of a warship or their coordinated fire in naval warfare, or a measurement of a warship's maximum simultaneous firepower which can be delivered upon a single target (because this concentration is usually obtained by firing a broadside). From the 16th century until the early decades of the steamship, vessels had rows of guns set in each side of the hull. Firing all guns on one side of the ship became known as a "broadside". The cannon of 18th-century men of war were accurate only at short range, and their penetrating power mediocre, which meant that the thick hulls of wooden ships could only be pierced at short ranges. These wooden ships sailed closer and closer towards each other until cannon fire would be effective. Each tried to be the first to fire a broadside, often giving one party a decisive headstart in the battle when it crippled the other ship.Platt (1993) p. 18 History Since anci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge (nautical)
The interior of the bridge of the Sikuliaq'', docked in Ketchikan, Alaska">RV_Sikuliaq.html" ;"title="Research Vessel ''RV Sikuliaq">Sikuliaq'', docked in Ketchikan, Alaska file:Wheelhouse of Leao Dos Mares.jpg, Wheelhouse on a tugboat, topped with a flying bridge The bridge, also known as the pilothouse or wheelhouse, is a room or platform of a ship from which the ship can be commanded. When a ship is under way, the bridge is manned by an officer of the watch aided usually by an able seaman acting as a lookout. During critical maneuvers the captain will be on the bridge, often supported by an officer of the watch, an able seaman on the wheel and sometimes a pilot, if required. History and etymology The compass platform of a British destroyer in the Battle of the Atlantic during the Second World War with central binnacle">Second_World_War.html" ;"title="Battle of the Atlantic during the Second World War">Battle of the Atlantic during the Second World War with central bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarterdeck
The quarterdeck is a raised deck behind the main mast of a sailing ship. Traditionally it was where the captain commanded his vessel and where the ship's colours were kept. This led to its use as the main ceremonial and reception area on board, and the word is still used to refer to such an area on a ship or even in naval establishments on land. Many such facilities have areas decorated like shipboard quarterdecks. In the 20th century the word came to be applied to the area at the stern of the ship, often (on naval vessels) used for secondary weapons and (on battleships) seaplane catapults. In modern military designs the stern has been roofed over by the helicopter deck but a large space remains underneath which is typically used for sonar equipment or small boats and which is still referred to as the quarterdeck in Commonwealth navies. Ceremonial use There are ancient traditions of offering special deference to the quarterdeck. Greek, Roman, and Carthaginian warships all c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forecastle
The forecastle ( ; contracted as fo'c'sle or fo'c's'le) is the upper deck of a sailing ship forward of the foremast, or, historically, the forward part of a ship with the sailors' living quarters. Related to the latter meaning is the phrase " before the mast" which denotes anything related to ordinary sailors, as opposed to a ship's officers. History and design In medieval shipbuilding, a ship of war was usually equipped with a tall, multi-deck castle-like structure in the bow of the ship. It served as a platform for archers to shoot down on enemy ships, or as a defensive stronghold if the ship were boarded. A similar but usually much larger structure, called the aftcastle, was at the aft end of the ship, often stretching all the way from the main mast to the stern. Having such tall upper works on the ship was detrimental to sailing performance. As cannons were introduced and gunfire replaced boarding as the primary means of naval combat during the 16th century, the medieval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Shield
A U.S. Marine manning an M240 machine gun equipped with a gun shield A gun shield is a flat (or sometimes curved) piece of armor designed to be mounted on a crew-served weapon such as a machine gun, automatic grenade launcher, or artillery piece. Military Some mounted machine guns and artillery pieces are equipped with metal armor plates to protect the gunners from small arms fire and shrapnel from explosions. They were fitted to some armored fighting vehicles and patrol boats during the Vietnam War. Gun shields fell out of widespread use after the Vietnam war, but they have seen a resurgence in popularity during the 1990s. Israeli military analysts began urging the use of gun shields, pointing to the grave risk to soldiers exposed to fire from automatic weapons. In particular, it was noted that many casualties were hit in areas not protected by body armor or a helmet, such as the neck or face. The U.S. began using gun shields during the 2000s-era wars in Iraq and Afghanista ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quick-firing Gun
A quick-firing or rapid-firing gun is an artillery piece, typically a gun or howitzer, which has several characteristics which taken together mean the weapon can fire at a fast rate. Quick-firing was introduced worldwide in the 1880s and 1890s and had a marked impact on war both on land and at sea. Characteristics The characteristics of a quick-firing artillery piece are: *A breech-loading weapon with a breech mechanism that allows rapid reloading *Single-part cased ammunition, i.e. a cartridge containing both shell and propellant *Recoil buffers to limit recoil, so the barrel can quickly return to the same position after firing *The use of smokeless powder – nitrocellulose, nitroglycerine, or cordite – which create far less smoke than gunpowder, meaning that gun crews could still see their target These innovations, taken together, meant that the quick-firer could fire aimed shells much more rapidly than an older weapon. For instance, an Elswick Ordnance Company 4.7-inch gun ... [...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] |
Forced Draught
The difference between atmospheric pressure and the pressure existing in the furnace or flue gas passage of a boiler is termed as draft. Draft can also be referred to as the difference in pressure in the combustion chamber area which results in the motion of the flue gases and the air flow. Types of draft Drafts are produced by the rising combustion gases in the stack, flue, or by mechanical means. For example, a boiler can be put into four categories: natural, induced, balanced, and forced. *Natural draft: When air or flue gases flow due to the difference in density of the hot flue gases and cooler ambient gases. The difference in density creates a pressure differential that moves the hotter flue gases into the cooler surroundings. * Forced draft: When air or flue gases are maintained above atmospheric pressure. Normally it is done with the help of a forced draft fan. * Induced draft: When air or flue gases flow under the effect of a gradually decreasing pressure below atmospheric p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draught (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 aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacentric Height
The metacentric height (GM) is a measurement of the initial static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre. A larger metacentric height implies greater initial stability against overturning. The metacentric height also influences the natural period of rolling of a hull, with very large metacentric heights being associated with shorter periods of roll which are uncomfortable for passengers. Hence, a sufficiently, but not excessively, high metacentric height is considered ideal for passenger ships. Metacentre When a ship heels (rolls sideways), the centre of buoyancy of the ship moves laterally. It might also move up or down with respect to the water line. The point at which a vertical line through the heeled centre of buoyancy crosses the line through the original, vertical centre of buoyancy is the metacentre. The metacentre remains directly above the centre of buoyancy by definition. In the diagra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_Driver_and_Commander_from_A_Squadron%2C_3rd_Cavalry_Regiment.jpg "Click for more on -> Gun Shield")
