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HMS Magdala (1870)
HMS'' Magdala'' was a breastwork monitor of the Royal Navy, built specifically to serve as a coastal defence ship for the harbour of Bombay (now Mumbai) in the late 1860s. She was ordered by the India Office for the Bombay Marine. The original specifications were thought to be too expensive and a cheaper design was ordered. While limited to harbour defence duties, the breastwork monitors were described by Admiral George Alexander Ballard as being like "full-armoured knights riding on donkeys, easy to avoid but bad to close with." Aside from gunnery practice ''Magdala'' remained in Bombay Harbour for her entire career. The ship was sold for scrap in 1903. Design and description In July 1866 the India Office asked for two floating batteries to defend Bombay and the Controller of the Navy, Vice Admiral Spencer Robinson recommended that monitors be used. He recommended a design with armour belt and protecting the gun turret, armed with the largest possible guns, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Of Magdala
The Battle of Magdala was the conclusion of the British Expedition to Abyssinia fought in April 1868 between British and Abyssinian forces at Magdala, from the Red Sea coast. The British were led by Robert Napier, while the Abyssinians were led by Emperor Tewodros II. In March 1866 a British envoy had been dispatched to secure the release of a group of missionaries who had first been seized when a letter Tewodros II had sent to Queen Victoria requesting munitions and military experts from the British, delivered by an envoy, Captain Cameron, had gone unanswered. They were released; however Tewodros II changed his mind and sent a force after them and they were returned to the fortress and imprisoned again, along with Captain Cameron. The British won the battle, and, rather than being subjected to capture, Tewodros committed suicide as the fortress was finally seized. Preparation and formation Advance elements of the British military units arrived at Annesley Bay on 4 Decembe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Alexander Ballard
Admiral George Alexander Ballard (7 March 1862 – 16 September 1948) was an officer of the Royal Navy and a historian. Biography Ballard was the eldest son of General John Archibald Ballard (1829–1880), and his wife Joanna, the daughter of Robert Scott-Moncrieff, and was born at Malabar Hill, Bombay on 7 March 1862. He joined the Royal Navy as a sub-lieutenant, was promoted lieutenant 15 March 1884, and commander 31 December 1897. In February 1902 he was ordered to six months' service at the Admiralty. He was further promoted captain 31 December 1903. In May 1913, Ballard was appointed a naval aide-de-camp to King George V, and in the King´s Birthday Honours 3 June 1913 he was appointed a Companion of the Order of the Bath. The following year he was appointed rear admiral 27 August 1914. He became Admiral Superintendent Malta Dockyard in September 1916. After a long and active career in the Navy he retired as vice-admiral in 1921 and was advanced to the rank of admiral o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wrought Iron
Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag Inclusion (mineral), inclusions (up to 2% by weight), which give it a wood-like "grain" that is visible when it is etched, rusted, or bent to structural failure, failure. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily forge welding, forge welded, but is more difficult to welding, weld electrically. Before the development of effective methods of steelmaking and the availability of large quantities of steel, wrought iron was the most common form of malleable iron. It was given the name ''wrought'' because it was hammered, rolled, or otherwise worked while hot enough to expel molten slag. The modern functional equivalent of wrought iron is Carbon steel#Mild or low-carbon steel, mild steel, also called low-carbon steel. Neither wrought iron nor mild steel contain enough carbon to be ... [...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 shot. Projec ... [...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 used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiler (steam Generator)
A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation. Heat sources In a fossil fuel power plant using a steam cycle for power generation, the primary heat source will be combustion of coal, oil, or natural gas. In some cases byproduct fuel such as the carbon monoxide rich offgasses of a coke battery can be burned to heat a boiler; biofuels such as bagasse, where economically available, can also be used. In a nuclear power plant, boilers called steam generators are heated by the heat produced by nuclear fission. Where a large volume of hot gas is available from some process, a heat recovery steam generator or recovery boiler can use the heat to produce steam, with little or no extra fuel consumed; such a configuration is com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Load
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 merc ... [...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 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] |
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, 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, naturally that length changes as the draught of the ship changes, therefore it is measured from a defined loaded condition. See also * Length overall __NOTOC__ Length overall (LOA, o/a, o.a. or oa) is the maximum length of a vessel's hull measured para ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monitor (warship)
A monitor is a relatively small warship which is neither fast nor strongly armored but carries disproportionately large guns. They were used by some navies from the 1860s, during the First World War and with limited use in the Second World War. The original monitor was designed in 1861 by John Ericsson, who named it . They were designed for shallow waters and served as coastal ships. The term also encompassed more flexible breastwork monitors, and was sometimes used as a generic term for any turreted ship. In the early 20th century, the term was revived for shallow-draught armoured shore bombardment vessels, particularly those of the Royal Navy: the s carried guns firing heavier shells than any other warship ever has, seeing action (albeit briefly) against German targets during World War I. The ''Lord Clive'' vessels were scrapped in the 1920s. The term "monitor" also encompasses the strongest of riverine warcraft, known as river monitors. During the Vietnam War these much sm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Spencer Robinson
Admiral Sir Robert Spencer Robinson, (6 January 1809 – 27 July 1889) was a British naval officer, who served as two five-year terms as Controller of the Navy from February 1861 to February 1871, and was therefore responsible for the procurement of warships at a time when the Royal Navy was changing over from unarmoured wooden ships to ironclads. As a result of the ''Captain'' disaster, Robinson was not given a third term as Controller. Robinson has been "described as having one of the best brains of any Victorian admiral". Personal life He was born at Welford Park, Berkshire, the son of Sir John Freind Robinson, 1st Baronet (1754–1832), Archdeacon of Armagh, who had changed the family surname from Freind to Robinson in 1793. On 10 May 1841, he married Clementina, daughter of Admiral Sir John Louis. Early naval career Robinson entered the Navy on 6 December 1821. He was promoted to lieutenant on 27 September 1830, and from 5 May 1831 until 1834 served as lieutenant in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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