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Japanese Submarine Ro-68
''Ro-68'' was an Imperial Japanese Navy Type L submarine of the L4 subclass. First commissioned in 1925, she served in the waters of Japan prior to World War II. During World War II, she supported Japanese forces during the Battle of Wake Island and the invasion of Rabaul and took part in the Aleutian Islands campaign. She served as a training submarine from late 1942 to late 1944 before returning to a combat role in Japanese waters late in the war. She surrendered to the Allies in 1945 at the conclusion of the war and was scuttled in 1946. Design and description The submarines of the Type L4 sub-class were copies of the Group 3 subclass of the British L-class submarine built under license in Japan.Chesneau, Roger, ed., ''Conway′s All the World′s Fighting Ships 1922–1946'', New York: Mayflower Books, 1980, , p. 203. They were slightly larger and had two more torpedo tubes than the preceding submarines of the L3 subclass. They displaced surfaced and submerged. The submar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitsubishi Heavy Industries
is a Japanese multinational engineering, electrical equipment and electronics corporation headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group and its automobile division is the predecessor of Mitsubishi Motors. MHI's products include aerospace and automotive components, air conditioners, elevators, forklift trucks, hydraulic equipment, printing machines, missiles, tanks, power systems, ships, aircraft, railway systems, and space launch vehicles. Through its defense-related activities, it is the world's 23rd-largest defense contractor measured by 2011 defense revenues and the largest based in Japan. History In 1857, at the request of the Tokugawa Shogunate, a group of Dutch engineers were invited, including Dutch naval engineer Hendrik Hardes, and began work on the ''Nagasaki Yotetsusho'' 長崎鎔鉄所 , a modern, Western-style foundry and shipyard near the Dutch settlement of Dejima, at Nagasaki. This was renamed ''Naga ... [...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] |
1st Fleet (Imperial Japanese Navy)
The was the main battleship fleet of the Imperial Japanese Navy. History First established on 28 December 1903, the IJN 1st Fleet was created during the Russo-Japanese War when the Imperial General Headquarters divided the Readiness Fleet into a mobile strike force of cruisers and destroyers to pursue the Imperial Russian Navy's Vladivostok-based cruiser squadron (the Imperial Japanese Navys 2nd Fleet), while the remaining bulk of the Japanese fleet (the IJN 1st Fleet) continued to blockade Port Arthur in hopes of luring the battleships of the Russian Pacific Fleet out into a classic line-of-battle confrontation. The two fleets were combined into the Combined Fleet for the final Battle of Tsushima. The decisive victory of the Japanese fleet over the Imperial Russian Navy at the Battle of Tsushima validated the doctrine of the "decisive victory", or '' kantai kessen'' as stipulated by naval theorists such as Alfred Thayer Mahan and Satō Tetsutarō in the eyes of the Imperia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squadron (naval)
A squadron, or naval squadron, is a significant group of warships which is nonetheless considered too small to be designated a fleet. A squadron is typically a part of a fleet. Between different navies there are no clear defining parameters to distinguish a squadron from a fleet (or from a flotilla), and the size and strength of a naval squadron varies greatly according to the country and time period. Groups of small warships, or small groups of major warships, might instead be designated flotillas by some navies according to their terminology. Since the size of a naval squadron varies greatly, the rank associated with command of a squadron also varies greatly. Before 1864 the entire fleet of the Royal Navy was divided into three squadrons, the red, the white, and the blue. Each Royal Navy squadron alone was more powerful than most national navies. Today, a squadron might number three to ten vessels, which might be major warships, transport ships, submarines, or small craft i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maizuru Naval District
was one of four main administrative districts of the pre-war Imperial Japanese Navy. Its territory included the entire Sea of Japan coastline from northern Kyūshū to western Hokkaidō. History The strategic importance of the location of Maizuru, Kyoto, Maizuru and its potential for development into a military port for operations in the Sea of Japan towards Korea, Russia and even China was early recognized by the Imperial Japanese Navy. During the administrative re-organization of the Navy in 1889, Maizuru was designated as the headquarters of the ''Fourth Naval District'' (, ''dai-yon kaigunku''), and its harbor was dredged, a Breakwater (structure), breakwater constructed and docking facilities for warships were established. With the First Sino-Japanese War, the port was fortified with the addition of heavy coastal artillery. However, the naval bases at Sasebo and Kure, Hiroshima, Kure were geographically more convenient for the Navy during the war, and received the bulk of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Commissioning
Ship commissioning is the act or ceremony of placing a ship in active service and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to placing a warship in active duty with its country's military forces. The ceremonies involved are often rooted in centuries-old naval tradition. Ship naming and launching endow a ship hull with her identity, but many milestones remain before she is completed and considered ready to be designated a commissioned ship. The engineering plant, weapon and electronic systems, galley, and other equipment required to transform the new hull into an operating and habitable warship are installed and tested. The prospective commanding officer, ship's officers, the petty officers, and seamen who will form the crew report for training and familiarization with their new ship. Before commissioning, the new ship undergoes sea trials to identify any deficiencies needing corre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceremonial Ship Launching
Ceremonial ship launching involves the performance of ceremonies associated with the process of transferring a vessel to the water. It is a nautical tradition in many cultures, dating back thousands of years, to accompany the physical process with ceremonies which have been observed as public celebration and a solemn blessing, usually but not always, in association with the launch itself. Ship launching imposes stresses on the ship not met during normal operation and, in addition to the size and weight of the vessel, represents a considerable engineering challenge as well as a public spectacle. The process also involves many traditions intended to invite good luck, such as christening by breaking a sacrificial bottle of champagne over the bow as the ship is named aloud and launched. Methods There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching". The oldest, most familiar, and most widely used is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keel-laying
Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one of the four specially celebrated events in the life of a ship; the others are launching, commissioning and decommissioning. In earlier times, the event recognized as the keel laying was the initial placement of the central timber making up the backbone of a vessel, called the keel. As steel ships replaced wooden ones, the central timber gave way to a central steel beam. Modern ships are most commonly built in a series of pre-fabricated, complete hull sections rather than around a single keel. The event recognized as the keel laying is the first joining of modular components, or the lowering of the first module into place in the building dock. It is now often called "keel authentication", and is the ceremonial beginning of the ship's life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Gun
A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) are typically designed more for firing short bursts rather than continuous firepower, and are not considered true machine guns. As a class of military kinetic projectile weapon, machine guns are designed to be mainly used as infantry support weapons and generally used when attached to a bipod or tripod, a fixed mount or a heavy weapons platform for stability against recoils. Many machine guns also use belt feeding and open bolt operation, features not normally found on other infantry firearms. Machine guns can be further categorized as light machine guns, medium machine guns, heavy machine guns, general purpose machine guns and squad automatic weapons. Similar automatic firearms of caliber or more are classified as autocannons, rat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow (ship)
The bow () is the forward part of the hull of a ship or boat, the point that is usually most forward when the vessel is underway. The aft end of the boat is the stern. Prow may be used as a synonym for bow or it may mean the forward-most part of the bow above the waterline. Function A ship's bow should be designed to enable the hull to pass efficiently through the water. Bow shapes vary according to the speed of the boat, the seas or waterways being navigated, and the vessel's function. Where sea conditions are likely to promote pitching, it is useful if the bow provides reserve buoyancy; a flared bow (a raked stem with flared topsides) is ideal to reduce the amount of water shipped over the bow. Ideally, the bow should reduce the resistance and should be tall enough to prevent water from regularly washing over the top of it. Large commercial barges on inland waterways rarely meet big waves and may have remarkably little freeboard at the bow, whereas fast military ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Motor
An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagnetic coil, wire winding to generate force in the form of torque applied on the motor's shaft. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, Inverter (electrical), inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be powered by AC or DC, be Brushed motor, brushed or Brushless motor, brushless, single-phase, Two-phase electric power, two-p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller Shaft
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint. History The term ''driveshaft'' first appeared during the mid-19th centu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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