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HMCS Tillsonburg (K496)
HMS ''Pembroke Castle'' was a built for the British Royal Navy during the Second World War. Before completion, the ship was transferred to the Royal Canadian Navy and renamed HMCS ''Tillsonburg''. ''Tillsonburg'' saw service as a convoy escort during the Second World War in the Battle of the Atlantic. Following the war, the corvette was converted for merchant use and sold to Chinese interests. The ship was renamed ''Ta Ting'' in 1946, ''Chiu Chin'' in 1947 before being taken over the Nationalist Chinese government in 1951, rearmed and renamed ''Kao An''. The ship remained in service with the Republic of China Navy until being discarded in 1963. Design and description The Castle class were an improved corvette design over their predecessor . The Flower class was not considered acceptable for mid-Atlantic sailing and was only used on Atlantic convoy duty out of need. Though the Admiralty would have preferred s, the inability of many small shipyards to construct the larger ships r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pembroke Castle
Pembroke Castle ( cy, Castell Penfro) is a medieval castle in the centre of Pembroke, Pembrokeshire in Wales. The castle was the original family seat of the Earldom of Pembroke. A Grade I listed building since 1951, it underwent major restoration during the early 20th century. In 1093, Arnulf of Montgomery built the first castle at the site when he fortified the promontory beside the Pembroke River during the Norman invasion of Wales. A century later, the castle was given by Richard I to William Marshal, who became one of the most powerful men in 12th-century Britain. He rebuilt Pembroke Castle in stone, creating most of the structure that remains today. The castle is open to the public and is the largest privately owned castle in Wales. Construction The castle is sited on a strategic rocky promontory by the Milford Haven Waterway. The first fortification on the site was a Norman motte-and-bailey. It had earthen ramparts and a timber palisade. In 1189, Pembroke Castle was acqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-frequency Direction Finding
High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters. HF/DF was primarily used to catch enemy radios while they transmitted, although it was also used to locate friendly aircraft as a navigation aid. The basic technique remains in use to this day as one of the fundamental disciplines of signals intelligence, although typically incorporated into a larger suite of radio systems and radars instead of being a stand-alone system. Earlier systems used a mechanically rotated antenna or solenoid and an operator listening for peaks or nulls in the signal, which often took considerable time to determine the bearing on the order of a minute or more. Later systems used a set of antennas to receive the same signal in slightly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASDIC
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels. "Sonar" can refer to one of two types of technology: ''passive'' sonar means listening for the sound made by vessels; ''active'' sonar means emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, and SODAR (an upward-looking in-air sonar) is used for atmospheric investigations. The term ''sonar'' is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extrem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Charge
A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive Shock factor, hydraulic shock. Most depth charges use explosive, high explosive charges and a fuze set to detonate the charge, typically at a specific depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters. Depth charges were developed during World War I, and were one of the first viable methods of attacking a submarine underwater. They were widely used in World War I and World War II, and remained part of the anti-submarine arsenals of many navies during the Cold War, during which they were supplemented, and later largely replaced, by anti-submarine homing torpedoes. A depth charge fitted with a nuclear warhead is also known as a "nuclear depth bomb". These were designed to be dropped from a patrol plane or deployed by an anti-submarine missile from a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Numerals
Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, each letter with a fixed integer value, modern style uses only these seven: The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced by Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some applications to this day. One place they are often seen is on clock faces. For instance, on the clock of Big Ben (designed in 1852), the hours from 1 to 12 are written as: The notations and can be read as "one less than five" (4) and "one less than ten" (9), although there is a tradition favouring representation of "4" as "" on Roman numeral clocks. Other common uses include year numbers on monuments and buildings and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Triple Expansion
A compound steam engine unit is a type of steam engine where steam is expanded in two or more stages. A typical arrangement for a compound engine is that the steam is first expanded in a high-pressure ''(HP)'' cylinder, then having given up heat and losing pressure, it exhausts directly into one or more larger-volume low-pressure ''(LP)'' cylinders. Multiple-expansion engines employ additional cylinders, of progressively lower pressure, to extract further energy from the steam. Invented in 1781, this technique was first employed on a Cornish beam engine in 1804. Around 1850, compound engines were first introduced into Lancashire textile mills. Compound systems There are many compound systems and configurations, but there are two basic types, according to how HP and LP piston strokes are phased and hence whether the HP exhaust is able to pass directly from HP to LP ( Woolf compounds) or whether pressure fluctuation necessitates an intermediate "buffer" space in the form of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-drum Boiler
Three-drum boilers are a class of water-tube boiler used to generate steam, typically to power ships. They are compact and of high evaporative power, factors that encourage this use. Other boiler designs may be more efficient, although bulkier, and so the three-drum pattern was rare as a land-based stationary boiler. The fundamental characteristic of the "three-drum" design is the arrangement of a steam drum above two water drums, in a triangular layout. Water tubes fill in the two sides of this triangle between the drums, and the furnace is in the centre. The whole assembly is then enclosed in a casing, leading to the exhaust flue. Firing can be by either coal or oil. Many coal-fired boilers used multiple firedoors and teams of stokers, often from both ends. Development Development of the three-drum boiler began in the late 19th century, with the demand from naval ships that required high power and a compact boiler. The move to water-tube boilers had already begun, with ... [...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 Overall
__NOTOC__ Length overall (LOA, o/a, o.a. or oa) is the maximum length of a vessel's hull measured parallel to the waterline. This length is important while docking the ship. It is the most commonly used way of expressing the size of a ship, and is also used for calculating the cost of a marina berth (for example, £2.50 per metre LOA). LOA is usually measured on the hull alone. For sailing ships, this may ''exclude'' the bowsprit and other fittings added to the hull. This is how some racing boats and tall ships use the term LOA. However, other sources may include bowsprits in LOA. Confusingly, LOA has different meanings. "Sparred length", "Total length including bowsprit", "Mooring length" and "LOA including bowsprit" are other expressions that might indicate the full length of a sailing ship. LOD Often used to distinguish between the length of a vessel including projections (e.g. bow sprits, etc.) from the length of the hull itself, the Length on Deck or LOD is often repor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-boat
U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role (commerce raiding) and enforcing a naval blockade against enemy shipping. The primary targets of the U-boat campaigns in both wars were the merchant convoys bringing supplies from Canada and other parts of the British Empire, and from the United States, to the United Kingdom and (during the Second World War) to the Soviet Union and the Allied territories in the Mediterranean. German submarines also destroyed Brazilian merchant ships during World War II, causing Brazil to declare war on both Germany and Italy on 22 August 1942. The term is an anglicised version of the German word ''U-Boot'' , a shortening of ''Unterseeboot'' ('under-sea-boat'), though the German term refers to any submarine. Austro-Hungarian Navy submarines were also kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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