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Pit Sword
The pit sword (also known as a rodmeter) is a blade of metal or plastic that extends into the water beneath the hull of a ship. It is part of the pitometer log, a device for measuring the ship's speed through the water. See also * Electromagnetic log *Pitot tube A pitot tube ( ; also pitot probe) measures fluid flow velocity. It was invented by French engineer Henri Pitot during his work with aqueducts and published in 1732, and modified to its modern form in 1858 by Henry Darcy. It is widely use ... References External links Historical site with information on US Navy submarine pitometer log systems during World War II. This site shows the pit sword or rodmeter as it is deployed. {{DEFAULTSORT:Pit Sword Measuring instruments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blade
A blade is the Sharpness (cutting), sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are intended to cut. This includes early examples made from flaked stones like flint or obsidian, evolving through the ages into metal forms like copper, bronze, and iron, and culminating in modern versions made from steel or ceramics. Serving as one of humanity's oldest tools, blades continue to have wide-ranging applications, including in combat, cooking, and various other everyday and specialized tasks. Blades function by concentrating force at the cutting edge. Design variations, such as serrated edges found on bread knives and saws, serve to enhance this force concentration, adapting blades for specific functions and materials. Blades thus hold a significant place both historically and in contemporary society, reflecting an evolution i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not. Metals are typically ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polythiazyl, polymeric sulfur nitride. The general science of metals is called metallurgy, a subtopic of materials science; aspects of the electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry, it is a multidisciplinary topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are nonmetallic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding, molded, Extrusion, extruded, or Compression molding, pressed into a diverse range of solid forms. This adaptability, combined with a wide range of other properties such as low weight, durability, flexibility, chemical resistance, low toxicity, and low-cost production, has led to their widespread use around the world. While most plastics are produced from natural gas and petroleum, a growing minority are produced from renewable resources like polylactic acid. Between 1950 and 2017, 9.2 billion metric tons of plastic are estimated to have been made, with more than half of this amount being produced since 2004. In 2023 alone, preliminary figures indicate that over 400 million metric tons of plastic were produced worldwide. If global trends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported Geographic exploration, exploration, Global trade, trade, Naval warfare, warfare, Human migration, migration, colonization, and science. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a Full-rigged ship, ship-rigged sailing ship with three or more masts, each of which is Square rig, square-rigged. The earliest historical evidence of boats is found in Egypt during the 4th millennium BCE. In 2024, ships had a global cargo capacity of 2.4 billion tons, with the three largest classes being ships carrying dry bulk (43%), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitometer Log
Pitometer logs (also known as pit logs) are devices used to measure a ship's speed relative to the water. They are used on both surface ships and submarines. Data from the pitometer log is usually fed directly into the ship's navigation system. History All nautical instruments designed to measure the speed of a ship through water are known as logs. This nomenclature dates back to days of sail when sailors tossed a log attached to rope knotted at regular intervals off the stern of a ship. The sailors would count the number of knots that passed through their hands in a given period of time. Today sailors still use the unit of knots to express a ship's speed. The speed of the ship was needed to navigate the ship using dead reckoning, which was standard practice in the days before modern navigation instruments like GPS. During World War II, pitometer logs were often interfaced directly into warship fire control systems. This interface was necessary to allow gunnery and torpedo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Log
An Electromagnetic Log, sometimes called an "EM log", is an electronic sensor which measures the speed of a vessel through sea water. Like many other technologies, its name derives from the traditional chip log. It makes use of Faraday's law of induction by measuring the EMF induced in water moving through a magnetic field generated by the sensor. Mechanism of operation # Electricity flows through a coil inside the device, inducing a magnetic field perpendicular to the flow of water # Since sea water is an electrical conductor, an EMF is induced when it moves relative to the magnetic field, according to Faraday's law. # This EMF creates a local voltage differential, which can be measured by two electrodes in contact with the water. # The speed of the water flowing past the sensor is directly proportional to this measured voltage. Some EM logs have three electrodes arranged in a right triangle; this allows the speed to be calculated even if the electrodes are not perfectly alig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitot Tube
A pitot tube ( ; also pitot probe) measures fluid flow velocity. It was invented by French engineer Henri Pitot during his work with aqueducts and published in 1732, and modified to its modern form in 1858 by Henry Darcy. It is widely used to determine the airspeed of aircraft; the water speed of boats; and the flow velocity of liquids, air, and gases in industry. Theory of operation The basic pitot tube consists of a tube pointing directly into the oncoming fluid flow. Pressure in the tube can be measured as the moving fluid cannot escape and stagnates. This pressure is the stagnation pressure of the fluid, also known as the total pressure or (particularly in aviation) the pitot pressure. The measured stagnation pressure cannot just by itself be used to determine the fluid flow velocity (airspeed in aviation) directly. However, with a measured static pressure as well it can be determined by the use of Bernoulli's equation which states: :Stagnation pressure = static pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
