|
Hogging And Sagging
In solid mechanics, structural engineering, and shipbuilding, hogging and sagging describe the shape that a beam or similar long object will deform into when loading is applied. ''Hogging'' describes a beam that curves upwards in the middle, and ''sagging'' describes a beam that curves downwards. Ships Dynamic stress Hogging is the stress a ship's hull or keel experiences that causes the center or the keel to bend upward. Sagging is the stress a ship's hull or keel is placed under when a wave is the same length as the ship and the ship is in the trough of two waves. This causes the middle of the ship to bend down slightly, and depending on the level of bend, may cause the hull to snap or crack. Sagging or dynamic hogging may have been what sank the ''Prestige'' off Spain on 19 November 2002. The 2013 loss of container ship '' MOL Comfort'' off the coast of Yemen was attributed to hogging. Subsequent lawsuits blamed the shipbuilder for design flaws. Time-induced stress Hoggi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid Mechanics
Solid mechanics (also known as mechanics of solids) is the branch of continuum mechanics that studies the behavior of solid materials, especially their motion and deformation (mechanics), deformation under the action of forces, temperature changes, phase (chemistry), phase changes, and other external or internal agents. Solid mechanics is fundamental for civil engineering, civil, Aerospace engineering, aerospace, nuclear engineering, nuclear, Biomedical engineering, biomedical and mechanical engineering, for geology, and for many branches of physics and chemistry such as materials science. It has specific applications in many other areas, such as understanding the anatomy of living beings, and the design of dental prosthesis, dental prostheses and surgical implants. One of the most common practical applications of solid mechanics is the Euler–Bernoulli beam theory, Euler–Bernoulli beam equation. Solid mechanics extensively uses tensors to describe stresses, strains, and the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drydock
A dry dock (sometimes drydock or dry-dock) is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform. Dry docks are used for the construction, maintenance, and repair of ships, boats, and other watercraft. History China The use of dry docks in China goes at least as far back as the 10th century A.D. In 1088, Song dynasty scientist and statesman Shen Kuo (1031–1095) wrote in his '' Dream Pool Essays'': Europe Greco-Roman world The Greek author Athenaeus of Naucratis (V 204c-d) reports something that may have been a dry dock in Ptolemaic Egypt in the reign of Ptolemy IV Philopator (221-204 BC) on the occasion of the launch of the enormous '' Tessarakonteres'' rowing ship. However a more recent survey by Goodchild and Forbes does not substantiate its existence. It has been calculated that a dock for a vessel of such a size might have had a volume of 750,000 gallons of water. Renaissa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hog Chains
Hog chains were a technological device that permitted river boats to have lightly built hulls so they could travel in shallow water. Engineering problem It was advantageous for river vessels to operate in very shallow water, so that work could be done at all seasons and in areas that lacked deeper rivers. This required flat-bottomed boats with lightly built hulls. However, the hulls tended to bend out of shape over time, particularly with sternwheelers, which had heavy components at stern (the sternwheel) and also towards the bow (the boilers). If the boat hull became bowed upwards in the middle, this was called "hogging". If the boat bowed down in the middle, this was called "sagging". Description To forestall hogging and sagging, since about 1850, the hulls of wooden river boats were held in shape by a system of wire trusses, called "hog chains".Hunter, Louis C., ''Steamboats on the Western Rivers'' (1949), at pages 97-101. These were not chains at all, but rather i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strength Of Ships
The strength of ships is a topic of key interest to naval architects and shipbuilders. Ships which are built too strong are heavy, slow, and cost extra money to build and operate since they weigh more, whilst ships which are built too weakly suffer from minor hull damage and in some extreme cases catastrophic failure and sinking. Loads on ship hulls The hulls of ships are subjected to a number of loads. *Even when sitting at dockside or at anchor, the pressure of surrounding water displaced by the ship presses in on its hull. *The weight of the hull, and of cargo and components within the ship bears down on the hull. *Wind blows against the hull, and waves run into it. *When a ship moves, there is additional hull drag, the force of propellers, water driven up against the bow. *When a ship is loaded with cargo, it may have many times its own empty weight of cargo pushing down on the structure. *In heavy seas, water flowing over or crashing down onto the weather deck applies (possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Nautical Terms (other)
Glossary of nautical terms may refer to: * Glossary of nautical terms (A–L) This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water (mostly though not necessarily on the sea). Some remain current, while many date from the 17th ... * Glossary of nautical terms (M–Z) {{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deflection (engineering)
In structural engineering, deflection is the degree to which a part of a long structural element (such as Beam (structure), beam) is deformation (mechanics), deformed laterally (in the direction transverse to its longitudinal axis) under a Structural load, load. It may be quantified in terms of an angle (angular displacement) or a distance (linear displacement (geometry), displacement). A longitudinal deformation (in the direction of the axis) is called ''elongation (mechanics), elongation''. The deflection distance of a member under a load can be calculated by Integral, integrating the function that mathematically describes the slope of the deflected shape of the member under that load. Standard formulas exist for the deflection of common Beam (structure), beam configurations and load cases at discrete locations. Otherwise methods such as virtual work, Direct integration of a beam, direct integration, Castigliano's method, Macaulay's method or the direct stiffness method are use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simpson's Rules (ship Stability)
Simpson's rules are a set of rules used in ship stability and naval architecture, to calculate the areas and volumes of irregular figures. This is an application of Simpson's rule for finding the values of an integral, here interpreted as the area under a curve. Simpson's 1st rule Also known as the 1–4–1 rule (after the multipliers used ). : \text = \frac( a + 4b + c). Simpson's 2nd rule Also known as the 1–3–3–1 rule, Simpson's second rule is a simplified version of Simpson's 3/8 rule. : \text = \frac 8 (a + 3b + 3c + d). Simpson's 3rd rule Also known as the 5–8–1 rule, SImpson's third rule is used to find the area between two consecutive ordinates when three consecutive ordinates are known. : \text = \frac h (5a + 8b - c ). This estimates the area in the left half of the figure for Simpson's 1st Rule while using all three pieces of data. Use of Simpsons rules Simpson's rules are used to calculate the volume of lifeboats, and by surveyors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cargo
In transportation, cargo refers to goods transported by land, water or air, while freight refers to its conveyance. In economics, freight refers to goods transported at a freight rate for commercial gain. The term cargo is also used in case of goods in the cold-chain, because the perishable inventory is always in transit towards a final end-use, even when it is held in cold storage or other similar climate-controlled facilities, including warehouses. Multi-modal container units, designed as reusable carriers to facilitate unit load handling of the goods contained, are also referred to as cargo, especially by shipping lines and logistics operators. When empty containers are shipped each unit is documented as a cargo and when goods are stored within, the contents are termed containerized cargo. Similarly, aircraft ULD boxes are also documented as cargo, with an associated packing list of the items contained within. Description Marine Seaport terminals handle a wide ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UK P&I Club
The UK P&I Club is a marine mutual liability insurer in the United Kingdom providing P&I insurance for the global shipping industry. The UK P&I Club is one of the 12 members of the International Group of P&I Clubs. The club is one of the largest of the global P&I Clubs and in 2002 covered more than 100 million tons across 6,000 ships. In 2019, the Club provided insurance for over 144 million gross tons of merchant shipping. History The UK P&I Club was founded as the United Kingdom Mutual Steam Ship Assurance Association. In 1886, Thomas Miller, took over the management of the club and the company Thomas Miller still manages the UK P&I Club as of 2023. In 2018, the insurer began the process of setting up a subsidiary in Rotterdam as a result of the Brexit. The club is responsible for the Protection and Indemnity (third party) liabilities insurance coverage for the container ship Ever Given that grounded and blocked the Suez Canal in 2021. The club was responsible for reaching an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Line (watercraft)
The load line, also known as Plimsoll line, indicates the legal limit to which a ship may be loaded for specific water types and temperatures in order to safely maintain buoyancy, particularly with regard to the hazard of waves. The load line is a waterline that corresponds to the maximum draft of the ship, thus yet another name, load waterline. Varying water temperatures will affect a ship's draft, because warm water is less dense than cold water, providing less buoyancy. In the same way, fresh water is less dense than salinated or seawater, with a similar lessening effect upon buoyancy. The rules for international load lines are defined by the International Convention on Load Lines from 1966. For inland water transport regional, national or local rules apply. Load lines are indicated by special markings on the hull. The marking for the main load line, the summer load line, is called load line mark or Plimsoll mark (positioned amidships), the marks for other conditions are n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yemen
Yemen, officially the Republic of Yemen, is a country in West Asia. Located in South Arabia, southern Arabia, it borders Saudi Arabia to Saudi Arabia–Yemen border, the north, Oman to Oman–Yemen border, the northeast, the south-eastern part of the Arabian Sea to the east, the Gulf of Aden to the south, and the Red Sea to the west, sharing maritime boundary, maritime borders with Djibouti, Eritrea, and Somalia across the Horn of Africa. Covering roughly 455,503 square kilometres (175,871 square miles), with a coastline of approximately , Yemen is the second largest country on the Arabian Peninsula. Sanaa is its constitutional capital and largest city. Yemen's estimated population is 34.7 million, mostly Arabs, Arab Muslims. It is a member of the Arab League, the United Nations, the Non-Aligned Movement and the Organisation of Islamic Cooperation. Owing to its geographic location, Yemen has been at the crossroads of many civilisations for over 7,000 years. In 1200 BCE, the Sab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
