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A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships having the degree of freedom zero (in the terms of theory of machines).
As stated above, superstructure consists of the parts of the ship or a boat, including sailboats, fishing boats, passenger ships, and submarines, that project above her main deck. This does not usually include its masts or any armament turrets. Note that in modern times, turrets do not always carry naval artillery, but they can also carry missile launchers and/or antisubmarine warfare weapons.
The size of a watercraft's superstructure can have many implications in the performance of ships and boats, since these structures can alter their structural rigidity, their displacements, and/or stability. These can be detrimental to any vessel's performance if they are taken into consideration incorrectly.
The height and the weight of superstructure on board a ship or a boat also affects the amount of freeboard that such a vessel requires along its sides, down to her waterline. In broad terms, the more and heavier superstructure that a ship possesses (as a fraction of her length), the less the freeboard that is needed.
On a bridge, the portion of the structure that is the span and directly receives the live load is referred to as the superstructure. In contrast, the abutment, piers, and other support structures are called the substructure.
In order to improve the response during earthquakes of buildings and bridges, the superstructure might be separated from its foundation by various civil engineering mechanisms or machinery. All together, these implement the system of earthquake protection called base isolation.
Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and muscles' that create the form and shape of man-made structures. Structural engineers need to understand and calculate the stability, strength and rigidity and earthquake of built structures for buildings and nonbuilding structures. The structural designs are integrated with those of other designers such as architects and building services engineer and often supervise the construction of projects by contractors on site. They can also be involved in the design of machinery, medical equipment, and vehicles where structural integrity affects functioning and safety. See glossary of structural engineering.
A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.
A monitor was a relatively small warship which was neither fast nor strongly armored but carried 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. During the Vietnam War they were used by the United States Navy. The Brazilian Navy's Parnaíba is the last monitor in service.
HMS Captain was an unsuccessful warship built for the Royal Navy due to public pressure. She was a masted turret ship, designed and built by a private contractor against the wishes of the Controller's department. The Captain was completed in April 1870 and capsized on 07 September 1870 with the loss of nearly 500 lives because of design and construction errors that led to inadequate stability.
The Kearsarge-class was a group of two pre-dreadnought battleships built for the United States Navy in the 1890s. The two ships—USS Kearsarge and USS Kentucky—represented a compromise between two preceding battleship designs, the low-freeboard Indiana class and the high-freeboard USS Iowa, though their design also incorporated several improvements. Their primary advances over earlier designs consisted of new quick-firing guns and improved armor protection, but their most novel feature was their two-story gun turrets that consisted of a secondary 8-inch (203 mm) gun turret fixed to the top of their primary 13-inch (330 mm) turrets. The ships suffered from a number of problems, however, including a tertiary battery mounted too low in the hull and poorly-designed turrets, though the latter were attempted again with the Virginia class in the early 1900s, also with negative results.
HMS Hood was a modified Royal Sovereign-class pre-dreadnought battleship built for the Royal Navy in the early 1890s. She differed from the other ships of the class in that she had cylindrical gun turrets instead of barbettes and a lower freeboard. She served most of her active career in the Mediterranean Sea, where her low freeboard was less of a disadvantage. The ship was placed in reserve in 1907 and later became the receiving ship at Queenstown, Ireland. Hood was used in the development of anti-torpedo bulges in 1913 and was scuttled in late 1914 to act as a blockship across the southern entrance of Portland Harbour after the start of World War I.
A cutter is generally a small- to medium-sized vessel, depending on its role and definition. Historically, it was a smallish single-masted, decked sailcraft designed for speed rather than capacity. As such, it was gaff-rigged, with two or more headsails and often a bowsprit of some length, with a mast sometimes set farther back than on a sloop. While historically a workboat, as used by harbor pilots, the military, and privateers, sailing cutters today are most commonly fore-and-aft rigged private yachts.
The County class was a class of heavy cruisers built for the Royal Navy in the years between the First and Second World Wars. They were the first post-war cruisers constructed for the Royal Navy and were designed within the limits of the Washington Naval Treaty of 1922. Such ships, with a limit of 10,000 tons, standard displacement and 8-inch calibre main guns may be referred to as "treaty cruisers".
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary or upper deck is the horizontal structure that forms the "roof" of the hull, strengthening it and serving as the primary working surface. Vessels often have more than one level both within the hull and in the superstructure above the primary deck, similar to the floors of a multi-storey building, that are also referred to as decks, as are certain compartments and decks built over specific areas of the superstructure. Decks for some purposes have specific names.
Turret ships were a 19th-century type of warship, the earliest to have their guns mounted in a revolving gun turret, instead of a broadside arrangement.
This is a partial glossary of nautical terms; some remain current, while many date from the 17th to 19th centuries. See also Wiktionary's nautical terms, Category:Nautical terms, and Nautical metaphors in English. See the Further reading section for additional words and references.
A turret deck ship is a type of merchant ship with an unusual hull, designed and built in the late 19th and early 20th centuries. The hulls of turret deck vessels were rounded and stepped inward above their waterlines. This gave some advantages in strength and allowed them to pay lower canal tolls under tonnage measurement rules then in effect. The type ceased to be built after those rules changed.
The waterline is the line where the hull of a ship meets the surface of the water. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line, that indicates the draft of the ship and 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 that may arise. 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 the same lessening effect upon buoyancy.
A gun turret is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in some degree of azimuth and elevation.
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.
Earthquake engineering is an interdisciplinary branch of engineering that designs and analyzes structures, such as buildings and bridges, with earthquakes in mind. Its overall goal is to make such structures more resistant to earthquakes. An earthquake engineer aims to construct structures that will not be damaged in minor shaking and will avoid serious damage or collapse in a major earthquake. Earthquake engineering is the scientific field concerned with protecting society, the natural environment, and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels. Traditionally, it has been narrowly defined as the study of the behavior of structures and geo-structures subject to seismic loading; it is considered as a subset of structural engineering, geotechnical engineering, mechanical engineering, chemical engineering, applied physics, etc. However, the tremendous costs experienced in recent earthquakes have led to an expansion of its scope to encompass disciplines from the wider field of civil engineering, mechanical engineering, nuclear engineering, and from the social sciences, especially sociology, political science, economics, and finance.
HMS Glatton was a breastwork monitor which served in the Victorian Royal Navy.
Seakeeping ability or seaworthiness is a measure of how well-suited a watercraft is to conditions when underway. A ship or boat which has good seakeeping ability is said to be very seaworthy and is able to operate effectively even in high sea states.
A trunk deck ship is a type of merchant ship with a hull that was stepped inward in order to obtain more favourable treatment under canal toll rules then in effect. As those tolls were set by net tonnage, a measure of volume, and as the tonnage rules did not account for all of the cargo space of such vessels, trunk deck ships incurred lower tolls than more conventional ships of equivalent capacity. When the measurement rules were changed, the type was no longer built.
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