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Spar (sailing)
A spar is a pole of wood, metal or lightweight materials such as carbon fibre used in the rigging of a sailing vessel to carry or support its sail. These include yards, booms, and masts, which serve both to deploy sail and resist compressive and bending forces, as well as the bowsprit and spinnaker pole. In larger vessels during the age of sail, spare spars could be roped together to provide a temporary surface known as a "spar deck". These served as jury-rigged repairs for permanent decks, or as an additional platform under which to shelter goods or crew. The term was also informally applied to areas of the forecastle or quarterdeck where spare spars were stored by laying them flat against the existing decking. In the modern era the term has been used to describe the uppermost deck on flush deck Flush deck is a term in naval architecture. It can refer to any deck of a ship which is continuous from stem to stern. History The flush deck design originated with rice ships built ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timber
Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). Lumber has many uses beyond home building. Lumber is sometimes referred to as timber as an archaic term and still in England, while in most parts of the world (especially the United States and Canada) the term timber refers specifically to unprocessed wood fiber, such as cut logs or standing trees that have yet to be cut. Lumber may be supplied either rough- sawn, or surfaced on one or more of its faces. Beside pulpwood, ''rough lumber'' is the raw material for furniture-making, and manufacture of other items requiring cutting and shaping. It is available in many species, including hardwoods and softwoods, such as white pine and red pine, because of their low cost. ''Finished lumber'' is supplied in standard sizes, mostly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bending
In applied mechanics, bending (also known as flexure) characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element. The structural element is assumed to be such that at least one of its dimensions is a small fraction, typically 1/10 or less, of the other two.Boresi, A. P. and Schmidt, R. J. and Sidebottom, O. M., 1993, Advanced mechanics of materials, John Wiley and Sons, New York. When the length is considerably longer than the width and the thickness, the element is called a beam. For example, a closet rod sagging under the weight of clothes on clothes hangers is an example of a beam experiencing bending. On the other hand, a shell is a structure of any geometric form where the length and the width are of the same order of magnitude but the thickness of the structure (known as the 'wall') is considerably smaller. A large diameter, but thin-walled, short tube supported at its ends and loa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarterdeck
The quarterdeck is a raised deck behind the main mast of a sailing ship. Traditionally it was where the captain commanded his vessel and where the ship's colours were kept. This led to its use as the main ceremonial and reception area on board, and the word is still used to refer to such an area on a ship or even in naval establishments on land. Many such facilities have areas decorated like shipboard quarterdecks. In the 20th century the word came to be applied to the area at the stern of the ship, often (on naval vessels) used for secondary weapons and (on battleships) seaplane catapults. In modern military designs the stern has been roofed over by the helicopter deck but a large space remains underneath which is typically used for sonar equipment or small boats and which is still referred to as the quarterdeck in Commonwealth navies. Ceremonial use There are ancient traditions of offering special deference to the quarterdeck. Greek, Roman, and Carthaginian warships all c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forecastle
The forecastle ( ; contracted as fo'c'sle or fo'c's'le) is the upper deck of a sailing ship forward of the foremast, or, historically, the forward part of a ship with the sailors' living quarters. Related to the latter meaning is the phrase " before the mast" which denotes anything related to ordinary sailors, as opposed to a ship's officers. History and design In medieval shipbuilding, a ship of war was usually equipped with a tall, multi-deck castle-like structure in the bow of the ship. It served as a platform for archers to shoot down on enemy ships, or as a defensive stronghold if the ship were boarded. A similar but usually much larger structure, called the aftcastle, was at the aft end of the ship, often stretching all the way from the main mast to the stern. Having such tall upper works on the ship was detrimental to sailing performance. As cannons were introduced and gunfire replaced boarding as the primary means of naval combat during the 16th century, the medieval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jury-rig
In maritime transport terms, and most commonly in sailing, jury-rigged is an adjective, a noun, and a verb. It can describe the actions of temporary makeshift running repairs made with only the tools and materials on board; and the subsequent results thereof. The origin of jury-rigged and jury-rigging lies in such efforts done on boats and ships, characteristically sail powered to begin with. Jury-rigging can be applied to any part of a ship; be it its super-structure ( hull, decks), propulsion systems ( mast, sails, rigging, engine, transmission, propeller), or controls (helm, rudder, centreboard, daggerboards, rigging). Similarly, after a dismasting, a replacement mast, often referred to as a jury mast (and if necessary, yard) would be fashioned, and stayed to allow a watercraft to resume making way. Etymology The phrase 'jury-rigged' has been in use since at least 1788. The adjectival use of 'jury', in the sense of makeshift or temporary, has been said to date fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Age Of Sail
The Age of Sail is a period that lasted at the latest from the mid-16th (or mid- 15th) to the mid- 19th centuries, in which the dominance of sailing ships in global trade and warfare culminated, particularly marked by the introduction of naval artillery, and ultimately reached its highest extent at the advent of the analogue Age of Steam. Enabled by the advances of the related Age of Navigation, it is identified as a distinctive element of the early modern period and the Age of Discovery. Especially in context of the latter, it refers to a more particular Eurocentric Age of Sail, while generally the Age of Sail is the culminating period of a long intercontinental history of sailing. Periodization Like most periodic eras, the definition is inexact but instead serves as a general description. The term is used differently for warships and merchant vessels. Sailing ships are an ancient technology, making far-reaching trade like the ancient spice trade possible. With the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinnaker Pole
A spinnaker pole is a spar used in sailboats (both dinghys and yachts) to help support and control a variety of headsails, particularly the spinnaker. However, it is also used with other sails, such as genoas and jibs, when sailing downwind with no spinnaker hoisted. (Since the load on a spinnaker pole is very light on this point of sailing, sometimes a special light spinnaker pole called a whisker pole is used in these circumstances.) The spinnaker pole is rigged to run from the base of the mast, where there is a special fitting for attaching one end of the pole, out to windward over the side of the boat. There, one of the control lines of whichever sail it is to be used with is run through a fitting on the other end of the spinnaker pole. This allows for more precise control of the corner of the sail to which the line is attached. For a spinnaker, the line attached to the pole is the guy, or brace, and the corner is the tack. For other headsails, such as a jib, the line would ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowsprit
The bowsprit of a sailing vessel is a spar extending forward from the vessel's prow. The bowsprit is typically held down by a bobstay that counteracts the forces from the forestays. The word ''bowsprit'' is thought to originate from the Middle Low German word ''bōchsprēt'' – ''bōch'' meaning "bow" and ''sprēt'' meaning "pole". It is sometimes used to hold up the figurehead In politics, a figurehead is a person who ''de jure'' (in name or by law) appears to hold an important and often supremely powerful title or office, yet ''de facto'' (in reality) exercises little to no actual power. This usually means that they .... References References * {{Sailing ship elements Sailboat components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compressive Stress values.
Compressive stress is defined in the same way as the tensile stress but it has negative values so as to express the compression since dL has the opposite direction. ( L is the length of the object.)
Compression stress= -( F/A)
Where F= Force applied on the object.
A= Area of cross section of the objec ...
In long, slender structural elements — such as columns or truss bars — an increase of compressive force ''F'' leads to structural failure due to buckling at lower stress than the compressive strength. Compressive stress has stress units (force per unit area), usually with negative values to indicate the compaction. However, in geotechnical engineering, compressive stress is represented with positive Positive is a property of positivity and may refer to: Mathematics and science * Positive formula, a logical formula not containing negation * Positive number, a number that is greater than 0 * Plus sign, the sign "+" used to indicate a posi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the ''metallic bond'' between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mast (sailing)
The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the centre-line of a ship or boat. Its purposes include carrying sails, spars, and derricks, and giving necessary height to a navigation light, look-out position, signal yard, control position, radio aerial or signal lamp. Large ships have several masts, with the size and configuration depending on the style of ship. Nearly all sailing masts are guyed. Until the mid-19th century, all vessels' masts were made of wood formed from a single or several pieces of timber which typically consisted of the trunk of a conifer tree. From the 16th century, vessels were often built of a size requiring masts taller and thicker than could be made from single tree trunks. On these larger vessels, to achieve the required height, the masts were built from up to four sections (also called masts). From lowest to highest, these were called: lower, top, topgallant, and royal masts. Giving the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boom (sailing)
In sailing, a boom is a spar (pole), along the of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the ''foot'' flatter when the sail angle is away from the centerline of the boat. The boom also serves as an attachment point for more sophisticated control lines. Because of the improved sail control it is rare to find a non-headsail without a boom, but lateen sails, for instance, are loose-footed. In some modern applications, the sail is rolled up into the boom for storage or reefing (shortening sail). Boom attachment The forward end of the boom attaches to a mast just below the sail, with a joint called the gooseneck. The gooseneck pivots allowing the other end of the boom to move freely. The clew (back corner) of the sail attaches to the free end of the boom. The entire ''foot'' of the sail may be attached to the boom or just the clew. If the ''foot'' is not attached to the boom, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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