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Waterline Length
A vessel's length at the waterline (abbreviated to L.W.L) is the length of a ship or boat at the level where it sits in the water (the ''waterline''). The LWL will be shorter than the length of the boat overall (''length overall'' or LOA) as most boats have bows and stern protrusions that make the LOA greater than the LWL. As a ship becomes more loaded, it will sit lower in the water and its ambient waterline length may change; but the registered L.W.L is measured from a default load condition. Measurement This measure is significant in determining several of a vessel's properties, such as how much water it displaces, where the bow and stern waves occur, hull speed, amount of bottom-paint needed, etc. Traditionally, a stripe called the "boot top" is painted around the hull just above the waterline. In sailing boats, longer waterline length will usually enable a greater maximum speed, because it allows greater sail area, without increasing beam or draft. Greater beam and draft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Length Measurements
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] |
Waterline
The waterline is the line where the hull of a ship meets the surface of the water. A waterline can also refer to any line on a ship's hull that is parallel to the water's surface when the ship is afloat in a level trimmed position. Hence, waterlines are a class of "ships lines" used to denote the shape of a hull in naval architecture lines plans. The load line (also known as Plimsoll line) is the waterline which indicates the legal limit to which a ship may be loaded for specific water types and temperatures in order to safely maintain buoyancy. For vessels with displacement hulls, the hull speed is defined by, among other things, the waterline length. In a sailing boat, the waterline length can change significantly as the boat heels, and can dynamically affect the speed of the boat. Aircraft In the aircraft design the term ''waterline'' designates a horizontal reference line used in alignment checks. The base line of the aircraft is designated as waterline 0 (zero). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Overall
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 reported. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow (ship)
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. Prow may be used as a synonym for bow or it may mean the forward-most part of the bow above the waterline. Function A ship's bow should be designed to enable the hull to pass efficiently through the water. Bow shapes vary according to the speed of the boat, the seas or waterways being navigated, and the vessel's function. Where sea conditions are likely to promote pitching, it is useful if the bow provides reserve buoyancy; a flared bow (a raked stem with flared topsides) is ideal to reduce the amount of water shipped over the bow. Ideally, the bow should reduce the resistance and should be tall enough to prevent water from regularly washing over the top of it. Large commercial barges on inland waterways rarely meet big waves and may have remarkably little freeboard at the bow, whereas fast military ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stern
The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Originally, the term only referred to the aft port section of the ship, but eventually came to refer to the entire back of a vessel. The stern end of a ship is indicated with a white navigation light at night. Sterns on European and American wooden sailing ships began with two principal forms: the ''square'' or ''transom'' stern and the ''elliptical'', ''fantail'', or ''merchant'' stern, and were developed in that order. The hull sections of a sailing ship located before the stern were composed of a series of U-shaped rib-like frames set in a sloped or "cant" arrangement, with the last frame before the stern being called the ''fashion timber(s)'' or ''fashion piece(s)'', so called for "fashioning" the after part of the ship. This frame i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hull Speed
Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well. When hull speed is exceeded, a vessel in displacement mode will appear to be climbing up the back of its bow wave. From a technical perspective, at hull speed the bow and stern waves interfere constructively, creating relatively large waves, and thus a relatively large value of wave drag. Ship drag for a displacement hull increases smoothly with speed as hull speed is approached and exceeded, often with no noticeable inflection at hull speed. The concept of hull speed is not used in modern naval architecture, where considerations of speed/length ratio or Froude number are considered more helpful. Background As a ship moves in the water, it creates standing waves that oppose its movement. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetted Surface
In fluid dynamics, the wetted area is the surface area that interacts with the working fluid or gas. * In maritime use, the wetted area is the area of the watercraft's hull which is immersed in water. This has a direct relationship on the overall hydrodynamic drag of the ship or submarine. * In aeronautics, the wetted area is the area which is in contact with the external airflow. This has a direct relationship on the overall aerodynamic drag of the aircraft. See also: Wetted aspect ratio. * In motorsport, such as Formula One, the term wetted surfaces is used to refer to the bodywork, wings and the radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ..., which are in direct contact with the airflow, similarly to the term's use in aeronautics.Archived aGhostarchiveand thWayb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Between Perpendiculars
Length between perpendiculars (often abbreviated as p/p, p.p., pp, LPP, LBP or Length BPP) is the length of a ship along the summer load line from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. When there is no sternpost, the centerline axis of the rudder stock is used as the aft end of the length between perpendiculars. Measuring to the stern post or rudder stock was believed to give a reasonable idea of the ship’s carrying capacity, as it excluded the small, often unusable volume contained in its overhanging ends. On some types of vessels this is, for all practical purposes, a waterline measurement. In a ship with raked stems, naturally that length changes as the draught of the ship changes, therefore it is measured from a defined loaded condition. See also * Length overall Length overall (LOA, o/a, o.a. or oa) is the maximum length of a vessel's hull measured parallel to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Terminology
Seamanship is the skill, art, competence (human resources), competence, and knowledge of operating a ship, boat or other craft on water. The'' Oxford Dictionary of English, Oxford Dictionary'' states that seamanship is "The skill, techniques, or practice of handling a ship or boat at sea." It involves topics and development of specialised skills, including navigation and international Admiralty law, maritime law and regulatory knowledge; weather, meteorology and forecasting; watchkeeping; ship-handling and small boat handling; operation of deck equipment, anchors and cables; ropework and line handling; communications; sailing; engines; execution of evolutions such as towing; cargo handling equipment, dangerous cargoes and cargo storage; dealing with emergencies; survival at sea and search and rescue; and fire fighting. The degree of knowledge needed within these areas is dependent upon the nature of the work and the type of vessel employed by a sailor, seafarer. History Shi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shipbuilding
Shipbuilding is the construction of ships and other Watercraft, floating vessels. In modern times, it normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history. Until recently, with the development of complex non-maritime technologies, a ship has often represented the most advanced structure that the society building it could produce. Some key industrial advances were developed to support shipbuilding, for instance the sawing of timbers by Saw#Mechanically powered saws, mechanical saws propelled by windmills in Dutch shipyards during the first half of the 17th century. The design process saw the early adoption of the logarithm (invented in 1615) to generate the curves used to produce the shape of a hull (watercraft), hull, especially when scaling up these curves accurately in the mould Lofting, loft. Shipbuilding and ship repairs, both commercial an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
