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Draft Survey
A draft survey is a calculation of the weight of cargo loaded or unloaded to or from a ship from measurents of changes in its displacement. The technique is based on Archimedes' principle. The procedure is standardized by the United Nations Economic Commission for Europe for the measurement of coal cargoes. Procedure The draft survey is performed by reading the ship's draft on the draft markings at six standard points on the hull: forward, midships and aft on both port and starboard Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which a ... sides. Corrections for factors such as trim, water density and non-cargo weight changes are made before calculating the cargo weight change. References {{reflist Measurement Nautical terminology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Displacement (fluid)
In fluid mechanics, displacement occurs when an object is largely immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, and from this, the volume of the immersed object can be deduced: the volume of the immersed object will be exactly equal to the volume of the displaced fluid. An object that sinks displaces an amount of fluid equal to the object's volume. Thus buoyancy is expressed through Archimedes' principle, which states that the weight of the object is reduced by its volume multiplied by the density of the fluid. If the weight of the object is less than this displaced quantity, the object floats; if more, it sinks. The amount of fluid displaced is directly related (via Archimedes' principle) to its volume. In the case of an object that sinks (is totally submerged), the volume of the object is displaced. In the case of an object that floats, the amount of fluid displaced will be equal in weight to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
