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The line coinciding approximately with the 180th meridian, at which each calendar day first begins; the boundary between the -12 and +12 time zones. The date on each side of this line differs by 1 day, but the time is the same in these two zones. When crossing this line on a westerly course, the date must be advanced 1 day; when crossing on an easterly course, the date must be put back 1 day. Sometimes called INTERNATIONAL DATE LINE.

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A freight fixing system for tankers. In the tanker market, the 'freight fixing system' differs a lot. The use of an 'International Scale' now called the ''New World-wide Tanker Nominal Freight Scale' or simply the '(new) Worldscale' (NWS), is the main characteristic of the tankers' chartering. Normally the Worldscale is being used for tanker cargoes over 10,000 tons. By using such an international scale (the new Worldscale), the parties can compare and evaluate the freight rates for different voyages and different market levels in an easier way. The Worldscale is a table containing freight rates for several tanker trades, taking into account all 'cost related' items involved in each one of them. Such items are: The distances between practically all conceivable tankers trades which are comparatively few and which distances for owners' information are printed in the NWS table. The port costs (disbursement accounts D/A etc.). The port time (four days). Bunker costs. Other costs. And an additional fictional cost element of USDollars 12,000 per day. The basis of the Worldscale is a standard tanker of 75,000 tons dwt , on which round voyage calculations are made taking into account the above mentioned 'cost' items. In this way the freight per metric ton required by the standard ship in each trade has been calculated. The result is found in the Worldscale tables given as a certain amount of dollars (freight) per ton for each trade. These results (values) are called WS 100 or WS Flat. It is obvious that the daily cost of USDollars 12,000 is an imaginary amount, used only as a basis for calculations. Therefore WS 100 is not the actual figure which would cover the daily and voyage costs of the standard ship but an indicator used as a convenient basis level. The Worldscale tables are being updated / revised yearly, in an effort to keep the basis for the calculations in line with actual conditions and actual costs such as port costs, bunker prices etc. Nevertheless the 'fixed hire element' of USDollars 12,000 is maintained. Usually, the tanker owners / managers, produce a series of voyage calculations for the most frequent trades applying to the type and size of their own ships according to the WS. In this way they have available a number of different WS rates which they can compare at a glance with the offered alternative employments. A fixture concluded at WS 80, actually means that the owners will be paid a freight equal to 80% of the freight which appears on the Worldscale table for the specific trade. A direct comparison between a fixture concluded, for instance, at WS 80 and another fixture in an other trade which was concluded at a higher or lower rate, is not correct, since the various cost elements (bunkers, port costs, daily costs) have a different impact on different voyages.


The time recorded when the last mooring line attaching the vessel to the pier, terminal, or mooring is let go and brought aboard. The official time the vessel left the berth, pier or mooring.


A north-south reference line, particularly a great circle through the geographical poles of the earth. The term usually refers to the upper branch, the half, from pole to pole, which passes through a given place; the other half being called the lower branch. An astronomical (terrestrial) meridian is a line connecting points having the same astronomical longitude. A geodetic meridian is a line connecting points of equal geodetic longitude. Geodetic and sometime astronomical meridians are also called geographic meridians. Geodetic meridians are shown on charts. The prime meridian passes through longitude 0°. Sometimes designated TRUE MERIDIAN to distinguish it from magnetic meridian, compass meridian, or grid meridian, the north-south lines relative to magnetic, compass, or grid direction, respectively. A fictitious meridian is one of a series of great circles or lines used in place of a meridian for certain purposes. A transverse or inverse meridian is a great circle perpendicular to a transverse equator. An oblique meridian is a great circle perpendicular to an oblique equator. Any meridian used as a reference for reckoning time is called a time meridian. The meridian used for reckoning standard zone, daylight saving, or war time is called standard, zone, daylight saving, or war meridian respectively. The meridian through any particular place or observer, serving as the reference for local time, is called local meridian, in contrast with the Greenwich meridian, the reference for Greenwich time. A celestial meridian is a great circle of the celestial sphere, through the celestial poles and the zenith. Also called CIRCLE OF LATITUDE.


The period from midnight to midnight. The calendar day is 24 hours of mean solar time in length and coincides with the civil day unless a time change occurs during a day


  1. A rate of rise or fall of a quantity against horizontal distance expressed as a ratio, decimal, fraction, percentage, or the tangent of the angle of inclination. 2. The rate of increase or decrease of one quantity with respect to another. 3. A term used in radionavigation to refer to the spacing between consecutive hyperbolas of a family of hyperbolas per unit time difference. If the gradient is high, a relatively small time-difference error in deter- mining a hyperbolic line of position will result in a relatively high position error. See also GEOMETRIC DILUTION OF PRECISION


  1. The boundary line of a circle or other closed plane curve or the outer limits of a sphere or other round body. 2. The length of the boundary line of a circle or closed plane curve or of the outer limits of a sphere or other rounded body. The circumference of a sphere is the circumference of any great circle on the sphere.


A general term for the boundary defined as the line (or measured from the line or points thereon) used to depict the intersection of the ocean surface and the land at an elevation of a particular datum, excluding one established by treaty or by the U.S. Congress.


A vertical line at the intersection of the summer load line and the after side of the rudder post or sternpost, or the centerline of the rudder stock if there is no rudder post or sternpost


An area either side of a line of position, within which, for a stated level of probability, the true position is considered to lie.


A survey made to establish or to reestablish a boundary line on the ground or to obtain data for constructing a map or plat showing a boundary line.

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