3.1.3 Zones & Loadline Marks


Different parts of the world and different seasons are considered to vary in their degree of danger and so vary in the amount of freeboard necessary for safety. International convention has divided the world into zones, the least dangerous of which is titled 'Tropical' zone and the most dangerous is 'Winter, North Atlantic'. Furthermore, salt water provides more buoyancy to a ship than fresh water, so that if the ship loads in fresh water she may be loaded to a deeper draft as she will rise up to the correct draft when reaching the ocean.


=          Tropical Zone, Fresh Water

=          Fresh Water

=          Tropical Zone (Salt water)

=          Summer (in other zones)

=          Winter (in other zones)


Loadline marks

For these reasons a ship's loadline can have as many as six marks, each of which has an initial against it which represents:


TF Tropical Freshwater (loadline)




W Winter (loadline), West (cardinal direction)

WNA =   Winter North Atlantic




The actual mark (the disc with a line through it) is the Summer Mark. On the line are placed the initials of the Classification Society that surveyed the ship to determine the positioning of the mark. In the illustration is LR Lloyd's Register of Shipping (Lloyds Register) but there are several more such as AB (American Bureau) or Rl (Registro Italiana) and so on.


Ships used for carrying lumber (timber) can be granted an additional privilege, because of the inherent buoyancy of the cargo, and allowed to load deeper than ships carrying other cargoes. Additional loadline marks (corresponding to those mentioned above) are painted on the ship and prefixed with the letter L. If the ship happens not to be carrying timber on a particular voyage then the maximum draft will be in accordance with the standard marks.



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