The development of the International Convention on Load Lines (ICLL) can be traced by to the United Kingdom in the 1870s as an attempt to prevent merchant ships from being overloaded. Lloyd’s Register established a minimum freeboard requirement for its classed ships, and after much pressure from Mr Samuel Plimsoll, the British Parliament extended this requirement to all British merchant ships. This is where the term “Plimsoll mark” originates from.
Similar load line regulations were implemented by other maritime nations, until they were standardized in the Load Line Convention of 1930. The present International Convention on Load Lines (ICLL) was drawn up in 1966 and adopted by the International Maritime Organization. It entered into force on July 21, 1968.
The regulations take into account the potential hazards present in different zones and different seasons and ensures, amongst others, the design of a robust hull that can cope with adverse sea states, the weathertight and watertight integrity of the vessel, adequate drainage of any water on deck,
All assigned load lines must be marked amidships on each side of the ship, together with the deck line. Ships intended for the carriage of timber deck cargo are assigned a smaller freeboard as the deck cargo provides protection against the impact of waves.
The International Convention on Load Lines applies to all commercial yachts if over 24 meters and over 500GT and provides detailed regulations on the assignment of freeboard, the effects on stability, and most importantly, the safe transportation of guests and crew.
Class Societies issue Load Line Certificates, and if a vessel has been built to Class, a certificate can be obtained from the relevant society.