The determinations of the freeboard of ships are calculated and/or verified by classification societies which issue International Load Line Certificates in accordance with the legislation of participating States.

[3][4] International Convention on Load Lines has 8 amendments, the last one (to make the use of the III Code mandatory) is adopted on 4 December 2013 and entered into force on 28 February 2018.

The Convention provides for the terms of ship's surveys, issuance, duration, validity and acceptance of International Load Line Certificates, as well as relevant State control measures, agreed exemptions and exceptions.

Annexes to the Convention contain various regulations for determining load lines, including details of marking and verification of marks, conditions of assignment of freeboard, freeboard tables and corrections, special provisions for ships intended for the carriage of timber[1] and the prescribed form of International Load Line Certificates.

[6] According to the Annexes to the convention, also taken into account are the potential hazards present in different zones and different seasons and additional safety measures concerning doors, hatchways, etc.