Amendment Procedure
A1. The IMO and the international regulatory frameworkDefinition
Process by which IMO conventions are modified, typically by tacit acceptance for technical annexes.
IMO conventions are amended either by an explicit amendment procedure requiring positive acceptance or, for technical annexes, by tacit acceptance under which an amendment enters force on a set date unless a stated number of parties object. SOLAS uses tacit acceptance for its annex (Article VIII), as does MARPOL (Article 16). The default biennial amendment cycle for SOLAS and the codes flows from this design.
Source: SOLAS Article VIII; MARPOL Article 16