IMO amends its conventions by tacit acceptance: an amendment enters into force unless enough Parties object in time

Background

The International Maritime Organization is responsible for more than 50 international conventions and agreements and has adopted numerous protocols and amendments.
IMO has six main bodies concerned with the adoption or implementation of conventions: the Assembly and the Council are the main organs, and the committees involved are the Maritime Safety Committee, the Marine Environment Protection Committee, the Legal Committee and the Facilitation Committee.
In early conventions, amendments came into force only after a percentage of Contracting States, usually two thirds, had accepted them, which in practice led to long delays.
Under the tacit acceptance procedure an amendment enters into force at a particular time unless, before that date, objections to the amendment are received from a specified number of Parties.
Under the International Convention for the Safety of Life at Sea (SOLAS), 1974, an amendment to most of the Annexes, which constitute the technical parts of the Convention, is deemed to have been accepted at the end of two years from the date on which it is communicated to Contracting Governments.
It is not accepted if objected to by more than one third of Contracting Governments, or by Contracting Governments owning not less than 50 per cent of the world's gross merchant tonnage.
This period may be varied by the Maritime Safety Committee, with a minimum limit of one year, and amendments generally enter into force within 18 to 24 months.
Enforcement of IMO conventions depends upon the Governments of Member Parties, which enforce the provisions for their own ships and set the penalties for infringements.