Convention- Is the Framework of an Agreement between countries.
Regulations- Technical provisions of the convention.
Protocol - modification in a convention. It is used to react quickly to a serious accident at sea or recent development which needs changes.
Amendment- Changes to improve the context of the regulation of the convention.
Resolutions- Amendments made by the council committee sub-committee for conventions, which are brought by resolutions by IMO.
Code- Gives specific technical requirements for the convention.
Binding code (eg. ISM Code)
Recommended code (eg Code of Safety for Special purpose Ship)