The International Regulations for Preventing Collisions at Sea 1972 (COLREGs) are published by the  IMO

Before the development of one set of international rules and practices, there existed separate practices and various conventions and informal procedures in different parts of the world, as advanced by various maritime nations. As a result, there were inconsistencies and even contradictions that gave rise to unintended collisions. Vessel navigation lights for operating in darkness, as well as navigation marks, also were not standardized, giving rise to dangerous confusion and ambiguity between vessels at risk of colliding.

IALA BUOYAGE SYSTEM AND DIFFERENT TYPES OF MARKS.

ROR

Part A – General

Part B – Steering and sailing (rule 4-18)

Section III (Conduct of vessels in restricted visibility)

Part D – Sound and light signals