The International Regulations for Preventing Collisions at Sea 1972 (COLREGS) are published by the International Maritime Organization (IMO), and set out the “rules of the road” to be followed by ships and other vessels at sea. COLREGS can also refer to the specific political line that divides inland waterways (subject to one set of navigation rules) and coastal waterways (subject to international navigation rules).
Although rules for navigating vessels inland may differ, the international rules specify that they should be as closely in line with the international rules as possible. In mainland Europe, “CEVNI” (European Code for Vessels Navigating Inland) apply. In the US, the rules for vessels navigating inland are published alongside the international rules.
The Racing Rules of Sailing, which govern the conduct of yacht and dinghy racing, are based on the Colregs, but differ in some important matters such as overtaking and right of way close to turning marks.