International Regulations for Preventing Collisions at Sea

The International Regulations for Preventing Collisions at Sea, commonly called the COLREGs, were adopted by IMO in 1972 and apply to all vessels on the high seas and in waters connected therewith. The rules prescribe the conduct of vessels in all conditions of visibility, sound and light signals, traffic separation schemes, and the definitions of vessels restricted in ability to manoeuvre, not under command, constrained by draught, and engaged in fishing. For a watchkeeping officer, the COLREGs are the rules of the road. Rule 5 requires a proper look-out at all times; Rule 8 demands that avoiding action be taken in ample time and be readily apparent to the other vessel; Rule 16 places the burden of keeping clear on the give-way vessel. Misapplication of the rules — particularly confusion between head-on, crossing, and overtaking situations — is a recurring cause of collisions. The COLREGs do not override the judgement of a prudent mariner: Rule 2 preserves the right and duty to depart from the rules when departure is necessary to avoid immediate danger. Officers must be able to quote and apply each rule under examination for certification under STCW. Port state control inspectors and marine casualties investigators reference the COLREGs when determining whether a vessel was navigated in a seamanlike manner.