Rule 5 (COLREG)

Rule 5 of the COLREGs requires every vessel to keep a proper lookout by sight, hearing, and all available means appropriate to the prevailing conditions, so as to fully appraise the situation and risk of collision. It belongs to the 1972 Convention on the International Regulations for Preventing Collisions at Sea, not SOLAS, but it works alongside SOLAS V on safety of navigation: the V/19 carriage equipment, including radar and ECDIS, are among the available means a lookout must use. Rule 5 is the most frequently cited rule in collision liability findings because lookout failures usually precede other rule breaches.