Final answer:
In open waters, a power-driven vessel must give way to a sailing vessel according to COLREGs Rule 18, due to the sailing vessel's limited maneuverability.
Step-by-step explanation:
On open waters, a power-driven vessel shall keep out of the way of a sailing vessel. According to the International Regulations for Preventing Collisions at Sea (COLREGs), Rule 18 details the responsibilities between vessels and gives sailing vessels the right of way over power-driven vessels under sail, considering other factors such as each vessel's maneuverability, size, and the sea conditions. This rule is in place as sailing vessels are generally less maneuverable and cannot adjust their course and speed as quickly as power-driven vessels.