What is an open water of navigable depth commonly referred to as?

An open water of navigable depth is referred to as a fairway. This term specifically describes a designated area or corridor in a body of water that is safe for navigation, allowing vessels to pass through without encountering significant hazards. Fairways are essential for maritime traffic, as they ensure that ships can travel efficiently and safely while avoiding shallower areas or obstructions.

Harbors, while also important for navigation, are typically enclosed or protected areas where ships can dock, load, and unload cargo. Channels can refer to smaller water passages, often manmade, designed to guide vessels through shallow or obstacle-filled areas, but they do not encompass the broader concept of navigable depth like fairways do. Coral reefs are natural underwater structures that can pose navigational hazards rather than safe channels for marine vessels. Thus, the best term that accurately describes a navigable water route is indeed fairway.