IALA Maritime Buoyage System Practice Exam – Prep, Questions, and Study Guide

A light rhythm of "Morse Code A" on a Safe Water Mark is indicative of an occulting light. This type of light is characterized by a specific pattern of light emissions where the light is on for a brief duration followed by a longer duration of darkness. "Morse Code A" specifically correlates to a short flash followed by a longer interval of darkness, which directly aligns with the definition of an occulting light.

Safe Water Marks are utilized to indicate navigable waters and are typically seen in deep water. The use of an occulting light helps mariners decipher the light pattern and confirm their position relative to navigational hazards. Understanding this characteristic of Safe Water Marks is vital for safe navigation and for the identification of safe passage routes.