What is a key characteristic of isolated danger marks when illuminated at night?

Isolated danger marks are navigational aids used to indicate a hazard to navigation, such as a submerged rock or wreck that is surrounded by safe water. When illuminated at night, these marks typically have a distinctive light characteristic to aid in their identification.

The correct answer refers to the specific behavior of the light emitted by isolated danger marks, which is a flashing white light. This characteristic is crucial because it helps mariners differentiate these marks from others while navigating in low visibility conditions. The flashing pattern serves both as a warning of potential danger and as a unique identifier, ensuring that vessels can recognize the hazards associated with these marks clearly.

In contrast, other options do not accurately describe the light characteristics of isolated danger marks. Continuous white lights and colored lights are associated with different types of navigational aids, while the description of lights that do not flash wouldn’t apply, as the unique flashing pattern is a defining feature of these navigational markers. Understanding these characteristics helps ensure safe navigation by allowing mariners to recognize hazards marked by isolated danger marks promptly.