What does a yellow flare fired by a submarine indicate?

A yellow flare fired by a submarine is used to indicate the intent to surface. This signal serves an important purpose in maintaining safe operations, especially in controlled waters where submarines may be operating beneath the surface. Firing a yellow flare is a clear visual cue to other vessels in the vicinity, informing them that the submarine is about to come to the surface, allowing for avoidance of potential collisions and enhancing navigation safety.

The other options represent different signaling situations but do not accurately describe the meaning of a yellow flare specifically associated with submarines. Understanding this signaling is crucial for maritime safety and operations, especially in environments where submarines are prevalent.