What signaling method is often used for visual communication at sea?

Flags or pennants are the correct answer when it comes to visual communication at sea. This method, known as flag signaling, utilizes a standardized set of flags to convey messages between vessels. Each flag represents a letter or a specific meaning, enabling ships to communicate important information such as navigational warnings, distress calls, or operational coordination without the need for sound.

Visual signaling, particularly with flags, is essential in maritime situations where sound signals may not be effective due to distance or the presence of background noise. Additionally, the use of flags is a time-tested method that conforms to international regulations such as the International Code of Signals (ICS), making it universally understood among mariners worldwide.

While horns, flares, and light beams from searchlights are indeed methods for signaling, they serve different purposes or are less standardized compared to flag systems. Horns are primarily used for auditory signals and may not convey a specific message without additional context. Flares are typically used for distress signaling and are more one-time, emergency indicators rather than regular communication. Light beams from searchlights can be used for signaling, but they are usually less effective than flags for routine communication due to their reliance on line of sight and limited range.