What is the signal for a vessel at anchor?

The signal for a vessel at anchor is indeed indicated by one prolonged blast. This sound signal serves multiple purposes in maritime communication, particularly to notify other vessels in the vicinity of the anchored ship's presence. When a vessel is at anchor, it is not making way, and the sound signal is a way of ensuring that other vessels are aware of the potential hazard that might arise if they come too close.

In the context of navigation and maritime safety, sound signals are crucial for preventing collisions and maintaining situational awareness. The one prolonged blast effectively communicates to others that the vessel is stationary and at anchor, which is important information for approaching vessels to navigate safely. Understanding this signal is essential for mariners to ensure proper communication and safety on the water.