Which signal is used to indicate a vessel is in distress?

The correct signal to indicate a vessel is in distress is represented by three short blasts. This specific signal is a standardized acknowledgment of a vessel's situation when they require assistance. In maritime communication, these blasts serve to alert nearby boats and vessels of the distress situation, prompting them to maintain a lookout and be ready to assist.

In contrast, the other signals have different meanings or uses within maritime communication. For instance, one long blast is typically used to signify a vessel's position or intention, while three long blasts serve to indicate that a vessel is backing up. The continuous ringing of a bell is usually associated with anchoring or signaling within a harbor, not a distress situation. Each of these signals plays a distinct role in marine communication, highlighting the importance of using the correct signal to convey specific messages.