What is the sound signal for a power-driven vessel indicating "I am operating astern propulsion"?

The sound signal indicating "I am operating astern propulsion" is three short blasts. This signal is used by power-driven vessels to communicate their maneuvering intentions to other vessels, ensuring safe navigation, especially in crowded or narrow waterways.

By using this specific sound signal, the operator informs other mariners that the vessel is reversing its operations, which is crucial for avoiding collisions and for maintaining overall situational awareness among nearby vessels. This practice is part of the International Regulations for Preventing Collisions at Sea (COLREGs), which established a universal set of rules for maritime navigation communication.

Each sound signal serves a distinct purpose, and understanding these signals is vital for effective maritime operations and safety.