What is the first step when responding to a communications fast reaction drill?

The first step when responding to a communications fast reaction drill is to send a messenger to get the Command Duty Officer (CDO). This action is fundamental because the CDO is responsible for overseeing the ship's operations and ensuring that the chain of command is maintained during drills and emergencies. By notifying the CDO first, it ensures that the proper authority is aware of the situation and can coordinate an appropriate response.

The CDO plays a critical role in managing communications and directing personnel during drills or actual events, allowing for a swift and organized reaction to the situation at hand. Promptly involving the CDO also ensures that any strategic decisions or changes in operations can be handled effectively.

In contrast, calling base to repeat the message or sending for the captain later may delay the response, as those actions do not immediately involve key personnel who are crucial for the operational response. Similarly, while notifying available personnel is important, it is secondary to ensuring that command structure is activated by engaging the CDO first. Therefore, initiating communication with the CDO establishes a clear line of authority and allows for a prompt chain of action to unfold.