What must be maintained by the Officer of the Deck?

The Officer of the Deck (OOD) is responsible for the safe navigation and operation of the ship while it is underway or moored. One of the primary duties of the OOD is to maintain the deck log, which is a crucial document that provides a record of events occurring during the watch. This log includes information such as the ship's course, speed, any changes in personnel or watch status, communications received, and notable occurrences on board.

Maintaining an accurate deck log is essential for several reasons. It serves as an official historical record, which can be referenced for accountability and operational analysis. Additionally, the deck log can be vital in investigations following incidents or accidents, providing a clear timeline of events. This responsibility underscores the importance of careful documentation and situational awareness that the OOD must uphold during their watch.

In contrast, the other options—managing the budget, crew training records, or the ship's inventory—fall outside the immediate responsibilities of the OOD, making them less relevant to this particular question about maintaining the deck log.