Final answer:
The principal assistant to the Officer of the Deck is the Boatswain's Mate of the Watch. They help with navigation, oversee deck activities, and ensure crew safety.
Step-by-step explanation:
The principal assistant to the Officer of the Deck is the Boatswain's Mate of the Watch.
The Boatswain's Mate of the Watch is responsible for assisting the Officer of the Deck in maintaining a safe and efficient watch on the ship's deck. They assist with the navigation and operation of the ship, overseeing the deck activities, and ensuring the safety of the crew.
For example, they may help with the lookout duties, oversee the lowering and raising of boats, or assist in the execution of general orders on the deck.