What does the phrase "close the hatches" mean?

The phrase "close the hatches" refers specifically to sealing openings on a ship, such as those on the deck that lead below, in order to prevent water from entering the vessel during an emergency, such as flooding or rough seas. This action is critical for maintaining buoyancy and the stability of the ship. When hatches are properly closed and secured, they create a barrier against incoming water, which could otherwise compromise the integrity of the ship and pose a risk to the safety of the crew and passengers.

In contrast, locking the ship's doors for security focuses more on safety against intruders rather than water intrusion. Preparing for bad weather involves a broader set of actions, including securing equipment and notifying crew members, but does not specifically address the need to seal hatches. Storing equipment safely is an important practice, particularly in adverse conditions, but it doesn't involve the specific action of closing hatches. Thus, the importance of closing the hatches during an emergency is paramount in ensuring the vessel's safety against water ingress.