What is the purpose of a ship's keel in naval design?

The purpose of a ship’s keel in naval design is to provide structural integrity and stability. The keel is the backbone of the ship, running along the bottom from the bow to the stern. It acts as the primary source of strength for the vessel's hull, ensuring it can withstand the forces encountered when navigating through water.

This structural component also plays a vital role in enhancing the ship's stability by lowering the center of gravity, which helps prevent capsizing and allows the ship to remain upright in various sea conditions. By offering stiffness to the overall design, the keel contributes to the ship's ability to handle rough seas while maintaining balance and control, essential for safe operation at all times.

The other options do address important aspects of naval design, but they do not accurately reflect the primary function of the keel itself.