What does the term "deadrise" refer to in ship design?

The term "deadrise" is specifically defined as the angle between the bottom of the hull and the horizontal plane. This measurement is crucial in ship design as it affects the vessel's stability, performance, and ability to navigate in different types of waters. A greater deadrise angle typically results in better performance in rough seas, as it helps to cut through waves rather than allowing the hull to slam, while also influencing how the vessel interacts with water and how it displaces water when moving.

Understanding deadrise is essential for naval architects and marine engineers, as it plays a significant role in determining the ship’s handling characteristics and operational efficiency. The other terms, while related to various aspects of ship design, do not accurately describe the deadrise concept. For instance, the angle between the hull bottom and the vertical plane pertains to a different measurement relevant to the hull's orientation rather than its deadrise.