What does a ship need to adjust for when determining the water depth?

When determining water depth, a ship must consider the draft of the vessel, which is the vertical distance between the waterline and the bottom of the hull (keel). This measurement is crucial because it indicates how much of the ship is submerged below the waterline. By knowing the draft, the ship's crew can assess how much water is needed to ensure safe navigation without risking running aground.

In many cases, the water depth must be greater than the draft of the vessel to provide a safe margin. This ensures that the ship remains stable and avoids contact with the seabed. The draft can vary based on factors such as the weight of the cargo and fuel, but the draft itself is the primary measurement for determining whether the vessel can safely navigate through a particular body of water.

Other considerations, such as wind speed, height of the ship, and weight of the cargo, are important for overall navigation and vessel performance but do not directly impact the measurement of water depth in relation to the ship's safe passage.