What are velocity and STW used for in navigation?

Velocity and Speed Through Water (STW) are fundamental concepts in navigation, particularly when determining the current state of a vessel’s movement. They are used to assess how fast a vessel is moving over the water and in which direction. Velocity refers to the speed of the vessel and its directional component, while STW provides information on the vessel’s speed relative to the water, which may differ from speeds derived from other factors such as the influence of tides or currents.

In navigation, these measurements are vital for cruising predictions, allowing officers to anticipate arrival times at destinations based on current speed and heading. Additionally, they can be necessary for calculating the ship’s course and ensuring it maintains a safe and accurate route, taking into account environmental conditions.

Although the correct answer is about pitsword calculation, it's essential to recognize that the role of velocity and STW is prominently featured in making navigational decisions and adjustments. Students should understand how these concepts apply in a practical context, contributing significantly to effective navigation practices on the water.