Question 328Safety & Environmental - 1st Asst/Chief

The correct answer is B) Heave. Heave is the vertical motion of a vessel, which affects the vessel's positional motion stability. Positional motion stability refers to the vessel's ability to maintain its position and orientation in the water. Heave, being the up-and-down movement of the vessel, directly impacts the vessel's stability and its ability to remain upright and in the desired position. The other options, such as surge (forward-backward motion), sway (side-to-side motion), and pitch (forward-backward rotation), do not directly affect the vessel's positional stability, which is the key focus of this question.