As Chief Engineer or First Assistant Engineer you should be familiar with the six motions of a vessel. Which of these motions affects the governing "positional motion" stability?

Correct Answer: Option B — Heave

Heave represents the vertical linear motion of a vessel along the Z-axis. It directly impacts the vessel's displacement and the instantaneous draft, which are critical factors in calculating the metacentric height (GM) and overall transverse stability during heavy weather operations or when navigating in restricted waters.