What effect do moving waves have on a ship's stability compared to calm seas?

When considering the effect of moving waves on a ship's stability, higher waves indeed create more fluctuations in stability. This is due to the dynamic forces exerted on the vessel as it moves through the water. In waves, a ship experiences changes in its position and angle of heel, which can cause the center of gravity and center of buoyancy to shift more dramatically than in calm seas.

As the ship rises and falls with the waves, the heeling angle can change rapidly, leading to temporary loss of stability. The vessel may also experience periods of increased rolling or pitching, which are phenomena closely linked to wave action. These fluctuations can affect the vessel's righting arm and overall stability, potentially causing it to become less stable during adverse wave conditions.

In contrast, a ship in calm waters maintains a more predictable and consistent stability profile, as no external forces from waves are acting upon it. Therefore, the role of waves in creating instability and fluctuations is significant, making the statement that higher waves create more fluctuations in stability accurate and relevant.