How do environmental factors like swells and waves impact a vessel's stability?

Environmental factors such as swells and waves introduce forces that can cause a vessel to heel, which is the leaning of a vessel to one side. When waves strike the hull of a vessel, they exert lateral forces that can shift the center of gravity and change the righting moment, impacting the vessel's overall stability.

Heel refers to the angle at which a vessel tilts away from an upright position, and this tilting can be influenced by external forces. If a vessel is positioned in such a way that waves strike it from the side, the resulting force can push the vessel over to one side, increasing its heel angle. A higher heel reduces the effectiveness of the vessel's righting levers, which are crucial for restoring the vessel to an upright position after it has been tilted.

In contrast, options suggesting that swells and waves either increase the vessel's weight, stabilize the vessel, or have no impact on stability do not accurately reflect the dynamics at play. The introduction of waves and swells does not add weight; rather, it can create instability if the forces are strong enough to overwhelm the righting moments of the vessel. Therefore, option A accurately describes the impact of environmental factors on vessel stability.