What is the effect of a rising center of buoyancy on stability?

The effect of a rising center of buoyancy on stability is significant, and the selected answer correctly reflects that a higher center of buoyancy can enhance the vessel's stability by contributing positively to the righting moment.

When a vessel is inclined due to external forces, the center of buoyancy shifts to a new position. If the center of buoyancy rises as the ship heels, this means that the buoyant force is acting further upward relative to the center of gravity. The greater the distance between the point of buoyancy and the center of gravity, the larger the righting lever arm becomes. This righting lever arm is critical because it is the moment that acts to return the vessel to an upright position. A rising center of buoyancy therefore creates a stronger righting moment, which enhances the stability of the vessel.

This relationship is foundational to understanding a vessel's stability dynamics, as having a higher center of buoyancy reduces the risk of capsizing and helps maintain the vessel's upright attitude in the face of heeling forces. Thus, the assertion that it enhances stability is grounded in how buoyancy works in relation to the forces and moments acting on the vessel.