What shapes are shown by a vessel aground?

A vessel that is aground is required to display specific day shapes to indicate its situation to other vessels. The correct signal for a vessel aground consists of three balls arranged in a vertical line. This configuration serves to alert nearby vessels of the grounded status and its potential hazard.

The vertical arrangement is significant because it clearly communicates to other mariners that the vessel has run aground, differentiating it from other day shapes that might signify different statuses, such as being anchored or restricted in ability to maneuver. The use of three balls emphasizes the seriousness of the situation, ensuring visibility and understanding for other navigators in the vicinity.

The other options, while they represent various configurations of day shapes, do not correctly identify the specific signal required for a vessel aground.