Who normally takes over the duties of the executive officer if they become incapacitated?

The duties of the executive officer typically fall to the next senior line officer on board if the executive officer becomes incapacitated. This practice ensures that there is a clear and established chain of command, which is critical in maintaining operational effectiveness and continuity of leadership within the ship's hierarchy. The next senior line officer is likely to be familiar with the executive officer's responsibilities and the ship's operations, enabling them to step in seamlessly.

This arrangement helps to maintain the command structure and provides reassurance to the crew that leadership is stable during an unexpected situation. The other alternatives, while relevant in different contexts, do not align with naval protocols regarding officer hierarchy and succession.