Who is designated as the 2nd Substitute when the Chief of Staff is ashore?

The correct choice designates the other embarked officer as the 2nd Substitute when the Chief of Staff is ashore. In naval operations, the hierarchy and chain of command are critical for maintaining order and effective decision-making, especially when the primary leaders are unavailable.

When the Chief of Staff is not present, the officer who takes on that role must be capable of carrying out the necessary responsibilities and ensuring continuity in leadership. The "2nd Substitute" typically refers to a secondary representative who can act in the Chief of Staff's absence and step into their duties, ensuring that all operational and administrative tasks proceed smoothly.

The other options do not align with the established protocol for who would directly fill in for the Chief of Staff. The 3rd Substitute may not have the requisite authority or experience needed for such a critical position. The commanding officer (CO) usually retains ultimate responsibility, but they would not normally act as the 2nd Substitute directly. Lastly, the Chief of Staff, by definition, is the individual who is absent, reinforcing that someone else must take on their role in their absence.