What does a vessel flying the International flag hoist 'N' over 'C' indicate?

The combination of the International code flags 'N' over 'C' signifies that a vessel requires assistance, as the flag 'N' (November) denotes "No" and 'C' (Charlie) stands for "Yes." When displayed together, they convey the message "I require assistance." This communication is essential for safety at sea, enabling nearby vessels to understand that the signaling vessel is in distress or in need of help.

In contrast, the other flags and their respective meanings do not apply in this context. For instance, signaling a vessel engaged in fishing would involve different flag codes that specifically indicate that activity. Likewise, navigating in restricted visibility or requesting a pilot involves other established protocols with distinct flag signals designed to convey those specific messages.