Radar mast is displaying 4 flags that are possible to be flying in port,
not all at the same time though. From top down...

ZULU: I require a tug. Internationally = same                
PAPA: All personnel return to ship; I am proceeding to sea. Internationally = same
QUEBEC: Boat call; all boats return to ship. Internationally = Quarantine.
ROMEO: Ready duty ship. Internationally = no meaning