The harbor grasp notes wind route by way of flying flags, jotting angles as masts clink and buoys bob on easy swells.
https://waylonrzco743.raidersfanteamshop.com/what-flags-does-the-u-s-navy-fly-at-sea-a-guide-to-ensigns-jacks-and-pennants
The harbor grasp notes wind path by using flying flags, jotting angles as masts clink and buoys bob on soft swells.