I'm sure there have been many a post on this, but I've been doing research and thought I'd put the ideas here.
So flags/signals have been used in various ways over the centuries and I do believe we can come up with somewhat of a simple understanding of them. I'll add links to simple sources as well.
White - passive doesn't want a fight, won't stop you from sinking, freely hand over resources and treasure
internationally known as truce or ceasefire.
Blue - just passing. Doesn't want to start a fight but may defend themselves. When passing it will be done on the portside [left]
Yellow - not looking for a fight, passing ships are free to stop and communcate.
Red - no quarter will be given. Sole intention is to kill pirates and steal treasure, not looking to sink your ship.
Jolly Roger - sole intention is to take your treasure, kill your men, sink your ship.
Black - do not approach, will fight back.
Hungering - hunting sea monsters and is willing to team
Bilge Rat - trying to finish achievements and is willing to team
Rainbow- friendly vessel looking to have fun, and team up.
White flag - Wikipedia
