The Mug and Other Symbols come from your Crew HUD display when you are crewed up... you have to have Crew HUD turned on to see the Symbols.
On your screen in crew of the left is where you will see each crew member and what they are doing (manning a cannon, just sailing or a weapon in hand).
Above the crew heads you will see different colors of mugs (now theres a thread telling you the colors - one is basic, another is a member, so on... but I can't seem to find it at the moment...
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