Wikipedia has a good entry detailing the meaning behind each of the Signal Flags. Click on the image above to view the rest.
About John Konrad
Captain John Konrad is the founder and CEO of gCaptain and author of the book Fire On The Horizon. John is a USCG licensed Master of Unlimited Tonnage, has sailed a variety of ships from ports around the world and is a distinguished alumnus of SUNY Maritime College.