Flag alphabet

Ships use the flag alphabet to exchange messages. They do this optically, using signal flags. There are different ways in which this can be done:

 Each flag can represent a letter, all the flags spell out the message
 A flag used alone usually has a special meaning. A boat supporting a diver will show the "A flag"
 Several flags used together can form a code, which can be looked up in a code book both ships have.
 In ship races, flags have different meanings: 

 Related pages 
 Flag semaphore

Category:Flags