Signal flags are used to send messages from ship-to-ship and ship-to-shore. There are two types of signal flags, semaphore and maritime. Semaphore flags are used to spell out the words in a message one letter at a time. Maritime flags can represent a single letter in the alphabet or an entire message. The US Coast Guard also uses weather advisory flags (scroll down page to the Day Time Coastal Warning Display Signals) to post small craft coastal warnings.

 

Think about all of the things you could do in your classroom with nautical flags. Here are a couple of ideas: