

Signal Book for Ships of War

Name of Corresponding Unit Plan: War of 1812

Grade Level: 6-12

Common Core Standards
RS.9-10.4. Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context.

Content Areas: Reading, Social Studies, Math

Recommended Length/Duration: Two 45-60 minute class periods

Learning Goals: Students will understand the historical importance of codes in military communications. Students will become familiar with using primary source documents. Students will learn to decode and encode numerical messages using the 1799 Signal Book for Ships of War.


  1. This activity should be embedded in a study of the Battle of Plattsburg or another historic event. Students should have read or discussed multiple accounts of the event so that they are familiar enough to describe it in detail.
  2. Discuss the sequence of events that took place during the Battle of Plattsburg. List the main events and Lead a class discussion about, read aloud, or have students read independently the background article describing the use of signal flags and the Royal Navy Signal Book for Ships at War.
  3. Project on a screen, or have students use individual computers to view the images of the Signal Book for Ships of War; PDF can be downloaded online at the University of Rhode Island’s Special Collections (Paper 15):
  4. Orient students to the document by slowly proceed from the cover, through the Table of Contents, and to the code section of the book. Point out that the letter “s” was often printed as “f” at this time. Also point out that the signal flags used in 1799, while similar to modern signal flags, had different meanings.
  5. Have students look on pages 7-11 at the signal flag signals. Have them look over the commands and discuss any they don’t understand. (These are signals related to sailing ships in archaic language. If no one understands the meaning, this could become a mini research project.)
  6. Have students proceed to page 12 to identify the numerical flags used in 1799. Point out that they are different from today.
  7. Have students proceed to page 13 and point out how each signal is assigned a number written into the signal book. The numerical signals continue from page 14 – 45. Point out that there are additional visual and sound signals at the back to the signal book.
  8. Distribute Signal Book for Ships of War worksheets. Explain that students will use the on-line images of the 1799 signal book to find the meaning of various signals given on the worksheet. They will also be asked to encode a signal and create a “hoist” communicating it.
  9. After students have had time to complete the worksheet, review the results. Discuss any errors or disagreements about the proper meaning or coding of the messages.

Assessments: Review worksheets for accuracy and effort.

Materials/Resources: Computers with internet access, Signal Book for Ships of War article and worksheet, Crayons, markers, colored pencils

Special Considerations: This lesson requires access to the on-line image of the 1799 Signal Book for Ships of War. This can be accomplished in many ways. If the class has only one computer, it can be done as a whole group activity. It can also be done individually or in small groups around multiple computers. It may be set up as a center at an individual computer over the course of a day or week.


Interested students might want to read the signal procedures more carefully to learn how the flags were actually used in practice.

Students might be interested in comparing the flags used by the Royal Navy in 1799 to the flags in use today. Which are the same? Which are different? How have the meanings of the same flags changed over time?

Students may be able to find images of period fighting ships and see if they can identify any of the signals the ships are flying.