Daily Journal

December 7, 2004: Signals/Emergency Communication

Most ships nowadays have satellite communication ability. However, there are times when satellite reception may not be available. When modern technology fails, ships may communicate using methods that are hundreds of years old. Three of those methods are signal flags, flashing lights, and radiotelegraphy.

Signal flags each stand for a letter of the alphabet.

International Signal Flags

The first international signal code was drafted in 1855 by a committee set up by the British Board of Trade. It consisted of 70,000 signals using 18 flags. A revision was completed in 1897, but it didn't stand up to the needs discovered during WWI. In 1930, it was revised again and prepared in 7 languages. Codes contain one, two or three letters.

Single letter codes are used for messages that that are urgent, important, or used frequently. Some examples are the letter C for "yes," the letter K for "I wish to communicate with you," and the letter R for "received."

Two letter codes are used for general signaling: SG is "My present speed is (number) knots," NP, "The depth of the water at the bow is (number feet or meters), and KG, "Do you require a tug?" Three letter codes begin with "m" and are used for medical use only: MCU means "The patient is unconscious," MAA, "I request medical advice," and MTQ 8, "You should repeat every 8 hours." Only one code is used at a time and the receiving ship sends up a reply.

Activity 1: You are on the Titanic (lucky you!) You have hit the iceberg and need to send out some signals. Using the graphic, draw the flags that indicate the following messages:

a. HX2 I have serious damage below the waterline.

b. DX I am sinking (latitude and longitude, if necessary) Bonus activity: Can you find the longitude and latitude where the Titanic sank?

c. AE I must abandon my vessel

Most of you will not encounter emergencies at sea; however, there are times when winter weather may cause you to get stranded on or off the highway. Other emergency situations can also cause you to lose your ability to communicate by phone and get help.

Suggested group activity: Write down at least 5 emergency situations. List ways to prepare for these events. Tell what items you might need in order to communicate/signal other people that you need assistance.

Example: You have been left by the producers of the TV show "Survivor" on a deserted island. Who could you attempt to signal and how? What might you wish that you had brought with you?

Look at the pictures of Linda and Marian. Identify the letters symbolized by each of the flags.

Identify these flags

when all else fails...

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