International Signal Flags

  • Posted on: 20 September 2010
  • By: Eve

How to say, communicate with me, in foreign languages?

In the summer of 2010 Suwena was going first time out of EU waters when we travelled through Saimaa Canal. The Saimaa Canal guide book suggested that at least somebody on the board understands international single letter signal flags, in case the Russian coastguard would like to communicate with the vessel. In this case the L-flag is probably the most important, because it is used to order the vessel to stop. Of course we've VHF in Suwena which we also listen whenever we are sailing. But as it's written in guide book, if Russian military vessel asks you to stop by any known communication method, you better to comply. So we decided that Suwena will stop instantly if ordered to do so. On our trip through Russian Federation territorial waters we did not need neither VHF nor signal flags, but we learned again new seamanship skills.

Other better known signal flags are A and Q. A-flag is used to signal other vessels that we've a diver down in the water. Q-flag is probably known to all long distance cruisers as it is used to notify customs that the vessel is not declared yet. We Googled around and there was quite a lot of information about signal flags but none of the pages we found provided short printable overview. So Andrus had an idea to make quick reference card about single letter signal flags.

Quick Reference Card

Spelling the words with signal flags is rather slow and tedious job and therefore internationally there is an agreement about multiple letter codes. Most known of them is of course 'NC' which means 'I'm in distress'. Less known is that same code abbreviations can be used on other communication channels e.g. by using the Morse code with hand flags, arms, flashing light or sound signal and in addition by using the international phonetic alphabet on megaphone, VHF or SSB radio. Multiple letter signal codebook belongs to required equipment on internationally travelling ships.

We did not find an European edition of multiple letter codebook which can be freely distributed. However, we did find a book of International Code of Signals that has been published by US government for anybody to use. Even thou this book is a US version it is based on international treaties.

International Code of Signals

With this quick guide about signal flags we wish to all fellow boaters the code UW.