Naval Flags
This image is licensed under the Creative Commons Attribution 3.0 Unported License. © Jean-Philippe Boulet
These flags form an internationally recognised set of signals (intended for use by ships at sea). There are the usual flags for alphanumeric characters (26 letters, 10 numbers) but there are others.
There is an answering pennant for acknowledging a received signal, and three 'subsitute' flags which are used to represent flags already used.
The substitute flags are used when you wish to show a flag that has already been used. The type of flag indicates which flag in the list you should repeat. For example if you wanted to send the message
A B C D E B
you would place the flags for A, B, C, D and E normally, and for the last flag you would use the blue/white second subsitute flag. This instructs the observer to 'repeat' the second flag in the list, namely the B.
Naval Signals - Flags
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| A I have a diver down, keep well clear and at a slow speed | B I am taking on, carrying or discharging dangerous goods | C Yes, affirmative | D Keep clear of me, I am manoeuvring with difficulty |
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| E I am directing my course to starboard | F I am disabled, communicate with me | G I require a pilot; I am hauling nets | H I have a pilot on board |
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| I I am directing my course to port | J I am on fire and have dangerous cargo on board. Keep well clear | K I wish to communicate with you | L You should stop. I have something important to communicate |
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| M My vessel is stopped and making no way through the water | N No, negative | O Man overboard | P The ship is about to leave port; Your lights are out or burning badly |
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| Q My ship is healthy and I request free pratique | R No signal | S My engines are going full astern | T Keep clear, I am engaged in pair trawling |
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| U You are standing into danger | V I require assistance | W I require medical assistance | X Stop carrying out your intentions and watch for my signals |
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| Y I am dragging my anchor | Z I require a tug; I am shooting nets |
Naval Signals - Numerics
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| 1 | 2 | 3 | 4 |
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| 5 | 6 | 7 | 8 |
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| 9 | 0 |
Naval Signals - Special
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| Answering Pennant | First Substitute | Second Substitute | Third Substitute |