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International Maritime Flags

Marine Flags The sea is a property of no one…Commercial vessels, mega yachts, and adventures boaters cross the seas, oceans, and lakes around the world headed to somewhere…whether going to a specific port to deliver goods or just browsing the waters in the search of the ultimate joy, a number of vessels cross each other’s path every day, every hour, every minute. Most of the times ships can pass each other without any need of communication or just saying “hi there, have a great trip”. Well, life is not perfect and sometimes the situation requires that vessels interchange more detailed messages. If we all spoke one language and radio and satellite communications were as reliable as we wished that would not be a problem. The reality, however, is that even now – in the 21st century, communication between people from different countries can be a problem. That’s why the men of sea have never stopped using one old-fashioned but understandable to any mariner language – the language of nautical flags.

Nautical flags are used by ships to communicate between each other or to send messages to the shore. Developing a system of flags acceptable, easy to understand and apply by all countries around the world was not an easy task and took time and effort, but at the end it is a fact and it is all worth. Nowadays, almost all countries recognize and follow the International Code of Signals (ICS) as a primary way of communication using color flags. The main purpose of the flags has remained intact over the centuries. Flags main application is to help ensure safety – both for the vessel and crew displaying the flag(s) and for the observers of the communicated message(s) – either other vessels or people on the shore.

The ICS flag system is the most common and almost exclusively used by all vessels around the world. NATO ships also use the ICS flags with some exceptions. The details, however, are pertinent to the military and, thus, of no specific interests to the general public. Please note that racing and regatta events use a different flag system to communicate specific messages. As noted earlier, the ICS flag system’s main purpose is to provide a way of communication between ships and/or shore to help ensure the safety of crew and/or people on land.

Overall flags fall into four major groups – a single flag can denote a letter, a number, a specific message, or can indicate a repetition of a flag already displayed (these flags help eliminate the need of having multiple duplicates of the same flag on board). Flags can be used individually – for example, the letter flags can be used to spell out a word. However, letter flags also have a general message implied when used on its own. In addition, certain two or three flag combinations spell out more detailed messages as described by the International Code of Signals (last official edition was published in 1969 and the last revision is from 2003).

Explore the sections below to learn more about nautical flags and their practical use.

Flag Letters
Flag Numerals
Flag Substitutes
Flag Miscellaneous Flags
Weather Flags
Flag Combinations