What Are International Maritime Signal Flags?

Have you ever wondered why certain ships are dressed overall with different colored flags? Well, those are not just any flags. They are called international maritime signal flags and are widely used at seas for communication between ships. They can be used individually as well as in combination with other flags to convey various messages. For instance, consider the Zulu flag, which has the appearance of a diagonally quartered square and is filled with four different colors—yellow, blue, red, and black. It is also known as the Z flag and represents the letter Z in the English alphabet. When it is used alone, it means “I require a tug” but when used near fish vessels, it means “I am shooting nets”. Many a time, it is also used in combination with number flags to convey time; where the first two letters denote hours and the last two letters denote minutes. Apart from this, there are 25 letter flags such as Sierra, Alfa, and Mike that are also used to convey important information. 

These are usually built on sturdy white canvas with the use of strong and dark colors to make sure they do not fade away while the ship is at sea. Considering the fact that only certain colors are readily distinguishable at the sea, the signal flags are made by using just 5 colors— Red, Blue, Yellow, Black, and White. Of all the patterns and colors that are used for these maritime signal flags, interestingly, the Zulu flag is the only flag in the set that uses four different colors. It also happens to have special significance in Japan because of the Battle of Tsushima, which was an important naval battle, fought during the Russo-Japanese War. These flags are incredibly useful to the sailors who have depended on these signals for communication for multiple decades now.