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How did streamers or pennants help identify warships at sea?
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flag
Various shapes of flags: (from left) rectangle (Algeria), square (Switzerland), pennant (Nepal), swallowtail (Ohio, U.S.).
Streamers, now commonly known as pennants, were essential for identifying warships at sea due to their distinct shape and length. Because of their significant size—historically ranging from 18 to 60 feet long—they were uniquely suited for maritime use, typically flown from a yardarm, topmast, or a pole above the fighting top.1
These flags served specific identification purposes:
- Distinguishing Vessel Types: Pennants helped differentiate warships from merchant vessels.1
- Commission Status: They were used to identify a warship in commission—meaning it was active and under the command of a captain—as opposed to a ship that was laid up in harbor.12
- Command Authority: The hoisting of a commission pennant traditionally signaled that a captain had assumed command of the vessel.1
Beyond identification, flags were also fundamental to military communication at sea. Starting in the 16th century, navies developed complex codes using the position and number of flags to transmit messages between ships.3