The Meanings of Boat Flags

If you’ve ever been down to your local dock, you’ve probably seen all the boat flags hanging from the flagpoles of each boat. What’s the point? Here’s a hint: they’re not just for decoration.

Instead, most of the boat flags you see are actually nautical flags – a system of flags used to convey messages from ship to ship or ship to shore. Each flag has a different meaning, and they can be used alone or in a group for even more different boat flag meanings.

What do the boat flags mean?

When it comes to nautical flag meanings on boats, it depends on what kind of boat you’re talking about – there are different meanings for each flag depending on whether you’re using them internationally, as part of the US Navy, or as part of a sailing regatta. Here’s a list of the different ship flag meanings.

Flag Name Flag International Navy Regatta
ALFA  alpha boat flags I have a diver down; keep well clear at slow speed. n/a
BRAVO  bravo boat flags I am taking in, discharging, or carrying dangerous cargo. n/a
CHARLIE  charlie nautical flag Yes or affirmative. Change of course.
DELTA  delta signal flag I am maneuvering with difficulty; keep clear. n/a
ECHO  echo boat flags I am moving to starboard (right). n/a
FOXTROT  foxtrot nautical flag I have been disabled – please communicate with me; on aircraft carriers it means that flight operations are underway. n/a
GOLF  golf boat flags I need a pilot; for fishing boats, it means “I am hauling nets.” n/a n/a
HOTEL  hotel boat flags I have a pilot on board (used as a response to “GOLF”) n/a n/a
INDIA  india nautical flag I am altering my course to port (left). I am coming alongside you. Indicates that the around-the-ends rule is in effect at the start.
JULIET  juliet nautical flag Keep well clear of me – I am on fire and/or leaking dangerous cargo n/a
KILO  kilo boat flags I wish to communicate with you by:

  1. Morse signaling by hand-flags or arms
  2. Megaphone
  3. Morse light signals
  4. Sound signaling
LIMA  lima nautical flag You should stop immediately. Ashore: A notice to the competitors has been posted.
Afloat: Come within hail; follow me.
MIKE  mike signal flag My vessel is stopped. This boat flag signals that the mark is missing and that all boats should round the boat bearing the flag.
NOVEMBER  november nautical flag No/negative. Abandonment and re-sail.
OSCAR   Man overboard.
PAPA   In port: All sailors return to the ship; the vessel is going out to sea.

Fishing vessels at sea use this to signal that their nets are caught on something.

All personnel return to the ship – the vessel is proceeding out to sea. Used as a preparatory flag, this flag goes up four minutes before the start of the race.
QUEBEC (kay-bec)   The ship meets health regulations and is requesting clearance into port. Boats are being recalled – all boats are to return to the ship. n/a
ROMEO   n/a At sea: Planning to replenish fuel or supplies.
In port: Ready the duty ship.
SIERRA (see-air-uh)   Moving astern (to the rear of the ship being signaled). Conducting flag hoist drill. This flag means that the regatta course has been shortened. The finish line is now between this flag and the nearest rounding mark.
TANGO   Keep clear of me – I am engaged in trawling. Do not pass ahead of me. n/a
UNIFORM   You are running into danger.
VICTOR   I require assistance.
WHISKEY   I require medical assistance.
X-RAY   Stop your intentions and watch for my signals. Individual recall.
YANKEE   I am pulling my anchor behind me. The ship flying this flag is assigned to visual communications duty. Wear life jackets.
ZULU   I require a tug. 20% scoring penalty.


Using multi-flag signals

Knowing how to use the nautical flag system is hugely important when danger is imminent or communications break down. Boat flags can be seen easily when out on the open water, especially if you have a pair of binoculars. They don’t require Wi-Fi or other types of electrical signals, either: all you have to do is use a certain number of ship flags to signal exactly what you mean.

  • Single-flag signals are used for urgent messages to other ships, such as signaling JULIET when your ship is leaking dangerous cargo.
  • Two-flag signaling indicates distress or changes to maneuvers, such as signaling DELTA and then ECHO.
  • Three-flag signals indicate relative bearings (the angle from the ship’s centerline heading to a straight line drawn from the observation station on the vessel to the object), compass points and are used as general code and decode signals.
  • Signaling with four flags is used to relay absolute bearings and other geographical signals.
  • Five-flag signals are used to relate time and position.
  • Six-flag signals are used to relay latitude and longitude coordinates, as well as compass directions.
  • Seven-flags are for longitude signals containing more than one hundred degrees.

In order to communicate using multi-flag signals, there is a second system of numbered flags indicating 0-9 (shown below).

Number NATO Flag International Flag


Some of the original 26 nautical flags also have separate meanings when used with numbers:

  • ALFA: Begin relaying an azimuth or bearing
  • CHARLIE: I am relaying a course in degrees magnetic
  • DELTA: I am relaying a date
  • GOLF: Longitudinal coordinates (the first two numbered flags are degrees; the last two flags are minutes)
  • KILO: See International/NATO.
  • LIMA: Latitudinal coordinates (the first two flags show degrees; the last two show minutes)
  • ROMEO: Distance from/range to an object in nautical miles
  • SIERRA: Speed in knots
  • TANGO: Local time (first two flags display hours; second set of flags shows minutes)
  • VICTOR: Speed (Kilometers/hour)
  • ZULU: Time in UTC (first two flags display hours; second set of flags shows minutes)

Using boat flags & nautical flags to start a regatta

When it comes to the starting sequence of a sailing regatta, there’s a specific type and number of nautical flags that need to be raised and lowered in order to signal different parts of the starting sequence of a sailing regatta. Those boat flags are as follows:



Flag Name Flag Meaning
Racing Committee flag Used to show where committee boat end of the start line is.
Orange start flag Shows where the start line ends. Placed parallel to the committee boat on a buoy.
Answering pennant Used to tell the racers that the race has been postponed.
Class flag N/A — outlined in the Sailing Instructions. Alerts the racers that there’s five minutes to go before the race begins.
P flag Signals that there are four minutes left before the race begins.

Here’s how the regatta sequence goes:

  1. The racers line up at the Committee Boat. At this point, only the Racing Committee flag and the orange start flag are up.
    1. If there are any postponements, the answering pennant goes up. If or when the answering pennant goes down, it signifies one minute until the class flag goes up.
  2. The class flag goes up five minutes before the start of the race and remains up until the race starts.
  3. The P flag goes up four minutes before the start of the race and remains up for three minutes.
  4. The P flag goes down a minute before the race begins.
  5. The class flag goes down, accompanied by a sound signal, and the race begins!

Proper flag sizes for boats

When people buy boat flags for regatta races or other uses, they often buy flags that are a little too small. Use the following chart for the proper flag sizes to ensure that you’re getting the right size flag for your boat. Round up to the next size of commercially-available flag as necessary.

Powerboat/Sailboat Length (feet) Ensign Size (inches)
12′ – 18′ 12″ x 18″
19′ – 24′ 16″ x 24″
25′ – 30′ 20″ x 30″
31′ – 36′ 24″ x 36″
37′ – 48′ 30″ x 48″
49′ – 60′ 36″ x 60″ (3′ x 5′)
61′ – 72′ 48″ x 72″ (4′ x 6′)
Powerboat Length (feet) Other Flags – Club & Private Signals (inches)
12′ – 18′ 10″ x 15″
19′ x 24′ 10″ x 15″
25′ – 30′ 12″ x 18″
31′ x 36′ 16″ x 24″
37′ x 48′ 20″ x 30″
49′ x 60′ 24″ x 36″
61′ x 72′ 30″ x 48″
Sailboat Mast Height (feet) Other Flags – Club & Private Signals (inches)
12′ – 30′ 10″ x 15″
31′ – 36′ 12″ x 18″
37′ – 48′ 16″ x 24″
49′ – 60′ 20′ x 30′
61′ – 72′ 24″ x 36″


If your boat doesn’t fit within any of the sizes listed on the chart above, follow these rules:

  • Your country’s ensign should be one inch long per foot of overall length. So if you have an 84′ long boat, you should fly a flag that’s 7′ feet (84″ inches) long.
  • For sailboats, all other flags should be 1/2″ long for each foot of the mast that’s above the water. A sailboat with a 55-foot length should have a non-ensign flag that is 27″ long.
  • For power boats, all other flags should be 5/8″ long for each foot of overall length. A 56-foot boat should have a 35-inch long flag.

Proper boat flag size varies depending on the size of the boat in question. Semaphore flags (discussed below) are always made as an 18″ x 18″ square.

Flag courtesies

There are a couple courtesies to be aware of when you’re flying your boat flags:

  • When in US waters, fly the US national ensign or US yacht ensign from the back end of your boat (the stern).
  • Fly the “Q” flag in international waters before you have cleared customs or entered port.
The “Q”/”QUEBEC” flag.
  • Fly the “Q” flag from the starboard spreader on all sailboats, and from the bow on all powerboats.
  • After clearing customs, replace the “Q” flag with the colors of the country whose waters you’re in.
  • Upon returning to US waters, immediately replace the flag of the country you visited with the US national or yacht ensign.

Using boat flags to signal other boats

You can certainly use the list of nautical flags above to signal other boats. What do you do if you if have to convey a message that’s longer than the ones listed with the flags above? Or worse, not on that list at all? You use semaphore. Using visual signals made by a pair of flags, paddles, wands or even your bare hands, you can convey information at a distance using semaphore.

In flag semaphore, each letter of the English alphabet and each number from 0 to 9 is assigned a signal consisting of two flags held in a specific position. When the flags come to rest in that signal position, the signal can be read. For example, if someone were to signal the letter “R” to you, they would hold both flags out parallel to the ground. Here are the different signal positions for all of the other letters and numbers that you might see in English semaphore:

Note that A through I stand in for 1 – 9, with K standing in for 0. In order to signal that you’re signaling a series of letters, first signal “J” and then begin signaling the letters of the message. Here’s how you begin signaling a message in semaphore:

  1. First, the sender uses the “Attention” signal (not shown). Signal by waving the boat flags upward in a ‘V’ shape and then downward in an upside-down version of the same to request permission to start transmitting a message.
  2. The receiver acknowledges using a “ready to receive” signal — the same as the “SPACE” signal above. Raise both flags vertically overhead and then drop them into the SPACE signal position.
  3. Once the sender has signaled all of their message, they end with the same “ready to receive” signal.
  4. If the original receiver has a message of their own to send, they respond with their own “Attention” signal.
  5. After this, the sender and receiver switch roles and the process begins again.

Create custom flags with your own nautical themed design or model a flag design from one of the popular boat flags listed above.


Semaphore Flag Signaling System:

All About Those Race Committee Flags:

Flag and Etiquette Committee — Flag Etiquette:

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