Signal · 40 flags

Code flags

Each letter flag spells its letter, and flown alone it carries a complete, urgent message that every ship understands in any language. Two- and three-flag groups look up longer messages in the Code book.

Letter flags and their single-flag meanings

A Alfa

I have a diver down; keep well clear at slow speed.

B Bravo

I am taking in, or discharging, or carrying dangerous goods.

C Charlie

Affirmative: “yes”, or the previous group is to be read as affirmative.

D Delta

Keep clear of me; I am manoeuvring with difficulty.

E Echo

I am altering my course to starboard.

F Foxtrot

I am disabled; communicate with me.

G Golf

I require a pilot.

Made by fishing vessels working close together on the fishing grounds: “I am hauling nets”.

H Hotel

I have a pilot on board.

I India

I am altering my course to port.

J Juliett

I am on fire and have dangerous cargo on board: keep well clear of me, or I am leaking dangerous cargo.

K Kilo

I wish to communicate with you.

L Lima

You should stop your vessel instantly.

M Mike

My vessel is stopped and making no way through the water.

N November

Negative: “no”, or the previous group is to be read as negative.

Visual or sound signalling only; by voice or radio the signal is “NO”.

O Oscar

Man overboard.

P Papa

In harbour: all persons should report on board, as the vessel is about to proceed to sea.

At sea, made by fishing vessels: “My nets have come fast upon an obstruction”. Traditionally called the Blue Peter.

Q Quebec

My vessel is “healthy” and I request free pratique.

R Romeo

No meaning as a single flag.

Before 1969 it meant “The way is off my ship; you may feel your way past me”.

S Sierra

I am operating astern propulsion.

T Tango

Keep clear of me; I am engaged in pair trawling.

U Uniform

You are running into danger.

V Victor

I require assistance.

W Whiskey

I require medical assistance.

X X-ray

Stop carrying out your intentions and watch for my signals.

Y Yankee

I am dragging my anchor.

Z Zulu

I require a tug.

Made by fishing vessels working close together on the fishing grounds: “I am shooting nets”.

Meanings and designs: International Code of Signals, 1969 edition revised 2005 (US edition: NGA Pub. 102, 2020). Wording is lightly shortened; the Code is authoritative.

Then and now

The present Code dates from 1969 (revised 2005). Under the earlier code many single flags meant something else, and its flags were named Affirm, Baker and so on rather than Alfa, Bravo.

Numeral pennants

0 Nadazero

1 Unaone

2 Bissotwo

3 Terrathree

4 Kartefour

5 Pantafive

6 Soxisix

7 Setteseven

8 Oktoeight

9 Novenine

Substitutes and the answering pennant

First substitute

Repeats the uppermost flag of the same class in the hoist.

Second substitute

Repeats the second flag of the same class, counting from the top.

Third substitute

Repeats the third flag of the same class, counting from the top.

Answering pennant

Hoisted to acknowledge a signal; also used as a decimal point between numeral pennants.

A ship carries one flag of each kind. When a letter appears twice in a hoist, a substitute stands in for the repeated flag: try it on the hoist page.