Flag

Letter

Meaning

 Alfa

Diver below (when stationary); Keep clear 
see note...

 Bravo

 I am taking on, discharging, or carrying dangerous cargo

 Charlie

 "Yes" or "affirmative"

 Delta

 I am maneuvering with difficulty; keep clear

I am altering my course to starboard

I am disabled, communicate with me

I require a pilot

I have a pilot on board

I am altering my course to port

I am on fire and have dangerous cargo; keep clear

I wish to communicate with you

You should stop your vessel immediately

My vessel is stopped (Not international but commonly used: Doctor on board)

"No" or "negative"

Man overboard

All personnel return to ship; about to sail - theBlue Peter

Ship meets health regs; request clearance into port

None (previous meaning: The way is off my ship. You may feel your way past me)

I am moving astern

Keep clear (Not international but commonly used: Request for club launch)

You are standing into danger

I require assistance (not distress)

I require medical assistance

Stop carrying out your intentions and watch for my signals

I am dragging anchor

I require a tug

I am in distress

The red flag with white diagonal stripe, while not international, is commonly used to indicate a diver in the water. Many states now require this flag. It is usually exhibited on a float to mark the diver's approximate location whereas the "A" flag should be used on the vessel.

0

Numeral zero

1

Numeral 1

2

Numeral 2

3

Numeral 3

4

Numeral 4

5

Numeral 5

6

Numeral 6

7

Numeral 7

8

Numeral 8

9

Numeral 9

Message is understood. Also, numeric decimal point

Substitute for the first flag in this hoist

Substitute for the second flag in this hoist

Substitute for the third flag in this hoist

Substitute for the forth flag in this hoist