D - keep clear of me, I am manuevering with difficulty
K - you should stop your vessel instantly
L - you should stop, I have something important to communicate
P - (At sea) your lights are out or burning badly
R - the way is off my ship. You may feel your way past me
S - my engines are going full speed astern
U - you are standing into danger
V - I require assistance (not distress)
W - I require medical assistance
X - stop carrying out your intentions and watch for my signals