CHAPTER 6 — Operational Planning
Change A 6-23
Figure 6-12. International Code Signal Flags.
IN: “I require a diver.”
IO: “I have no diver.”
IN1: “I require a diver to clear my propeller.”
IP: “A diver will be sent as soon as pos-
sible or at time indicated.”
IN2: “I require a diver to examine bottom.”
IQ: “Diver has been attacked by diver’s
disease and requires decompression
chamber treatment.”
IN3: “I require a diver to place collision mat.”
IR: “I am engaged in submarine survey
work (underwater operations). Keep
clear of me and go slow.”
IN4: “I require a diver to clear my anchor.”
A: “I have a diver down; Keep well clear at
slow speed.”
Code Flag (Note 1)
Sport Diver (Unofficial)
General Note: Rule 27 of Navigation Rules-International -Inland of December 1983 states the lights
and shapes that must be displayed when engaged in diving operations.
Note 1: International Signal Code – All signals must be preceded by the code flag to signify that they
are international signals. (Do not use code flag in inland waters.)
