Signals Used to Attract Attention
International Rules and Inland Rules on signals to attract attention are
almost identical. If it becomes necessary to attract the attention of
another vessel, any vessel may make light or sound signals that cannot
be mistaken for any signal authorized elsewhere in these rules, or may
direct the beam of its searchlight in the direction of the danger in such a
way as not to embarrass any vessel.
The following paragraph from the International Rules is not included in
the Inland Rules.
Any light to attract the attention of another vessel will be such that it
cannot be mistaken for any aid to navigation. For the purpose of this
rule, the use of high-intensity intermittent or revolving lights, such as
strobe lights, must be avoided.
There is no basis in the rules of the road for the popular notion that the
national ensign, hoisted upside down, is a recognized signal of distress.
No man-of-war would ever subject the colors to this indignity. But if
you should see a private craft with the ensign hoisted upside down, it is
probably in distress. Signals covered by the International Rules and
Inland Rules are as follows (fig. 4-21):
The following signals, although not part of the rules of the road, are
prescribed for submerged submarines in emergency situations involving
rising to periscope depth or surfacing:
1. A white or yellow smoke flare fired into the air from a submarine
indicates the submarine is coming to periscope depth to carry out
surfacing procedures. Ships should clear the immediate vicinity but
should not stop propellers.
2. A red smoke flare fired into the air from a submarine is a signal that
the submarine is in serious trouble and will surface immediately if
possible. Smoke flares of any color, fired into the air at short intervals,
mean that the submarine requires assistance. All ships in the area
should clear the immediate vicinity but stand by to give aid.