The SCREEN pennant is spoken, written, and
transmitted SCREEN. It is used in signaling various
Whenever possible, substitutes are used to prevent
alphabet flags, numeral flags, or numeral pennants
from appearing more than once in the same hoist. As
their names imply, they are substitutes for other flags
or pennants used in the hoist.
FIRST SUB repeats the first flag or pennant in the
SECOND SUB repeats the second flag or pennant
in the hoist.
THIRD SUB repeats the third flag or pennant in the
FOURTH SUB repeats the fourth flag or pennant in
To illustrate, the signal CORPEN PORT ZERO
ZERO ZERO would read CORPEN PORT ZERO 3rd
THIRD SUB repeats the third flag, and FOURTH
SUB repeats the fourth flag, which already repeats
When more than one halyard is used to hoist a
signal, each hoist is considered separately as regards
substitutes. When a tackline separates hoist
components, it is disregarded in the substitute count.
Substitutes also are used as absence indicators
when a ship is not under way. This is discussed in
chapter 10, Honors and Ceremonies.
UNITS OF REFERENCE
When a signal makes reference to numbers,
distances, ranges, heights, depths, speeds, or weights,
the unit of reference is as indicated (see fig. 5-7)
unless otherwise stated in the meaning of the signal.
However, for clarity, the units of reference are stated
against some groups using the standard units, which
otherwise would not need such a statement.
SIGNALING TIMES AND DATES
When the originator desires to have a signal
executed at a specific time instead of when the signal is
hauled down, the time indicator, TANGO flag, is used.
In the text of signals, times are expressed as four
numerals; the first two denote the hours (00-23) and
. . . . . . . . . hundreds of feet
Distance . . . . . . . . . nautical miles (2,000
Range . . . . . . . . . . hundreds of yards
Height . . . . . . . . . . feet
. . . . . . . . . . feet
speed . . . . . . . . . . knots
Weight . . . . . . . . . . tons (2,000 pounds)
Sector boundaries . . . . tens of degrees
Sector limits . . . . . . . thousands of yards
Figure 5-7.Reference units of measurement.
the second two the minutes. ANSWER, instead of the
last two figures of a time signal, may be used to
express 30 minutes. Thus, 1630 is sent as 16 ANS.
Date-time groups in the text of signals are
expressed as six numerals plus the zone indicator; the
first set of two numerals denotes the date, the second
set the hour, and the third set the minutes. When
unable to make this display in one hoist, you may
break it between the date and the time group.
When time is sent together with a signal group,
TANGO has the following meanings:
T preceding numeralsAction will commence at
T following numeralsAction will be completed
by that time.
T between numeral groupsTime by which action
is to be completed and time at which action is to
CO2 means Assume command.
CO2 TACK T1845Commence assuming
command at 1845.
CO2 TACK 1845TComplete assuming
command by 1845.
CO2 TACK 19T1845Commence assuming
command at 1845; complete assuming by 1900.
When time is referred to in the meaning of the
signal group, the flag indicator TANGO may be
omitted, provided no confusion results.
A time signal applies only to the group
immediately preceding it. If signaled time applies to
more than one group, flags BRAVO TANGO (BT) are