Transcript
Lesson 9 - VISUAL COMMUNICATIONS
OVERVIEW- Visual Comm Methods- Terminology- Answering, Acknowledging
& Executing - Visual Responsibility
OVERVIEW- Governing Pennants- Uses of Interrogative- Single Flags & Pennants- Visual Message Blank
Visual Communications Overview
- Provides real time or near real time exchange of information
- Primary advantage is information can be exchanged during periods of radio silence
- Limiting factors are distance and visibility
- Strictly line-of-sight communications
Visual Communications Overview- Utilized by the Navy both underway and
inport- Signalmen stand watch on signal bridge
- Directed by bridge watch officers to transmit messages using one of the three methods of visual communications
- ATP-1 and PUB 102 used to encode and decode msgs in a similar manner to R/T signals
- As a bridge watch officer you must be familiar with the three methods of visual communications- Be able to identify your ship’s flashing light call
sign- Be able to read flaghoists
VISUAL COMMS METHODS
SEMAPHORE
FLAGHOIST
FLASHING LIGHT
SEMAPHORE
-Quickest method, but difficult to read
- Signalman uses flags or lighted wands
- Position of flags/wands placed into different positions at different points about a vertical circle to
indicate a letter or symbol of message
- transmit long msgs via short distance
- substitute for handling admin traffic during radio silence
FLASHING LIGHT- involves the use of Morse Code
alphabet of “.” and “-” to transmit letters
- Can be used over extended distances during day and night, directionally or onmidirectionally, infrared if necessary
FLASHING LIGHTTwo forms of flashing light1. Directional transmissions – sent out by signal
searchlight pointed and trained directly on receiver - large white beam lights fixed to the ship to allow for 360 degrees coverage
-morse code is sent by means of shutter device that interrupts the light beam *change light to amber, red,
infrared - smaller hand-held multipurpose light used in small
boat operations*battery powered and operated by trigger
switch
FLASHING LIGHT EQUIPMENT
Directional searchlight
Multipurpose light
FLASHING LIGHT2. Non-directional signals – sent out from
omnidirectional signal lights (yardarm blinkers) operated from transmission key located in pilothouse or signal bridge
- light visible in any direction away from ship
- effective way to simultaneously address all ships
Omni-directional signal lights/yardarm blinkers
(Regular or infrared lights)
FLASHING LIGHT2. Non-directional signals –
-Nancy gear also positioned on each yardarm
*infrared lights that operate similar to yardarm blinkers
*transmitted light not visible to naked eye
*read with infrared viewing equipment (AN/PVS-7 or AN/PVS-8)
FLAG HOISTBridge watch officers MUST be able to read
flaghoist signals
Involves use of colored flags and pennants
FLAG HOIST
Rapid, accurate system of handling tactical and informational signals of reasonable length during daylight between ships in proximity *ensures more uniform execution of maneuver than any other signal
Navy uses allied flag bag = 68 total flags *letter flags, number flags, number pennants,
maneuvering pennants, governing pennants, substitutes, special flags and pennants, tacklines
TERMINOLOGYHalyard - a line
running from the flagbag to the
yardarm
Flagbag - a metal box containing a set of flags
and pennants
Retriever - line attached to a halyard in order to recover it if necessary
Bend on - to hook a flag/pennant onto a halyard but not actually hoisting them aloft
Hoist - A signal consisting of one or more flags or pennants on a single halyard
Display - A complete signal; can be on one or more hoists
Point of hoist - highest point on halyard to which the signal is
raised
At the dip
Closed up
Hauled down
Hoisted ¾ of the way up
Return to the deck
Flaghoists are read as follows:
Bow aspect
Stbd Port
Stbd to portOutboard to
inboardTop to bottom
Max of FIVE flags per hoist
TACKLINES
A length of line, equal in length to a flag/pennant
Used in visual displays just as “tacks” are used
in R/T signals
Tacklines do not count toward the five flag max per halyard
Tacks are understood, as necessary, between adjacent hoists
SUBSTITUTE PENNANTS
1st Sub
2nd Sub
3rd Sub
4th Sub
The four sub pennants are used to repeat a flag
in the same hoist
First sub repeats the first flag on the hoist,
second sub repeats the second flag, etc.
A sub pennant can stand for another sub pennant.
TurnPortOne
3rd sub = 3rd flag = One
4th sub = 4th flag = One
ANSWERING, ACKNOWLEDGING, &
EXECUTINGOriginator sends signal
(closed up)
Addressee answers by repeating each hoist at
the dip
When signal is understood, addressee closes it up
Originator executes signal
by hauling it down
Visual Responsibility In a line formation
OTC sends signalIntermediate ships hold their
displays at the dip
Ship farthest from the OTC closes up the signal when it's
understood
- Intermediate ships close up their displays
- When all ships have acknowledged, OTC executes by hauling down the signal
Governing PennantsUsed to change the meaning
of a signal
Interrogative Negative
Preparative (“Prep”)
turnporttree
eighteight
To question a signal that is not understood:
- hoist the signal at the dip- hoist INT closed up
Intturnporttree
eighteight
Other Uses of INTINT ONE
- when an addressee cannot distinguish the
signal now flying
Used by originator to tell an addressee that
they are repeating a signal
incorrectly
INT TWO
PREP - tells addressee toprepare for an evolution
NEGAT - cancels all or part of a signal
Signal Cancels entire signal
Cancels part of signal
Single Pennants & FlagsFlags & pennants have spec meanings when flown singly
CO’s absentee
Guide Trans fuel or ammo
Signals from Pub 102
will begin with the Code Pennant
Pub 102 uses number pennants
NOT number flags
Code Hotel Tango
VISUAL MESSAGE BLANK
HEADING
INFO:
TO:
FROM: DATE RELEASED BY
SYSTEM PRECEDENCE
CALL UP
OPERATOR SUPERVISOR
TOR/TOD VISUAL NR
FLAG C OF S CAPT OOD COMM CEN DTG
Msgs received/transmitted by visual means will be prepared using this form
HOTEL
SPEEDTACK
TWOTACK
CHARLIE
Questions?
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