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”)

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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?