GMDSS Concepts

8/16/2019 GMDSS Concepts

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GMDSS concepts

Functional requirements

The GMDSS regulations (chapter IV of the International SOLAS Convention), reuire that ever!

GMDSS euippe" ship shall #e capa#le of$

1. transmitting ship-to-shore Distress Alerts by at least two separate and

independent means, each using a different radio communication serice!

". receiing shore-to-ship Distress Alerts!

#. transmitting and receiing ship-to-ship Distress Alerts!

$. transmitting and receiing search and rescue co-ordinating communications!

%. transmitting and receiing on-scene communications!

&. transmitting and receiing locating signals!

'. receiing maritime safety information!

(. transmitting and receiing general radiocommunications relating to the

management and operation of the essel! and

). transmitting and receiing bridge-to-bridge communications.

Application

The GMDSS applies to vessels su#%ect to the SOLAS Convention & that is'

*ommercial essels of #++ Gross egistered ons G/ and aboe, engaged on

international oyages.

he GMDSS became mandatory for such essels as at February 1, 1))).

Coercial vessels un"er ** G+T, or those a#ove ** G+T engage" on "oestic vo!ages onl!

are su#%ect to the reuireents of their lag State- Soe lag States have incorporate" GMDSS

reuireents into their "oestic arine ra"io legislation & ho.ever an! have not-


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0quipment s perational requirements

The a%or "ifference #et.een the GMDSS an" its pre"ecessor s!stes is that the ra"io

counications euipent to #e fitte" to a GMDSS ship is "eterine" #! the ship/s area of

operation, rather than #! its si0e-

1ecause the various ra"io s!stes use" in the GMDSS have "ifferent liitations .ith regar"s to

range an" services provi"e", the ne. s!ste "ivi"es the .orl"/s oceans into 2 areas'

Area A1 lies .ithin range of shorease" V3 coast stations (4* to * nautical iles)$

Area A" lies .ithin range of shore #ase" M coast stations (e5clu"ing A6 areas) (appro5iatel!

6** & 67* nautical iles)$

Area A# lies .ithin the coverage area of Inarsat counications satellites (e5clu"ing A6 an"

A4 areas & appro5iatel! latitu"e 8* "egrees north to latitu"e 8* "egrees south)$ an"

Area A$ coprises the reaining sea areas outsi"e areas A6, A4 an" A (the polar regions)-

Australia an" its surroun"ing SA+ area are "eclare" as Sea Area A-

There are no A6 or A4 areas in Australia-

GMDSS communication systems

The GMDSS utilises #oth satellite an" terrestrial (ie' conventional) ra"io s!stes-

Sea Area A6 reuires short range ra"io services & V3 is use" to provi"e voice an" autoate""istress alerting via Digital Selective Calling (DSC)-

Sea Area A4 reuires e"iu range services & Me"iu reuencies (M & 4 M30) are use" for

voice an" DSC-

Sea Areas A an" A2 reuire long range alerting & 3igh reuencies (3 & to * M30) are use"

for voice, DSC an" 9arro. 1an" Direct :rinting (91D: & a;a ra"io tele5)-


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0quipment requirements

As "iscusse" a#ove, euipent fit reuireents var! accor"ing to the Sea Area(s) a vessel

operates in or through-

It shoul" #e note" that the reuireents are cuulative in nature & ie' an A2 vessel is also

euippe", #! "efinition, .ith euipent for A6, A4 an" A Sea Areas-

In areas .here A6 Services are provi"e", coastal vessels are onl! reuire" to fit V3 euipent,

provi"e" of course that the! reain .ithin the "eclare" Sea Area & norall! .ithin 4* to *

nautical iles of the coast-

Vessels that tra"e further fro lan" are reuire" to carr! M euipent, in a""ition to V3-

Ocean going vessels fit V3, M, 3 an" Inarsat euipent-

The process is "epicte" #elo.'


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3o.ever, it shoul" #e note" that the a#ove e5aples assue a linear transition fro A6 to A2

sea areas & in an! areas of the .orl", (such as Australia) A areas e5ten" right up to the coast

line- GMDSS vessels operating in or through those areas are reuire" to fit A euipent-

Shore 2nfrastructure


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navigate" (ie$ the #ri"ge)-

- (see 9ote 6)-

One SA if un"er 7** G+T, 4 SA+Ts if over 7** G+T-

T.o portable 34F transceiers for use in survival craft if un"er 7** G+T, three if over 7**G+T-

A 5A306 receier, if the ship is engage" on vo!ages in an! area .here a 9AVT


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adio equipment - Sea area Al

*7

;30 an" 48,7** ;30- (This reuireent is norall! fulfille" #! the M euipent referre" to

earlier & all GMDSS M transceivers also cover 3)

An Inarsat ship station-

'ypical GM!! "2 ship station

adio equipment - Sea areas A1, A" and A#

These vessels have t.o options to satisf! their GMDSS reuireents- The options allo. a vessel


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to choose fro the priar! etho" to #e use" for ship&shore alerting $

*7 ;30 an" 48,7** ;30 using DSC,

ra"iotelephon! an" 91D:-

An M=3 DSC .atch;eeping receiver capa#le of aintaining DSC .atch on 4,6@8-7 ;30,

@,262-7 ;30 an" on at least one of the "istress an" safet! DSC freuencies 2,4*8-7 ;30, >,64

;30, 64,788 ;30 or 6>,@*2-7 ;30$ at an! tie, it shall #e possi#le to select an! of these DSC

"istress an" safet! freuencies

A5D

Ships shall #e capa#le of transitting an" receiving general ra"iocounications using

ra"iotelephon! or "irect&printing telegraph! #! an M=3 ra"io installation operating on

.or;ing freuencies in the (arine) #an"s #et.een 6,>*7 ;30 an" 48,7** ;30- This

reuireent is norall! fulfille" #! the a""ition of this capa#ilit! in the M=3 euipent

referre" to earlier & there is no M( only euipent a"e-


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'ypical GM!! "# ship station

adio equipment - Sea areas Al, A", A# and A$

In a""ition to carr!ing the euipent liste" previousl!, ever! ship engage" on vo!ages in all sea

areas shall #e provi"e" .ith'

An M=3 ra"io installation as "escri#e" earlier

An M=3 DSC .atch;eeping receiver as "escri#e" earlier

In a""ition, ships shall #e capa#le of transitting an" receiving general ra"iocounications

using ra"iotelephon! or "irect&printing telegraph! #! an M=3 ra"io installation as "escri#e"

earlier-

'ypical GM!! "$ ship station

Confused ? Wait, there's more..!

Means of ensuring aailability of ship station equipment

+egulation 67 of the SOLAS GMDSS regulations "efines etho"s to ensure availa#ilit! of

GMDSS euipent at sea$

At sea electronic maintenance, reuiring the carriage of a ualifie" ra"io=electronic officer

(hol"ing a GMDSS irst or Secon" class +a"io&


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Duplication of certain euipent$ or

Shore based maintenance

Ships engage" on vo!ages in sea areas A6 an" A4 are reuire" to use at least one of the threeaintenance etho"s outline" a#ove, or a co#ination as a! #e approve" #! their

a"inistration- Ships engage" on vo!ages in sea areas A an" A2 are reuire" to use at least t.o

of the etho"s outline" a#ove-

An" of course .hat all that eans is that B of A GMDSS ships, along .ith pro#a#l! 6**B of

A6 an" A4 GMDSS ships "o not opt for at sea aintenance & the! either "uplicate the euipent

an" use shore #ase" aintenance (for A ships), or use shore #ase" aintenance onl! (A6 an"

A4 ships)-

0quipment to be duplicated for area A# essels

GMDSS ships operating in A areas are reuire" to provi"e the follo.ing "uplicate" euipent$

T.o coplete V3 installations (inclu"ing DSC), an" either$

T.o coplete Inarsat C s!stes an" one M ra"io s!ste, or$

One coplete Inarsat C s!ste an" one coplete M=3 ra"io s!ste (inclu"ing a scanning

DSC receiver an" 91D: euipent)-

Man! GMDSS ships opt for the latter option (6 Inarsat C an" one M=3 DSC s!ste), on

cost groun"s- nfortunatel!, this has proven to #e one of the un"erl!ing causes of the present

e5treel! high false alerting rate on soe GMDSS s!stes-

8o:er supply requirements

GMDSS euipent is reuire" to #e po.ere" fro three sources of suppl!'

ship/s noral alternators=generators$

ship/s eergenc! alternator=generator (if fitte")$ an"

a "e"icate" ra"io #atter! suppl!-


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The #atteries are reuire" to have a capacit! to po.er the euipent for 6 hour on ships .ith an

eergenc! generator, an" > hours on ships not fitte" .ith an eergenc! generator-

The #atteries ust #e charge" #! an autoatic charger, .hich is also reuire" to #e po.ere"

fro the ain an" eergenc! generators-

Changeover fro AC to #atter! suppl! ust #e autoatic, an" effecte" in such a .a! that an!

an! "ata hel" #! the euipent is not corrupte" (ie' no #rea;)-

perator qualifications

There are a nu#er of "ifferent t!pes of GMDSS ualifications, as follo.s'

irst Class +a"io&


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This results in increase" range copare" .ith ra"iotelephone transissions-

nfortunatel!, DSC reains one of the GMDSS/ least un"erstoo" su#&s!stes- This lac; of

un"erstan"ing is reflecte" in the ver! high DSC false alert rate-

perations

DSC is use" to establish initial contact #et.een stations-

ollo.ing an alert #! DSC, counications are norall! carrie" out #! ra"iotelephone or

9arro. 1an" Direct :rinting (91D: & ra"io tele5)-

DSC can #e consi"ere" as a replaceent for the ra"iotelephone an" ra"iotelegraph (Morse)

alar signals-

+ather than %ust in"icate that the sen"ing station is in "istress, the DSC s!ste allo.s a great

"eal ore inforation to #e transitte", inclu"ing'

the priorit! of the call & DIST+


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9ote that oice transmissions are 842920D on the DS* channels.

The M=3 channels are restricte" to "istress, urgenc! an" safet! traffic onl! #ecause of the

relativel! lo. spee"s of transission of 6** #au"- If too an! calls .ere peritte" on the

M=3 channels, the channels .oul" uic;l! #ecoe overloa"e" to the point .here a "istresscall a! #e #loc;e"-

V3 DSC operates at 64 ties the spee" of M=3 & accor"ingl!, all priorities of call are allo.e"

on the V3 channels-

The IT has also allocate" a suite of 3 channels "e"icate" to DSC coercial operations-

These a! #e foun" in the IT DSC operational specification (the lin; is at the #otto of this

page)-

DS* call categories

The DSC s!ste supports a nu#er of call categories- These categories irror the stan"ar"

aritie prioritisation of essage traffic, ie'

D2S0SS

?G05*=

SAF0=

?250

Distress alerts are autoaticall! a""resse" to all stations-

rgenc!, safet! an" routine calls can #e a""resse" to all stations, an in"ivi"ual station, or a

group of stations-

Maritime Mobile Serice 2dentities MMS2/

All DSC euipent is prograe" .ith a uniue nine "igit i"entification nu#er, ;no.n as a

Maritie Mo#ile Service I"entit! (MMSI)-

The MMSI is sent autoaticall! .ith each an" ever! DSC transission a"e-

Maritime 2dentification Digits M2D/


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The first three "igits of the MMSI are ;no.n as the Maritie I"entification Digits (MID)- The

MID represents the countr! of registration of the vessel, or the countr! in .hich the DSC shore

station is locate"- MIDs are allocate" on an international #asis #! the IT, in uch the sae

.a! as a callsign prefi5-

The MID list a! #e foun" here (opens in ne. .in"o.)-

Formation of MMS2@s

MMSIs allocate" to erchant vessels are norall! allocate" .ith three trailing 0ero/s-

Those allocate" to recreational craft have t.o or one trailing 0ero, Coast Station MMSI/s are

fore" .ith t.o lea"ing 0ero/s, those allocate" to SA+ aircraft use 666 as the first three "igits,

han" hel" ra"ios have @ as a lea"ing "igit an" Man Over#oar" #eacons have their o.n co"e

structure, starting .ith 84-

or e5aple'

ypical Australian merchant essel MMS2& %+#++1+++

.here'

7* is the Australian MID$

an"

*6*** is the in"ivi"ual ship nu#er

ypical Australian recreational essel MMS2 & %+#+++1++

.here'

7* is the Australian MID$

an"

***6** is the in"ivi"ual ship nu#er

*oast Station MMS2 & ++%+#+++1

http://www.itu.int/online/mms/glad/cga_mids.sh?lng=Ehttp://www.itu.int/online/mms/glad/cga_mids.sh?lng=Ehttp://www.itu.int/online/mms/glad/cga_mids.sh?lng=E


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.here'

7* is the Australian MID$ an"

***6 is the in"ivi"ual Coast Station nu#er

SA aircraft MMS2 & 111%+#1"#

.here'

7* is the Australian MID$ an"

64 is the in"ivi"ual aircraft nu#er

4and held radio :ith DS* MMS2 & (%+#1"#$%

.here'

7* is the Australian MID$ an"6427 is the in"ivi"ual ra"io nu#er

ypical DS* man oerboard beacon & )'"$%+++1

.here'

84 is the DSC Mo1 co"e$

$% is the anufacturer co"e

an"

***6 is the in"ivi"ual #eacon nu#er

MMS2 databases


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The IT operate an international .e#ase" "ata #ase of MMSI/s, ;no.n as the Maritie

Mo#ile Access an" +etrieval S!ste (MA+S)-

The Australian MMSI list a! #e foun" here-

DS* equipment

GMDSS DSC euipent is norall! coprise" of a stan" alone control unit, .ith an alpha&

nueric "ispla! screen an" a ;e!#oar" on .hich to copose essages-

'ypical V)( !& controller - note display screen and *ey+oard.

The control unit controls the actions of the DSC o"e (o"ulator "eo"ulator)- The o"e

is interface" to a DSC .atch;eeping receiver & this receiver is fi5e" tune" to either the V3 DSC

channel (ch- 8*), the 4 M30 DSC channel, or the 3 DSC channels-

3 DSC .atch;eeping receivers are "esigne" to scan the > M=3 DSC channels in rapi"

seuence (4 secon"s or less)-

DSC .atch;eeping receivers are fitte" .ith their o.n "e"icate" antennas-

The DSC o"e "eco"es all calls on the freuenc! to .hich the .atch;eeping receiver is tune"-

If calls are receive" a""resse" to all ships, or to the particular ship on .hich the DSC s!ste is

fitte", the DSC controller soun"s an alar, an" "ispla!s the "eco"e" inforation on the alpha&

nueric "ispla!-

http://www.itu.int/ITU-R/index.asp?category=terrestrial&rlink=mars&lang=enhttp://www.itu.int/ITU-R/index.asp?category=terrestrial&rlink=mars&lang=enhttp://www.itu.int/ITU-R/index.asp?category=terrestrial&rlink=mars&lang=enhttps://apps.amsa.gov.au/mmsisearch/https://apps.amsa.gov.au/mmsisearch/http://www.itu.int/ITU-R/index.asp?category=terrestrial&rlink=mars&lang=enhttp://www.itu.int/ITU-R/index.asp?category=terrestrial&rlink=mars&lang=enhttps://apps.amsa.gov.au/mmsisearch/


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M()( !& operator control unit

To transit a DSC call, a GMDSS operator enters the reuire" coan"s to i"entif! the station

(or stations) .ith .hich counication is "esire", the priorit! (DIST+


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transission of a "istress call .ith iniu "ela!- The #utton is reuire" to #e protecte" #! a

cover, an" also can onl! #e activate" after 4 separate an" in"epen"ent actions-

3ideos of DS* traffic being receied and sent on *oast Station equipment may be

found here.

80A25A> 8*0D?0S

The official gui"e to DSC proce"ures is containe" in IT recoen"ation IT&+ M-726&- The

coplete te5t of the recoen"ation a! #e foun" here-

IMO have issue" a circular .hich contains further clarifications on DSC proce"ures'

IMO Cosar Circular 47 & :roce"ure for respon"ing to "istress alerts #! ships-

("ate" March 67th 4**6 & inclu"es flo. chart-)

2M DS* flo: charts

The IMO have issue" flo. charts to provi"e gui"ance to users of DSC s!stes'

(These files reuire A"o#e Acro#at rea"er)

IMO flo. chart & Actions on receipt of a V3 DSC call

IMO flo. chart & Actions on receipt of a M DSC call

IMO flo. chart & Actions on receipt of a 3 DSC call

(Than;s to the SCG for these)

Let/s ta;e a loo; at 9AVT


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The 9AVT


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in .hich

CC "efines the en" of the phasing perio",

the 16 character is a letter (A&) i"entif!ing the transitter coverage area,

the 14 character is a letter (A&) for each t!pe of essage-

112 is a t.o&character serial nu#er for each essage, starting .ith *6 e5cept in special cases

.here the serial nu#er ** is use"-

The transitter i"entification character (16) is a single letter allocate" to each 9AVT


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& Other electronic navai" essages

L & A""itional navigational essages

V & Special services

H & Special services (possi#le other languages use)

? & Special services E& Special services

& 9o essage on han" (J+)

Shipboard 5A306 equipment

A 9AVT


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GMDSS is for eeryone, not ust merchant ships.....let@s see :hy.

GMDSS for recreational essels

So, .h! shoul" !ou fit GMDSS euipent to !our pri"e an" %o!K

The GMDSS is not ust a sstem for ocean "oin" Merchant #essels -

The GMDSS is "esigne" to cater for all types of craft & fro a ;a!a; to a VLCC-

DS* is the GMDSS technology :ith the most potential for recreational users.

Bhy DS*C

DSC greatl! iproves !our chances of getting a "istress essage through to the rescue

authorities an" surroun"ing vessels-

A simple push button operation sends a distress call.

All GMDSS essels in range receie the call directly.

2f you are called, an alarm :ill sound.

2n addition, DS* automates your radio - no more listening to hash and noise on 4F

nor idlechatter. he radio remains quiet until you are called.

4F DS* for yachts

3 ra"ios .ith #uilt in DSC suita#le for !achts an" sall craft are rea"il! availa#le-

The Ico IC&M@*6< is a popular choice for cruising sailors-

The .ell ;no.n arine ra"io station 9runei 9ay adio has pro"uce" an e5cellent series of

articles on use of 3 DSC #! !achts'

HF/SSB radio with DSC - For cruising, racing and rallies

HF/SSB radio wtih DSC - A comms strategy for race, rally or cruising

34F DS* for small essels

http://www.icom-australia.com/products/marine/marine_ic-m801e.htmlhttp://www.icom-australia.com/products/marine/marine_ic-m801e.htmlhttp://www.bruneibay.net/bbradio/Documents/HF-SSB%20DSC-forYachtRace,Rally&Cruise.pdfhttp://www.bruneibay.net/bbradio/Documents/HF-SSB%20DSC-CommsStrategyYachtRace,Rally&Cruise.pdfhttp://www.icom-australia.com/products/marine/marine_ic-m801e.htmlhttp://www.bruneibay.net/bbradio/Documents/HF-SSB%20DSC-forYachtRace,Rally&Cruise.pdfhttp://www.bruneibay.net/bbradio/Documents/HF-SSB%20DSC-CommsStrategyYachtRace,Rally&Cruise.pdf


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More inforation on V3 DSC for sall vessels a! #e foun" at the V3 DSC inforation .e#

site-

Abandon ship Bhat neEtC

Surial *raft radio equipment

So, !ou have a#an"one" !our sin;ing GMDSS vessel, an" !ou fin" !ourself in a life#oat or

liferaft-

Hhat no. K

Hell the GMDSS "oesn/t stop !et & there are specific GMDSS ra"io s!stes "evelope" for

operation fro survival craft-

These s!stes are "esigne" to alert rescuers to !our plight an" gui"e the to !our location-

Search And escue adar/ ransponders SAs/

SA+T is a self containe", porta#le an" #uo!ant +a"ar Transpon"er (receiver an" transitter)-

SA+Ts operate in the G30 arine ra"ar #an", an" .hen interrogate" #! a searching ship/s

ra"ar, respon" .ith a signal .hich is "ispla!e" as a series of "ots on a ra"ar screen-

http://www.vhf-dsc.info/http://www.vhf-dsc.info/http://www.vhf-dsc.info/http://www.vhf-dsc.info/


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Although SA+Ts are priaril! "esigne" to #e use" in life#oats or liferafts, the! can #e "eplo!e"

on #oar" a ship, or even in the .ater-

SA+Ts are po.ere" #! integral #atteries .hich are "esigne" to provi"e up to > hours of

operation-

Operation

Hhen activate", a SA+T respon"s to a searching ra"ar interrogation #! generating a s.ept

freuenc! signal .hich is "ispla!e" on a ra"ar screen as a line of 64 "ots e5ten"ing out.ar"

fro the SA+Ts position along its line of #earing-

The spacing #et.een each "ot is *-> nautical iles-

As the searching vessel approaches the SA+T, the ra"ar "ispla! .ill change to .i"e arcs- These

a! eventuall! change to coplete circles as the SA+T #ecoes continuall! triggere" #! the

searching ship/s ra"ar-


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"lthou/h not an actual !"0' response, this radar picture /ives an impression of how a !"0'

si/nal would +e displayed

Soe slight position error .ill also #e cause" #! the SA+T s.itching fro receive to transit

o"e-

SA+Ts .ill also provi"e a visual an" au"i#le in"ication to users .hen interrogate" #! a

searching ra"ar-

+ange

The range achieva#le fro a SA+T is "irectl! proportional to its height a#ove the .ater-

A SA+T ounte" at 6 (ie' in a liferaft) shoul" #e a#le to #e "etecte" at 7 nautical iles #! a

ship/s ra"ar ounte" at 67-

The sae SA+T shoul" #e a#le to #e "etecte" at * nautical iles #! an aircraft fl!ing at @***

feet-

GMDSS carriage reuireents

GMDSS vessels fro ** to 7** G+T are reuire" to carr! 6 SA+T, an" vessels over 7** G+Tare reuire" to carr! 4-

A2S SAS

Manufacturers have recentl! "evelope" SA+Ts .hich .or; in con%unction .ith the V3

Autoatic I"entification S!ste (AIS)-


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IMO has recognise" AIS SA+Ts as #eing euivalent to ra"ar SA+Ts for SOLAS carriage & i-e-

ships can su#stitute an AIS SA+T for a ra"ar SA+T-

The AIS SA+T coprises a t.o channel V3 AIS transitter an" a G:S receiver integrate" into

one .aterproof enclosure & .hich is ver! siilar in si0e to a tra"itional ra"ar SA+T-

AIS SA+T technical paraaters are "efine" in I6*8&62- These can #e

suarise" as follo.s'

:o.er output' 6 H 4-*47 M30)- This tie frae is "esigne" to a5iise the perio" that the

SA+T .ill #e visa#le to other ships AIS receivers- +eception of onl! 6 of the @ essages .ill

ena#le accuratle location of the SA+T-

AIS SA+Ts are co"e" .ith a unique ) digit identification code #eginning .ith 8* & ver!


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siilar to a DSC MMSI- The i"entification co"e is structure" as follo.s'

)'+66==== , .here

8* is the SA+T prefi5

?? is the anufacturer/s 4 "igit co"e

EEEE is the in"ivi"ual SA+T nu#er

Ship#oar" AIS s!stes .ill recognise the 8* prefi5 as a SA+T, an" "ispla! the target as a circle

.ith a cross-

The AIS SA+T offers significent adantages over the ra"ar version & the uch lo.er

operating freuenc! (6>* M30 vs *** M30) eans that range is significantl! increase"-

Moreover, #ecause V3 can (to a certain e5tent) propagate aroun" hills, SA+Ts can literall! #e

seen /aroun" corners/-

More info on AIS SA+Ts can #e foun" at the follo.ing anufacturer/s .e#sites'

Fotron

McMur"o

8ortable 34F transceiers

These units are "esigne" to allo. counications #et.een searching vessels an" survivors in

liferafts- The! operate on the V3 arine #an" in voice o"e- DSC capa#ilit! is not fitte"-

:erforance stan"ar"s

The IMO perforance stan"ar" reuires that the euipent'

provi"e operation on V3 channel 6> (the ra"iotelephone "istress an" calling channel) an" one

other channel

#e capa#le of operation #! uns;ille" personnel

#e capa#le of operation #! personnel .earing gloves

http://www.jotron.com/Kategori/Maritime-Products/AIS-SART--Radar-SART/485.phphttp://www.jotron.com/Kategori/Maritime-Products/AIS-SART--Radar-SART/485.phphttp://mcmurdo.co.uk/products/product.html?product_type=18&product_sector=3&product=107http://www.jotron.com/Kategori/Maritime-Products/AIS-SART--Radar-SART/485.phphttp://mcmurdo.co.uk/products/product.html?product_type=18&product_sector=3&product=107


27/35

#e capa#le of single han"e" operation, e5cept for channel changing

.ithstan" "rops on to a har" surface fro a height of 6 etre

#e .atertight to a "epth of 6 etre for at least 7 inutes, an" aintain .atertightness .hen

su#%ecte" to a theral shoc; of 27 "egrees Celsius-

not #e un"ul! effecte" #! sea.ater or oil

have no sharp pro%ections .hich coul" "aage survival craft

#e of sall si0e an" .eight

#e capa#le of operating in the a#ient noise level li;el! to #e encountere" on #oar" survival

craft

have provisions for attachent to the clothing of the user

#e either a highl! visi#le !ello.=orange colour or ar;e" .ith a surroun"ing !ello.=orange

ar;ing strip

#e resistant to "eterioration #! prolonge" e5posure to sunlight


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'ypical GM!! V)( porta+le transceivers

GMDSS carriage reuireents

GMDSS vessels fro ** to 7** G+T are reuire" to carr! 4 V3 porta#les, an" vessels over

7** G+T are reuire" to carr! -

Alas, the GMDSS is not perfect.....

he GMDSS is not perfect....

Despite .hat soe .oul" have !ou #elieve, the GMDSS is 9OT a perfect s!ste-

The s!ste suffers fro a nu#er of fla.s, all of .hich have the potential to seriousl!

un"erine aritie safet!-

The pro#les (an" their possi#le solutions) are "iscusse" #elo. an" in the follo.ing 4 sections-

:o maritime distress systemsC

The GMDSS .as intro"uce" .orl".i"e on e# 6, 6-

To "ate, there are no facilities in an! areas of the .orl", inclu"ing an! South :acific nations-

In a""ition, the a%orit! of vessels operating through an! areas are not GMDSS euippe"-

It can #e argue" that the GMDSS is a s!ste priaril! "esigne" for "evelope" nations, .ith no

real thought given to the nee"s of the "eveloping .orl"-

GMDSS ipleentation #! an! lag States is less than satisfactor! & soe ships, particularl!

those registere" un"er lags of Convenience, are operating un"er e5eptions, in "irect #reach

of the SOLAS Convention-

Hhilst the theor! of one universal glo#al aritie counications s!ste is soun", the

ipleentation of the s!ste has #een less than successful- or e5aple, lag States are left to

"eterine their o.n reuireents for vessels not covere" #! SOLAS & i-e-' those engage" on

"oestic vo!ages, an" those vessels un"er ** G+T, engage" on an international vo!age-


29/35

Hhilst this solution presents no real pro#les for


30/35

Accor"ingl!, an! Coast +a"io Stations are no. force" to rel! "irectl! on fun"ing fro their

Governents an" SA+ agencies- nfortunatel!, soe "eveloping countries have precious little

revenue to allocate to Coast +a"io 9et.or;s-


31/35

The IMO also coissione" the "esign an" costing (#! Dunstan an" Associates) of a coplete

GMDSS Coast +a"io net.or; for the :acific region-

nfortunatel!, these initiatives a! not coe into effect for soe tie-

Continue to :art 4 for ore pro#les an" possi#le solutions-

he DS* mess

The GMDSS DSC s!ste, particularl! on 3, is plague" #! an appallingl! high false alert rate &

in e5cess of -7B-

This situation has reache" critical levels, to the point that there is tal; of "iscontinuing DSC---

The root of the pro#le is that there is no real central operational an" a"inistrative authorit!

to oversee the DSC s!ste & the operation of DSC s!stes on vessels is effectivel!

anage"=regulate" #! in"ivi"ual lag States-

The Inarsat s!ste use" to suffer fro a false alert rate approaching that of DSC & Inarsat

institute" a strong an" .ell anage" progra to co#at the pro#le, .ith the result that the

Inarsat false alert rate has "roppe" to negligi#le levels-

The situation has reache" the point that DSC has #ecoe an ipe"ient to safet! at sea-

0quipment compleEity

Much of the DSC euipent availa#le to"a! is far too cople5 to operate-

In a""ition, the operating routines var! significantl! fro #ran" to #ran", such that a user

traine" on one t!pe of euipent .ill have consi"era#le "ifficult! operating another-

DSC controller operation is coplicate" #! the inclusion of an! (unnecessar!) coercialfunctions & DSC controllers can #e use" to a;e autoatic telephone calls via suita#l! euippe"

3 Coast Stations- nfortunatel!, there are ver! fe., if an!, Coast Stations that offer this

service-

Man! controllers are euippe" .ith sall "ispla! screens & this a;es operation ver! "ifficult-

There .as a ove soe tie ago at IMO to an"ate a iniu DSC "ispla! screen si0e of 2

lines #! >2 characters per line-


32/35

This recoen"ation .as o"ifie" to reuire that a iniu of 6>* characters #e "ispla!e" in

t.o or ore lines- These o"ifications have ta;en effect for all ne. euipent fitte" to ships as

fro 6 Fanuar! 4***-

There is nothing in the IMO perforance stan"ar"s to prevent anufacturers using a :ersonal

Coputer t!pe s!ste for DSC, i-e-' one .ith a large "ispla! screeen & ho.ever none have #een

pro"uce", pro#a#l! #ecause of cost-

The o"ifications also an"ate" connection of a G:S an" also the provision of an alar to

in"icate that no position "ata is receive" fro the G:S or, in the case of anual input, the

position inforation is over 2 hours ol"- An! position inforation not up"ate" for ore than

4N hours is also reuire" to #e erase" fro the s!ste-

Soe anufacturers are pro"ucing siple to use DSC s!stes, .ith large "ispla! screens-

It is hope" that this tren" .ill sprea"-

instigate" #! the author

A ne: DS* standard is here

After seven !ears of effort, IT an" I


33/35

e5aple), an" the MMSI is often euall! "u#ious (6427>8@, 666666666, 444444444, etc)-

*an the system be too effectie C

3 DSC/s effectiveness an" .orl"&.i"e range is lea"ing to its "o.nfall-

Alerts are often receive" fro stations uite literall! on the other si"e of the .orl"- It is not

uncoon to receive a 64 M30 DSC alert fro the 9orth Sea in the South :acific----

Hhilst this is uite interesting fro a technical perspective, it is a coplete .aste of tie fro a

SA+ vie.point-

Copare the DSC s!ste .ith Inarsat & .ith Inarsat, alerts are "irecte" straight to the +CC &

surroun"ing ships are onl! alerte" via a carefull! controlle" reroa"cast fro the +CC-

Although 3 DSC is "esigne" for ship&shore alerting, it operates in a #roa"cast o"e & all ships

onitoring the freuenc! receive the call, an" all are therefore a#le to rela! it------

?sers are too enthusiastic...

The IT operational gui"elines for 3 DSC reuire that, #asicall!, a vessel receiving a 3 DSC

alert is to ie"iatel! set .atch on the correspon"ing +=T or 91D: channel for the #an" in

.hich the DSC alert .as receive" an" a.ait counications fro the vessel in "istress-

3o.ever, this is not happening & vessels are rela!ing 3 DSC alerts in"iscriinatel!-

Ironicall!, the original "istress alert #eing rela!e" is, in itself, pro#a#l! false---

This is lea"ing to serious congestion of the DSC channels & to the point that the original alert has

#ecoe so corrupte" that it appears a Coast Station is in "istress

nfortunatel!, DSC is #ecoing an en" in itself, rather than a siple alerting echanis-

Man! ships fail to a"euatel! consi"er the inforation in a receive" alert #efore rela!ing & an

alert fro a ship .ith an o#viousl! false MMSI (such as 6427>8@) shoul" not #e rela!e"-

:erusal of the international MID list reveals that the follo.ing MID nu#ers are not allocate"'

+++ 1"# """ ### $$$ ''' ((( )))


34/35

It is ver! "ifficult for a ship/s operator to change his=her DSC s!ste/s MMSI at sea, so one can

safet! assue that MMSI/s .ith the a#ove MID/s ust #e #ogus-

sers receiving a DSC "istress alert fro a vessel .ith a MMSI starting .ith an! of these MID/s

can therefore IG9O+< the alert & it can not #e genuine-

Misplace" enthusias "oes not stop at the shoreline either---- Man! Coast +a"io Stations are

also guilt! of %uping in too uic;l! an" rela!ing or ac;no.le"ging alerts that are clearl! out of

their area-

Continue to part for soe solutions-

Solutions to the DS* mess...

So, ho. "o .e coe to ters .ith the 3 DSC fiasco K

A lot of the pro#les can #e overcoe #! ships directing relays to specific coast stations,

an" #! *oast Stations using the geographic addressing capability of the system.

$ ship recei%in" a & DSC alert must(

). W$*T and +*ST- on the correspondin" radiotelephone or -D/ channel in

the band in which the DSC alert was recei%ed.

0. *f no communications can be heard from the ship in distress, and1or the ship in

distress continues to send alerts, then the alert should be relaed to the nearest

Coast Station 2 -3T T3 $++ S&*/S.

Coast stations recei%in" a & DSC alert out of their area must wait for a closer

station to respond, rather than umpin" in first.

DSC distress alert relas from Coast Stations should be addressed to aGeo"raphic area around the distressed %essel's position, in the same wa as an

*nmarsat GC messa"e, not ust broadcast to all ships.

urther, Coast Stations recei%in" a DSC alert from a bo"us MMS* should not

rela the alert, onl ac4nowled"e it to stop the offendin" e5uipment from

sendin" an more.

(DSC "istress ac;no.le"gent essages autoaticall! terinate the transission of DSC


35/35

"istress alerts)-

These siple steps .ill go a long .a! to iproving the current chaotic situation .ith 3 DSC-

The IMO has finall! release" DSC flo. charts to serve as a siple gui"e for ship#oar" users- Alin; to these charts a! #e foun" at the #otto of the DSC page-

Hhilst the charts are not as clear an" siple as the! ight #e, at least the! are a step in the right

"irection-

Soe ore i"eas on sorting out the GMDSS a! #e foun" here-

GMDSS forum and mailing list

3ave a burning GMDSS issue !ou .oul" love to get off !our chestK

3ave !ou foun" the solution to the .orl"/s GMDSS pro#lesK

Loo;ing to share inforation an" i"eas .ith other GMDSS usersK

Or %ust intereste" in the s!steK

Then .h! not %oin the GMDSS foru an"=or the GMDSS ailing list, the .e#/s onl! GMDSS&

specific "iscussion forus-

The list an" foru are "esigne" to cater for all .ith an interest in the s!ste & .hether the! #e

e5perience" professionals or ne.coers-

All are .elcoe-

9oral forus=e&ail list rules appl! & no profanit!, no flaes & #e nice to each other--

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GMDSS Concepts

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Transcript of GMDSS Concepts