GMDSS - Radio communication

Attention Reader's......

2012-01-12T09:52:00.000-08:00

From 14th January 2012 onwards... this blog become a private 1...... So, anybody wants to read the blog in future must SEND their E-mail id as a COMMENT to this post...otherwise...i'm sorry i can't add you as a reader.....

The changes are not because of any selfishness... but because of more open sources ie, more Useful Question banks...and Opportunity pages are coming from the very next week....so..... take ur own decision....

Atlantic rowers rescued after activating their McMurdo EPIRB

2012-01-04T07:26:00.000-08:00

4 January 2012

A McMurdo EPIRB (Emergency Position Indicating Radio Beacon) has saved the lives of two Trans-Atlantic rowers, who were successfully rescued when they activated the beacon after their boat sank in the middle of the Atlantic.
The transatlantic rowers, Briton Tom Fancett and Dutchman Tom Sauer, were nine days into the Talisker Whiskey Atlantic Challenge, a 3,000 mile endurance rowing event from the Canary Islands to Barbados, when a freak wave struck their boat and caused it to capsize and sink.
The Falmouth Coastguard received the alert at 7:54pm on Tuesday 13th December, 480 miles South West of the Canary Islands from the UK registered McMurdo beacon, belonging to the Atlantic Challenge rowing boat PS Vita. The Falmouth Coast Guard broadcast an alert to all vessels in the area. Four vessels picked up the alert however approximately 120 miles from the location, and closest to the scene, was Crystal Serenity a Bahamian registered cruise ship which was en route to St Martin in the Caribbean from Tenerife.
The two rowers, who had spent at least 10 hours adrift in their tiny life raft before being saved, were rescued uninjured by the crew of Crystal Serenity in the early hours of the morning on Wednesday 14th December.
McMurdo offers a range of emergency location beacon products including EPIRBs, PLBs (Personal Location Beacons), SARTs, AIS Beacons, NAVTEX and VHF Radios – must-have devices for all safety-conscious sailors.
McMurdo’s range of EPIRBs are designed to alert search and rescue services in the event of an emergency by transmitting a coded message on the 406 MHz distress frequency. The G5 Smartfind EPIRB also includes a GPS receiver ensuring that the exact position of a casualty is relayed to the rescue services.
For further information on McMurdo’s range of safety and emergency location beacon products, visit www.mcmurdo.co.uk.

data courtesy: websites

UK GMDSS _ Exam tips

2011-11-15T20:38:00.000-08:00

Most important in UK GMDSS exam is ..

GK Paper---> for 25 min exam---> SOLAS is the scoring chapter for the descriptive part..and in objective part for 15 marks... the antenna, battery and some twisting quetions...

RT communication is easy ....but with the GREY box ....be cautious with the POSTION copying and time.....

OPT---- InmarSAT- C is the important.... As the Scenario model is implemented in OPT so the chance of scoring is easy ....but must have deep knowledge in SAT C and B ....

there you can also expect random wise qns......

Model Qns,,, 2

2011-10-07T05:17:00.001-07:00

1. With respect to Distress communications the MAIN function of the On Scene Co-ordinator (OSC) is to

ANS: maintain communication with all Search and Rescue (SAR) facilities

2. Routine RT inter-ship VHF messages may be passed on

ANS: Ch.08 VHF is the only ship-to-ship channel listed in the options. Ch.16, Ch.13 and Ch.70 are used for other purposes.

3. According to international regulations VHF Ch.06 may be used for

ANS: VHF Ch.06 has two functions. First it is the primary inter-ship RT (voice) channel. Secondly it is used for ship to aircraft communications during SAR operations

4. n the terrestrial radio service, the category, message with the highest priority is a

ANS: weather observation

5. The correct format for on-going on-board communications between sub station and bridge is

ANS: SEAQUEST CONTROL) this is SEAQUEST BRAVO is the correct format as per ITU radio regulations. It is used to avoid confusing with other vessels in crowded anchorages etc.

Model Qns,,,

2011-10-02T10:33:00.000-07:00

· After transmitting a MF DSC Safety Alert, the RT call should be transmitted on

You answered:	2182 kHz
Correct

· The correct format for an RT Urgency Call to Clyde Coastguard is

You answered:	PAN PAN (x3) Clyde Coastguard (x3) this is Nonsuch (x3) GABC 232123456
Correct

· Your vessel is in GMDSS Sea Area A1, drifting ashore and you require a tow. You should initially transmit by Ch. 70 DSC

You answered:	an All Stations Urgency Alert
Correct

· After transmitting a VHF DSC Urgency Alert, the RT call and message is usually sent on

After transmitting a VHF DSC Urgency Alert, the RT call and message is sent on Ch. 16.

· The correct format for an RT Safety Call to Clyde Coastguard is

You answered:	SECURITE (x3) Clyde Coastguard (x3) this is Nonsuch (x3) GABC 232123456

· After receiving a DSC Distress Relay Alert from an MRCC on MF, you should

You answered:	listen for a MAYDAY RELAY message on 2182 kHz

· To announce an unscheduled meteorological warning a coast station should transmit a DSC

You answered:	Safety Alert

· You are in GMDSS Sea Area A2 and have received a DSC Distress Alert you should

You answered:	wait a short period, then acknowledge by RT on 2182 kHz

· A DSC Distress Relay Alert should only be sent on the authority of

You answered:	person responsible for radio communications in an emergency

A DSC Distress Relay Alert should only be sent on the authority of the Master or person responsible for of the vessel.

· You are in Sea Area A2 and require medical advice from Humber Coastguard. You should initially transmit by MF DSC on 2187.5 kHz

You answered:	an Urgency Alert addressed to Humber Coastguard’s MMSI
	...............................................

FOLLOW for the Complete series........

Inmarsat Device

2011-09-28T10:15:00.000-07:00

The standard Inmarsat C device on board consists of an Inmarsat terminal (this is the transmitter and receiver), a message terminal with disc drive and keyboard or another computer system, a printer, a power supply, an omnidirectional antenna, an antenna cable and, if not built-in, a GPS receiver.

Example of an Inmarsat C device.

The Inmarsat C device can be used for sending and receiving messages. These messages consist of data which is generated or decoded by the message terminal or computer connected to the Inmarsat C terminal. So it offers the possibility of sending and receiving various types of messages such as E-mail, Fax, TELEX, SMS etc.

Inmarsat Communication

2011-09-27T10:30:00.000-07:00

The Inmarsat system is a satellite communication network.

It is used by ships, and also by other users. This Inmarsat system supports the GMDSS system and for that reason it is used a lot on SOLAS ships as well as on non-SOLAS ships.
Within the GMDSS system the Inmarsat system may be used for distress- alerting in sea area A3. Although areas A1 and A2 are not excluded from distress-alerting by Inmarsat, in these areas the GMDSS system offers better solutions for distress-alerting. It is also used for transmission of Maritime Safety Information (MSI) outside the coverage of a NAVTEX station.

History

The International Maritime Satellite Organization was founded on 16 July 1979.
At this time Inmarsat took over the Marisat-network from the American company Comsat.
From this moment on it was possible for ships at sea to communicate via satellite. In the beginning the system was only used by ships.
Now Inmarsat is offering a wide range off products/services also for airplanes and other landmobile users.
Apart from commercial activities, Inmarsat is committed to the IMO to ensure a 100% functioning communication network for Distress communication.

Satellite Propagation

The Inmarsat services will use 'direct wave' propagation (just like at the VHF 'Line of Sight'). There should always be a direct line of sight between the ship's Inmarsat antenna and the satellite used. For this reason the antennae should be fitted clear of the superstructure or other obstructions. Coverage for GMDSS purposes is considered reliable up to latitudes 70 degrees North and 70 degrees South (assuming not 'in shadow' of mountains, terrain or buildings), though service can often be accessed further North or South than the mentioned 70 degrees. The further you are from the equator, the lower the angle of sight from the antenna to the satellite, and the greater the possibility of losing sight of the satellite when near to land or other obstruction.

Inmarsat satellites 36000 km above the earth

The picture above shows the position of the four Inmarsat satellites. These geo-stationary orbiting satellites are situated in fixed positions above the equator

Last Radio Traffic from TITANIC

2011-09-19T04:23:00.000-07:00

Distress Radio Traffic

Distress calls
The message "CQD" means a general call to all vessels, which indicates the vessel sending is in distress and requires immediate assistance. At the time of the sinking, the Marconi company's "CQD" was still in common use, although it had been officially replaced by the well known "SOS" - which, by the way, does NOT mean "Save Our Souls" or anything so melodramatic - it was chosen specifically to be easily and instantly recognisable in morse - "dit dit dit, dah dah dah, dit dit dit".
Such was the dominance of Marconi over the infant marine radio industry that many ships still used CQD, rather than the official distress signal SOS.
This can be seen in the Titanic's initial and final distress calls - Jack Phillips stuck to the company CQD signal to the end....

The messages -

*Titanic time*	*Message(s)*
12-15 a.m	CQD (6 times) DE (this is) MGY (6 times) position 41.44 N. 50.24 W La Provence and Frankfurt receive Titanic's first distress signals. Titanic sends position to Frankfurt. Frankfurt says "OK: stand by"
12-15 a.m	Mount Temple heard Titanic sending CQD Says require assistance. Gives position. Cannot hear me (sic). Advise my Captain (sic) his position at 41.46 N. 50.24 W.
12-15 a.m.	Cape Race coast station hears Titanic giving position on CQD 41.44 N. 50.24 W.
12-18 a.m.	Ypiranga hears CQD from Titanic. Titanic gives CQD here (sic). Position 41.44 N. 50.24 W. Require assistance (calls about 10 times).
12-25 a.m.	Carpathia calls Titanic and says "do you know that Cape Cod is sending a batch of messages for you ?" Titanic says "Come at once. We have struck a berg. It's a CQD OM (it's a distress situation old man) Position 41.46 N. 50.14 W." Carpathia says "Shall I tell my Captain ?. Do you require assistance ?" Titanic says "yes, come quick"
12-25 a.m.	Cape Race hears MGY (Titanic) give corrected position 41.46 N. 50.14 W. Calling him, no answer. (Titanic's 4^th Officer Boxhall had just provided a corrected position to the radio room)
12-25 a.m.	MGY (Titanic) says CQD, Here (is my) corrected position 41.46 N. 50.14 W. Require immediate assistance. We have collision with iceberg. Sinking. Can hear nothing for noise of steam (engineers releasing excess steam pressure from boilers to minimise risk of explosion) Sent about 15 to 20 times to Ypiranga.
12-26 a.m.	DKF (Prinz Friedrich Wilhelm) calls MGY (Titanic) and gives position at 12 a.m. 39.47 N. 50.10 W. MGY (Titanic) says, "Are you coming to our ?" "We have collision with iceberg. Sinking. Please tell Captain to come." DKF says, "O.K. will tell"
12-27 a.m.	Titanic sends following: "I require assistance immediately. Struck by iceberg in 41.46 N. 50.14 W."
12-30 a.m.	Caronia sent CQ message (message addressed to all ships) to MBC Baltic and CQD (ie: a distress relay message): MGY (Titanic) struck iceberg, require immediate assistance
12-30 a.m.	Mount Temple hears MGY (Titanic) still calling CQD. Our (sic) Captain reverses ship. We are about 50 miles off.
12-34 a.m.	Mount Temple hears Frankfurt give MGY (Titanic) his position 39.47 N. 52.10 W. Titanic says (to Frankfurt) " are you coming to our assistance ?" Frankfurt says : "what is the matter with you ?" Ttianic says "We have struck an iceberg and sinking. Please tell Captain to come" Frankfurt replies "O.K. Will tell the bridge right away" Titanic says "O.K., yes, quick."
12-45 a.m.	Titanic calls Olympic (Olympic is Titanic's sister ship - 500 miles away en route to England) SOS - (first use of "SOS" by Titanic- Bride jokingly suggests to Phillips that it may be his last chance to use the new distress call).
12-50 a.m.	Titanic calls CQD and says, "I require immediate assistance. Position 41.46 N. 50.14 W." Received by Celtic.
12-53 a.m.	Caronia to MBC (Baltic) and SOS,"MGY (Titanic) CQD in 41.46 N. 40.14 W. Wants immediate assistance."
1-0 a.m.	MGY gives distress signal. DDC (Cincinatti) replies. MGY's position 41.46 N. 50.14 W. Assistance from DDC (Cincinatti) not necessary as MKC (Olympic) shortly afterwards answers distress call.
1-0 a.m.	Titanic replies to Olympic and gives his position as 41.46 N. 50.14 W., and says, "We have struck an iceberg."
1-2 a.m.	Titanic calls Asian and said, "Want immediate assistance" Asian answered at once and received Titanic's position as 41.46 N. 50.14 W., which he immediately takes to the bridge. Captain instructs operator to have Titanic's position repeated.
1-2 a.m.	Virginian calls Titanic but gets no response. Cape Race tells Virginian to report to his Captain the Titanic has struck iceberg and requires immediate assistance.
1-10 a.m.	Titanic to MKC (Olympic), "We are in collision with berg. Sinking Head down. 41.46 N. 50.14 W. Come soon as possible."
1-10 a.m.	Titanic to MKC (Olympic), Captain says, "Get your boats ready. What is your position?"
1-15 a.m.	Baltic to Caronia, "Please tell Titanic we are making towards her."
1-20 a.m	Virginian hears MCE (Cape Race) inform MGY (Titanic) "that we are going to his assistance. Our position 170 miles N. of Titanic."
1-25 a.m.	Caronia tells Titanic, "Baltic coming to your assistance"
1-25 a.m	Olympic sends position to Titanic 4-24 a.m. G.M.T. 40.52 N. 61.18 W, and asks "Are you steering southerly to meet us?" Titanic replies, "We are putting the women off in the boats."
1-27 a.m	Titanic says, "We are putting the women off in the boats."
1-30 a.m	Titanic tells Olympic, "We are putting passengers off in small boats." "Women and Children in boats, can not last much longer"
1-35 a.m.	Olympic asks Titanic what weather he had. Titanic replies, "Clear and calm."
1-35 a.m	Baltic hears Titanic say "Engine room getting flooded." (Captain Smith had just visited the Titanic's radio room and advised this to Phillips and Bride)
1-35 a.m.	Mount Temple hears DFT (Frankfurt) ask "are there any boats around you already?" No reply
1-37 a.m.	Baltic tells Titanic, "We are rushing to you."
1-40 a.m.	Olympic to Titanic "Am lighting up all possible boilers as fast as (we) can."
1-40 a.m.	Cape Race says to Virginia: "Please tell your Captain this: "The Olympic is making all speed for Titanic, but his (Olympic's) position is 40.32 N. 61.18 W. You are much nearer to Titanic. The Titanic is already putting women off in the boats, and he says the weather there is calm and clear. The Olympic is the only ship we have heard say, "Going to the assistance of Titanic. The others must be a long way from Titanic
1-45 a.m.	Last signals heard from Titanic by Carpathia, "Come as quickly as possible old man: the engine-room is filling up to the boilers"
1-45 a.m.	Mount Temple hears Frankfurt calling Titanic. No reply.
1-47 a.m.	Caronia hears Titanic though signals unreadable still
	Virginia hears Titanic calling very faintly, his power being greatly reduced. (At 2-05 a.m. the Captain visits the wireless room for the last time and says: "Men, you have done your full duty. You can do no more. Abandon your cabin. Now it's every man for himself" Phillips looks up for a second, and then bends over the equipment once more. Captain Smith tries again "You look out for yourselves. I release you." A pause, then he adds softly "That's the way of it at this kind of time....every man for himself" He then leaves the wireless room. Phillips continues sending)
1-48 a.m.	Asian heard Titanic call SOS Asian answers Titanic but receives no answer. DFT (Frankfurt) calls Titanic and says, "What is the matter with u ?"
1-50 a.m.	Titanic says to Frankfurt "You fool, stdbi and keep out" Caronia hears Frankfurt working to Titanic. Frankfurt according to position 172 miles from MGY (Titanic) at time first SOS sent out.
1-55 a.m.	Cape Race says to Virginian "we have not heard Titanic for about half an hour. His power may be gone."
	During this period Phillips and Bride are struggling with a stoker who entered the wireless room and tried to steal Phillips life jacket. Bride holds the stoker, while Phillips punches him. The stoker is (presumably) knocked unconscious.
2-10 a.m.	Virginian hears 2 v's signalled faintly in spark similar to Titanic's (Most probably Phillips was transmitting a test signal whilst Bride adjusted the main transmitter motor-generator field regulators to compensate for the dying power supply from the engine room).
2-17 a.m.	Virginian hears Titanic call CQ (call to all ships) , but unable to read him. Titanic's signals end very abruptly as (if) power suddenly switched off. His spark rather blurred or ragged... (Phillips had actually intended to send "CQD DE MGY", however at this point there is a loss of all power to the radio room - water can be heard flooding the wheelhouse - Phillips says to Bride "Come on, let's clear out". Bride climbs to the roof of the officer's quarters and assists with launching collapsible lifeboat B - Phillips disappears aft.)
2-17 a.m.	Virginian Called Titanic and suggested he should try emergency set, but heard no response
2-20 a.m.	Virginian to Olympic,"have you heard anything about Titanic" Olympic says, "No. Keeping strict watch, but hear nothing more from Titanic. No reply from him"
about 2-20 a.m.	This was the official time the ship foundered in 41.46 N. 50.14 W. as given by the Carpathia in message to the Olympic.
2-35 a.m.	Mount Temple hears MPA (Carpathia) send, "If you are there we are firing rockets."
2-40 a.m.	MPA (Carpathia) calling MGY (Titanic).
2-58 a.m.	SBA (Birma) thinks he hears Titanic so sends, "Steaming full speed for you. Shall arrive you 6-0 in morning. Hope you are safe. We are only 50 miles now."
3-0 a.m.	MPA (Carpathia) calling MGY (Titanic)
3-28 a.m.	La Provence to Celtic, "Nobody has heard the Titanic for about 2 hours."
4-24 a.m.	SBA (Birma) says "we are 30 miles S.W. off Titanic".
6-40 a.m.	Parisian hears weak signals from MPA (Carpathia) or some station saying Titanic struck iceberg. Carpathia has passengers from lifeboats
6-40 a.m.	Asian, with German oil tank in tow for Halifax asked what news of MGY (Titanic). Sends service (message) later saying heard MGY (Titanic) v. faint working. C. Race up to 10.0 p.m., local time. Finished calling SOS midnight.
7-40 a.m.	6-45 a.m. Mount Temple hears MPA (Carpathia) report rescued 20 boat loads.
8-07 a.m.	Baltic sends following to Carpathia: "Can I be of any assistance to you as regards taking some of the passengers from you? Will be in position about 4-30. Let me know if you alter your position."
8-10 a.m.	Baltic in communication with MPA. (Carpathia). Exchanged traffic re passengers, and get instructions to proceed to Liverpool
8-15 a.m.	Baltic turns round for Liverpool, having steamed 134 miles W. towards Titanic
8-40 a.m.	Mount Temple hears MPA (Carpathia) call CQ and say, no need to std. Bi (stand by) him. Advise my Captain (sic), who has been cruising round the icefield with no result. Ship reversed.
8-45 a.m.	Olympic sent MSG (message) to Owners, New York via Sable Island saying, "Have not communicated with Titanic since midnight."
8-55 a.m.	Carpathia replies to Baltic, "Am proceeding to Halifax or New York full speed. You had better proceed to Liverpool. Have about 800 passengers on board."
9-0 a.m.	Carpathia to Virginian: "We are leaving here with all on board about 800 passengers. Please return to your Northern course."

Radio callsigns
Radio call signs for the ships and shore stations involved are listed below.
In 1912, ships were issued with 3 letter call signs (this later changed to 4, as more ships were fitted with wireless).

Wireless shore stations:
Cape Race Newfoundland MCE
Sable Island Nova Scotia MSD
Sea Gate New York MSE
Sagaponack New York MSK
Siasconset Massachusetts MSC
Cape Sable Nova Scotia MSB

Vessels name and radio callsign (with the Captain's name listed where known):
Antillian Capt. Japha MJL
Amerika Capt. Knuth DDR
Asian Capt. Wood MKL
Baltic MBC
Blucher DDB
Birma SBA
Californian Capt. S.Lord MWL
Caronia Capt. Barr MSF
Carpathia Capt. A.H.Rostron MPA
Celtic MLC Cedric MDC
USS Chester Capt. S.G. Decker NDG
Franconia Capt. Smith MEA
Frankfurt DFT
Empress of Britain MPB
La Touraine Capt. Coussin MLT
Titanic Capt. Smith MGY
Mount Temple MLQ
Mesaba Capt. Clark MMU
Minnehaha MMA
Minnewaska Capt. Gates MMW
Noordam Capt. Krol MRA
Olympic Capt. Haddock MKC
Parisian MZN
Prinz Friedrich Wilhelm DKF
Virginian Capt. Gambell MGN

Distress, Urgency and safety calls - Tx + Dx

2011-09-19T00:42:00.000-07:00

Transmitting, Receiving and Relaying Distress, Urgency and Safety Calls

Reception of a Distress Alert

A vessel receiving a DSC distress alert should not normally acknowledge the alert by DSC, but should do so by voice or telex on the emergency frequency indicated in the alert. A DSC acknowledgement is usually done only by a Coast Station, because acknowledging the alert by DSC will stop the transmitting station from sending further alerts. Generally, it is much better for all concerned if a Coast Station hears and acknowledges the alert, and then assumes control of the operation.

Another vessel should only acknowledge the alert by DSC if it is being transmitted on VHF or MF, and if it seems that no Coast Station has received the call and the transmission of the distress alert is continuing. In this situation, the receiving vessel may acknowledge the call by DSC to terminate the transmissions. But the receiving vessel is then required to contact the nearest Coast Station by any practical means and inform them of the situation.

A DSC distress alert on HF should never be acknowledged by DSC by another vessel, because by the nature of HF propagation the two vessels are likely to be many hundreds of miles apart. Transmission of a DSC acknowledgement will stop the transmission of further alerts, and it would be better for the distressed vessel to continue sending alerts in the hope that a Coast Station will receive the call directly and take control of the situation. A vessel receiving an alert on HF should relay the alert to a Coast Station.

Reception of a DSC DISTRESS ALERT on VHF or MF

If a DSC distress alert is received on VHF or MF, the normal procedure to follow is:

(a) Watch the DSC control unit for reception of a DSC acknowledgement from a Coast Station. Such an acknowledgement will stop further transmissions of the distress alert.
(b) Tune the radio to the frequency and mode indicated in the DSC alert.
(c) Acknowledge the receipt of the distress alert on the frequency indicated, either by voice or by telex as indicated in the DSC alert.

The message acknowledging the distress alert should be as follows:

Mayday - The word Mayday indicates that it is a distress message.

Identity of Distressed vessel - This will be their MMSI, repeated three times - neither the name nor the call sign of the distressed vessel will be indicated on the DSC alert.

This is......... - Your identity - your MMSI and/or name and call sign, repeated three times.

Received Mayday.

Over.

If there is a Coast Station, or Rescue Co-ordination Centre controlling the operation and they want you to help, they will call you back. If no Coast Station nor RCC has taken control, the distressed vessel should hear your acknowledgement and may call you back to ask for your assistance if it is needed. If no Coast Station nor RCC has taken control and you do not hear any response to your acknowledgement by the distressed vessel, then you should send a distress alert relay.

Reception of a DISTRESS ALERT on HF

Vessels operating in Areas A3 and A4 are expected to monitor at least two of the DSC HF emergency frequencies. Normally 8414.5 kHz is designated as one and the other is chosen according to conditions - a lower frequency by night or a higher one by day. Many DSC watch-keeping receivers will in fact scan through all the DSC emergency frequencies; which are:

4207.5 kHz 6312 kHz 8414.5 kHz 12577 kHz 16804.5 kHz

If you receive a DSC distress alert on HF from another ship you must not acknowledge it by DSC. Because of the likely propagation of the HF signal it is probable that the other vessel is several hundreds, or possibly thousands of miles away. If the distress alert was acknowledged by DSC then no further distress alerts would be transmitted by the distressed station, and this could well reduce the chances of it being heard by a shore station who could co-ordinate rescue attempts.

If you do receive an HF DSC distress alert then the correct procedure is:

a. Note on which band or bands the DSC alert was received.

b. Note the position of the distressed vessel, and compare to your own. Unless the HF signal was received on ground wave, it is likely to be many hundreds of miles from your own position.

c. Tune the HF radio to the mode and frequency indicated in the alert, or if no frequency and mode was specified then to the emergency frequency in the band on which the DSC alert was received. The HF emergency frequencies are:

Voice emergency frequencies:
4125 kHz 6215 kHz 8291 kHz 12290 kHz 16420 kHz

Telex emergency frequencies:
4177.5 kHz 6268 kHz 8376.5 kHz 12520 kHz 16695 kHz

If telex was specified in the alert then the telex frequency should be monitored, but if it is possible to monitor the voice frequency on the same band as well then this should be done. If the DSC alert was received on several frequencies then monitor the most likely band, probably 8 MHz if the alert was received on this band.

d. If no distress traffic is heard on the frequency to which you tuned within two minutes, then switch to the emergency frequency on another band on which the DSC alert was received or another of the emergency frequencies that might be appropriate, considering the position of the other vessel in relation to you and the likely propagation.

e. If distress working is heard, then the situation should be monitored until it is obvious that the Coast Station has the situation under control. If no distress working is heard and no DSC acknowledgement has been transmitted by a Coast Station, then transmit a DSC distress alert relay to inform the nearest Rescue Co-ordination Centre or Coast Station by any means possible.

Transmission of a Distress Alert Relay

A vessel should transmit a distress alert relay if:

(a) the distressed vessel herself is not able to transmit a distress alert.
(b) the master of the relaying ship considers that more assistance is required.
(c) a distress alert has been received but no contact with the distressed vessel has been possible and no Coast Station has responded to the alert.

The distress alert relay could be sent to 'all stations', to vessels in a particular area or to a specific Coast Station or RCC. On VHF or MF an 'all stations' call might be considered appropriate to alert vessels in the vicinity as well as any Coast Stations within range. Usually, in the case of an HF DSC alert relay, it will be better to send it to a specific Coast Station or Rescue Co-ordination Centre, and let them co-ordinate the rescue. Do not do an 'all stations' call. There is no point in alerting vessels, for example, in the Indian Ocean for a vessel in distress in the North Atlantic.

A DSC distress alert relay is sent as follows.

a. Tune the radio to the DSC emergency frequency of the most suitable band.
b. Select 'distress relay' on the DSC control unit.
c. Address the call as 'all stations', or to the MMSI of a specific Coast Station or RCC.
d. Key in the MMSI of the distressed vessel, if known.
e. Select the nature of the distress, if known.
f. Key in position of distressed vessel.
g. Key in UTC time that the position was valid.
h. Indicate frequency and mode for subsequent traffic.
i. Transmit the DSC distress alert relay.
j. Watch on the DSC control unit for a DSC acknowledgement. Tune the radio to the stipulated frequency and mode, and transmit the distress relay message.

The distress relay message should take the format:

Mayday relay - Mayday indicates that there is a distress situation, but by adding the word 'relay' it indicates at once that it is not you in distress.

This is......... - Your MMSI, name of vessel, and call sign.
Text of message - Indicating identity and position of distressed vessel, nature of distress, assistance needed and number of persons on board if known.

Reception of a Distress Alert Relay

See a typical Mayday Relay transmitted via Inmarsat-A by JRCC PIRAEUS.

When a Coast Station, RCC, or indeed another vessel, has received, and acknowledged a DSC distress alert it may elect to transmit a distress alert relay to other vessels. It can do this to all stations, a group of vessels, vessels in a particular geographic area, or to one specific vessel. Vessels receiving such a DSC alert should not acknowledge it by DSC, but instead should tune to the indicated frequency and mode and acknowledge it on the appropriate frequency on the same band as it was received. The procedure is: -

a. Do not acknowledge by DSC. Tune the radio to the appropriate frequency and mode indicated in the relay call.
b. Acknowledge the alert relay by voice or telex as appropriate.

The format of the acknowledgement message is:

Mayday - The word Mayday indicates that it is a distress message.

Identity of Distressed vessel - This will be their MMSI, repeated three times. (Neither the name nor the call sign of the distressed vessel will have been indicated on the DSC alert.

This is......... - Your identity, including your MMSI and/or name and call sign, repeated three times.

Received Mayday.

Over.

If there is a Coast Station or Rescue Go-ordination Centre controlling the operation and they want you to help, they will call you back. Continue to monitor the frequency after you have transmitted the acknowledgement.

If a DSC distress alert relay is received from another ship who has perhaps done an 'all stations' distress alert relay, the procedure is exactly the same. Do not acknowledge by DSC, instead acknowledge by voice or telex as appropriate, in exactly the same way as above.

Urgency Calls

An urgency call is for serious situations but not one where the ship or a person is in 'grave and imminent' danger. An example of an urgency call might be a vessel which has lost her engines and may be swept ashore in the next hour or so. The danger is grave, but not yet imminent, so the correct call is an urgency call rather than a distress call. A serious medical problem may warrant an urgency call for assistance or evacuation. An urgency call must not be broadcast to the world in general, it must be addressed to somebody, even if it is to 'all stations.'

Transmission of an Urgency Alert

DSC is used to alert other stations that an urgency message is about to be transmitted on a nominated frequency. The message itself is then transmitted on an appropriate frequency in the normal way. The procedure is:

a Select 'urgency call' on the DSC control unit.

b. Select on which band you want to transmit the DSC alert.

c. Tune the radio to the DSC frequency of the chosen band. The DSC control unit may do this for you.

d. Address the call to 'all stations' or to the MMSI of a particular Coast Station or vessel, or group of vessels.

e. Key in the mode and frequency on which the urgency message will be transmitted.

f. Transmit the DSC urgency alert.

Transmission of an Urgency Message

The radio can now be tuned to the emergency frequency of the band on which the DSC alert was sent for transmission of the urgency message.
The format of an urgency message is:

Pan Pan - The words Pan Pan indicate that the message is an urgency message, and as such, it should have priority over all but distress traffic. In the case of a request for medical assistance, the signal is Pan Pan Medico. Note that this is for medical assistance. A request for medical advice is not a Pan Pan.

Address - All messages except distress must be addressed to somebody. A general call, perhaps for a tow, would be addressed to 'all stations'. A Pan Pan Medico is more likely to be addressed to a specific Coast Station, but under some circumstances that too could be addressed to 'all stations'.

Identity - You must identify yourself in all transmissions. Any station that has received your urgency call on DSC has received your MMSI number as part of the call, so your identity should include the MMSI number as well as the name and call-sign of your vessel.

Position - This may have been included in the DSC call, but it should be repeated here. If somebody is to help you, they need to know where you are. As in the distress message, your position as a distance and bearing from a prominent landmark may mean more to the receiving station than a latitude and longitude.

Assistance - State what assistance is needed.

Over - Terminate the message with Pan Pan, name of your vessel and call-sign, and the word 'over', so the other stations know you have finished, and they can respond.

Once communications have been established with a suitable station, the subsequent traffic will normally transfer off the emergency frequency onto a working channel. If the communication is on VHF and the traffic is inter-ship, then channel 6 could be used. If the communication is with the Coastguard, then they will probably transfer operations to channel 67 in the UK or 22A in the USA. A Coast Station will move communications to one of their working channels.

Reception of an Urgency Alert

Vessels receiving a DSC urgency alert should not acknowledge by DSC but should switch to the indicated channel, normally the emergency frequency for the band where the DSC alert was received, and listen for the urgency message.

Safety Calls

A safety call is to warn other vessels of a particular danger. It may be some danger to navigation, such as a drifting derelict or it could be an urgent weather warning. Again, the call and the message must be addressed to somebody even if it is to 'all stations'. The DSC safety alert can be addressed to 'all stations', a particular Coast Station, a group of vessels, vessels in a specified geographic area, or an individual vessel.

Safety messages if they are short (less than a minute in duration), and if they are primarily intended for vessels in the immediate vicinity can be transmitted on the emergency frequency, but any longer messages should be transmitted on a working channel.

If the message is addressed to 'all stations' and is primarily intended for reception by other vessels in the vicinity, then VHF will be used both for the DSC alert and the subsequent traffic and the message itself could be transmitted on channel 6, the inter-ship safety channel, or channel 13, the bridge-to-bridge navigational safety channel. For example, if you were entering a narrow channel in thick fog and you wanted to warn other vessels of your location, you would do this on channel 13.

Transmission of a Safety Alert

As with the urgency call, DSC is used to alert a station or stations that there is a safety message about to be transmitted and advises them of the frequency and mode. To send a DSC safety alert:

a. Tune the radio to the DSC frequency of the band on which it is desired to transmit the alert.

b. Select 'safety call' on the DSC control unit.

c. Address the call to 'all stations' or to the MMSI of a particular Coast Station or vessel or group of vessels.

d. Key in the channel on which the urgency message will be transmitted. For most safety messages a working channel (such as VHF channel 13 or 6) is selected, rather than the emergency channel.

e. Transmit the DSC safety alert.

Transmission of a Safety Message

The radio can now be tuned to the appropriate channel and the message transmitted. The message should be in the format:

Securite - The word securite - pronounced securitay - indicates that this is a safety message.

Address - The message must be addressed to somebody, very often in this case to 'all stations'.

Identity - Give your MMSI, which will have been given in the DSC call, and the name of your vessel and/or call-sign. All transmissions must be identified, even if you are not expecting a reply.

Message - The text of the safety message.

Out- Terminate the transmission with the name/call-sign of the vessel, and the word 'out', which signifies the end of the transmission and that you are not expecting a reply. 'Over' signifies the end of that part of the transmission and that you are standing by for a reply. Although one hears it every day, it is incorrect to say 'over and out' - the two together are contradictory.

Reception of a Safety Alert

Another vessel may want to issue a safety message to warn of a danger to navigation, or perhaps a Coast Station has an urgent gale warning or navigational warning to transmit. The DSC alert may be addressed to 'All Stations', a group of vessels, vessels in a particular area, or it may be addressed to you specifically. If the DSC control unit recognises that the safety call concerns you, you will be alerted.

a. Do not acknowledge by DSC, unless the alert is addressed only to your vessel.
b. Tune the radio to the frequency and mode indicated in the call
c. Listen for the transmitted message.

Non-DSC equipped vessels should make distress, urgency, or safety calls on the emergency frequency of a suitable band prior to transmitting the message. The call is Mayday, repeated three times, for a distress call; Pan Pan repeated three times for an urgent call; or Securite repeated three times for a safety call. This should be followed by your vessel's name and/or call sign again repeated three times. Then the message should be transmitted in exactly the same way as if a DSC alert had been sent, e.g., MIPDANIO for distress.

Under the GMDSS regulations there is no obligation for anybody to monitor any of the emergency frequencies other than the DSC frequencies, although hopefully somebody will hear you.

UTC Time - Converter

2011-09-19T00:02:00.001-07:00

UTC TIME Converter

MF radio communication

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In the High Frequency range and partly in the MF range (actually from about 1 MHz to 30 MHz), sky-wave propagation is most affected by ionospheric reflection, and as the density of atmospheric ionization fluctuates, so must the frequency, a higher frequency corresponding to higher density of ionization. Variations in propagation length occur according to such factors as time of day, year, sunspots as well as other ionospheric conditions.

During the day, the reflection of the wave back from the ionosphere occurs lower (layer E), so more waves are necessary for longer propagation and therefore, a higher frequency must be used. At night, the wave reflections are from the higher layer F2, so a lower frequency generally suffices.
The data about the height of ionosphere is provided daily by several observatories. The most known European observatory is the National Observatory of Athens in Greece, which publishes data for the whole world (www.iono.noa.gr). Here an operator can find the current status of layer height ( h ) and density (f0).
The angle of reflection (alpha) depends on both the layer height and distance (d) across land or sea of the point of reflection and may be calculated by the formula:
alpha = arc tg ((d/2)/h)
Where only one reflection occurs during propagation, this is called 'single hop' propagation. The more hops, the greater the distance of propagation, but the lesser the quality of transmission and the more energy required. Whenever possible single hop is used.
To reach a certain station (ship, RCC, etc.) with a single hop the communication may be done only within the limits from LUF (Lowest Usable Frequency) and MUF (Maximum Usable Frequency). The optimum communication is called OTF (Optimum Traffic Frequency), which is around 85% of MUF. As the radio operator may not choose just any frequency, but only those designated for maritime traffic, the operator should use the nearest available frequency. MUF and OTF are calculated by the formula:
MUF=f₀/cos (alpha)
OTF=MUF * 0.85
LUF depends upon transmitter power, sensitivity and tuning of the receiver
The distance the signal travels before reaching the earth again is called the skip distance. It will also be found that there is often an area between the limit of the ground wave coverage and the reflection zone (where the skywave returns to earth) where no signal can be received. This area is called the dead zone or skip zone. To communicate within the skip zone, the frequency must be lowered.
In general:

day MUF is higher than night MUF
summer MUF is greater than winter MUF
if sun activity arises, MUF and OTF increases, skip distance decreases
if sun activity decreases, MUF and OTF decrease, skip distance increases

The ground wave propagates at all times, day and night. The day time service area of a MF station is determined by the characteristics of the ground wave's mode of propagation. This is affected by the carrier wave frequency and the effective conductivity of the ground. On the sea the conductivity is higher than on earth. The distance significantly depends on the power of the transmitting station. All registered ship stations should have enough power to reach shore stations within 150 nautical miles (the minimum requirement for Sea area A2).

During the night a signal is propagated as a sky wave via the ionosphere as well as a ground wave, so the distance of possible communication is greater. The reflection from the ionosphere causes what is called a skip distance, but within MF propagation, this distance is covered by the ground wave so there is no skip zone.

Normally the ship is using DSC to establish the connection with other stations. For priority communications (distress, urgent, safety) the DSC frequency 2187.5 kHz should be used. But for the ship's routine calls (all non-priority) the simplex frequency 2177 kHz is used for ship to ship calls, while for ship to shore call the duplex frequency 2189.5 kHz (ship transmit)/2177 kHz (ship receive) must be used.

When the connection is established, the radio operator should move to working frequency. For priority communications (distress, urgent, safety) by radiotelephony frequency 2182 kHz should be used. For routine communications, the operator should consider the frequency list for a particular MF region (see appendix). Ship to ship communications are possible on frequencies 2045 kHz or 2048 kHz in region 1, while for regions 2 and 3, the frequencies are 2635 kHz or 2638 kHz. For ship to shore communications, the shore station provides the ship working frequencies.

VHF radio communication

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The wavelength of frequencies within the VHF band is approximately 2 m. Practically, this means that the length of a VHF antenna (dipole antenna) for a VHF radio need not be longer than about half this length, about 1 m., which makes VHF radio communications ideally suitable for all vessels: from large passenger ships down to the smallest fishing boat or yacht.

Electro-magnetic waves of such a relatively small wavelength tend to travel or propagate in an almost straight line between Tx and Rx and extend only as far as the visible horizon (line of sight). These space waves, as they are referred to, will not pass through objects such as hills or large buildings, but may be reflected by such structures. For these reasons, it is best to site the VHF antenna at the highest point of the vessel in order to obtain the greatest communication range (in Tx and Rx).

The range of VHF radio communications (distance from antenna to the visible horizon) is calculated by the following formula (the symbol √ stands for square root):
Range [NM] = 2.25 x √height of antenna [m]
When calculating the range between two antennas, the range of both antennas have to be taken into consideration. The formula is:
Range between two antennas [NM] = 2.25 x (√height of antenna I [m] + √height of antenna II [m])
Example: the range between vessel antenna (30 m above sea level) and CRS antenna (62 m above sea level) is 2.25 x (√30 + √62) = 30.04 NM

The range of VHF radio communications at sea may vary greatly between different types of vessel and between different types of vessel and CRS. This is due to the varying heights of antennas ( h ) in use, and is dependent on the size of vessels and locations of CRS. Under normal radio conditions the expected radio communication range at VHF will normally be expected to be between 20 to 30 NM.

The marine frequency band for VHF radio communication, extending between 156 MHz and 174 MHz, contains 57 individual VHF CH (channels) numbered consecutively from VHF CH 1 to VHF CH 28 and from VHF CH 60 to VHF CH 88.

DSC - Detailed notes

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The GMDSS enables Maritime Rescue Centres and radio stations to keep automatic watch on the
distress channels. A ship equipped with a DSC apparatus can make a distress call by simply
pressing a button, which results in an automatic alarm signal at the maritime rescue centre nearest
to the vessel.
DSC can be used for all kinds of radio calls between ship-ship and ship-shore–ship. DSC calls are
made on channel 70, which means that any voice communication on this channel is not allowed.
The DSC call includes and shows the following information:
- Format or Type of Call
- Receiver or Party ID
- Call Category or Priority
- Telecommand
(follow-up radio communication)
- Working Channel
1. FORMAT OR TYPE OF CALL
One of the following are chosen on the DSC apparatus:
- distress alert / distress call in a distress
- all ships a call to all stations
- selective/individual a call to one station
(e.g. in routine calls)
- group a group of stations
- area / geographical call to stations in a
particular area

2. PARTY/RECEIVER ID (IDENTIFICATION)
The receiver of the call (Party ID) you can click either the Maritime Mobile Service Identity (MMSI)
number of the recediving station, a group call number or area call number. The MMSI always
contains nine digits.
Example of MMSI Number system:
MMSI Vessel Explanation
230252000 230 country code (Finland)
always three digits
252000 (ship’s number)
MMSI Coast Station Explanation
002301000 00 means coast station in general
230 country code (Finland)
number of particular coast station
1000 (Turku Maritime Rescue Coordination Centre)
3. CALL CATEGORY OR PRIORITY
- distress
- urgency
- safety
Routine Communication can be of two kinds:
- routine
- ship’s business
4. TELECOMMAND
This gives information on what kind of follow-up radio communication the sender wishes to have. It
also gives information on what kind of message the sender is giving. The most common
telecommand choices include:
- telephony G3E/F3E simplex
o voice communication on VHF
- distress acknowledgement
o request for acknowledgement of distress call
- distress relay alert
o request for relay of distress
- ship’s position
o request for a vessel’s position to be shown on DSC (routine call)
5. WORKING CHANNEL
The one who sends a DSC call can suggest a working channel for continued voice radio
communication.
NOTE: When a vessel is calling a coast station it does not suggest a working channel. The coast
station announces which radio channel to continue on.

ROUTINE COMMUNICATION WITH DSC CALL
EXAMPLE 1

A RADIO MESSAGE FOR SUOMENLINNA COAST GUARD STATION
COMPARE THE FOLLOWING TO THE EXAMPLES SENT WITHOUT DSC:
A Russian yacht Marlene is approaching the Finnish coast on its way to spend a holiday partly in
Helsinki and partly by sailing in the Finnish archipelago. According to European union laws a
foreign pleasure boat must report for passport control when she has entered the territorial waters
of one of the member states. The Marlene is a luxury yacht and is linked to GMDSS and has DSC.
It is 12.30 at Suomenlinna Coast Guard Station on a fine summer day.
The DSC at Suomenlinna starts signalling and shows the following message:
Format: SELECTIVE
Party ID: 002300005
Category ROUTINE
Telecom 1 TELEPHONY (F3E/G3E SIMPLEX)
Work channel NONE
Transmitted CH 70
NOTE: Marlene does not suggest a working channel. In communication between ship and coast
station, it is always the coast station that determines the choice of working channel.
SELECTIVE directed to a specific station only
PARTY ID 002300005 the MMSI number of Suomenlinna Coast Guard Station

The Coast Guard station sends the following acknowledgement:
Format: SELECTIVE
Party ID: 273678951
Category: ROUTINE
Telecom 1: TELEPHONY (F3E/G3E SIMPLEX)
Work Channel: 74
Transmitted: Ch 70
Party ID 273678951 = the MMSI number of Marlene
Format SELECTIVE = directed towards one station
The Coast Guard Station suggests:
Work channel 74
After this Marlene CONTINUES BY VOICE COMMUNICATION on channel 74:
Calling Finnish Coast Guard Suomenlinna, Finnish Coast Guard Suomenlinna,
This is Russian vessel Marlene, JAAA,
Russian vessel Marlene JAAA,
On VHF channel 74.
Over.

Russian Vessel Marlene JAAA,
This is Finnish Coast Guard Station
Suomenlinna,
Over.

Finnish Coast Guard station,
This is Russian yacht Marlene,
My position is: Latitude: 59° 56.9´ N Longitude : 024° 56.3´ E
I am in the approach channel passing Helsinki Lighthouse. I am proceeding to the Coast Guard
Station for passport control. REQUEST: Please give instructions to reach Suomenlinna Coast
Guard Station. Over.
Marlene,
This is Finnish Coast Guard.
INSTRUCTIONS: Proceed along the fairway. Pass Harmaja Lighthouse and proceed along the fairway
distance 1.6 miles. Take fairway depth 9.6, course 328°.
Proceed distance 0.8 miles. You can see the information on your starboard side.
I repeat: Proceed along the fairway. Pass Harmaja
Lighthouse and proceed along the fairway distance 1.6 miles. Take fairway depth 9.6, course 328°. Proceed
distance 0.8 miles. You can see the information on your starboard side. Over.
Finnish Coast Guard ,
This is Marlene.

UNDERSTOOD. I will proceed along the fairway and pass Harmaja Lighthouse. I will take fairway
depth 9.6, steering course 328°. I will proceed along the fairway distance 0.8 miles ahead. I can
see information sign on starboard side. THANK YOU AND OUT.
AS YOU NOTICED THE DSC CALL REPLACES THE INITIAL VOICE COMMUNICATION CALL
AND ANSWER ON CHANNEL 16. CHANGING TO A WORK CHANNEL ALSO HAPPENED VIA
DSC.
THUS A TRADITIONAL VOICE TRANSMISSION ON CHANNEL 16 DIFFERS SLIGHTLY IN THE INITIAL STAGE BUT RADIO PROCEDURE IS OTHERWISE THE SAME.
DSC DISTRESS COMMUNICATION

DSC DISTRESS INFORMATION:
A distress alert by Digital selective call should include the following information:
· the nature of call is DISTRESS
· MMSI number of vessel in distress
· position of vessel in distress in coordinates
· position at TIME
· nature of distress
· suggestion for follow up communication ( voice or text)
NOTE:
· A distress call is always addressed at all stations.
· Voice communication always takes place on channel 16.
NATURE OF DISTRESS
The DSC apparatus has a menu including the following choices for nature of distress:
· fire, explosion
· flooding
· collision
· grounding
· listing in danger of capsizing
· sinking
· disabled and adrift
· undesignated distress
· abandoning ship
· piracy/armed robbery attack
· man overboard
· EPIRB

EXAMPLE - DISTRESS CALL DSC
Area A1 on VHF
The DSC shows the following information:
Format: DISTRESS
Distress ID 230136780 (MMSI number of vessel)
Postion: 59 23 N 020 36 E
Pos.UTC: 1345 UTC
Nature of distress: LISTING IN DANGER OF CAPSIZING
Telecom: TELEPHONY (F3E/G3E SIMPLEX)
Transmitted: Ch 70
EXAMPLE - DISTRESS ACKNOWLEDGEMENT DSC
Area A1 on VHF
The Distress call is acknowledged by MRCC Turku:
The acknowledgement repeats the information in the Distress Call.
It is directed to and seen on the DSC apparatus by all ships in the vicinity.
Format: ALL SHIPS
From: 002301000
Category: DISTRESS
Telecom 1: DISTRESS ACKNOWLEDGEMENT
Distress ID: 230136780
Position: 59 23 N 020 36 E
Pos.UTC: 1345 UTC
Nature of distress: LISTING IN DANGER OF CAPSIZING
Telecom: TELEPHONY (F3E/G3E SINPLEX)
Transmitted: Ch 70
AFTER THIS FOLLOWS VOICE COMMUNICATION ON CHANNEL 16
DISTRESS MESSAGE
MAYDAY
This is 230136780
VERA
CALL SIGN JULIETT ALFA BRAVO CHARLIE
POSITION: 59º 23´ NORTH 020º 36´ EAST
Heavy leaking, danger of capsizing. Sea is rough.
Three men on board, five men in dinghy.
REQUEST: I require immediate assistance.
DISTRESS ACKNOWLEDGEMENT
MAYDAY
VERA VERA VERA
Call sign Juliett Alfa Bravo Charlie
This is RESCUE CENTRE TURKU RESCUE CENTRE TURKU
RESCUE CENTRE TURKU
RECEIVED MAYDAY
Over
FOLLOWED BY A MAYDAY RELAY FROM THE RESCUE
CENTRE ON CHANNEL 16...
MAYDAY RELAY MAYDAY RELAY MAYDAY RELAY

ALL STATIONS ALL STATIONS ALL STATIONS
This is 002301000
Rescue Centre Turku Rescue Centre Turku Rescue Centre Turku
Following received from Vera Juliett Alfa Bravo Charlie at 1200 UTC on VHF channel 16 :
Begins
Mayday
This is Vera
Juliett Alfa Bravo Charlie
In position 59º 23´ NORTH 020º 36´ EAST
Heavy leaking, danger of capsizing. Sea is rough.
Three men on board, five men in dinghy.
REQUEST: I require immediate assistance.
Ends
Ships in area report to Rescue centre Turku
Over
DSC SAFETY COMMUNICATION
The following is an example of the MESSAGE STRUCTURE of a Safety Call with DSC by Turku
Radio. This call is seen by vessels in the area.
Format: All ships
From: MMSI NUMBER (002300230)
Category SAFETY
Telecom: TELEPHONY (F3E/G3E SIMPLEX)
Work Channel 16
Transmitted: Ch 70
It is followed by a safety call by voice communication sent by Turku Radio on VHF channel 16, so
that every vessel, even smaller ones without DSC will receive the warning. The safety message is
then read on the traffic channel:
SAFETY CALL ON CHANNEL 16:
SECURITÉ SECURITÉ SECURITÉ
ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS: MMSI NUMBER
NAME OF STATION 1 X:
NAVIGATIONAL WARNING
PLEASE SWITCH TO TRAFFIC CHANNELS
SAFETY MESSAGE ON TRAFFIC CHANNEL:
SECURITÉ SECURITÉ SECURITÉ
ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS: MMSI NUMBER
NAME OF STATION 1 X:
NAVIGATIONAL WARNING ….

DSC URGENCY COMMUNICATION
A vessel or a coast station can send an urgency call (Pan-Pan call) by DSC. The DSC call contains
information on which channel the voice communication will be read (Channel 16). The call can be
directed to all stations or directly to the nearest Maritime Rescue Centre.
A Pan-Pan message may be sent in, for example, the following situations:
· a person has fallen overboard and the ship needs help with search and rescue
· signals have been observed that might be distress signals
· when reporting on missing vessels
· if a person on board a vessel needs immediate medical assistance
· red rockets have been observed
EXAMPLE
The following is an example of an Urgency call to all stations by DSC:
A
Format ALL SHIPS
Category URGENCY
Telecom 1 TELEPHONY (F3E/G3E SIMPLEX)
Work Channel 16
Transmitted 70
A vessel can send an urgency call directly to the nearest Maritime Rescue Centre. Example of a
call sent to MRCC Turku:
B
Format SELECTIVE
Party ID 002301000
Category URGENCY
Telecom 1 TELEPHONY F3E/G3E SIMPLEX)
Work channel NONE
Transmitted CH 70

NOTE: when sending a DSC call to a Rescue Centre or Coast Station a vessel does not suggest
the working channel. This is done by the Coast Station or Rescue Centre.

Communications systems in the GMDSS

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Satellite communications
Satellite communications are particularly important elements of the GMDSS.
1The Inmarsat system, which employs geostationary satellites and operates in the 1.5 and 1.6 GHz band (Lband),
provides ships fitted with ship earth stations with a means of distress alerting and a capability for two-way
communications using direct-printing telegraphy, data transmission and radiotelephone. L-Band satellite EPIRBs
are also used for distress alerting. The International SafetyNET system is used as a main means to provide MSI to
areas not covered by the International NAVTEX system.
2 A polar-orbiting satellite system, operating in the 406 MHz band using satellite EPIRBs (COSPAS–
SARSAT system), provides one of the main means of distress alerting and determining the identity and position
of the ship in distress or its survivors in the GMDSS.
Terrestrial communications
3 With terrestrial communications, DSC forms the basis of distress alerting and safety communications.
Distress and safety communications following a DSC call can be performed by radiotelephony or direct-printing
telegraphy or both.
Long-range service
4 Use of HF provides a long-range service in both the ship-to-shore and shore-to-ship directions. In areas
covered by Inmarsat it can be used as an alternative to satellite communications and outside these areas it provides
the only long-range communication capability. Frequencies have been designated in the 4, 6, 8, 12 and 16 MHz
bands for this service.
Medium-range service
5 MF radiocommunications provide the medium-range service. In the ship-to-shore, ship-to-ship and
shore-to-ship directions 2187.5 kHz is used for distress alerts and safety calls using DSC, and 2182 kHz is used for distress and safety traffic by radiotelephony, including SAR co-ordinating and on-scene communications. 2174.5 kHz is used for distress and safety traffic by direct-printing telegraphy.
Short-range service
6 VHF provides short-range service on the frequencies:
. 156.525 MHz (channel 70) for distress alerts and safety calls using DSC, and
. 156.8 MHz (channel 16) for distress and safety traffic by radiotelephony, including SAR co-ordinating
and on-scene communications.
There is no short-range direct-printing telegraphy service on VHF.

Portside and Starboard side

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(Information collected from Net)

Most of you might have heard the term Portside and Starboard side in relation to a ship.. These are actually nautical terms which refer to the left and right side of the ship respectively when you are looking towards the Bow (the front of the ship – also known as Fore).. The rear of the ship is termed as Stern (also known as Aft)..

As per Wikipedia, before ships had rudders on their centerlines, they were steered by use of a specialized steering oar.. This oar was held by an oarsman located in the stern (back) of the ship.. However, like most of society, there were many more right-handed sailors than left-handed sailors. This meant that the steering oar (which had been broadened to provide better control) used to be affixed to the right side of the ship..

If you find yourself on a ship, how do you know which side is starboard and which side is port? As a Naval Man the answer is quite simple - Port is left and starboard is right. But if you were travelling on a ship for the first time, how could you remember that? Well, it is really quite simple. There are four letters in the words PORT and LEFT so you can easily remember that the left side of a ship is the port side.

Mnemonic devices

The sailor left port with a red nose.
Port and left both contain four letters.
"No, port left"
The common abbreviation P.S. (for postscript) can be viewed as port ("left") and starboard ("right").
"Star light, star bright, starboard is to the right."
A ship that is out on the ocean has "left port".
Terms referring to the right side are longer words ("starboard", "right", and "green"), while terms referring to the other side are shorter words ("port", "left", and "red").
The phrase "Any red port left in the can?" can be a useful reminder. It breaks down as follows:
- The drink port is a fortified red wine—which links the word "port" with the color red, used for navigational lights (see below).
- "Left" comes from the phrase and so port must be on the left.
- The reference to "can" relates to the fact that port-hand buoys are "can"-shaped.
A variation on the above is "Two drops of red port left in the bottle." Also: "Port wine is red; so is the port light."

Must watch the video

2011-08-17T04:47:00.000-07:00

Duties of Radio Officer in an Oil Rig

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· Maintain radio communications with shore bases, other vessels and helicopters.

· Maintain watch on international distress frequencies in order to be of assistance if required.

· In the event of rig emergency maintains communication with bases and outside emergency co-ordination centers.

· Provide helicopters with current weather information as required.

· Maintain SAR watch whilst helicopters in transit to and from rig.

· Liaise with Helicopter Landing Officer reference helicopter movements.

· Relay helicopter flight information to helicopter shore base if requested by pilot.

· Ensure compliance with requirements for radios and associated equipment during radio silence periods.

· Advise supply vessels of helicopter movements, emergency drills and radio silence requirements.

· Make regular PA announcements reference helicopter movements, radio silence and other safety related information.

· Conduct planned maintenance on radio and navigation equipment.

· Conduct weekly checks on emergency batteries (radio equip) and charger system.

· Conduct scheduled inspections and maintenance on all radio and navigation equipment.

· Including emergency communication and navigation equipment in lifeboats etc.

· Assist Electronic Technician to troubleshoot and repair faulty radio an navigation equipment.

· Make weather observations and reports if required

GOC~~ EXAMINATION SYLLABUS

2011-08-02T10:11:00.000-07:00

GOC 5. EXAMINATION SYLLABUS
The information contained in Sections 5.1 and 5.2 has been extracted from
Annex 1 of the text of the recommendation proposed by the Working Group
“Radio Regulatory” (RR) for the Harmonised Examination Procedures for the
General Operator’s Certificate (GOC) – Recommendation T/R 31-03 E (Bonn
1993) – Edition of 1st May 1993 and ERC Decision Annex 1 of ERC/DEC/(99)01
of 10 March 1999.
GOC 5.1 Examination Syllabus for the GMDSS General Operator’s Certificate (GOC)
The examination should consist of theoretical and practical tests and shall
include at least:
5.1.1 Knowledge of the General Principles and Basic Features of:
(a) The Maritime Mobile Service.
(b) The Maritime Mobile -Satellite Service.
5.1.2 Detailed Practical Knowledge and Ability to use the Basic
Equipment of a Ship Station:
(a) Practical use of the basic equipment of a ship station.
(b) Digital Selective Calling (DSC).
(c) General principles of Narrow Band Direct Printing (NBDP) and Telex Over
Radio (TOR) Systems. Ability to use maritime NBDP and TOR equipment
in practice.
(d) Usage of Inmarsat Systems. Inmarsat equipment or simulator in
practice.
(e) Fault locating.
5.1.3 Operational Procedures and Detailed Practical Operation of GMDSS
Systems and Sub-Systems:
(a) Global Maritime Distress and Safety Systems (GMDSS).
(b) Inmarsat.
(c) NAVTEX.
(d) Emergency Position Indicating Radio Beacons (EPIRBs).
(e) Search and Rescue Radar Transponder (SART).
(f) Distress, Urgency and Safety Communication Procedures in the GMDSS.
(g) Distress, Urgency and Safety communications with non-SOLAS ships
which only use radiotelephony
(h) Search and Rescue Operation (SAR).
5.1.4 Miscellaneous Skills and Operational Procedures for General
Communications:
(a) Ability to use English Language, both written and spoken, for the
satisfactory exchange of communications relevant to the safety of life at
sea.
(b) Obligatory procedures and practices.
(c) Practical and theoretical knowledge of general communication
procedures.
GOC 5.2 Examination Syllabus Guidelines for the GMDSS GOC
5.2.1 Knowledge of the Basic Features of the Maritime Mobile Service
and the Maritime Mobile-Satellite Service:
(a) The general principles and basic features of the Maritime Mobile Service:
(i) Types of communication in the Maritime Mobile Service:
Distress, Urgency and Safety Communications
Public Correspondence
Port Operation Service
Ship Movement Service – Intership Communication
Onboard Communication.
(ii) Types of station in the Maritime Mobile Service:
Ship Stations
Coast Stations
Pilot Stations, Port Operations Station etc
Aircraft Stations
Rescue Co-ordination Centre (RCC).
(iii) Elementary knowledge of frequencies and frequency bands:
The concept of frequency
The equivalence between frequency and wavelength
The unit of frequency: Hz, kHz, MHz, GHz
The sub-division of the most significant part of the radio
spectrum: MF, HF, VHF, UHF, SHF.
(iv) Characteristics of frequencies:
Different propagation mechanisms: propagation in free space,
ground wave, ionospheric propagation
Propagation on MF
Propagation on different HF bands
Propagation on VHF and UHF.
(v) Knowledge of the role of the various modes of communication:
DSC
Radiotelephony
NBDP
Facsimile
Data
Morse Telegraphy.
(vi) Knowledge of the different types of modulation and classes of
emission:
Classes of emission
Carrier frequency and assigned frequency
Bandwidth of different emissions
Official designations of emissions (e.g. F1B, J3E, A3E, A1A, etc.)
Unofficial designations of emissions (e.g. TLX, SSB, AM, CW, etc.).
(vii) Frequencies allocated to the Maritime Mobile Service:
The usage of MF, HF, VHF, UHF, and SHF in the Maritime Mobile
Service
The concept of radio channel – simplex, semi-duplex and duplex
Paired and unpaired frequencies
Frequency plans and channelling systems: HF and VHF telephony
(relevant appendix of the Radio Regulations), HF NBDP (relevant
appendix of Radio Regulations)
MF telephony and NBDP for Region 1 (Geneva 85 plan)
GMDSS distress and safety frequencies
Distress and safety frequencies of the pre -GMDSS system
Calling frequencies.
(b) The general principles and basic features of the Maritime Mobile Satellite
Service:
(i) Basic knowledge of satellite communications:
Inmarsat space segment
Modes of communication: telex services, telephone services, data
and facsimile communications, store and forward operation
Distress and safety communications
Inmarsat-A/B communication services
Inmarsat-C communication services
Inmarsat Enhanced Group Call (EGC) System.
Inmarsat-M communication services
(ii) Types of station in the Maritime Mobile Satellite Service:
Land Earth Station (LES)
Network Co-ordination Station (NCS)
Mobile Earth Station (MES) Ship Earth Station (SES).
5.2.2 Detailed Practical Knowledge and Ability to use the Basic
Equipment of a Ship Station
(a) Knowledge of, and ability to use in practice, the basic equipment of a
ship station:
(i) Watchkeeping Receivers:
The controls and usage of VHF DSC watch receiver.
The controls and usage of MF DSC watch receiver and MF/HF
DSC watch receiver.
(ii) VHF Radio Installation:
Channels.
Controls.
Usage.
DSC.
(iii) MF/HF Radio Installation:
Frequencies.
Typical controls and usage, e.g. connecting the power, selected
Rx/Tx frequency, selecting ITU channel number, tuning the
transmitter, selecting the class of emission, using volume control
and squelch, using clarifier or Rx fine tuning, controlling RF gain,
using automatic gain control, using the 2182 kHz instant selector,
testing the alarm generator, using the alarm generator.
(iv) Antennae:
Antennae Isolators.
VHF Whip Antennae.
MF/HF Whip Antennae.
MF/HF Wire Antennae.
Satellite antennas.
(v) Batteries:
Types of Marine Batteries and their Characteristics.
Charging.
Maintenance of Batteries.
UPS Systems
(vi) Survival Craft Radio Equipment:
Portable Two-Way VHF Radiotelephone Apparatus.
SART.
EPIRB.
(b) Digital Selecting Calling:
(i) Call Format Specifier:
Distress Call.
All Ships Call.
Call to Individual Station.
Geographical Area Call.
Group Call.
Automatic, Semi-Automatic Service.
(ii) Call Address Selection with the MMSI Number System:
The Nationality Identification.
Group Calling Numbers.
Coast Station Numbers.
Ship Station Numbers.
(iii) Call Categorisation:
Distress.
Urgency.
Safety.
Other Communications.
(iv) Call Telecommand and Traffic Information:
Distress Alerts.
Other Calls.
Working Frequency Information.
(c) Knowledge of the General Principles of NBDP and TOR Systems.
Ability to use Maritime NBDP and TOR Equipment in practice:
(i) NBDP Systems:
Automatic Systems.
Semi-Automatic Systems.
Manual Systems.
ARQ, FEC Modes.
ISS/IRS Arrangement.
Master and Slave.
Radio Telex Number.
Answerback.
Numbering of the SSFC Selective Calling System.
(ii) TOR Equipment (Telex Over Radio):
Controls and Indicators.
Keyboard Operation.
(d) Knowledge of the Usage of Inmarsat Systems. Ability to use Inmarsat
Equipment or Simulator in Practice:
(i) Inmarsat-A/B Mobile (Ship) Earth Station.
Satellite Acquisition.
Telex Services.
Telephone Services.
Data and Facsimile Communications.
(ii) Inmarsat-C Mobile (Ship) Earth Station.
Components of an Inmarsat-C Terminal.
Entering and Updating Position.
Usage of an Inmarsat-C MES (SES).
Sending and Receiving Text Messages.
(iii) Inmarsat EGC Receiver.
Pre-programming an MES (SES) for EGC Message Reception.
Selecting Operating mode for EGC reception.
(e) Fault Locating:
Proficiency in Elementary Fault Localisation by means of built-in
Instruments or Software in accordance with Equipment Manuals.
Elementary Fault Diagnosis and Repair such as Replacement of Fuses,
Indicator Lamps, Antenna Maintenance.
5.2.3 Operational Procedures and Detailed Practical Operation of GMDSS
System and Sub-Systems.
(a) Global Maritime Distress and Safety System (GMDSS):
(i) Sea Areas and the GMDSS Master Plan.
(ii) Watchkeeping on Distress Frequencies.
(iii) Functional Requirements of Ship Stations.
(iv) Carriage Requirements of Ship Stations.
(v) Sources of Energy of Ship Stations.
(vi) Means of Ensuring Availability of Ship Station Equipment.
(vii) Licences, Radio Safety Certificates, Inspections and Surveys.
(b) Inmarsat Usage in the GMDSS:
(i) Inmarsat-A/B MES (SES):
Distress Communications: Use of Distress Facility, Satellite
Acquisition, Telex and Telephony Distress Calls, Procedures for
Distress Calls, Rescue Co-ordination Centres associated with
CESs.
(ii) Inmarsat-C MES (SES):
Distress and Safety Services: Designated and Undesignated
Distress Alert, Distress Priority Message, 2-Digit Code Service
Codes.
(iii) Inmarsat EGC:
Purpose of the EGC System:
All-Ships Messages and Inmarsat System Messages, Classes of
Inmarsat-C SES and their EGC reception.
(c) NAVTEX:
(i) The Navtex System:
Purpose of Navtex.
Navtex Frequencies.
Reception Range.
Message Format (Transmitter ID, Message Type, Message Number).
(ii) Navtex Receiver:
Selection of Transmitters.
Selection of Message Types.
Messages which cannot be Rejected.
Use of Operator Controls and Changing Paper.
(d) Emergency Position Indicating Radio Beacons (EPIRBs):
(i) Satellite EPIRBs:
Basic Characteristics and Operation of 406 MHz and 1.6 GHz.
121.5 MHz EPIRBs including Homing Functions.
Information Contents of a Distress Alert.
Manual Usage.
Float-Free Function.
Routine Maintenance: Testing, Checking Battery Expiry Date,
Cleaning of the Float-Free Release Mechanism.
(ii) VHF DSC EPIRB:
Basic Characteristics of operation on Ch 70.
(e) Search and Rescue Radar Transponder (SART):
Primary Technical Characteristics.
Operation.
Range of a SART Transmitter.
Testing and Checking Battery Expiry Date.
(f) Distress, Urgency and Safety Communication Procedures in the GMDSS:
(i) Distress Communications:
DSC Distress Alert:
Definition of Distress Alert.
Transmission of Distress Alert.
Transmission of Shore-to-Ship Distress Relay.
Transmission of Distress Alert by Station not itself in Distress.
Receipt and Acknowledgement of a DSC Distress Alert:
Acknowledgement Procedures by Radiotelephony.
Acknowledgement Procedures by NBDP.
Receipt and Acknowledgement by a Coast Station.
Receipt and Acknowledgement by Ship Station.
Handling of Distress Alerts:
Preparations for Handling of Distress Traffic.
Distress Traffic Terminology.
Testing DSC Distress and Safety Calls.
On-Scene Communications.
SAR Operation.
(ii) Urgency and Safety Communications:
The Meaning of Urgency and Safety Communications.
Procedures for DSC Urgency and Safety Calls.
Urgency Communications.
Radio Medical services, Medical transports.
Safety Communications.
(iii) Radiotelephony Communications with Non-GMDSS Stations:
Distress Signal.
Distress Call.
Distress Message.
Acknowledgement of a Distress Message.
Distress Traffic Terminology.
Transmission of a Distress Message by a Station not itself in Distress.
Medical Advice.
Safety Signal.
(iv) Reception of Maritime Safety Information (MSI):
Reception by NAVTEX, INMARSAT EGC, HF NBDP.
The Navigational Warning Signal of the Old Distress and Safety System.
The Navigational Warnings Transmitted by Radiotelephony.
(v) Protection of Distress Frequencies:
Guard Bands.
Tests on Distress Frequencies.
Transmissions during Distress Traffic.
Avoiding Harmful Interference.
Prevention of Unauthorised Transmissions.
(g) Search and Rescue Operation (SAR):
(i) The Role of RCCs.
(ii) International Aeronautical and Maritime Search and Rescue Manual
(IAMSAR).
(iii) Maritime Rescue Organisations.
(iv) Ship Reporting Systems.
5.2.4 Miscellaneous Skills and Operational Procedures for General Communications:
(a) Ability to use English Language, both Written and Spoken, for the Satisfactory
Exchange of Communications relevant to the Safety of Life at Sea:
(i) Use of the International Code of Signals and the IMO Standard Marine
Navigational Vocabulary/Seaspeak.
(ii) Recognised Standard Abbreviations and Commonly Used Service Codes.
(iii) Use of International Phonetic Alphabet.
(b) Obligatory Procedures and Practices:
(i) Effective Use of Obligatory Documents and Publications.
(ii) Radio Record Keeping.
(iii) Knowledge of the Regulations and Agreements Governing the Maritime
Mobile Service and the Maritime Mobile-Satellite Service.
(c) Practical and Theoretical Knowledge of General Communication Procedures:
(i) Selection of Appropriate Communication Methods in Different
Situations.
(ii) Traffic Lists.
(iii) Radiotelephone Call:
Method of Calling a Coast Station by Radiotelephony.
Ordering for Manually Switched Link Call. Ending the Call.
Special Facilities of Calls.
Method of Calling a Coast Station by DSC.
Selecting an Automatic Radiotelephone Call.
(iv) Radiotele gram:
The Parts of a Radiotelegram: Preamble
Service Instructions and Indications
Address, Text, Signature.
Addresses: Full Address
Registered Address
Telephonic Address
Telex Address.
Word Count.
Transmission of a Telegram by Radiotelephony.
Transmission of a Telegram by Radiotelex.
(v) Traffic Charges:
International Charging System.
Inmarsat Communications Charging System.
AAIC Code.
The Meaning of Land Line (LL), Coast Station (CS) and Ship Station (SS)
charges.
Currencies used in International Charging.
(vi) Practical Traffic Routines.
(vii) World Geography, especially the Principle Shipping Routes and Related
Communication Routes.
GOC 5.3 Conditions of the Awards
The GMDSS General Operator’s Certificate (GOC) will be awarded to applicants who
have, by means of satisfactorily completing the appropriate standard written and
practical tests, demonstrated their knowledge and ability in the area detailed in
Sections 5.1 and 5.2.

Maritime Mobile Service Identity -- MMSI

2011-07-31T21:11:00.000-07:00

A Maritime Mobile Service Identity (MMSI) is a unique 9 digit number and acts in the same way as a telephone number. The MMSI allows radio operator to make automatic calls through VHF DSC radio and is the identity that is automatically transmitted within DSC calls.

These MMSI numbers are issued by the appropriate authorities in the country of registration of the vessel and can be referenced back to a database of information about the vessel and it’s owners and so forth. So, the MMSI belongs to the vessel. Also CRSs (Coast Radio Stations) have their own MMSI because they have their own VHF DSC radio and could be called by any vessels VHF DSC radio.

The MMSI is programmed into the VHF DSC radio. The MMSI number assigned to the vessel must be programmed by the VHF DSC radio supplier.

Before a new VHF DSC radio could be used on a vessel, the following procedure must be taken:

If a vessel already has its own MMSI number, then its MMSI number should be programmed by an authorized VHF DSC radio supplier.
If a vessel doesn't have its own MMSI number, then the vessel owner must apply for a MMSI number at appropriate authorities and when the MMSI number is assigned, it should be programmed by an authorized VHF DSC radio supplier.

For ship stations the first three digits are known as the MID (Maritime Identification Digit) number and indicate nationality, e.g. MIDs allocated to United Kingdom are 232,233,234 and 235. The last six digits uniquely identify the individual vessel.
MID xxxxxx
For example, Cunard Lines Queen Mary 2 MMSI number 235 762000.
For CRS (Coast Radios Stations) the first two digits of the MMSI number are always 00, followed by the 3 digit MID nationality indicator, followed by the individual station number.

00 MID xxxx

For example, Palermo Italy MMSI number 00 247 0002.

For a group of stations the first digit of the MMSI number is always 0, followed by the 3 digit MID nationality indicator, followed by the group station number. Group MMSIs are usually acquired by companies for their fleet, or by category of operation or by nationality. The group MMSI is an additional MMSI to the MMSI of a vessel (ship station) and it is used to call all vessels with the same group MMSI with only one call.

0 MID xxxxx

All MIDs available are as follows:

COUNTRY	MID
Adelie Land	501
Afghanistan	401
Alaska (State of)	303
Albania (Republic of)	201
Algeria (People's Democratic Republic of)	605
American Samoa	559
Andorra (Principality of)	202
Angola (Republic of)	603
Anguilla	301
Antigua and Barbuda	304, 305
Argentine Republic	701
Armenia (Republic of)	216
Aruba	307
Ascension Island	608
Australia	503
Austria	203
Azerbaijani Republic	423
Azores	204
Bahamas (Commonwealth of the)	308, 309, 311
Bahrain (Kingdom of)	408
Bangladesh (People's Republic of)	405
Barbados	314
Belarus (Republic of)	206
Belgium	205
Belize	312
Benin (Republic of)	610
Bermuda	310
Bhutan (Kingdom of)	410
Bolivia (Republic of)	720
Bosnia and Herzegovina	478
Botswana (Republic of)	611
Brazil (Federative Republic of)	710
British Virgin Islands	378
Brunei Darussalam	508
Bulgaria (Republic of)	207
Burkina Faso	633
Burundi (Republic of)	609
Cambodia (Kingdom of)	514, 515
Cameroon (Republic of)	613
Canada	316
Cape Verde (Republic of)	617
Cayman Islands	319
Central African Republic	612
Chad (Republic of)	670
Chile	725
China (People's Republic of)	412, 413
Christmas Island (Indian Ocean)	516
Cocos (Keeling) Islands	523
Colombia (Republic of)	730
Comoros (Union of the)	616
Congo (Republic of the)	615
Cook Islands	518
Costa Rica	321
Côte d'Ivoire (Republic of)	619
Croatia (Republic of)	238
Crozet Archipelago	618
Cuba	323
Cyprus (Republic of)	209, 210, 212
Czech Republic	270
Democratic People's Republic of Korea	445
Democratic Republic of the Congo	676
Denmark	219, 220
Djibouti (Republic of)	621
Dominica (Commonwealth of)	325
Dominican Republic	327
Ecuador	735
Egypt (Arab Republic of)	622
El Salvador (Republic of)	359
Equatorial Guinea (Republic of)	631
Eritrea	625
Estonia (Republic of)	276
Ethiopia (Federal Democratic Republic of)	624
Falkland Islands (Malvinas)	740
Faroe Islands	231
Fiji (Republic of)	520
Finland	230
France	226, 227, 228
French Polynesia	546
Gabonese Republic	626
Gambia (Republic of the)	629
Georgia	213
Germany (Federal Republic of)	211, 218
Ghana	627
Gibraltar	236
Greece	237, 239, 240
Greenland	331
Grenada	330
Guadeloupe (French Department of)	329
Guatemala (Republic of)	332
Guiana (French Department of)	745
Guinea (Republic of)	632
Guinea-Bissau (Republic of)	630
Guyana	750
Haiti (Republic of)	336
Honduras (Republic of)	334
Hong Kong (Special Administrative Region of China)	477
Hungary (Republic of)	243
Iceland	251
India (Republic of)	419
Indonesia (Republic of)	525
Iran (Islamic Republic of)	422
Iraq (Republic of)	425
Ireland	250
Israel (State of)	428
Italy	247
Jamaica	339
Japan	431, 432
Jordan (Hashemite Kingdom of)	438
Kazakhstan (Republic of)	436
Kenya (Republic of)	634
Kerguelen Islands	635
Kiribati (Republic of)	529
Korea (Republic of)	440, 441
Kuwait (State of)	447
Kyrgyz Republic	451
Lao People's Democratic Republic	531
Latvia (Republic of)	275
Lebanon	450
Lesotho (Kingdom of)	644
Liberia (Republic of)	636, 637
Liechtenstein (Principality of)	252
Lithuania (Republic of)	277
Luxembourg	253
Macao (Special Administrative Region of China)	453
Madagascar (Republic of)	647
Madeira	255
Malawi	655
Malaysia	533
Maldives (Republic of)	455
Mali (Republic of)	649
Malta	215, 248, 249, 256
Marshall Islands (Republic of the)	538
Martinique (French Department of)	347
Mauritania (Islamic Republic of)	654
Mauritius (Republic of)	645
Mexico	345
Micronesia (Federated States of)	510
Moldova (Republic of)	214
Monaco (Principality of)	254
Mongolia	457
Montenegro (Republic of)	262
Montserrat	348
Morocco (Kingdom of)	242
Mozambique (Republic of)	650
Myanmar (Union of)	506
Namibia (Republic of)	659
Nauru (Republic of)	544
Nepal	459
Netherlands (Kingdom of the)	244, 245, 246
Netherlands Antilles	306
New Caledonia	540
New Zealand	512
Nicaragua	350
Niger (Republic of the)	656
Nigeria (Federal Republic of)	657
Niue	542
Northern Mariana Islands (Commonwealth of the)	536
Norway	257, 258, 259
Oman (Sultanate of)	461
Pakistan (Islamic Republic of)	463
Palau (Republic of)	511
Palestine (In accordance with Resolution 99 Rev. Antalya, 2006)	443
Panama (Republic of)	351, 352, 353, 354, 355,356, 357, 371, 372
Papua New Guinea	553
Paraguay (Republic of)	755
Peru	760
Philippines (Republic of the)	548
Pitcairn Island	555
Poland (Republic of)	261
Portugal	263
Puerto Rico	358
Qatar (State of)	466
Reunion (French Department of)	660
Romania	264
Russian Federation	273
Rwanda (Republic of)	661
Saint Helena	665
Saint Kitts and Nevis (Federation of)	341
Saint Lucia	343
Saint Paul and Amsterdam Islands	607
Saint Pierre and Miquelon (Territorial Collectivity of)	361
Saint Vincent and the Grenadines	375, 376, 377
Samoa (Independent State of)	561
San Marino (Republic of)	268
Sao Tome and Principe (Democratic Republic of)	668
Saudi Arabia (Kingdom of)	403
Senegal (Republic of)	663
Serbia (Republic of)	279
Seychelles (Republic of)	664
Sierra Leone	667
Singapore (Republic of)	563, 564, 565
Slovak Republic	267
Slovenia (Republic of)	278
Socialist People's Libyan Arab Jamahiriya	642
Solomon Islands	557
Somali Democratic Republic	666
South Africa (Republic of)	601
Spain	224, 225
Sri Lanka (Democratic Socialist Republic of)	417
Sudan (Republic of the)	662
Suriname (Republic of)	765
Swaziland (Kingdom of)	669
Sweden	265, 266
Switzerland (Confederation of)	269
Syrian Arab Republic	468
Taiwan (Province of China)	416
Tanzania (United Republic of)	674, 677
Thailand	567
The Former Yugoslav Republic of Macedonia	274
Togolese Republic	671
Tonga (Kingdom of)	570
Trinidad and Tobago	362
Tunisia	672
Turkey	271
Turkmenistan	434
Turks and Caicos Islands	364
Tuvalu	572
Uganda (Republic of)	675
Ukraine	272
United Arab Emirates	470
United Kingdom of Great Britain and Northern Ireland	232, 233, 234, 235
United States Virgin Islands	379
United States of America	338, 366, 367, 368, 369
Uruguay (Eastern Republic of)	770
Uzbekistan (Republic of)	437
Vanuatu (Republic of)	576
Vatican City State	208
Venezuela (Bolivarian Republic of)	775
Viet Nam (Socialist Republic of)	574
Wallis and Futuna Islands	578
Yemen (Republic of)	473, 475
Zambia (Republic of)	678
Zimbabwe (Republic of)	679

Marine traffic thru Satellite

2011-07-24T21:46:00.000-07:00

http://www.marinetraffic.com/ais/shipdetails.aspx?MMSI=636090238

Mayday mayday.. this is Estonia... I am sinking due to fire on board

2011-07-24T21:35:00.000-07:00

Phonetic Alphabet - in GMDSS communication

2011-07-24T21:21:00.000-07:00

The phonetic alphabet is used to spell out parts of a message or call sign that are critical or otherwise hard to recognize during voice communication.

The phonetic alphabet assigns code words to the letters of the English alphabet so that code words can be pronounced and understood by those who transmit and receive voice messages regardless of their native language.

The phonetic alphabet is a part of INTERCO (International Code of Signals).

A - Alfa
B - Bravo
C - Charlie
D - Delta
E - Echo
F - Foxtrot
G - Golf
H - Hotel
I - India
J- Juliet
K- Kimo
L - Lima
M - Mike
N- November
O - Oscar
P - Papa
Q- Quebec
R - Romeo
S - Sierra
T - Tango
U- Uniform
V- Victor
W- Whisky
X- X-ray
Y - Yankee
Z - Zulu

0 - Nadazero
1- Unaone
2- Bissotwo
3 - Terrathree
4- Kartefour
5- Pantafive
6- Soxisix
7- Setteseven
8- Oktoeight
9- Novenine

Before spelling out part of a message or call sign are used the words "I SPELL". For example, the message "this is S5L12" could be transmitted as "THIS IS S5L12, I SPELL Sierra Pantafive Lima Unaone Bissotwo".

Some parts of a message are almost always spelled:

Position (Latitude and Longitude), for example "Position 45⁰ 36' North 013⁰ 32' East" is transmitted as "Position Kartefour Pantafive degrees Terrathree Soxisix minutes North, Nadazero Unaone Terrathree degrees Terrathree Bissotwo minutes East";
Position (Bearing and Distance to a point), for example “ Position 240⁰ from Koper Castle, 2 miles” is transmitted as “Position Bissotwo Kartefour Nadazero degrees from Koper Castle, Bissotwo miles;
Course, for example "My course is 095⁰" is transmitted as "My course is Nadazero Novenine Pantafive degrees";
Speed, for example “My speed is 14 knots” is transmitted as “ My speed is Unaone Kartefour knots";
Time, for example "at 0810" ( LT at 8:10 AM) is transmitted as "at Nadazero Oktoeight Unaone Nadazero Local Time".

Compass navigation

2011-06-26T22:18:00.000-07:00

Marine compass

In China compasses have been in use since the Han dynasty (2nd century BCE to 2nd century CE) when they were referred to as “south-pointers”. However at first these magnets were only used for geomancy much like in the art of Feng Shui. Eventually, during the Sung dynasty (1000 CE) many trading ships were then able to sail as far as Saudi Arabia using compasses for marine navigation. Between 1405 and 1433, Emperor Chu Ti's Treasure Fleet of the Dragon Throne ruled the entire South Pacific and the Indian Ocean, a territory that ranges from Korea and Japan to the Eastern coast of Africa.
At this time Western mariners were still rather ignorant of the navigational use of the magnet. Petrus Perigrinus van Maricourt wrote a first treatise on the magnet itself: “De Magnete” (1269). And though its nautical use was already mentioned in 1187 by the English monk Alexander Neckham, the use onboard only came about around the 13th and 14th century in the Mediterranean Sea.
Much later, in 1545, Pedro de Medina (Sevilla 1493-1567) wrote the Spanish standard work “Arte de Navegar” on marine compass navigation. This masterpiece was first translated in Dutch (1580) and was -O Irony- used by Jacob van Heemskerk when the Dutch destroyed the Spanish fleet near Gibraltar in 1607. The drawback was of course Van Heemskerk's own death during this victory.

Magnetic Variation

In the fin-de-siècle of the sixteenth century mariners believed that the magnetic north pole coincided with the geographic north pole. Any suggestion otherwise had been denied by Pedro de Medina. Magnetic observations made by explorers in subsequent decades showed however that these suggestions were true. But it took until the early nineteenth century, to pinpoint the magnetic north pole somewhere in Arctic Canada (78° N , 104° W). From then on the angle between the true North and the Magnetic North could be precisely corrected for. This correction angle is called magnetic variation or declination.
It is believed that the Earth's magnetic field is produced by electrical currents that originate in the hot, liquid, outer core of the rotating Earth. The flow of electric currents in this core is continually changing, so the magnetic field produced by those currents also changes. This means that at the surface of the Earth, both the strength and direction of the magnetic field will vary over the years. This gradual change is called the secular variation of the magnetic field. Therefore, variation changes not only with the location of a vessel on the earth but also varies in time.
The correction for magnetic variation for your location is shown on the nearest! nautical chart's compass rose. In this example we find a variation of 4° 15' W in 2009, with an indicated annual correction of 0° 08' E. Hence, in 2011 this variation is estimated to be 3° 59', almost 4° West. This means that if we sail 90° on the chart (the true course), the compass would read 94°.
Another example: let's say the compass rose gives a variation of 2° 50' E in 2007, with a correction of 0° 04' E per year. In 2009 this variation is estimated to be 2° 58', almost 3° East. Now, if we sail 90° on the chart, the compass would read 87°.

Correcting for variation

These overlayed compass roses show the difference between true north and magnetic north when the magnetic variation is 10° West. From the image we find: tc = cc + var
in which “cc” and “tc” stand for “compass course” and “true course”, respectively.
To convert a true course into a compass course we need first assign a “-” to a Western and a “+” to a Eastern variation. Note that this makes sense! because of the clockwise direction of the compass rose. Here, the inner circle is turned 10° anticlockwise, hence -10°.
Now, use the same but re-written equation:
cc = tc - var
235° = 225° - (-10°)
So, to sail a true course of 225°, the helmsman has to steer a compass course of 235°.

To convert a compass course into a true course we can use the original equation. If we have steered a compass course of 200°, we have to plot a true course of 203° in the chart if the variation is 3° East or a true course of 190° if the variation is 10° West.

Magnetic deviation

Magnetic deviation is the second correctable error. The deviation error is caused by magnetic forces within your particular boat. Pieces of metal, such as an engine or an anchor, can cause magnetic forces. And also stereo and other electric equipment or wiring, if too close to the compass, introduce errors in compass heading. Furthermore, the deviation changes with the ship's heading, resulting in a deviation table as shown below. The vertical axis states the correction in degrees West or East, where East is again positive.

The horizontal axis states the ship's heading in degrees divided by ten. Thus, when you sail a compass course of 220°, the deviation is 4° W. (Note, that on most modern sailing yachts the deviation is usually not larger than 3°). When a compass is newly installed it often shows larger deviations than this and needs compensation by carefully placing small magnets around the compass. It is the remaining error that is shown in your deviation table.
You can check your table every now and then by placing your boat in the line of a pair of leading lights and turning her 360 degrees.

Correcting for both deviation and variation

Converting a compass course into a true course, we can still use our equation but we need to add the correction for deviation:
cc + var + dev = tc

Example 1: The compass course is 330°, the deviation is +3° (table) and the variation is +3° (chart);
330° cc + 3° var + 3° dev = ?° tc
giving a true course of 336° which we can plot in our chart
Example 2: The compass course is 220°, the deviation is -4° (table) and the variation is still +3° (chart).
220° cc + 3° var + -4° dev = ?° tc
giving a true course of 219°.
Example 3: The compass course is still 220°, therefore the deviation is still -4° (table) but let's use a variation of -10° this time.
220° cc + -10° var + -4° dev = ?° tc
giving a true course of 206°.

Converting a true course into a compass course is a little less straight forward, but it is still done with the same equation.

Example 4: The true course from the chart is 305° and the variation is +3° (chart), yet we don't know the deviation;
?° cc + 3° var + ?° dev = 305° tc
Luckily, we can rewrite this so this reads:
cc + dev = 305° tc - + 3° var = 302°
In plain English: the difference between the true course and the variation (305 - + 3) = 302 should also be the summation of the compass course and the deviation. So, we can tell our helms person to steer 300°, since with a cc of 300° we have a deviation of +2° (As can be deduced from the deviation table above).
Example 5: The true course from the chart is 150° and we have a Western variation of 7 degrees (-7°). We will use the rewritten equation to get:
150° tc - - 7° var = cc + dev = 157°
From the deviation table we find a compass course of 160° with a deviation of -3°.
Voilà!

Magnetic course

The magnetic course (mc) is the heading after magnetic variation has been considered, but without compensation for magnetic deviation. This means that we are dealing with the rewritten equation from above:
tc - var = cc + dev = mc. Magnetic courses are used for three reasons:

To convert a true course into a compass course like we saw in the last paragraph.
On vessels with more than one steering compass, also more deviation tables are in use; hence only a magnetic or true course is plotted in the chart.
Bearings taken with a handheld compass often don't require a correction for deviation, and are therefore useful to plot in the chart as magnetic courses.

Note, that the actual course lines the navigator draws in the chart are always true courses! These can subsequently be labeled with the true course or the corresponding magnetic or compass course if appropriate.

Some useful data in Youtube about Marine Radio related

2011-06-23T21:37:00.000-07:00

http://www.youtube.com/watch?v=hlt4c-Lh2aU&feature=related

http://www.youtube.com/watch?v=ga6WdGkaeNM&feature=related

Nautical charts

2011-06-21T01:05:00.000-07:00

Projections

The nautical chart is a 2-dimensional representation of a 3-dimensional world. And although this results in various distortions, as long as two requirements are met we can use this image for navigational purposes.

The angles between three objects in the chart should be the same as the angles between the real objects which they represent.
A straight course should appear as a straight line in the chart.

To fulfil these demands a nautical chart requires parallels and meridians that are both straight and parallel. Moreover, the meridians will need to be perpendicular to the parallels.
A well known method to create such a chart is called the Mercator projection after Gerard “Mercator” Kremer, a Flemish scholar who studied in 's Hertogenbosch (the Netherlands) and Leuven (now Belgium) and who invented his famous projection in 1569. The Mercator chart was designed for sailors and can be constructed by wrapping a cylinder around the planet so that it touches the equator. On this cylinder the surface of the earth is projected and finally the cylinder is cut open to yield the 2-dimensional chart.
But where the meridians converge on the globe they run parallel in the projection (see chart below), indicating the distortion. Look, for example, at a high parallel. The length of such a parallel on the globe is much smaller than the equator. Yet, on the chart they have exactly the same length creating a distortion which gets bigger nearer to the poles. The figure below shows the construction of the Mercator projection. From this it is clear that only the vertical scales should be used for measuring distances.

Click on the world map on the right to see the distortions of a Mercator projection. Each navy coloured circle/ellipse has a radius of 500 km.
The vertical scale depicted on the right demonstrates the distortion. The two little navy coloured markers have precisely the same size, the upper one measures only 0.64 degrees (= 38.4 nm) while the other measures 1.00 degrees (= 60 nm). So, distances (in degrees or in miles and minutes) should not only be read on the vertical scale, but also at approximately the same height. The horizontal scale is only valid for one latitude in the chart and can therefore only be used for the coordinates (a point, but not a line). If you divide the surface of the earth in eight pieces, and lift one out and project it, you end up with the figure below. The result is that both A-A' and B-B' are now as long as the bottom of the chart and are “too long”.
But there are of course other projections in use by sailors. An important one is the Stereographic projection, which is constructed by projecting on a flat plane instead of a cylinder. On this chart parallels appear as slightly curved and also the meridians converge at high latitudes. So, strictly speaking, a straight course will not appear as a straight line in the chart, but the parallels remain perpendicular to the meridians. Most often, distortions are scarcely noticed when this projection is used to chart a small area. Like the Mercator projection, the vertical scale represents a meridian and should be used for measuring distances.
Another projection is the Gnomeric projection on which the meridians are again converging. But most importantly, the parallels are arcs of a circle while great circles appear as straight lines. On a sphere the shortest route between A and B is not a straight line but an arc (part of a great circle). Though this is also true when you – for example – cross a little bay, we use for simplification a loxodrome (a handy straight line on your Mercator chart which does not reflect your shortest route). On a Gnomeric chart this same loxodrome is an arc, while your shortest route (a great circle) ends up as a straight line. Hence, the gnomeric projection is particularly useful when sailing great circles (like when you dabble in circumnavigation) and is beyond the scope of a coastal navigation course.

Organization of the chart

Authority: The publisher responsible for the information in the chart – “British Admiralty Charts”.
Title: The title gives a description of the area covered by the chart – “The Aegean Sea of Greece - Athens to Rhodes”.
Number: Different chart types of the same area can be distinguished by the chart's number.
Projection: Most likely the Mercator projection as described above. Charts covering small areas can be constructed by stereographic projection.
Scale: For example: 1:193.000. But since the chart is distorted this holds only for one specific latitude in the Mercator chart. The scale indicates how detailed the chart is (here 1 cm on the chart represents 193000 cm on earth).
Horizontal geodetic datum: The definition of the relationship between the ellipsoid adopted as the model of the Earth's shape, and the Earth itself. Though there are hundreds of datums in use, most are only locally valid.
Yet, the WGS-84 datum is global in scope and positions obtained by satellite navigation systems are usually referred to this datum. Therefore, a correction needs to be applied to a WGS-84 GPS position to agree with charts using other horizontal datums. For example to correct WGS-84 to the European datum, add 0,06'N , 0,04'E (style guide) to the WGS-84 position indicated by the GPS. Fortunately, most GPS receivers may be set to display positions in several other datums besides WGS-84 and perform the calculations for you.
Chart sounding datum: The tidal datum to which soundings and drying heights on a chart are referred. Often shortened to “chart datum” when it is clear that reference is not being made to a horizontal datum. Chart sounding datums are also used as reference for heights (lighthouses, mountains, bridges). Multiple datums can be used in one chart: L.A.T. for soundings and M.L. for heights.
Soundings & height units: Soundings and heights can be stated in - for example - metres, feet or fathoms. Today all charts worldwide are metric, except for USA Hydrographic Office charts, which sometimes still use feet instead of the international standard.
Horizontal scale: Natural scale at for example 40° 15,3' S latitude where the horizontal scale can be used for measuring distances and where the chart scale is true.
GPS compatibility: Most charts neither have the precision nor the resolution to fully use the (differential) GPS positioning potential. Moreover, still plenty of charts result from surveys done in the 19th century.
Also, GPS data often requires a correction for a local horizontal chart datum before it can be used in the chart.
Corrections & edition: The chart is for example a 2009 edition but is - when properly corrected - still valid in 2012. Corrections are published continuously and the changes made should be mentioned in the bottom left corner of the chart.

Information in the chart

Depths reduced to chart datum: A sounding like 3₅ indicates 3½ metres of water under Lowest Astronomical Tide (when the chart datum is “L.A.T.”). An underlined sounding like 0₄ indicates a height of 40 cm above L.A.T..
Heights above Chart Datum on drying areas are given in metres and decimetres. The metres figure is underlined.
Depths are given from 0.1 to 20.9 in metres and decimetres, and from 21 to 31 in metres and half metres. Greater depths are rounded down to the nearest safest metre (for example, 32.7 metres is rounded down to 32 metres).
The geographical position of a sounding is the centre of the depth figure.
Isobaths: Lines connecting positions with the same depth: depth contours.
Heights reduced to chart datum: Heights of for instance, lighthouses, mountains and cliffs are more often reduced to another datum such as Mean High Water (M.H.W.) or Mean High Water Spring.
Tidal information: Details of both the vertical and the horizontal movement of the water is often included in the chart.
Lighthouses, Buoys & marks: Lights, lateral and cardinal marks,
Seabed qualities: Pebbles, seaweed, rocks, wrecks, pipelines, sand and other seabed characteristics for anchoring.
Magnetic variation: The angle between the true North and the magnetic North varies in place and time. The local variation is indicated in the compass card, see
Landmarks: conspicuous positions on the shore: Churches, radio masts, mountain tops, etc. that can be used for compass bearings and other means of navigation, these will be put to good use in

Coordinates and positions

A pair of nautical dividers (single handed dividers) is used to obtain precise coordinates from the chart. This device enables you to take the distance between that particular position and the closest grid line. You then place the dividers on the scale with one end on this grid line, leaving the other end precisely at your coordinate. Do this twice to get both latitude and longitude at the scale on the edge of the chart.
Below are some examples.

Danger mark

32° 06,3' N , 25° 07,3' E

Fish farm

32° 04,4' N , 24° 54,7' E

Anchorage

31° 46,0' N , 25° 04,0' E

Church

31° 48,4' N , 25° 25,0' E

Windmill

32° 01,0' N , 24° 57,8' E

Castle

32° 14,2' N , 25° 29,6' E

Water tower

31° 54,9' N , 24° 54,8' E

Radio mast

31° 54,8' N , 25° 10,0' E

Beacon green

31° 52,0' N , 24° 44,3' E

Plotting a position in the chart is done by reversing this method. Some chart symbols come with a little line and circle indicating the precise location, like the “Radio mast”, otherwise the center of the symbol is the precise location.
Another possible notation of 33° 28,5' E is 33° 28′ 30" E, which however doesn't easily allow for more precision like 33° 28,500' E does. Also note that in most countries a comma - and not a dot - is used as the decimal separator. So instead of 33° 28.500' E, the consensus notation for mariners is 33° 28,500' E.

Distances

To measure the distance between, for instance, these two oil rigs, we will again need our dividers. Remember, we can only use the vertical scale. We first take a convenient distance like 10' (10 nautical miles) on the vertical scale using the middle latitude. Then we start walking with the dividers from the southern oil rig to northern one. Finally, we adjust the dividers to measure the small remaining part at its own height, i.e. its own latitude.
The image shows that the total distance is 37 nautical miles.

Courses

So, now we can measure distances and both plot and read out positions, but we also need directions. For example we need to find the course from safe-water buoy A to safe-water buoy B. To accomplish this we may use parallel rules as shown in this chart below:

First you line this instrument up with the two buoys. Then follows the intriguing part in moving the device to the compass rose without losing its alignment. Finally, when one of the rules is aligned with the heart of the compass card, you can read course A – B. In this example: 170°.
Besides the parallel rules there are other types of instruments available, notably the Breton plotter - also known as a Portland Course Plotter - which features an adjustable rose.

Selection of chart symbols

	Danger line in general
	Wreck, least depth unknown but usually deeper than 20 metres
	Visible wreck
	Wreck of which the mast(s) only are visible at Chart Datum
	Wreck, least depth known obtained by sounding only
	Wreck, least depth known, swept by wire drag or diver
or	Rock which covers and uncovers, height above Chart Datum
	Rock awash at the level of Chart Datum
	Underwater rock of unknown depth, dangerous to surface navigation
or	Underwater rock of known depth, dangerous to surface navigation
	Remains of a wreck, or other foul area, non-dangerous to navigation but to be avoided by vessels anchoring, trawling etc.
	Depth unknown, but considered to have a safe clearance to the depth shown
	Sounding of doubtful depth; Existence doubtful; Reported, but not confirmed
	Position approximate; Position doubtful
or	Wind turbine
	Chimney
	Tower; radio/television tower
	Monument
	Marina - boat harbour
	Mosque, minaret
	Silo
	Tanks
	Placeholder examples: Church (Ch) Tower (Tr) Hotel Cupola (Cu) Chimney (Chy). CAPITALS indicate that the landmark is conspicious.
	Quarrie, mine
	Major light; minor light
	Limit of safety zone around offshore installation
	Position of tabulated tidal stream data with designation “A”; Tidal levels data “a”
	Green or black buoys (symbols filled black): G = Green ; B = Black
	Single coloured buoys other than green and black: Y = Yellow ; R = Red
	Multiple colours in horizontal bands, the colour sequence is from top to bottom
	Multiple colours in vertical or diagonal stripes, the darker colour is given first. W = White
	Lighted marks on multicoloured charts, GPS displays and chart plotters. A yellow coloured lobe indicates a White light! Also note that beacons (here the rightmost symbol with the green light) has an upright G, instead of an oblique G

Glossary

Mercator projection: Most coastal nautical charts are constructed with this method. Angles are true and distances can be measured using the vertical scale.
Stereographic projection: Used for chart covering small areas. Like the Mercator projection use the vertical scale to measure distances.
Gnomeric projection: Used for vast areas. Great circles appear as straight lines on the chart.
Great circle navigation: The shortest course on earth between two positions is a great circle; for circumnavigating and ocean crossings.
Loxodrome: A line which makes the same angle with all meridians. Theoretically not the shortest route, but a handy straight line on a Mercator chart.
Horizontal geodetic datum: Defines the relationship between the ellipsoid adopted as the model of the Earth's shape, and the Earth itself. Coordinates which refer to, for instance, AIA should be corrected before plotting them in a chart based on another horizontal datum. If your GPS receiver consistently disagrees with known positions by a constant amount and direction, then check that you have set it to display the correct horizontal datum.
Chart sounding datum: The tidal datum (fictitious plane) to which soundings, heights, elevations and drying heights on a chart are referred.
Vertical scale: Distances in nautical miles or minutes (') should be measured at the same latitude on the vertical scale.
Corrections: Each chart is liable to corrections which are published by either a national body or the publisher of the nautical chart.