SRC Theorie

In the UK, CH 15 and 17 are used for on-board communication using low power

The “Vessel Traffic Service” monitors and assists ships entering and leaving a harbour

The maximum range for receiving VHF signals depends on the hight of the transmitting and receiving antennas and the power (1 or 25 Watt) used for transmitting.  

Between two sailing yachts (mast hight 16 m) the range is approximately about 16-25 NM. Tilting or heeling affects the range. 

The higher the antennas and the power, the greater the range.  

The communication via VHF and DSC is classified into four priorities.

• Routine

• Safety

• Urgency

• Distress 

The distress alert and urgency, safety or routine announcements by DSC are always being sent digitally on CH 70. There is no need to set CH 70 manually.

CH 70 is always activated automatically as soon as the DSC controller is switched on. 

Routine announcements are always sent only to individuals and groups – never to all stations.

 only communication relating to navigational interest is permitted

Distress alert, urgency and safety announcements are always sent to all stations – never to individuals or groups. 

observed a danger for all ships (drifting container, trees) and need to transmit a warning to all ships.

The procedure word (proword) for a safety message is “SECURITE”. 

Before transmitting by voice on CH 16, a “Securite Announcement” can be transmitted on CH 70 (digitally),

Safety Calls are always All Station Calls.  

SECURITE, SECURITE, SECURITE

all stations, all stations, all stations

this is Solent Coastguard, Solent Coastguard, Solent Coastguard

for an important weather warning listen to CH 25, 82, … OUT

The safety message will then be transmitted on a working channel:

SECURITE, SECURITE, SECURITE

all stations all, stations, all stations

this is Solent Coastguard, Solent Coastguard, Solent Coastguard  

Urgency means a danger for a ship or a person, but not life threatening, e.g. ship is not under command but not in a gale or drifting to a rocky lee shore, injured person, but not life threatening etc.

The proword for urgency is “PAN PAN“.  

Before transmitting by voice on CH 16 you will transmit an “URGENCY Announcement” on CH 70, 

Urgency Calls are always All Station Calls. 

PAN PAN, PAN PAN, PAN PAN

all stations, all stations, all stations

This is sailing yacht name of the yacht, name of the yacht, name of the yacht,

Call Sign xxxxx, MMSI xxxxxxxxx 

Position 2 miles NE of Light vessel ELBE

Engine broken down and drifting towards the TSS.

Require tug assistance.

OVER 

Distress means grave and imminent danger to a ship, a person or an aircraft, and immediate assistance is required. The proword for a Distress Call is “Mayday”. 

A Distress situation is always for yourself - never for anybody else.

Distress Calls are always All Station Calls with maximum power.  

A) Distress Alert: DSC  on CH 70  by pushing the "DISTRESS" button for 5 seconds

B) Distress Call: VHF   On CH 16 , transmit via voice the distress call and messag

• Transmit the DSC Alert on CH 70 by pushing the "DISTRESS" button for 5 seconds.
• This transmission will result in a strong audible alert on all VHF radios in a range of 20 - 40 miles,
• contains the identity (MMSI), position, time in UTC and, if entered, also the nature of distress.
• This transmission will be sent automatically every 4 minutes, until it is acknowledged on CH 70 by a Coast station.
• Yachts in vicinity of the ship in distress should never acknowledge a received distress alert: the station acknowledging takes the responsibility for the rescue operation, and yachts are not professional rescue units.  

 Mayday, Mayday, Mayday

This is Yacht “...”, “...”, “...” (3x name)

Call Sign... MMSI…  

Make a short break in your transmission, to give every operator receiving the message, the opportunity to prepare for writing down the message, start again with MAYDAY 

Distress Message:

Mayday Mayday

Identity This is Yacht “...”Call Sign / MMSI

Position Position

Distress Yacht is ... (nature of distress)

Assistance immediate assistance required

Number ... persons on board (number of persons)

Information … (useful info – e.g. having or not having liferaft)

Over Over 

Digital Selective Calling (DSC) Via a DSC controller you send a digital signal to other DSC controllers.

Global Maritime Distress and Safety System (GMDSS).

Safety of Life at Sea Convention (SOLAS)

SAR (Search and Rescue) forces and authorities

should also be equipped with: 

• VHF DSC radio (in Area A2/A3 MF/HF DSC radios) 

• EPIRB: Emergency Position Indicating Radio Beacon

• SART: Search and Rescue Transponder

• Radar

• Navtex: Navigational Text Messages

• Waterproof handheld VHF radio 

 Emergency Position Indicating Radio Beacon

 Search and Rescue Transponder

Navigational Text Messages  

Maritime Mobile Service Identity (MMSI) 

 a 9-digit number, that identifies a particular ship or coast station.  

The “MMSI” is the registered number for the DSC.

The “CALL SIGN” is the registered sign for the VHF.

The “T-NUMBER” is the registered sign for a handheld device. 

MMSI and call sign are issued by:

• UK – OFCOM (Office of Communication)

• Germany – Bundesnetzagentur  

 MRCC (Maritime Rescue Coordination Centres)

• is portable, battery operated, floatable and waterproof. 
• pinpoint the position of survivors. It works on 406 MHz
• has an integrated GPSThe
• needs regular maintenance. In emergency it should send the signal at least for 48 hours.
• The EPIRB must be registered with its HEX ID to the Ship Radio Licence
• is related to a ship

• The PLB (Personal Locator Beacon) is portable, battery operated and waterproof. 
• PLBs is related to a single person.  
•  PLB must also be registered with its HEX ID, but to a Ship Portable Radio Licence