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FCC Restricted GMDSS (RG) study materials
FCC Restricted GMDSS (RG) study resources

FCC Restricted GMDSS (RG) practice questions

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Question 1GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

In the GMDSS, what defines Sea Area A1?

  1. An area within coverage of an MF coast station providing continuous DSC alerting
  2. An area within the coverage of an Inmarsat geostationary satellite providing continuous alerting
  3. An area within radiotelephone coverage of at least one VHF coast station in which continuous DSC alerting is available Correct answer.
  4. An area outside all satellite and terrestrial distress alerting coverage

Explanation

Sea Area A1 is defined by VHF coverage: a vessel must be within radiotelephone range of at least one shore-based VHF coast station where continuous DSC alerting is available. The defining element is the combination of VHF range and continuous DSC capability, not satellite or MF coverage.

Question 2GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

A vessel certified for Sea Area A1 only proceeds on a voyage that will take it outside VHF DSC coverage. What is the correct understanding of its GMDSS obligations?

  1. The vessel may continue because A1 certification automatically covers all sea areas
  2. The vessel is not adequately equipped for that voyage and must not proceed beyond A1 Correct answer.
  3. The vessel may continue provided a handheld VHF is carried as a backup
  4. The vessel may continue if the master records the gap in the official logbook

Explanation

GMDSS equipment carriage follows the sea area in which the ship operates, so an A1-only certificate is valid only while the ship remains within A1. Leaving A1 without the additional equipment required for A2, A3 or A4 means the ship is not in compliance. A logbook entry or a portable VHF does not extend the certified sea area.

Question 3GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which item is a mandatory GMDSS carriage requirement for a vessel operating exclusively in Sea Area A1?

  1. A 406 MHz float-free EPIRB operating on the 121.5 MHz homing frequency only
  2. A NAVTEX receiver capable of receiving international broadcasts
  3. A VHF radio installation capable of DSC on channel 70 and radiotelephony Correct answer.
  4. An MF/HF radio installation with DSC and NBDP

Explanation

The core A1 requirement is a VHF installation able to transmit and receive DSC alerts on channel 70 and to work radiotelephony on the prescribed channels. NAVTEX, MF/HF and satellite equipment become relevant for MSI reception and for higher sea areas.

Question 4GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

For a ship operating only in Sea Area A1, which means of transmitting ship-to-shore distress alerts is required?

  1. An Inmarsat ship earth station
  2. A VHF radio installation capable of DSC on channel 70 Correct answer.
  3. An MF DSC transmitter on 2187.5 kHz
  4. A HF DSC transmitter on 8414.5 kHz

Explanation

In A1 the primary distress alerting path is VHF DSC on channel 70, which reaches coast stations with continuous DSC watch. Satellite and MF/HF alerting become the required options when the ship operates in A2, A3 or A4.

Question 5GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which piece of equipment provides the secondary means of initiating a distress alert from the survival craft or at the ship's position in an A1-only fit?

  1. A 406 MHz EPIRB Correct answer.
  2. A two-way VHF radiotelephone apparatus for on-scene communication
  3. A NAVTEX receiver
  4. A SART operating in the 9 GHz band

Explanation

The satellite EPIRB provides an alternative distress alerting path independent of the VHF coast-station network, complementing the VHF DSC installation. The SART and two-way VHF support on-scene location and communications rather than alerting the shore.

Question 6GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which NAVTEX frequency is used for international transmissions in the 518 kHz band?

  1. 490 kHz
  2. 8414.5 kHz
  3. 4209.5 kHz
  4. 518 kHz Correct answer.

Explanation

The international NAVTEX service uses 518 kHz for English-language broadcasts, while 490 kHz carries national-language transmissions. Frequencies such as 4209.5 kHz and 8414.5 kHz belong to other services.

Question 7GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

What is the principal purpose of NAVTEX within the GMDSS?

  1. To receive maritime safety information such as navigational and weather warnings Correct answer.
  2. To relay SART radar responses to rescue coordination centres
  3. To provide ship-to-ship radiotelephony on the bridge
  4. To broadcast distress alerts directly to coast stations

Explanation

NAVTEX is a broadcast reception system delivering MSI, including navigational warnings, meteorological warnings and search and rescue information, to ships. It is a receive-only service and does not transmit distress alerts or handle ship-to-ship voice traffic.

Question 8GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which statement correctly describes the relationship between Sea Area A1 and the other sea areas?

  1. A1 is defined by satellite coverage and A2 by VHF coverage
  2. A1, A2, A3 and A4 are mutually exclusive and a ship is certified for only one
  3. A1 is the innermost area and a ship equipped for A2 or A3 also satisfies A1 requirements Correct answer.
  4. A1 applies only to fishing vessels and A2 to merchant ships

Explanation

The sea areas are nested in terms of equipment capability: a ship fitted for A2 or A3 carries equipment that also meets A1 needs. The areas are not assigned as exclusive categories to a ship.

Question 9GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

A vessel operating in A1 must be able to receive MSI. Which combination is commonly used to meet this requirement?

  1. 406 MHz EPIRB and radar reflector
  2. MF/HF radiotelephone and NBDP terminal
  3. NAVTEX receiver or an Inmarsat Enhanced Group Call receiver Correct answer.
  4. SART and two-way VHF radiotelephone

Explanation

MSI reception is met by NAVTEX or by an EGC receiver, depending on the area and equipment fit. The other options list alerting, location or radiotelephony equipment that does not deliver MSI.

Question 10GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which GMDSS functional requirement is met by the VHF DSC installation on an A1 vessel?

  1. Transmission of locating signals for search and rescue
  2. Reception of MSI broadcasts
  3. Transmission of ship-to-shore distress alerts Correct answer.
  4. Reception of satellite distress alerts

Explanation

VHF DSC provides the ship-to-shore distress alerting function in A1 by reaching coast stations with continuous DSC watch on channel 70. MSI reception and locating signals are separate functions with their own equipment.

Question 11GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which frequency is used for VHF DSC distress alerting?

  1. Channel 06
  2. Channel 70 Correct answer.
  3. Channel 16
  4. Channel 13

Explanation

Channel 70 is reserved for digital selective calling on VHF and is the channel used for DSC distress alerts. Channel 16 is the radiotelephony distress and calling channel, and the other channels serve bridge-to-bridge or inter-ship working.

Question 12GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

What is the function of a SART in the GMDSS?

  1. To transmit a distress alert to a coast station by DSC
  2. To provide a radar-visible locating signal for rescue units Correct answer.
  3. To receive MSI broadcasts from shore
  4. To relay voice messages between survival craft

Explanation

A SART responds to radar interrogation by transmitting a signal that appears on the rescue vessel's radar, helping locate the survival craft. It does not alert coast stations, receive broadcasts or relay voice.

Question 13GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

A small passenger vessel certified for A1 carries a VHF DSC set, a 406 MHz EPIRB and a NAVTEX receiver. Which GMDSS function is NOT yet provided?

  1. On-scene locating of the survival craft Correct answer.
  2. Ship-to-shore distress alerting
  3. Transmission of a distress alert by satellite
  4. MSI reception

Explanation

The listed fit provides alerting and MSI reception but lacks a SART or equivalent means of generating a locating signal at the scene. A SART is required to help rescue units find the craft by radar.

Question 14GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which statement about the 406 MHz EPIRB is correct?

  1. It receives MSI broadcasts from coast stations
  2. It provides radar-visible responses to search radars
  3. It transmits a digital distress message to the COSPAS-SARSAT system Correct answer.
  4. It transmits a continuous voice message on 121.5 MHz

Explanation

A 406 MHz EPIRB sends a digital distress message via the COSPAS-SARSAT satellite system, which allows identification and location of the beacon. The 121.5 MHz homing signal is a separate low-power aid for local search.

Question 15GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which equipment is required to meet the on-scene communication function in A1?

  1. A NAVTEX receiver
  2. A two-way VHF radiotelephone apparatus for use in survival craft Correct answer.
  3. An Inmarsat ship earth station
  4. An MF/HF transceiver with NBDP

Explanation

Two-way VHF radiotelephones allow communication between the survival craft and rescue units at the scene. MF/HF, NAVTEX and Inmarsat serve other GMDSS functions and are not the on-scene communication means.

Question 16GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

A fishing vessel operates within VHF coverage of a coast station that maintains continuous DSC watch. Which sea area does this correspond to?

  1. Sea Area A1 Correct answer.
  2. Sea Area A3
  3. Sea Area A4
  4. Sea Area A2

Explanation

Continuous VHF DSC coverage from a coast station defines A1. A2 depends on MF coverage, A3 on satellite coverage, and A4 on the absence of A1, A2 and A3 coverage.

Question 17GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

What does the continuous DSC watch on channel 70 at a coast station enable?

  1. Automatic reception of satellite EPIRB signals
  2. Continuous voice watch on channel 16
  3. Continuous reception of NAVTEX broadcasts
  4. Automatic reception of distress alerts from ships with VHF DSC Correct answer.

Explanation

A coast station maintaining continuous DSC watch on channel 70 can receive digital distress alerts automatically, which is the basis of A1 coverage. Voice watch, satellite EPIRB reception and NAVTEX are separate services.

Question 18GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which document should a candidate consult to confirm the exact GMDSS equipment scale applicable to a particular ship?

  1. The ship's radio logbook
  2. The NAVTEX station list
  3. The ITU list of ship stations
  4. The ship's GMDSS radio certificate and the applicable national carriage regulations Correct answer.

Explanation

The radio certificate issued for the ship, read together with the applicable carriage regulations, states the equipment required for the sea areas in which the ship is certified to operate. Other documents provide operational or administrative information but do not set the carriage scale.

Question 19GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which of the following best describes the difference between Sea Area A1 and Sea Area A4?

  1. A1 requires MF equipment while A4 requires only VHF
  2. A1 has VHF DSC coverage while A4 has no A1, A2 or A3 coverage Correct answer.
  3. A1 has satellite coverage while A4 has VHF coverage
  4. A1 applies only to large ships while A4 applies to small ships

Explanation

A1 is the innermost area with VHF DSC coverage, while A4 covers the remaining sea areas outside A1, A2 and A3, typically polar regions. Equipment requirements increase as coverage becomes less available.

Question 20GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which of the following is a correct statement about the availability of GMDSS services in Sea Area A1?

  1. Distress alerting relies on satellite only
  2. Distress alerting relies on HF radio only
  3. Distress alerting is not possible in A1
  4. Distress alerting relies on VHF coverage from shore Correct answer.

Explanation

A1 is defined by VHF coast-station coverage, so the primary distress alerting path is terrestrial VHF DSC. Satellite and HF are alternatives used where VHF coverage is not available.

Question 21GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which of the following statements about the GMDSS sea areas is correct?

  1. A ship certified for A4 needs only a NAVTEX receiver
  2. A ship certified for A1 automatically meets A3 requirements
  3. A ship certified for A2 does not need VHF equipment
  4. A ship certified for A3 must also carry equipment meeting A1 requirements Correct answer.

Explanation

Higher sea-area certification includes the capability to operate in lower areas, so an A3 ship carries VHF DSC equipment that meets A1 needs. The reverse is not true, and A4 requires extensive long-range equipment.

Question 22GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

What is the purpose of the 121.5 MHz transmission from an EPIRB?

  1. To receive acknowledgements from the rescue coordination centre
  2. To broadcast MSI to nearby ships
  3. To provide a homing signal for search aircraft and vessels Correct answer.
  4. To carry the digital identification of the vessel

Explanation

The 121.5 MHz signal is a low-power homing aid that allows search units equipped with suitable receivers to home in on the beacon. The digital identification is carried on 406 MHz, and the beacon does not receive acknowledgements or broadcast MSI.

Question 23GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

A vessel is fitted with a VHF DSC set and an EPIRB but no means of receiving MSI. Which requirement is unmet for A1 operation?

  1. Reception of maritime safety information Correct answer.
  2. Two-way on-scene communication
  3. On-scene locating signal
  4. Ship-to-shore distress alerting

Explanation

MSI reception is a separate GMDSS function normally met by NAVTEX or an EGC receiver. The VHF DSC set and EPIRB cover alerting, but neither receives safety broadcasts.

Question 24GMDSS system overview, sea areas A1–A4, and carriage requirements for vessels operating in Sea Area A1

Which of the following correctly pairs a GMDSS function with the equipment typically used for it in A1?

  1. On-scene locating - NAVTEX receiver
  2. Bridge-to-bridge communication - 406 MHz EPIRB
  3. MSI reception - SART
  4. Distress alerting ship-to-shore - VHF DSC on channel 70 Correct answer.

Explanation

VHF DSC on channel 70 is the standard means of sending ship-to-shore distress alerts in A1. SART, NAVTEX and EPIRB serve locating, MSI reception and satellite alerting respectively.

Question 25VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

On which VHF channel is the radiotelephone distress, urgency and safety frequency located?

  1. Channel 13
  2. Channel 70
  3. Channel 06
  4. Channel 16 Correct answer.

Explanation

Channel 16 (156.800 MHz) is the international VHF distress, urgency and safety frequency and is also used for initial calling. Channel 70 is reserved for DSC and must never carry voice traffic.

Question 26VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which VHF channel is dedicated to Digital Selective Calling and must never be used for voice transmissions?

  1. Channel 09
  2. Channel 72
  3. Channel 70 Correct answer.
  4. Channel 16

Explanation

Channel 70 is reserved worldwide for VHF DSC alerting and is not permitted for radiotelephony. Voice follow-up to a DSC alert is made on a working channel such as Channel 16 or a designated working frequency.

Question 27VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What does the spoken radiotelephone distress signal consist of?

  1. Mayday, repeated three times Correct answer.
  2. Securite, repeated three times
  3. Pan Pan, repeated three times
  4. Distress, spoken once

Explanation

The distress signal in radiotelephony is the word Mayday, spoken three times in succession. It signals that a vessel or person is in grave and imminent danger and requests immediate assistance.

Question 28VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which spoken signal precedes a transmission concerning the safety of navigation or an important meteorological warning?

  1. Pan Pan
  2. Securite Correct answer.
  3. Mayday
  4. Silence Fini

Explanation

The safety signal is the word Securite, spoken three times, and it introduces messages about navigational hazards or important weather warnings. It has lower priority than distress and urgency traffic.

Question 29VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What is the meaning of the procedure word OVER in a VHF radiotelephone exchange?

  1. My transmission is ended and no reply is expected
  2. My transmission is ended and I expect a reply from you Correct answer.
  3. I am switching to another channel
  4. I have received your message and understood it

Explanation

OVER indicates that the transmitting station has finished speaking and expects a response from the other station. It is used to hand the conversation back without ending the communication.

Question 30VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which frequency band and channel are used for sending a VHF DSC distress alert?

  1. VHF Channel 13 using DSC
  2. MF 2182 kHz using DSC
  3. VHF Channel 16 using voice only
  4. VHF Channel 70 using DSC Correct answer.

Explanation

A VHF DSC distress alert is transmitted as a digital message on Channel 70, which is reserved for DSC. The subsequent voice distress traffic is normally conducted on Channel 16.

Question 31VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What does the urgency signal indicate when transmitted on VHF?

  1. A navigational warning is about to be broadcast
  2. Radio silence is being imposed
  3. A station has a very urgent message concerning the safety of a vessel or person Correct answer.
  4. A vessel or person is in grave and imminent danger

Explanation

The urgency signal Pan Pan, spoken three times, concerns the safety of a vessel or person but does not indicate immediate danger requiring distress assistance. It gives priority over all traffic except distress.

Question 32VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

How should a DSC distress alert on VHF normally be acknowledged by another vessel?

  1. By a DSC acknowledgement on Channel 16
  2. By voice on Channel 16 only, without any DSC acknowledgement
  3. By a DSC acknowledgement on Channel 70, followed by voice contact on Channel 16 Correct answer.
  4. By remaining silent until the coast station responds

Explanation

A DSC distress alert is normally acknowledged by a DSC acknowledgement transmitted on Channel 70, after which voice communication is established on Channel 16. This confirms to the distress station that the alert has been received.

Question 33VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

A vessel sights a person overboard and requires immediate assistance but the situation is not yet confirmed as grave and imminent danger. Which signal should be transmitted?

  1. Silence Mayday
  2. Pan Pan Correct answer.
  3. Mayday
  4. Securite

Explanation

An urgent situation that threatens the safety of a person but does not yet amount to grave and imminent danger is announced with Pan Pan. If the situation deteriorates into grave and imminent danger, the distress signal Mayday is used instead.

Question 34VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What is the correct spoken distress call from the vessel Sea Lark, callsign MLAB2?

  1. Mayday, Mayday, Mayday, this is Sea Lark, Sea Lark, Sea Lark, MLAB2 Correct answer.
  2. Mayday, Mayday, Mayday, MLAB2, MLAB2, MLAB2, receiving
  3. Pan Pan, Pan Pan, Pan Pan, this is Sea Lark
  4. Mayday, this is MLAB2, over

Explanation

The distress call consists of Mayday spoken three times, the words THIS IS, and the vessel's name or callsign spoken three times. This standard format ensures the station in distress is clearly identified.

Question 35VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

After transmitting a VHF DSC distress alert, what should the station do next?

  1. Switch off the radio to conserve battery power
  2. Follow the alert with a radiotelephone distress call and message on Channel 16 Correct answer.
  3. Wait silently for at least one hour before any voice transmission
  4. Immediately transmit a Securite message on Channel 06

Explanation

The DSC alert is normally followed by a voice distress call and distress message on Channel 16 to give full details of the emergency. This allows stations that did not receive the DSC alert to become aware of the distress.

Question 36VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which VHF channel is designated for intership navigation safety communications, particularly for ship-to-ship manoeuvring?

  1. Channel 13 Correct answer.
  2. Channel 70
  3. Channel 09
  4. Channel 16

Explanation

Channel 13 is the intership navigation safety channel used for communications relating to the safe navigation of vessels, such as manoeuvring intentions. It is restricted to one watt output in many administrations.

Question 37VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What is the purpose of the DSC 'routine' priority when calling another vessel on VHF?

  1. To establish contact for ordinary operational or private communications Correct answer.
  2. To impose radio silence during an emergency
  3. To send a distress alert automatically
  4. To broadcast a navigational warning

Explanation

Routine priority is used for ordinary ship-to-ship or ship-to-shore communications that have no distress, urgency or safety character. The DSC call includes the working channel on which the voice contact will follow.

Question 38VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

A vessel receives a DSC distress alert addressed to it specifically (individual distress alert). What is the correct action?

  1. Ignore it because it is not an all-ships alert
  2. Relay the alert on Channel 70 by voice
  3. Acknowledge the alert by DSC on Channel 70 and then establish voice contact on Channel 16 Correct answer.
  4. Acknowledge by voice on Channel 13 and continue normal working

Explanation

A distress alert addressed to a specific station must be acknowledged by that station with a DSC acknowledgement on Channel 70. Voice contact is then established on Channel 16 to offer assistance.

Question 39VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

When should a vessel transmit a Mayday relay on VHF?

  1. When a distress alert or call is received from a station unable to transmit its own distress message Correct answer.
  2. Only when the coast station has closed the case
  3. When the vessel is experiencing routine engine trouble
  4. Whenever the vessel wishes to test its distress equipment

Explanation

A Mayday relay is used when another station is in distress but cannot transmit its own distress message, or when a distress alert needs to be passed on. The relaying station identifies itself and passes on the details of the original distress.

Question 40VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What does the procedure word ROGER mean in a VHF exchange?

  1. I have received your entire message
  2. I am switching to Channel 70
  3. Please repeat your last transmission
  4. I have received all of your last transmission Correct answer.

Explanation

ROGER means that the last transmission has been received completely and understood. It does not mean yes, and it does not apply to the whole message if only part was heard.

Question 41VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which statement correctly describes the use of VHF Channel 16 for calling?

  1. It may be used for lengthy operational discussions
  2. It is reserved exclusively for DSC traffic
  3. It may be used only by coast stations
  4. It should be used only to establish contact, after which stations move to a working channel Correct answer.

Explanation

Channel 16 is the calling and distress channel and should be kept clear for that purpose. Once contact is established, stations should move to a working channel to conduct the conversation.

Question 42VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

A vessel is not in distress but wishes to warn other vessels of a drifting container that poses a navigation hazard. Which transmission is appropriate?

  1. Securite on Channel 16 Correct answer.
  2. A routine DSC call on Channel 70 followed by voice on Channel 13
  3. Mayday on Channel 16
  4. Pan Pan on Channel 16

Explanation

A hazard to navigation is announced with the safety signal Securite, spoken three times, followed by the safety message. This warns other vessels without implying danger to a vessel or person.

Question 43VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What information must a DSC distress alert on VHF contain to be effective?

  1. The vessel's MMSI and the nature of distress, with position and time if available Correct answer.
  2. Only the working channel to be used afterwards
  3. Only the vessel's name
  4. The vessel's cargo manifest

Explanation

A DSC distress alert identifies the vessel by its MMSI and, where the equipment allows, includes the nature of distress, position and time. This information allows rescue authorities to respond appropriately.

Question 44VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

A vessel transmits a DSC distress alert by mistake. What is the correct procedure?

  1. Transmit a Securite message on Channel 06 and continue normal working
  2. Wait for a coast station to call before taking any action
  3. Switch off the radio and say nothing
  4. Immediately transmit a distress cancellation on Channel 16, identifying the station and cancelling the false alert Correct answer.

Explanation

A false distress alert must be cancelled promptly by transmitting a distress cancellation on Channel 16 and informing the appropriate authority. This prevents unnecessary deployment of rescue resources.

Question 45VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Why is Channel 70 unsuitable for the voice follow-up to a DSC alert?

  1. It is used exclusively for navigation safety
  2. It is reserved for DSC digital transmissions and voice is prohibited there Correct answer.
  3. It has insufficient range for distress traffic
  4. It is only available to coast stations

Explanation

Channel 70 is dedicated to DSC and voice transmissions are prohibited on it to prevent interference with digital alerting. The voice follow-up is therefore made on Channel 16 or another designated working channel.

Question 46VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

During distress traffic, a station hears the coast station transmit 'Silence Mayday'. What does this require?

  1. All stations must switch to Channel 13
  2. All stations must stop transmitting until 'Silence Fini' is announced Correct answer.
  3. All stations must acknowledge the distress alert by DSC
  4. All stations must repeat the distress message

Explanation

Silence Mayday imposes radio silence on all stations except those handling the distress so that distress traffic is not interfered with. The silence remains in force until Silence Fini is announced.

Question 47VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

A vessel's VHF DSC controller shows an incoming distress alert from another vessel, but the vessel's own radio is not able to transmit on Channel 16. What is the most appropriate action?

  1. Ignore the alert because the vessel cannot transmit
  2. Transmit a Mayday relay on Channel 70 by voice
  3. Wait for the coast station to acknowledge before doing anything
  4. Acknowledge the alert by DSC and, if possible, relay the distress to a station able to assist Correct answer.

Explanation

A station that receives a distress alert should acknowledge it by DSC and ensure the distress is passed to a station able to render assistance. A relay may be used when the receiving station cannot itself communicate on the distress channel.

Question 48VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

Which of these VHF channels is a recognised intership working channel commonly used after an initial call on Channel 16?

  1. Channel 72 Correct answer.
  2. Channel 16
  3. Channel 70
  4. Channel 13

Explanation

Channel 72 is one of the designated intership working channels used for ship-to-ship communications after contact has been established. Channel 16 is reserved for calling and distress, and Channel 70 for DSC.

Question 49VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

What is the correct way to pronounce the digits in a VHF radiotelephone message to avoid confusion?

  1. Digits are replaced by letters
  2. Digits are read as whole numbers
  3. Each digit is spoken individually, with special pronunciations for some digits Correct answer.
  4. Digits are omitted

Explanation

In radiotelephony each digit is spoken separately and certain digits have special pronunciations, such as 'niner' for nine, to avoid confusion. This ensures numbers such as positions and channels are understood correctly.

Question 50VHF radiotelephony: channel usage, distress/urgency/safety procedures, and Digital Selective Calling (DSC) operations on VHF

On VHF, which channel is the single international calling and distress frequency for radiotelephony?

  1. Channel 16 Correct answer.
  2. Channel 06
  3. Channel 70
  4. Channel 13

Explanation

Channel 16 (156.800 MHz) is the international radiotelephone distress, safety and calling frequency. It is monitored by coast stations and ships for distress and for initial calls, after which stations should move to a working channel.