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Subelement E

Distress, Urgency & Safety Communications:

Section 32

Distress Relays:

Your ship received a Distress relay from a coast station on DSC freq. 2187.5 kHz. What action should the watch officer take?

  • Retransmit the DSC call on 2187.5 kHz to other vessels in the vicinity to assist in SAR operations.
  • Correct Answer
    Monitor 2182.0 kHz to determine if there are any genuine Distress communications.
  • Transmit a voice "Mayday Relay" call on 2187.5 kHz to other vessels in the vicinity.
  • Transmit a voice "Mayday Relay" call on 2182.0 kHz to other vessels in the vicinity.

Your ship received a Distress relay from a coast station on DSC freq. 2187.5 kHz. What action should the watch officer take?

(B). Monitor 2182.0 kHz to determine if there are any genuine Distress communications.

47 CFR 80.1123(d) On receipt of a distress alert transmitted by use of digital selective calling techniques, ship stations must set watch on the radiotelephone distress and safety traffic frequency associated with the distress and safety calling frequency on which the distress alert was received.

For more details, please see Code of Federal Regulations on § 80.1123 Watch requirements for ship stations.

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Your ship received a Distress relay from a coast station on DSC VHF channel 70. What action should the watch officer take?

  • Retransmit the DSC call on Ch-70 to other vessels in the vicinity.
  • Monitor Ch-06 to determine if there are any genuine Distress communications.
  • Correct Answer
    Monitor Ch-16 to determine if there are any genuine Distress communications.
  • Transmit a voice "Mayday Relay" call on Ch-13.

Your ship received a Distress RELAY from a coast station on DSC VHF channel 70. What action should the watch officer take?

(C). Monitor Ch-16 to determine if there are any genuine Distress communications.

Since Channel 16 is the distress channel, such communications will be made on it to verify channel 70 message.

47 CFR 80.1123(c) Every ship while at sea must maintain, when practicable, a continuous listening watch on VHF Channel 16. This watch must be kept at the position from which the ship is normally navigated or at a position which is continuously manned. § 80.1123 Watch requirements for ship stations.

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Under what condition would you not relay a DSC Distress alert?

  • If the mobile unit in Distress is incapable of further Distress alert communications.
  • If no Coast Station/Mobile Unit acknowledgement of the alert is observed.
  • No distress traffic has been heard and the DSC alert is unacknowledged via DSC.
  • Correct Answer
    A coast station DSC acknowledgment of the original Distress alert was received by your vessel.

Under what condition would you not relay a DSC Distress alert?

(D). A coast station DSC acknowledgment of the original Distress alert was received by your vessel.

§ 80.1117 Procedure for receipt and acknowledgement of distress alerts.

47 CFR 80.1117(a) Normally, distress calls received using digital selective calling are only acknowledged using a DSC acknowledgement by a coast station.

Ships should delay any acknowledgement in order to give sufficient time for a coast station to acknowledge the call.

In cases where no acknowledgement has been heard and no distress traffic has been heard, the ship should transmit a distress alert relay to the coast station.

Upon advice from the Rescue Coordination Center, the ship may transmit a DSC acknowledgement call to stop it from being repeated.

For more details, please see Code of Federal Regulations § 80.1117 Procedure for receipt and acknowledgement of distress alerts.

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The relay of DSC Distress alerts:

  • Correct Answer
    Can quickly overburden the GMDSS systems in the vicinity with improperly transmitted or inappropriately relayed DSC calls.
  • Was not originally an intended function of the GMDSS system but now is the preferred method to notify an RCC.
  • Remains the preferred method for passing Distress message traffic to an RCC or Coast Station.
  • Should always be done immediately to ensure a Coast Station receives the DSC Distress Alert.

The relay of DSC Distress alerts:

(A). Can quickly overburden the GMDSS systems in the vicinity with improperly transmitted or inappropriately relayed DSC calls.

This is the only reasonable answer.

47 CFR 80.1121(b) For VHF and MF, ships in receipt of a distress alert shall not transmit a distress alert relay, but should listen on the distress traffic channel for 5 minutes, and if appropriate, acknowledge the alert by radiotelephony to the ship in distress and inform the coast station and/or Rescue Coordination Center.

Distress alert relays to “all ships” on these bands may only be sent by a ship who has knowledge that another ship in distress is not itself able to transmit the distress alert, and the Master of the ship considers that further help is necessary.

47 CFR 80.1121(c) For HF, ships in receipt of a distress alert shall listen on the distress traffic channel for 5 minutes.

If no distress communications are heard and if the call is not acknowledged by a coast station the ship shall transmit a distress relay on HF to the coast radio station and inform the Rescue Coordination Center.

Distress alert relays to “all Ships” on HF may only be sent by a ship who has knowledge that another ship in distress is not itself able to transmit the distress alert, and the Master of the ship considers that further help is necessary.

See Code of Federal Regulations Reference

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Transmission of a Distress alert by a station on behalf of another vessel actually in Distress should not occur:

  • When the mobile unit actually in Distress is not itself in a position to transmit the Distress alert.
  • When the Master or responsible person on the mobile unit not in Distress so decides.
  • When the responsible person at the Coast Station determines further help is necessary.
  • Correct Answer
    When communications between the Distress vessel and a Coast station are already in progress.

Transmission of a Distress alert by a station on behalf of another vessel actually in Distress should not occur:

(D). When communications between the Distress vessel and a Coast station are already in progress.

§ 80.1111 Distress alerting.

47 CFR 80.1111(d) All stations which receive a distress alert transmitted by digital selective calling must immediately cease any transmission capable of interfering with distress traffic and must continue watch on the digital selective call distress calling channel until the call has been acknowledged to determine if a coast station acknowledges the call using digital selective calling.

Additionally, the station receiving the distress alert must set watch on the associated distress traffic frequency for five minutes to determine if distress traffic takes place.

The ship can acknowledge the call using voice or narrow band direct printing as appropriate on this channel to the ship or to the rescue authority.

For more details, please see Code of Federal Regulations, § 80.1111 Distress alerting.

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DSC Relays of DSC Distress alerts received from other ships should be done?

  • Correct Answer
    Only when the original DSC call is not acknowledged and no follow-on Distress traffic has been heard.
  • Only by Inmarsat-C TELEX with Distress priority conveying the follow-on Distress traffic that has been heard.
  • Only by Inmarsat-B voice or TELEX with Distress priority if no follow-on Distress traffic has been heard.
  • Preferably by MF/HF voice or TELEX directly to the RCC conveying the follow-on Distress traffic that has been heard.

DSC Relays of DSC Distress alerts received from other ships should be done?

(A). Only when the original DSC call is not acknowledged and no follow-on Distress traffic has been heard.

§ 80.1117 Procedure for receipt and acknowledgement of distress alerts.

47 CFR 80.1117(a) Normally, distress calls received using digital selective calling are only acknowledged using a DSC acknowledgement by a coast station.

Ships should delay any acknowledgement in order to give sufficient time for a coast station to acknowledge the call.

In cases where no acknowledgement has been heard and no distress traffic has been heard, the ship should transmit a distress alert relay to the coast station.

Upon advice from the Rescue Coordination Center, the ship may transmit a DSC acknowledgement call to stop it from being repeated.

For more details, please see Code of Federal Regulations § 80.1117 Procedure for receipt and acknowledgement of distress alerts.

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