If a VHF-DSC Distress alert is transmitted what channel is used for follow-on voice transmission?

(D). Ch-16

From US Coast Guard, article on DSC Distress, Actions on Receipt of a Distress Alert

Ships receiving a DSC distress alert from another ship shall:

• prepare for receiving the subsequent distress communication by tuning the radiotelephony receiver to the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF , channel 16 on VHF;
• acknowledge the receipt of the distress alert by transmitting the following by radiotelephony on the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF, channel 16 on VHF.

From RECOMMENDATION ITU-R M.541-9* Operational procedures for the use of digital selective-calling equipment in the maritime mobile service

1.2 Acknowledgement of a DSC distress alert

...prepare to handle the subsequent distress traffic by setting watch on radiotelephony and, if the “mode of subsequent communication” signal in the received distress alert indicates teleprinter,...frequencies should be those associated with the frequency on which the distress alert was received (on MF 2182 kHz for radiotelephony and 2174.5 kHz for NBDP, on VHF 156.8 MHz/channel 16 for radiotelephony

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If a MF-DSC Distress alert is transmitted what frequency is used for follow-on voice transmission?

(A). 2182.0 kHz

From US Coast Guard, article on DSC Distress, Actions on Receipt of a Distress Alert

Ships receiving a DSC distress alert from another ship shall:

• prepare for receiving the subsequent distress communication by tuning the radiotelephony receiver to the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF , channel 16 on VHF;
• acknowledge the receipt of the distress alert by transmitting the following by radiotelephony on the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF, channel 16 on VHF.

From RECOMMENDATION ITU-R M.541-9* Operational procedures for the use of digital selective-calling equipment in the maritime mobile service

1.2 Acknowledgement of a DSC distress alert

...prepare to handle the subsequent distress traffic by setting watch on radiotelephony and, if the “mode of subsequent communication” signal in the received distress alert indicates teleprinter,...frequencies should be those associated with the frequency on which the distress alert was received (on MF 2182 kHz for radiotelephony and 2174.5 kHz for NBDP, on VHF 156.8 MHz/channel 16 for radiotelephony

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If a HF-DSC Distress alert is transmitted what frequency is used for follow-on voice transmission?

(B). 8291.0 kHz

For frequency allocations, please see Blue Seas site article "MF/HF-SSB Radio - Distress, Urgency, Safety, & Hailing Frequencies," section "Distress, Safety and Hailing Frequencies," table.

Ship Transmit - 8291.0 kHz
Ship Receive - 8291.0 kHz
Simplex/Duplex - Simplex
USB/LSB - USB - upper side band (above frequency carrier)

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What is the proper format for a Distress follow on voice transmission? (3x is three times),

(C). Mayday 3x, this is Ship's Name/Call Sign 3x, Ship's position, nature of distress and assistance requested.

Watch out for (B), where Ship's Name/Call Sign is stated only ONCE. All ships and all stations in the other wrong answers sound like from an old cop-chase movie.

Repeating three times helps the receiver understand the message correctly. The is a long-held tradition from early radio days when reception came with interfering noise, and at times to alert radio operators to the distress call.

For more discussion on the "rule of 3" please see Why Repeat 3 Times.

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What information should be included in a Distress follow on voice transmission AFTER a DSC Alert?

(C). Ship's Name and Call Sign, MMSI number & position, the nature of distress and assistance requested.

Vital info

• Ship's position
• Nature of distress
• Assistance required
• Ship's name
• Call sign
• MMSI number
• Physical description of the vessel
• Number of POB (passengers on board)

In wrong answers, there are distractors: Ship's IMN(??), and DSC frequency, which was already established at start of the initial distress call.

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What information is NOT VITAL in a Distress follow on voice transmission after a DSC Alert?

(D). Company emergency contact information.

Vital info

• Ship's position
• Nature of distress
• Assistance required
• Ship's name
• Call sign
• MMSI number
• Physical description of the vessel
• Number of POB (passengers on board)

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