GMDSS and radio: oral questions and answers.

A good answer covers:

• An automatic broadcast of maritime safety information on 518 kHz in English, with 490 kHz and 4209.5 kHz for national and tropical services
• Each message carries B1, the station letter; B2, the subject; and B3 B4, the serial number
• Select the stations that cover the area, or use automatic selection by position, and change them as the passage goes on
• Subjects A (navigational warnings), B (meteorological warnings), D (search and rescue and piracy) and L cannot be rejected
• A message already received is not printed again, except serial 00, which always prints
• Range is about 200 to 400 miles, so it is a coastal service; beyond it, use the satellite EGC service

Show me on the bridgeOpen the NAVTEX and read the stations and subjects selected.

A good answer covers:

• Read it at once and work out where it applies against the planned track
• Plot it on the ECDIS as a note or mariner object, or on the paper chart
• Amend the passage plan if needed, and give the hazard the berth the warning asks for
• Tell the master if it affects the plan, and brief the next watch
• Keep it until it is cancelled or the passage is past it

A good answer covers:

• Weekly: a DSC test call with a coast station, when within range of one
• Monthly: the EPIRB self-test, its battery and hydrostatic release expiry dates; the SART and handheld VHF radios checked as the maker's instructions say
• Everything goes in the GMDSS radio log, with any faults and what was done about them
• Never send a real distress alert as a test; use the test functions only

A good answer covers:

• With too high an error rate the receiver does not store it as received
• So when the station broadcasts it again, it prints again
• Do not guess the missing parts of a warning; wait for the repeat or get it from another source, such as EGC
• Poor reception may mean the station is too far away, or interference, or a problem with the antenna

A good answer covers:

• MAYDAY three times, THIS IS, the name three times, the call sign and the MMSI
• MAYDAY, the name, call sign and MMSI once more
• The position, as latitude and longitude or a bearing and distance from a known point
• The nature of the distress: fire
• The assistance wanted
• The number of persons on board, and anything else that helps the rescue
• OVER

Show me on the bridgeThe GMDSS station: the VHF DSC, the handset and the radio log.

A good answer covers:

• Channel 70 on VHF
• Own MMSI, the position and the time of that position
• The nature of distress, if designated; undesignated if there is no time
• The channel for the follow-on voice traffic, channel 16 on VHF
• It repeats automatically every few minutes until it is acknowledged or reset

A good answer covers:

• The rescuers go to the position the alert carries
• Check it and its time before sending; an old position can be miles out
• If the GNSS is lost, enter the position and its time by hand, at least every four hours; most sets warn when it is getting old
• The radio log should note the position used

A good answer covers:

• Read the acknowledgement; the automatic repeats stop
• Carry on the distress traffic by voice on channel 16 with the coast station
• Do not send a DSC acknowledgement or relay of your own alert
• Write the alert, the acknowledgement and the traffic in the radio log

A good answer covers:

• Reset the equipment at once, so it does not repeat
• Cancel by voice on channel 16 to all stations
• ALL STATIONS three times, THIS IS the name three times, call sign and MMSI
• The position, then: please cancel my distress alert of, the date and time in UTC
• Close the distress cover, and write the false alert and its cancellation in the radio log
• Tell the master, and listen for any station that answers

Show me on the bridgeThe VHF DSC at the GMDSS station. Find the reset and the cover.

A good answer covers:

• It ties up the rescue services and ships that may be needed for a real distress
• It can bring a search to a place where nobody is in danger
• Know the equipment, keep the distress cover closed, and test only by the proper test call
• Train the crew, and label the distress controls clearly

A good answer covers:

• Failing to cancel, or hiding it, is the real fault
• The record in the radio log shows what happened and what was done

A good answer covers:

• Read the alert: who she is, where she is and what has happened; call the master
• Listen on channel 16 for the coast station and for her voice MAYDAY
• Do not acknowledge by DSC: the coast station or rescue centre should do that
• If the coast station has not answered after a short while, about five minutes, acknowledge her by voice on 16
• Tell the coast station or rescue centre by any means, for example a DSC relay addressed to it
• Go to her assistance unless the master decides otherwise, and log everything

Show me on the bridgeA distress alert will arrive in the DSC calls list a minute in.

A good answer covers:

• A DSC acknowledgement stops her set repeating the alert
• If the coast station missed the first alert, it then never hears the repeats
• An all-ships relay spreads the alert and can start a chain of relays that confuses the picture
• Relay to the coast station or rescue centre by name instead, when it is needed

A good answer covers:

• MAYDAY
• The name of the vessel in distress three times (or her MMSI or call sign)
• THIS IS, our own name three times (or MMSI or call sign)
• RECEIVED MAYDAY

A good answer covers:

• A radar SART shows on the X-band radar as a line of dots out from its position along its bearing
• Head for the dot nearest you; as you close the dots become arcs, then circles
• An AIS-SART shows as a SART target on the AIS, the ECDIS and the radar overlay, with its position
• Post lookouts, slow down as you close, and approach to make a lee for the raft