Communications and Electronic Aids
Core concepts
Know the VHF marine radio: channel usage (Ch 16 distress and calling, Ch 13 bridge-to-bridge, Ch 6 intership, Ch 9 marina, Ch 70 DSC), the correct phonetic alphabet, and the standard MAYDAY/PAN PAN call format. Understand DSC operation, MMSI numbers, and the use of an EPIRB and SART. Learn the basics of GPS, chartplotters, radar (range, bearing, ARPA), AIS (what it transmits and its limitations), echo sounders, and the magnetic compass. Know the limitations of electronic aids: GPS can fail, AIS does not show all vessels, and radar does not see everything.
Traps
A common error is using Ch 16 for routine chatter - keep it clear. Watch for the difference between an MMSI (vessel) and an EPIRB (distress beacon). Questions often test the phonetic alphabet and the correct MAYDAY structure. Remember that AIS is not a substitute for a visual lookout, and radar has blind sectors.
Worked example
MAYDAY call: 'MAYDAY MAYDAY MAYDAY. This is [vessel name] [vessel name] [vessel name], MMSI [number], position [lat/long], nature of distress, assistance required, number of persons on board, any other information. Over.'
Rule of thumb
Ch 16 for distress, safety, and calling; move to a working channel for the conversation. Keep a listening watch on Ch 16 when underway.