WPC GMDSS GOC Exam (India) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Sea area A3

An area within the coverage of an Inmarsat geostationary satellite, roughly between 70 degrees north and 70 degrees south, in which GMDSS equipment must include an Inmarsat terminal for distress alerting.

MMSI structure

A nine-digit Maritime Mobile Service Identity. The first three digits are the Maritime Identification Digits identifying the flag state; the remaining digits identify the ship station.

GMDSS functional requirements

Distress alerting, distress and safety communications, SAR coordinating communications, on-scene communications, locating signals, MSI reception and bridge-to-bridge communications. These functions define the equipment a ship must carry.

MAYDAY message content

Contains the distress signal, ship name and call sign, position, nature of distress, assistance required, number of persons on board and any other relevant information, ending with OVER.

PAN PAN meaning

The urgency signal used when a vessel or person is in grave and imminent danger but does not require immediate assistance. It is sent three times before the urgency message.

VHF Channel 16

The international radiotelephony distress, safety and calling channel. It is used for initial calls and distress traffic; Channel 70 is reserved for DSC and voice is prohibited there.

MF silence periods

On 2182 kHz, silence is kept for three minutes after the hour and after the half hour, i.e. from hh:00 to hh:03 and hh:30 to hh:33, to allow weak distress signals to be heard.

MAYDAY RELAY

The prefix used when a station not itself in distress retransmits a distress message, permitted when the station in distress cannot transmit or when assistance is required.

DSC distress alert

A digital alert sent on VHF Channel 70 or an MF/HF DSC distress frequency, carrying the ship's MMSI, position, time and nature of distress at DISTRESS priority.

DSC priority levels

Distress, urgency, safety, routine and ship business. The priority is encoded in the DSC message and determines how receiving stations handle and acknowledge the call.

DSC distress waiting time

After transmitting a DSC distress alert, the operator normally waits about five minutes for an acknowledgement before repeating the alert on another frequency or by another means.

DSC test call

A routine call addressed to a coast station on a non-distress frequency to verify that the DSC equipment and link are working. It must never be sent on a distress frequency.

Inmarsat-C distress alerting

A store-and-forward satellite terminal that sends a distress alert to a Rescue Coordination Centre through a Land Earth Station when the distress button is pressed or distress priority is selected.

SafetyNET

Inmarsat's enhanced group call service used to broadcast Maritime Safety Information, including navigational warnings, meteorological warnings, SAR information and piracy warnings, to ships at sea.

Inmarsat ocean regions

Four coverage areas: Atlantic Ocean Region East, Atlantic Ocean Region West, Indian Ocean Region and Pacific Ocean Region. The terminal must be logged into the correct region.

406 MHz EPIRB

A beacon that transmits a digital distress alert to the COSPAS-SARSAT satellite system, carrying its identity and, if GPS-equipped, its position, plus a 121.5 MHz homing signal.

EPIRB hydrostatic release

A unit that releases the beacon automatically when the vessel sinks, allowing it to float free and activate. It must be replaced by its expiry date and recorded.

SART radar signature

A radar transponder operating in the 9 GHz band that, when interrogated, produces a line of twelve dots on the radar display, allowing identification of the survival craft.

AIS-SART

A search and rescue transmitter that sends AIS position reports on AIS frequencies, displayed on AIS-equipped vessels and chart plotters as an alternative to the radar SART.

NAVTEX frequencies

518 kHz is the international English channel, 490 kHz is used nationally and 4209.5 kHz is the HF channel. The receiver must be kept on watch on 518 kHz.

NAVTEX message format

Begins with ZCZC, followed by the station identifier, message type, two-digit message number and text, and ends with NNNN. The type letter indicates the subject of the message.

NAVTEX message types

Letters classify content: A navigational warnings, B meteorological warnings, C ice reports, D SAR information, E forecasts, F pilot messages, G AIS messages and H GNSS messages.

MSI sources at sea

Coastal waters use NAVTEX; ocean passages use Inmarsat SafetyNET or HF narrow-band direct printing. MSI includes navigational and meteorological warnings, forecasts and SAR information.

Ship station licence

Issued by the flag state administration, it must be carried on board and made available for inspection. It authorises the radio equipment and its operating conditions.

GOC certificate

The General Operator's Certificate qualifies the holder to operate GMDSS distress and safety equipment. It must be valid and carried on board the ship.

Distress and safety frequencies

Key frequencies include 2182 kHz and 2187.5 kHz for MF, 8414.5 kHz for HF DSC, 4125 and 6215 kHz for HF radiotelephony, 518 kHz for NAVTEX, and VHF Channels 16 and 70.

Distress definition

A situation in which a vessel or person is in grave and imminent danger and requires immediate assistance. It is signalled with MAYDAY at distress priority on all GMDSS systems.

Distress cancellation

When a distress situation is resolved, a cancellation message is transmitted on the associated channel and the Rescue Coordination Centre is informed so that SAR action can be stood down.

False distress alert

An alert transmitted accidentally must be cancelled immediately by the appropriate DSC or voice means and the Rescue Coordination Centre informed to prevent unnecessary search and rescue action.

Weekly GMDSS tests

Test the DSC equipment with a test call or self-test, test the EPIRB and SART with their built-in test functions, and check the reserve battery voltage, recording the results.

Reserve battery requirement

The dedicated emergency battery must supply the GMDSS equipment for the period specified by SOLAS, typically one hour for VHF and MF and six hours for MF/HF installations.

Watchkeeping handover

The relieving operator must be briefed on equipment status, any faults and ongoing distress or safety traffic, and the handover must be recorded in the radio log.