WPC GMDSS ROC (India) flashcards

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

GMDSS functional requirements

Distress alerting, SAR coordination, on-scene communications, locating signals, MSI reception, and general radiocommunications including bridge-to-bridge.

Sea Area A1

Area within VHF coast station coverage providing continuous DSC alerting, approximately 20–30 nautical miles from the coast.

Sea Area A3

Area within Inmarsat geostationary satellite coverage (approx. 70°N to 70°S), excluding A1 and A2.

Sea Area A4

Area outside A1, A2, and A3; polar regions where Inmarsat coverage is not available; requires HF DSC and radiotelephony.

MAYDAY distress call

Spoken distress signal indicating grave and imminent danger; transmitted three times followed by ship name, position, nature of distress, and assistance required.

PAN PAN urgency signal

Spoken urgency signal concerning safety of a ship or person but not immediate distress; transmitted three times with ship name and details.

SECURITE safety signal

Spoken safety signal indicating a message concerning navigation safety or meteorological warning; transmitted three times before the message.

DSC distress alert

Digital alert sent on VHF Ch 70, MF 2187.5 kHz, or HF DSC frequencies by pressing DISTRESS button and selecting nature of distress.

MMSI structure

Nine-digit Maritime Mobile Service Identity: ship = MID + 6 digits; coast station = 00 + MID + 4 digits; group = 0 + MID + 5 digits.

DSC watchkeeping

Continuous automated watch on VHF Ch 70, MF 2187.5 kHz, and HF DSC distress frequencies as required by sea area.

VHF Channel 16

156.800 MHz international distress, safety, and calling frequency; used for radiotelephony and initial contact.

VHF Channel 70

156.525 MHz dedicated exclusively to Digital Selective Calling (DSC); voice transmission is prohibited.

MF 2182 kHz

International MF radiotelephony distress and calling frequency; used for voice distress communications and silence periods.

HF distress frequencies

Radiotelephony: 4125, 6215, 8291, 12290, 16420 kHz; corresponding DSC: 4207.5, 6312, 8414.5, 12577, 16804.5 kHz.

Inmarsat-C

Store-and-forward satellite terminal providing distress alerting, two-way messaging, and SafetyNET MSI reception in Sea Area A3.

SafetyNET

Inmarsat Enhanced Group Call service broadcasting Maritime Safety Information (MSI) to ships in specific sea areas.

406 MHz EPIRB

Emergency Position-Indicating Radio Beacon transmitting distress alert to COSPAS-SARSAT satellites with homing signal on 121.5 MHz.

SART

Search and Rescue Transponder operating in 9 GHz radar band; responds to radar with series of dots for locating survival craft.

AIS-SART

AIS-based search and rescue transmitter sending position and safety messages on AIS frequencies, displayed on AIS and compatible radar.

NAVTEX 518 kHz

International frequency for NAVTEX broadcasts in English, providing navigational warnings and meteorological information.

NAVTEX message categories

A = navigational warnings, B = meteorological warnings, C = ice reports, D = SAR information, E = weather forecasts, F = pilot messages.

MSI

Maritime Safety Information: navigational warnings, meteorological warnings, SAR information, and other urgent safety messages.

GMDSS ROC certificate

Restricted Operator's Certificate valid for Sea Area A1 only; allows operation of GMDSS equipment in VHF coverage.

GMDSS GOC certificate

General Operator's Certificate valid for all sea areas; required for operation of GMDSS equipment beyond A1.

Ship radio licence

Document issued by national administration (India: WPC) authorizing operation of radio equipment on board; must be valid and on board.

Silence periods

Periods of 00–03 and 30–33 minutes past each hour on 2182 kHz when only distress transmissions are permitted.

GMDSS reserve battery

Battery supplying distress and safety equipment for 1 hour (with emergency generator) or 6 hours (without) when main power fails.

Emergency generator start

Must start automatically within 30 seconds of main power failure and supply power for at least 3 hours.

SWR check

Standing Wave Ratio measurement indicating antenna/feeder condition; high SWR indicates fault such as corroded connection or water ingress.

Radio log entries

Record of date/time, frequencies, stations contacted, distress/urgency/safety traffic, watch periods, equipment failures, and false alerts.

False alert cancellation

Immediately notify coast station via DSC or radiotelephony, cancel alert if possible, and record details in radio log.

Watchkeeping obligations

Continuous DSC watch on VHF Ch 70, MF 2187.5 kHz, HF DSC frequencies, and Inmarsat as applicable while at sea.