Missing Typhoon Warnings in the Bay of Bengal
MV Coromandel Star is on passage from Chennai to Port Blair. At 0600 on 12 May she is about 300 nm east of Chennai. The bridge NAVTEX receiver is a JRC NCR-333 operating on 518 kHz in auto mode. The second officer reports that for the past 24 hours the printer has produced only navigational warnings from one station; a tropical cyclone warning for the Bay of Bengal issued at 0400 has not appeared. The receiver's station selection is set to a single station ID that does not cover the Bay of Bengal; message-type selection shows A, B and D enabled. The antenna is fed through a splitter shared with the MF/HF transceiver, and the receiver display shows 'receiving' but the print quality is faint. The vessel also has an Inmarsat C terminal with SafetyNET, but the operator has not checked it since departure. The master asks whether to alter course to the west and whether the NAVTEX is fit for purpose.
1. Diagnose the most likely reason the cyclone warning was missed and state the immediate bridge actions, including whether to alter course.
Read the worked answer
The receiver is printing, so the printer and power are not the primary problem. The key clue is station selection set to a single station ID. NAVTEX only prints messages from stations whose ID is selected. If that station does not cover the vessel's position east of Chennai, the Bay of Bengal cyclone warning will never be printed even though message types A, B and D are enabled. Faint print and a shared antenna splitter may reduce reception but would not selectively remove one station's messages. Immediate action: do not assume the absence of a warning means no danger. Check the NAVTEX station list for the area, select the correct stations, and obtain the cyclone warning via Inmarsat C SafetyNET or by requesting MSI from MRCC Chennai/Port Blair on VHF/MF. Alter course only after obtaining the actual warning and assessing its track, not merely because the printer is quiet. Inform the master and note the defect.
2. What NAVTEX configuration and antenna checks would you make, and how do 518 kHz, 490 kHz and 4209.5 kHz differ in use?
Read the worked answer
Check that selected station IDs cover the whole passage; that message types include A (navigational), B (meteorological), D (SAR) and any local types required; that 518 kHz international English is the normal bridge watch; that 490 kHz is national-language and may carry local warnings; and that 4209.5 kHz is used for NAVTEX in tropical/regional areas where 518 coverage is poor. Check the receiver is in auto mode for 518 and not accidentally on 490 only. Check antenna: coax, connectors, splitter loss, grounding, and whether MF/HF transmission is desensitising the receiver. Check printer paper, head and error log. Confirm time/date and that the receiver is not in test or program mode. If a station is received weakly, try a different antenna or a dedicated NAVTEX antenna; do not use the splitter if it causes loss. Record settings.
3. If the receiver cannot be restored, how would you maintain MSI watch for the next 24 hours and what would you record?
Read the worked answer
Maintain MSI watch by Inmarsat C SafetyNET: log in to the correct ocean region, set the coastal warning area for the Bay of Bengal/Andaman Sea, and monitor EGC. Also use VHF Ch 16 for coastal warnings, MF/HF RT for MSI broadcasts where available, and request scheduled MSI from MRCC Chennai/Port Blair. Keep a paper plot of the cyclone and use official warnings. Record in the radio log: time of failure, symptoms, station/message types checked, SafetyNET actions, MSI received, master informed, and repair request. If the vessel cannot receive MSI by any GMDSS means, that is a serious deficiency: the master should consider delaying the passage or remaining within VHF/coastal coverage until the receiver is repaired. Do not proceed on the assumption that no warning equals no hazard.