On June 10, 1995, the passenger ship Royal Majesty grounded on a shoal about 10 miles east of Nantucket Island, Massachusetts, whilst on passage from Bermuda to Boston.
The report from the National Transportation Safety Board (NTSB/MAR-97/01
http://www.ntsb.gov/ publictn/1997/mar9701.pdf) focuses on determining how this vessel could travel, unknown to the crew, more than 17 miles off course.
The immediate cause of the grounding was clear - the failure of the officer of the watch to take corrective action, despite these warning signs - but it is the root causes, and the human element connotations, that are of interest.
The ship's Master and watchkeeping officers were competent and experienced in passenger ship operations, but they had not received any formal training in the operation of the Integrated Bridge System.
The ship had been in service for 3 years without incident.
Presailing checks had indicated that all navigation equipment was operating correctly; but the echo sounder alarm had been set at zero metres, to prevent it from activating continuously during the pilotage out of Bermuda - it remained at zero throughout the rest of the passage.
Shortly after the Royal Majesty left Bermuda, the GPS receiver antenna cable - which had been re-sited some months previously and was openly routed across the deck - had separated, which caused the receiver to default to the 'Dead Reckoning' mode.
For the next 34 hours no one detected the ship's errant navigation, despite a number of warning signs that the vessel was off course.
The Navigation and Command System (NACOS) autopilot was not configured to compare position data from other position receivers.
The officers of the watch failed to recognize the warning signs on the GPS unit, which indicated that GPS position data was not reliable; the GPS receiver's brief aural alarm, the remoteness...