The National Transportation Safety Board today determined that the probable cause of an accident involving the cruise ship Crown Princess was the second officer's incorrect wheel commands, executed first to counter an unanticipated high rate of turn and then to counter the vessel's heeling.
Contributing to the cause of the accident were the captain's and staff captain's inappropriate inputs to the vessel's integrated navigation system while it was traveling at high speed in relatively shallow water, their failure to stabilize the vessel's heading fluctuations before leaving the bridge, and the inadequate training of crewmembers in the use of integrated navigation systems.
"We see from this accident the importance of having adequate training," said NTSB Mark V. Rosenker. "Had the crew been better trained in the equipment they were using, this accident may not have occurred, and implementing our recommendations is one way to help ensure this."
On July 18, 2006, the cruise ship Crown Princess, which had been in service about a month, departed Port Canaveral, Florida, for Brooklyn, New York, its last port on a 10-day round trip voyage to the Caribbean. About an hour after departing, the vessel's automatic navigation system caused the ship's heading to fluctuate around its intended course. Alarmed by a perceived high rate of turn, the second officer attempted to take corrective action that resulted in the ship heeling to a maximum angle of about 24 degrees to starboard. This caused people to be thrown about or struck by unsecured objects, resulting in 14 serious and 284 minor injuries to passengers and crewmembers. The vessel incurred no damage to its structure but sustained considerable damage to unsecured interior components, cabinets, and their contents.
The report adopted by the Board today states that the Crown Princess was operating at nearly full speed when the second officer took the controls. Because of instabilities in the automatic steering system, the officer faced the problem of navigating a vessel that exhibited both increasing course deviations and high rates of turn. The second officer took manual control of the steering and steered back and forth between port and starboard in increasingly wider turns. Rather than remedying the problem, the second officer's actions aggravated the situation, resulting in a very large angle of heel. The captain quickly returned to the bridge and brought the vessel under control by centering the rudder and reducing speed. The Safety Board concluded that the incident occurred because the second officer initially turned the wheel to port, when he should have turned it to starboard to counteract the turn.
The Safety Board also stated that the captain and staff captain made errors with regard to the ship's integrated navigation system. These errors included:
* Failure to recognize that the integrated navigation system could be unpredictable at high speed in shallow water.
* Failure to recognize that the rudder economy and rudder limit settings on the integrated navigation system were inappropriate for the vessel's speed and operating conditions.
The Board concluded that these errors stemmed from inadequate training and lack of familiarity with the integrated navigation system.
As a result of its investigation, the Safety Board made recommendations regarding integrated navigation system training to the U.S. Coast Guard, the Cruise Lines International Association, and to SAM Electronics and Sperry Marine, manufacturers of integrated navigation systems.
A synopsis of the Board's report, including the probable cause and recommendations, is available here, under "Board Meetings." The Board's full report will be available on the website in several weeks.