Ineffective Bridge Team Communication Led to Carnival Horizon Allision
The National Transportation Safety Board (NTSB) has released a Marine Accident Brief about the Carnival Horizon's August 28, 2018 allision as the vessel was being maneuvered to berth no. 2 at Manhattan Cruise Terminal’s Pier 88 in New York City. The cruise ship's bow struck the southwest corner of adjacent Pier 90.
The 1,062-foot (323.4 meter) vessel had 6,361 people on board at the time. No one was injured and no pollution occurred, but Pier 90’s walkway, roof parking garage, and facilities suffered extensive structural damage, and the ship sustained minor damage above the waterline, totaling about $2.5 million in cumulative damage.
The NTSB determined that the probable cause of the Carnival Horizon’s contact with Pier 90 was the ineffective interaction and communication between the master and the docking pilot who were maneuvering the vessel, and the bridge team’s ineffective oversight of the docking maneuver.
Contributing was the placement of the third officer in a location without view of the bow to monitor the close approach to Pier 90.
Carnival’s navigation policy requires closed-loop communication and a process called “thinking aloud,” meaning “sharing verbally a mental model of the current situation and future situations,” which allows for greater situational awareness of the bridge team, while closed-loop communications ensure that when an order or request is made, the person executing it understands and acknowledges that order. By repeating it back (acknowledging the order), the likelihood of miscommunications and misunderstandings is significantly reduced.
There was little audible evidence that the thinking-aloud concept was in practice during this accident sequence. While the pilot was issuing bow thruster and tug orders, the master used the stern azipods with the intention to bring the ship closer to Pier 90, but did not verbalize his actions to the pilot or bridge team.
The ship’s bridge team could have been more effectively engaged in the ship’s maneuvering to the dock, states the NTSB. The Metro docking pilot was conning the vessel, and the master was focusing on the starboard side, concerned about the ship being set onto the corner of Pier 88 due to the ebb current. Although Carnival’s navigation policy and task assignments require monitoring of the person conning the vessel, cross-checking of the ship’s position, and predicting track and headway, there was no evidence that any bridge team member probed or alerted the master and pilot of the headway of the vessel toward the corner of Pier 90.
For example, the staff captain was responsible for overseeing the entire bridge operation and monitoring the master and the pilot, yet he never voiced concern about the vessel’s speed of approach toward Pier 90 before impact.
In addition, there is no evidence that the bridge team discussed any minimum safe distances during the prearrival briefing or during the master/pilot exchange with the docking pilot. Had there been established “minimum clearances to dangers” for the maneuver?required to be pre-discussed per company navigation policies?the bridge team members (including the officers monitoring distances from forward and aft) may have had better awareness of the threshold for when they should alert each other or stop the maneuver, re-assess, and try again.
Further, the third officer was designated to communicate distances and clearances from the port and starboard mooring platforms forward but was not positioned in a suitable location. From his standing position on either platform?15 feet below the tip of the bow, at an angle of about 45 degrees, and in darkness?his view of the contact point was completely obstructed by the ship’s hull. Therefore, he had to estimate the distance from the tip of the bow?a point he could not see?to Pier 90.
Furthermore, moving between two points meant that he was estimating the distances from two different vantage points and was also losing time as he moved between the port and starboard platforms. These factors limited the third officer’s ability to accurately determine distances and provide timely reports to the bridge.
Carnival has amended its procedures for this vessel to include positioning a crewmember to report distances from the tip of the bow while maneuvering into the Manhattan Cruise Terminal.
As the ship continued to maneuver to the berth and rotated clockwise around the end of Pier 88, the bridge team and pilot progressively lost awareness of the vessel’s headway toward the end of Pier 90. The pilot was focused on reducing the vessel’s rate of turn to starboard, while the ship was still moving forward toward Pier 90. The closing distance went undetected or unchallenged by the bridge team until the ship was so close to the pier that no maneuver could have prevented the impact.
The report is available here.