NTSB Releases First Report on Mexican Navy Training Ship Accident
The National Transportation Safety Board has released the preliminary results of its investigation into the allision of the Mexican Navy training vessel Cuauhtémoc with the Brooklyn Bridge last month. The report covers the known facts of the incident, and does not provide any conclusions about the probable cause - typically a later part of the investigation. It also does not provide any factual findings about the propulsion system, which is still being examined.
On the evening of May 17, a bar pilot and a docking pilot boarded the Cuauhtémoc at Manhattan's Pier 17, preparing to get under way for an outbound voyage. They both conducted a master-pilot exchange, and the master told them that propulsion, steering and ships' systems were all in good working order. Winds were westerly at about 10-15 knots, towards the bridge.
At about 2016 hours, Cuauhtémoc slipped her mooring lines and got under way from the pier. The docking pilot had the conn, as is standard in New York Harbor for the initial minutes of a departure. A twin-screw assist tug helped her off the pier as the docking pilot ordered astern thrust to back her out into the East River.
Unusually, the transfer of engine and rudder commands from the docking pilot passed through multiple people on the way to the person at the helm. The docking pilot would give a command to the captain on the conning deck, who would then translate it into Spanish and relay it to a second crewmember on the deck below. This crewmember would then relay the command to other crewmembers in the navigation bridge, and these individuals would execute the command.
From 2020-2022 hours, the Cuauhtémoc moved astern from the pier, as ordered. Once the ship was clear, the docking pilot ordered all stop, then dead slow ahead, and ordered the tug to reposition to the starboard bow, where it would be best positioned to help with a turn to port. The tug took its line in and disconnected to effect this maneuver.
As this was in process, the docking pilot gave additional engine commands in the ahead direction. Despite this, the stern of Cuauhtémoc began to swing towards the Brooklyn Bridge, and the vessel accelerated astern. From 2023-2024, the speed astern increased to about six knots, culminating in the allision of the Cuauhtémoc's upper masts with the underside of the Brooklyn Bridge. She then drifted stern-first into a seawall on the east side of the river.
No appreciable damage to the bridge's structure occurred, though a traveling platform system for maintenance beneath the bridge received minor damage from the impact. The ship's three masts were all seriously damaged, and there was scraped paint on the port quarter, where Cuauhtémoc made contact with the seawall. The rudder was also damaged: the rudder post was deformed, and the rudder itself was stuck at 90 degrees to the centerline, oriented towards the port side.
NTSB is still examining the propulsion system, operating control system, and crew experience and training, among other factors.