Bollard failure caused breakaway of cruise ship Carnival from its moorings resulting in collision

The National Transportation Safety Board (NTSB) has issued Marine Accident Brief regarding bollard failure which caused breakaway of cruise ship Carnival Triumph from its moorings, resulting in collision with dredge Wheeler and towing vessel Noon Wednesday. Oneshipyard employee died in the accident; another was injured. The total damage amount wasestimated to be more than $2.9 million.

Carnival-Triumph

About 2 months before the accident, on February 10, 2013, the Carnival Triumph hadexperienced a fire in the aft engine room, which resulted in a loss of power and propulsion. Theship was towed to the Alabama Cruise Terminal in the Port of Mobile on the Mobile River. Itarrived there on the evening of February 14, and the passengers disembarked. The followingmorning, towing vessels shifted the Carnival Triumph to the BAE Systems shipyard so that repairscould begin.

During the repair work, the Carnival Triumph was moored port side to at the shipyard'sPier K, using high strength co-polymer (HSCP), 8-strand, 68-mm-diameter mooring lines, whichwere individually rated at a breaking strength of 93 tons. Forward on the ship, 10 mooring lineswere used (6 head, 2 breast, and 2 spring lines), affixed to 4 bollards. Aft on the ship, another10 mooring lines were used (in this case, 4 head, 4 breast, and 2 spring lines), also affixed to4 bollards. Sometime later, three work barges were arranged end to end, tied off to the aftstarboard side of the Carnival Triumph and to an adjacent finger pier (Pier J) to facilitatematerials transfer between the vessel and shore.

On April 3, 2013, a passing storm front generated unexpected winds out ofthe southeast that increased in speed from 25 to 55 mph over a 10- to 15-minute period.Personnel on the bridge of the Carnival Triumph observed a peak wind speed of 65 mph. Aboutthat time, the wind force caused the stern of the ship to swing away from Pier K in anorthwesterly direction, and this movement strained the aft mooring lines. The three aft mooringbollards parted from their mounts on Pier K, one stern winch paid out off its line under strain,and another line parted, setting the stern of the ship adrift.

NTSB-Carnival-Triumph

The approximate location of the Carnival Triumph before the collision is marked "A" (the shipicon is red), and its approximate location at the time of the collision (west side of the MobileRiver) is marked "B." The dredge Wheeler is shown as a green icon and the towing vessel NoonWednesday as an orange icon. Vessel icons and positions are not to scale. (Background byMicrosoft Trips and Streets) / Image Credit: NTSB Marine Accident Brief DCA-13-LM-015


The breakaway and collision resulted in the following damage:

  • Carnival Triumph: Damage at various points along the entire length of the starboardhull, just above the waterline, extending up to deck #5 aft, known as the Promenadedeck, and deck #4 forward, known as the Atlantic deck. Damage included punctureand inset of the hull plating, and distortion of vertical and horizontal framing. Theestimated damage amount was $2.7 million.
  • Wheeler: Damage to the forward portion of the starboard hull, including parts of thesuperstructure, which included inset of the plating and distortion of the framing.Some damage also occurred to dredging gear located on the main deck, starboard sideforward. The estimated damage amount was $200,000.
  • Noon Wednesday: Minor damage to the aft tank, starboard corner, which includedinset of the hull plating and some framing distortion. The estimated damage amountwas $3,000.
The National Transportation Safety Board determines that the probable cause of thebreakaway of the Carnival Triumph from its moorings and the subsequent collision with thedredge Wheeler and the towing vessel Noon Wednesday was the successive failure of multiplemooring bollards, which were known by BAE Systems to be in poor condition with anundetermined mooring load capability

For more details, please read NTSB Marine Accident Report