Instead of holding up, towboat was moving ahead before collision, NTSB saysAug 22, 2012 01:51 PM
A collision between an empty oil tanker and a barge at a Texas channel intersection happened because the towing vessel moved too close to the ship after a passing agreement, the National Transportation Safety Board (NTSB) said.
The impact in the Aug. 17, 2011, accident in the Bolivar Roads area carved a hole in a ballast tank of the 900-foot Naticina, which was in the Texas City Channel. The towboat Alliance, with two barges containing xylene, approached from the Gulf Intracoastal Waterway.
A Galveston-Texas City pilot had discussed a passing arrangement with the towboat master, who agreed to “hold up” outside the edge of the channel to the tanker’s starboard side, the NTSB said in a recent report. The towboat captain thought he was backing down, but the personnel aboard the ship noticed that the tow was still moving forward.
Officers on both vessels recognized the risk of collision and tried to take evasive action, but barge MMI 3024 cut a 16-foot-long hole in Naticina.
“The probable cause of the collision was the encroachment by the master of the Alliance and its two barges into the Texas City Channel and into the path of the Naticina despite the crossing agreement,” the NTSB report said.
The accident happened at 0805. Visibility was 10 miles, and there was a southwesterly wind at 4 knots, the report said. Wave height was less than one foot.
Alliance’s captain promised to wait near the Pelican Cut area and allow the tank ship to pass in front of him. According to Automatic Identification System (AIS) data, Naticina “had increasingly favored the starboard side of the channel” in the lead-up to the passing, the NTSB said.
The towboat captain did not expect the vessels to get so close, and he said a suction effect pulled the tow closer to green buoys marking the east side of the Texas City Channel.
The pilot aboard the tanker “stated that he attempted to use bank effect to prevent the collision,” the report said. “He indicated he gave a series of helm commands intended to position the port bow close to the eastern bank of the channel and then use bow deflection to swing the vessel’s stern away from the lead barge of the Alliance.”
Naticina “pushed a bunch of water out,” the towboat master said. “So he kind of sent me to the side a little bit towards the green. As he was coming up on me, the barges straightened up. Then that’s when I started kind of diving toward him. He had me in his suction.”
The towboat master ordered his 2,000-hp vessel full-astern, but the action didn’t prevent the 297-foot barge’s bow from striking the starboard side of the tanker. “The AIS data support the position that bow of MMI 3024 was very near the western boundary of the Texas City Channel at the time of the accident and probably was encroaching into the channel,” the NTSB said.
Alliance had been headed northeast from Corpus Christi, toward the BP refinery in Texas City. The Marshall Islands-flagged Naticina was transiting outbound, in a southeast direction after discharging cargo at the Seaway Crude Pipeline Co. terminal.
Naticina is owned by Front Loki Inc. and operated by STASCO Ship Management. The collision caused $124,000 in damage to the tanker, the report said.
Alliance and the two barges were operated by Houston-based Higman Barge Lines Inc. The company’s vice president, Kyle Shaw, said it agrees with the NTSB’s findings, noting that the pilot aboard Naticina had altered course a bit to starboard, closer to the tow. He said the company studied the incident and has since instructed its crews on the hazards of merging into channels at the busy Houston-region bottleneck.
The Coast Guard is still investigating the accident and is considering remedial actions, including changes to waterway management. The operators of both vessels have shared causal findings with their crews, the NTSB said.
Shaw said his captain failed to recognize that his tow was moving forward because there were no obvious visual cues in the water.
“We have tried our best to be as honest as we can be with ourselves about how this could happen,” Shaw told Professional Mariner. “We reviewed this a number of times on PortVision and brought it over to the Seamen’s Church Institute simulator and recreated the whole incident and have used it for training everybody. They were not aware that they could get sucked into the ship so strongly.”
The simulation “is available to anyone who wants to use it,” he said.