About 2230 on the evening before the accident, February 17, the Tristan Janice was shifted (moved) between berths near Golden Meadow, Louisiana. Four crewmembers were on board―a captain and a mate (both credentialed masters) and two deckhands. During the berth shifting, the captain had the conn, or navigational control, of the vessel.
According to crew statements, shortly after shifting berths, a brief watch turnover was held. During this turnover, the captain mentioned that the starboard engine throttle had a small air leak but that he did not think it was a serious problem. After the turnover, the mate took the conn, and at 2324, the Tristan Janice left Golden Meadow with company orders to proceed to Port Fourchon, Louisiana. On arriving at Port Fourchon, the vessel was to remain in the vicinity of the port overnight and then continue to sea at 0600 on February 18. However, the mate continued the transit and passed Port Fourchon, entering the open waters of the Gulf of Mexico at 0236 on February 18. The captain told investigators he did not know that the transit continued, as he was off duty and asleep at this time.
Although it could not be confirmed by data or crew statements, investigators believe that the steering on board the Tristan Janice was placed in autopilot mode about the time the vessel entered the open waters of the Gulf of Mexico.
The Tristan Janice was powered by twin diesel engines, each driving a propeller. Shortly after entering the Gulf of Mexico, the mate believed that the starboard engine was not maintaining full speed. He directed the on-duty deckhand to use a line to tie off the starboard engine throttle in the machinery space so that it would remain in the full-ahead speed position. This engine room alteration effectively removed control of the starboard engine throttle from the wheelhouse. Two crewmembers told the Coast Guard that the vessel owner, TRTB Inc., had tried to remedy the throttle problem a few days earlier but did not have the correct part. Investigators found no log book entry about the throttle problem, even though entries about faulty or unsafe equipment were required by TRTB’s safety management system.
According to automatic identification system (AIS) data, between 0242 and 0623, the Tristan Janice followed a southwest course of about 233 degrees. The vessel speed was full ahead, between 8.6 and 9.7 knots. The on-duty deckhand told investigators that, at 0615, the mate directed him to wake the other two crewmembers so that they could assume the watch. At 0623, according to AIS data, the vessel altered course to 260 degrees, or about west-southwest.
The captain told investigators he entered the wheelhouse at 0635 and found no one there. He said visibility was poor at the time―about 0.125 miles―due to heavy fog. He then spotted the mate, who was on the after deck, and walked aft to talk to him. The mate told the captain he was checking on an engine vibration he had detected; however, he did not inform the captain about the starboard engine throttle he had directed the deckhand to tie off in the engine room.
Shortly after the discussion about the engine vibration, the captain and the mate entered the wheelhouse, where, until 0700, they discussed log book entries, why the vessel did not stop at Port Fourchon as originally directed, and operating in fog. They did not discuss whether to post a lookout in the fog. The captain told investigators he then walked to the port side of the wheelhouse to smoke, and when he turned back to face the mate, the mate had exited the wheelhouse without a formal watch turnover. The captain then assumed control of the vessel and adjusted the radar and AIS.
According to AIS data, between 0653 and 0711, the vessel’s course was 280 degrees, or about west-northwest, and its speed was 9.5 knots. Visibility remained poor, but no lookout was posted. Sometime between 0700 and 0711, the mate returned to the wheelhouse where he and the captain discussed vessel traffic in the vicinity. No mention was made about oil or gas production platforms along the route. The captain told investigators he reduced the vessel speed; however, AIS data showed that the vessel maintained its speed.
The captain told investigators he then looked up from the radar and saw a gas platform about 200 yards ahead. He said he tried to slow the vessel but stated the speed “was entirely too fast for [the] clutch.” He said he tried to avoid the allision by turning the vessel while “throwing it into reverse,” but his turn was initially unsuccessful because the vessel was in autopilot and he had trouble disengaging it. Within 15–30 seconds, he managed to take the vessel out of autopilot. He placed it in manual steering and altered course, but his actions were too late to avoid the platform. About 0712, the Tristan Janice allided with the platform―Ship Shoal 119 W, which was unmanned at the time―at a speed of 9.3 knots, according to AIS data.
Shortly after the allision, with the starboard engine still engaged in the full-ahead position, the two deckhands entered the engine room and removed the line tied to the starboard engine throttle. About 0714, 2 minutes after the allision, the Tristan Janice’s course and speed were east-northeast at 74.9 degrees and 1.3 knots, according to AIS data. About 0730, without reporting the allision to the authorities, the crew navigated the vessel west-northwest toward Freshwater City, Louisiana, at 9 knots.