NTSB published its report on the 2020 incident where the offshore supply vessel Cheramie Bo Truc collided with the US Coast Guard cutter Harry Claiborne, which was servicing a buoy near Texas Point, Texas.
The incident
On the morning of October 11, at 0848, the Harry Claiborne left Galveston to service buoys in Sabine Pass and Calcasieu Pass that were potentially impacted by Hurricane Delta.
The bridge team consisted of a conning officer, an officer of the deck, the commanding officer, and a roving quartermaster of the watch. According to the officer of the deck, the crew used an electronic chart display and information system (ECDIS), automatic radar plotting aid (ARPA), and AIS for navigation and collision avoidance. All equipment was functioning properly.
Meanwhile, the Cheramie Bo-Truc No. 33 was moored at the Genesis Energy dock on the west side of Sabine Pass. On board the vessel were a captain, a mate, a chief engineer, an able seaman, and an ordinary seaman. At 1526, the Cheramie Bo-Truc No. 33 checked in with VTS for departure from the Genesis Energy dock with an 11-foot draft. VTS replied:
Roger, outbound 11-foot draft shows Genesis inbound [at] Texas Point. You got the tug Rachel, barge on the hawser, coming in the jetties. And be advised you got the Coast Guard cutter down there working buoys, minimum wake
The buoy on which the cutter crew was working was positioned on a bend of Sabine Pass marking charted shallow water. At 1538, the Cheramie Bo-Truc No. 33 met and passed the crew boat Genesis, port to port, in the channel just south of red buoy no. 32.
Around this time, the Harry Claiborne crew had secured on deck the 8-by-26-foot buoy no. 27, which had been tending south in the ebb current, and disconnected it from the mooring chain.
The crew was heaving in the chain while using the DP system to make 3-yard incremental moves aft to position-check the 12,000-pound sinker. The conning officer was maintaining the vessel’s position using the DP console, while the officer of the deck was watching the chain from the bridge wing.
The Cheramie Bo-Truc No. 33 captain told investigators that he believed the offshore supply vessel’s approach to the cutter was an overtaking situation. At 1540, just before passing green buoy no. 29, the captain called the Harry Claiborne via VHF radio to request a ”one-whistle” passing arrangement, indicating the offshore supply vessel would overtake the cutter on the cutter’s own starboard side. The Harry Claiborne, displaying dayshapes for a “vessel restricted in her ability to maneuver,” was working near the edge of the navigable channel in 30–40 feet of water, the conning officer estimated, and the buoy had 135 feet of chain.
At 1542, after passing green buoy no. 29, the Cheramie Bo-Truc No. 33 made a slight course change to starboard. Up to that point, the offshore supply vessel had been traveling about 13.1 knots. The captain reported that as the vessel approached the Harry Claiborne, the reading on the Cheramie Bo-Truc No. 33’s depth sounder quickly dropped, prompting the captain to abort his attempt to pass starboard of the cutter to avoid running aground.
Realizing the imminent danger of collision, the captain then reversed the vessel’s engines and used the bow thruster and rudder to turn to port to try to avoid hitting the cutter.
A safety officer on the deck of the Harry Claiborne radioed the bridge about the impending collision. The conning officer stated that while looking aft, she saw the offshore supply vessel’s starboard bow.
The officer of the deck stated he could see someone in the wheelhouse of the Cheramie Bo-Truc No. 33 turning the wheel to port. The commanding officer made a shipwide announcement to prepare the crew for collision while the conning officer sounded five short blasts on the ship’s whistle.
At 1544, while traveling at 6 knots, the Cheramie Bo-Truc No. 33 collided with the Harry Claiborne, its bow striking the cutter’s transom on the port side. The impact slightly displaced the cutter, which was within 10 yards of buoy no. 27’s assigned position on the edge of the dredged channel. Two crewmembers aboard the Harry Claiborne sustained minor injuries.
To avoid being swept out into the channel if they lost propulsion, the cutter crew secured the buoy chain with a hook and dropped the ship’s anchor. With the cutter’s DP system active, the thrusters moved the vessel back to its programmed position and heading.
Probable cause
NTSB determined that the probable cause of the initial collision between the offshore supply vessel Cheramie Bo Truc No. 33 and the US Coast Guard cutter Harry Claiborne was the offshore supply vessel captain’s assumption of the stationary cutter’s position, which led to his decision to pass the vessel outside the channel, resulting in a late maneuver toward the Harry Claiborne to avoid running aground.
Contributing to the collision was the cutter crew not questioning the passing arrangement proposed by the offshore supply vessel captain. Causing a second collision was the lack of coordination and communication between the two vessel operators when the offshore supply vessel crew refloated their vessel.
EXPLORE MORE AT NTSB’S ACCIDENT REPORT
