NTSB: Excessive Speed and Handling Issues Led to MSC Boxship-Tug Collision
Excessive speed during a containership maneuvering in the Houston Ship Channel as it proceeded toward its dock along with hydrodynamic forces and handling of the tugboat led to a collision that resulted in nearly $1 million of damages. A newly released report from the National Transportation Safety Board highlights these issues during the preparation to dock the MSC Aquarius (6,500 TEU) in Houston on April 14, 2022, using the information to highlight the importance of communication and following guidelines for speed during maneuvering.
The 983-foot containership registered in Cyprus arrived in Galveston Bay and shortly after midnight on April 14 boarded a pilot from the Houston Pilots to proceed to the Barbour’s Cut Container Terminal at the north end of Upper Galveston Bay. The containership was traveling at a speed of 11 to 12 knots as it was inbound.
Two tugboats were assigned to assist the containership in docking. The maneuver called for the vessel to be turned in the main channel before backing into Barbour’s Cut. The pilot determined that two tugs would be sufficient for the operation with one at a forward position and the other aft.
The George M, owned by Bay-Houston Towing Co. and operated by G & H Towing Company, was assigned the forward position for the maneuver. The tug, built in 2021, was reported to have a top speed of 13 knots and 11 to 12 knots astern. At the time of this maneuver, the George M was under the command of its mate, an individual with 15 years of experience but working his first rotation on the vessel. He had been aboard for 24 hours and on the prior day the vessel assisted three vessels’ movements before being assigned to the MSC Aquarius. The captain of the tug was not on watch and was asleep when the assignment came for the containership.
The George M and the other tug met the MSC Aquarius at 0330 south of Morgan’s Point and were traveling at just under 10 knots as they made their way to the vessel’s berth. Assigned the forward position in the docking maneuver, the George M was required to come into a position bow-to-bow with the cargo ship to secure the hawser.
During this operation, the NTSB reports the tug began to move off centerline from the containership’s bow. The mate at the controls of the tug increased engine speed but found the tug was “a little slower” to get propulsion engine power than what he expected so he added more engine power attempting to regain position. When the power kicked in the tug veered across the bow of the containership and its starboard bow struck the starboard bow of the containership. The mate attempted to work the tug back toward the centerline and reported that the tug’s speed slowed despite being put to full power.
The George M collided a second time with the containership damaging the tug’s port propulsion unit. It then slid alongside the port side of the MSC Aquarius becoming lodged in the flair of the containership’s bow. The master of the George M had come to the bridge and was able to dislodge the tug. The tug sustained a collapsed mast, damaged railings, and an indention of the deck above the wheelhouse. There was a small breach in the area of the bulbous bow of the containership. Repairs to the tug cost approximately $750,000 while the containership sustained more than $180,000 in damages.
George M after the collision (USCG photo)
The NTSB in its analysis of the collision finds that there was a blind sector from the bridge of the containership preventing the pilot and bridge crew from seeing what was going on with the tug. The pilot said their first indication of a problem was when they got a frantic radio call from the containership’s bow crew. The pilot then began to slow the containership and when they did not get a response from the George M ultimately slowed and ordered the stern tug to pull.
The NTSB concludes the collision was due to speed and operating beyond the safety parameters and reserve power recommendations. The speed of the containership was 2.7 knots above the towing-company-directed limit and 3.7 to 6 knots above the limit preferred by pilots, tugboat captains, and ship masters surveyed by an international tug masters association. The mate commanding the tug did not communicate with the pilot on the containership and did not request that they slow the vessel before beginning the maneuver.
Hydrodynamic forces created during the maneuver also impacted the ability of the tug to maneuver. The NTSB highlights that even a few knots of speed would have a significant effect on the forces acting on the tugboat in the center lead position.
After the incident, the tug company developed new performance assessment records and recommendations. The NTSB also recommended that tugboat operators in general should determine and communicate pre-determined speed limits to ship masters or pilots commanding vessels they are assisting before engaging in maneuvers.