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The George M after the collision

The George M (left) is pictured after the collision and the MSC Aquarius (right) is pictured in September 2022. (Source: U.S. Coast Guard (left) and Osvaldo Traversaro (right))

Excessive Speed Caused Tug and Containership Collision in Houston Ship Channel -NTSB

Mike Schuler
Total Views: 3934
July 26, 2023

The National Transportation Safety Board (NTSB) has found that excessive speed during a harbor-assist maneuver caused a tugboat to collide with a containership in the Houston Ship Channel last year.

The incident took place on April 14, 2022, involving the tugboat George M collided and the containership MSC Aquarius. The incident resulted in no injuries but damages totaled over $900,000 and 1,000 gallons of gear oil was released from the tugboat’s port propulsion unit.

At the time of the accident, the George M and another tugboat were performing a harbor-assist operation to dock the MSC Aquarius at a terminal. The George M was assigned the “center lead forward” position on the bow of the container ship. To make up to the bow of the MSC Aquarius, the tugboat had to maneuver into position ahead of the container ship, bow-to-bow. The investigation found that the mate was operating the tugboat during the collision and that it was their first rotation on that class of vessel.

In maneuvering the George M to the center forward position, the mate approached the container ship as it was transiting at 9.7 knots. While attempting to connect its line to the containership, the tug moved out of centerline. When the mate attempted to maneuver the tugboat back to the centerline, they was unable to regain position. The mate’s attempt resulted in two collisions between the vessels.

The NTSB said the mate could have requested the pilot of the MSC Aquarius to slow, but the mate did not communicate with the pilot after being assigned to the center lead forward position. The pilot was unaware of the status of the tugboat or the need to slow.

The NTSB determined the probable cause of the collision was the George M mate’s attempt to make up bow-to-bow while the tugboat and container ship transited at a speed that was excessive for the advanced harbor-assist maneuver. Contributing to the collision was the George M mate’s lack of experience operating the tugboat.

“The risk of a casualty during bow-to-bow harbor-assist operations with azimuthing stern drive (ASD) tugboats increases with increasing speed. Hydrodynamic forces around an assisted vessel’s bow increase exponentially with speed, while the amount of reserve propulsion power available to the tugboat operator decreases,” the report said. “Owners and operators of ASD tugboats that perform bow-to-bow harbor-assist operations should set speed limits for these maneuvers. These limits may vary for different classes of tugboats based on design. Tugboat operators should communicate these pre-determined speed limits to ship masters or pilots in command of the vessels that they are assisting before engaging in these maneuvers.”

Read the report: Marine Investigation Report 23-15

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