Excessive Speed Led to Tugboat Grounding -NTSB
Excessive speed during a bow-to-bow harbor-assist maneuver led to the grounding of the tugboat CC Portland in the Corpus Christi Ship Channel last year, the National Transportation Safety Board (NTSB) said Thursday.
It is the second marine casualty the NTSB investigated in 2022 caused by excessive speed in azimuthing stern drive, or ASD, tugboats while in the center lead forward position. The NTSB said it continues to encourage owners and operators of ASD tugboats that perform bow-to-bow harbor-assist operations to set speed limits.
“The risk of a casualty during these operations with ASD tugboats increases with increasing speed,” NTSB investigators said in the final report. “Higher speed reduces the amount of reserve propulsion power available to the operator. If the tugboat moves out of position, the operator has less power to regain position as compared to the same maneuver at a lower ship transit speed.”
The CC Portland grounded outside the Corpus Christi Ship Channel on August 7, 2022, while attempting to secure a tow line on the bow of an inbound liquefied natural gas (LNG) carrier. No injuries were reported. The grounding resulted in $1.3 million in damages to the CC Portland. The NTSB determined the probable cause of the grounding was the mate’s attempt to make up bow-to-bow with an LNG carrier while the tugboat and LNG carrier transited at a speed that was excessive for the advanced harbor-assist maneuver. Contributing to the grounding was the lack of a company policy regarding maximum allowable speed for bow-assist maneuvers.
On April 14, 2022, the tugboat George M and containership MSC Aquarius collided while the tugboat was positioning for a ship-assist maneuver and the container ship was transiting north in the Houston Ship Channel. No injuries were reported. Damages to both vessels totaled more than $900,000. 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 an excessive speed.
