(WASHINGTON) — 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 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.”
CC Portland grounded outside the Corpus Christi Ship Channel on Aug. 7, 2022, while attempting to secure a towline on the bow of an inbound liquefied natural gas (LNG) carrier. No injuries were reported. The grounding resulted in $1.3 million in damage to CC Portland.
The NTSB determined the probable cause of the grounding was the mate’s attempt to make up bow-to-bow with the 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 containership was transiting north in the Houston Ship Channel. No injuries were reported. Damage 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 containership transited at an excessive speed.
Click here to read the complete report on the CC Portland incident.
– National Transportation Safety Board
