George M, seen right here in a post-collision {photograph}, incurred an estimated $750,000 in harm. [Photo: USCG]
Excessive velocity throughout a sophisticated harbor-assist maneuver led to a tugboat collision with a containership within the Houston Ship Channel final 12 months, the National Transportation Safety Board stated Wednesday.
The vessels in concerned have been the tugboat George M and the containership MSC Aquarius. The incident occurred on April 14, 2022, when the vessels collided whereas the tugboat was positioning for a ship-assist maneuver and the containership was transiting north within the Houston Ship Channel. No accidents have been reported. About 1,000 gallons of substances oil have been launched from the broken George M’s port propulsion unit. Damages to each vessels totaled greater than $900,000. Damage to the George M was estimated at $750,000; harm to the MSC Aquarius was $183,665.
The George M, owned by Bay-Houston Towing Co. and operated by G & H Towing Company, was inbuilt 2021 by Gulf Island Shipyards in Jennings, La., and was a “30-80” class ASD (azimuthing stern drive) tugboat with a size of 30 meters and bollard pull of 80 tonnes. It was powered by two 3,386-hp Caterpillar diesel engines, every driving a Schottel Z drive.
The MSC Aquarius, owned and operated by Genious Shipping S.A. and managed by Cyprus Sealines Co., was a 983.9-foot lCyprus-flagged containership, inbuilt 2003 by Japan Marine United Corp. in Kure, Japan.
According to the NTSB abstract of its full report, the George M and one other tugboat have been performing a harbor-assist operation to dock the MSC Aquarius on the terminal. The George M was assigned the “center lead forward” place on the bow of the containership. To make as much as the bow of the MSC Aquarius, the tugboat needed to maneuver into place forward of the containership, bow-to-bow. The mate on the George M was working the tugboat on the time of the collision. It was the mate’s first rotation on board the George M’s class of vessel.
In maneuvering the George M to the middle ahead place, the mate approached the containership because it was transiting at 9.7 knots. While trying to attach its line to the containership, the tugboat moved out of centerline. The mate tried to maneuver the tugboat again to the centerline, however was unable to regain place. The mate’s try resulted in two collisions between the vessels.
The NTSB says the mate may have requested the pilot of the MSC Aquarius to sluggish, however the mate didn’t talk with the pilot after being assigned to the middle lead ahead place. The pilot was unaware of the standing of the tugboat or the necessity to sluggish.
The NTSB decided the possible reason behind the collision was the George M mate’s try and make up bow-to-bow whereas the tugboat and containership transited at a velocity that was extreme for the superior harbor-assist maneuver. Contributing to the collision was the George M mate’s lack of expertise working 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 stated. “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.”
As all the time, there’s far more element within the full NTSB report — together with extra particulars on how the tugboat collided with the containership twice.
“After striking the bow of the MSC Aquarius, the George M continued over to the port side and ahead of the containership,” says the total report. “The mate started working the George M again towards the centerline of the MSC Aquarius, however on the identical time the tugboat’s velocity slowed, bringing the George M towards the bow of the MSC Aquarius once more. According to the mate, he elevated velocity on the engines to full energy and tried to angle the tug away from the ship, however the tug didn’t reply rapidly. Consequently, the George M collided with the MSC Aquarius once more. During the collision, the tugboat’s port Z-drive struck the ship’s bulbous bow, disabling the propulsion unit.
“With the port Z-drive disabled, the George M slid aft along the port side of the MSC Aquarius until it became lodged in the flare of the containership’s bow.”
