Report: Inattentive Anchor Watch Led to $17M in Damage
An inattentive anchor watch in high current conditions led to two collisions and $17 million in damage, according to a new report by the NTSB.
On May 8, 2020, a pilot aboard the bulker Nomadic Milde anchored the vessel near Kenner Bend in the Lower Mississippi River, just upriver from New Orleans. Water conditions were high, with currents at the site of about 4-5 knots. The position of the anchorage was just 500 feet upriver from another bulker, the Atlantic Venus.
After setting the starboard and port anchors, the pilot departed the ship, and the crew took over the anchor watch. However, according to the NTSB's analysis of the vessel's trackline and heading, the starboard anchor likely started dragging before the pilot stepped off onto the pilot launch. It then dragged for a second time downriver, closer to the Atlantic Venus, closing about half the original distance between the two vessels. The engine was shut down and put on 10-minute standby status for a restart if needed.
NTSB found that there was no evidence that either watch officer aboard the Nomadic Milde checked the ship's position at frequent intervals, or that they used any means other than the ECDIS to monitor for movement. In addition, the radius of the ECDIS anchor watch alarm was set for 590 feet - far more than the distance to the Atlantic Venus' bow. Though a review of the ECDIS display (and other position-indicating means) would have suggested that the vessel was moving, the bridge team did not detect the movement for about 40 minutes after it began, and they were only alerted to the danger by a radio call from Atlantic Venus. It would be another 30 minutes before they called to restart the engine, and (after a VTS watchstander instructed them to wait for a pilot before maneuvering) another eight minutes before they began using their bow thruster, main engine and rudder. Shortly after, the Milde collided with the bulbous bow of the Atlantic Venus.
The Milde was caught on the Venus' bow, and tugs were called to pull her clear. Two pilots arrived to direct the maneuvers. However, when the Milde finally came free, she swiftly drifted towards the southern bank. Though the engine was running full astern, she allided with the upriver end of a specialty-chemical loading dock belonging to Cornerstone Chemical, making contact at six knots. The impact destroyed one cell of the dock, irreparably damaging about $11 million worth of equipment. The vessel herself sustained a long gash in her hull and severe damage to her propeller, with an estimated cost of about $6 million to repair.
The NTSB determined the probable cause of the collision was the bridge team on the Nomadic Milde not effectively monitoring the vessel's position.
“Monitoring a ship at anchor, especially in an area where the risks of nearby hazards and weather and current are present, requires a continuous state of vigilance and the use of all available means to determine whether a vessel is dragging or not," NTSB concluded. “Although ECDIS is a useful tool in determining a ship's position at anchor, the ship's radars would have provided information for the crew to determine or crosscheck if the range to a vessel or object had decreased, or if the ship had moved while at anchor."