NTSB: Lack of Anchor Monitoring Led To $16.9 Million Loss
The failure of a bridge crew to realize that their vessel was dragging its anchor led to a collision on the Lower Mississippi River that caused $16.9 million in damage.
That was the conclusion of the National Transportation Safety Board in its recently released report on the collision between the anchored Nomadic Milde and the anchored bulk carrier Atlantic Venus. On May 8, 2020, at 16:55 local time, the Nomadic Milde began to swing and drag its anchors in the current. After colliding with the Atlantic Venus, which had been anchored directly behind the cargo ship, the Nomadic Milde then struck a nearby chemical dock and grounded on the bank. While there were no injuries, the Nomadic Milde released an estimated 13 gallons of lube oil into the river. Damage to both vessels and the dock was estimated at $16.9 million.
The Nomadic Milde was a 453-foot-long general cargo ship flagged by the Republic of the Marshall Islands. It had a 7,241-hp. medium-speed diesel engine connected by a reduction gear to a single four-blade controllable-pitch propeller and was fitted with a 670-hp. bow thruster.
On the day of the accident, the river gage at Carrollton, Mile 102.8, was at 15.5 feet and falling, which was a “high water” event. The pilot who anchored the Nomadic Milde estimated the current at between 4 and 5 knots near the Kenner Bend anchorage, where the ship dropped anchor. The vessel was fully loaded with lead concentrate.
The pilot positioned the Nomadic Milde in between, and in line with, two bulk carriers in ballast. After the anchor was dropped, the master asked the pilot if he could stop the engine, to which the pilot replied he could, but cautioned that the engine should be kept on short standby (restart in 10 minutes). The bosun stoppered the anchor chain without witnessing any movement on it.
Closed circuit TV from the dock shows the boat swinging on its anchor and apparently shifting its position over ground. At 16:13, the officer on watch at the Atlantic Venus radioed the Nomadic Milde and asked it to check its position. The second officer asked the bosun to stand by the anchors.
At 16:41, the master of the Atlantic Venus radioed the Nomadic Milde that both vessels were very close and in an unsafe condition. The chief officer of the latter said he “noticed” and called the pilot station to report that the ship had “turned on its cable” and was too close to the ship behind it. The Nomadic Milde’s captain came to the bridge and radioed to the pilot station that he needed a pilot to change position.
At 16:47, VTS told the Nomadic Milde, “It looks like you are dragging anchor or maneuvering” and “make sure you do not raise your anchors…maneuver with your engines to stay safe but do not raise your anchors…do not raise your anchors…wait for a pilot.”
As the ship swung, despite having started the engines and using the bow thruster, the Nomadic Milde’s master said in testimony he realized the vessel could not turn to starboard. At 16:55, the port side of the Nomadic Milde collided with the bulbous bow and anchor chains of the Atlantic Venus. Both vessels remained in contact. The Atlantic Venus was facing upriver, and the port side of the Nomadic Milde was laying up against the bulbous bow of the Atlantic Venus with its bow facing the right descending bank. At 16:59, the second officer of the Nomadic Milde informed VTS that they had collided with the Atlantic Venus. Neither vessel reported any flooding. With the Nomadic Milde broadside to the current and pushing on the bow of the Atlantic Venus, both vessels moved toward the right descending bank and closed on the Cornerstone Chemical dock about 650 feet away. At 17:01, VTS called for any available tugs to proceed to the Kenner Bend anchorage to assist both vessels. The first assist tug arrived at 17:25 to help hold the Nomadic Milde in position.
About 30 minutes later, two NOBRA “rush” pilots arrived on scene and boarded the Nomadic Milde and Atlantic Venus. The rush pilots planned to separate both vessels using two stronger tractor tugs that were on their way to assist. The first tractor tug arrived at 18:54 and took up position on the port bow of the Nomadic Milde.
At about the same time, the pilot on the Nomadic Milde noticed the ship move ahead on the bow of the Atlantic Venus. He requested an increase in propeller pitch of 10 percent astern, and the master increased the pitch to 40 percent from the previous 30 percent pitch astern. Just after this, the chief engineer felt an excessive vibration in the engineroom, which was followed by multiple machinery automation system alarms.
At 18:56, the speed of the Nomadic Milde increased ahead toward the Cornerstone Chemical dock, so the pilot requested full astern. Although the master moved the pitch lever to 100 percent pitch astern, the ship’s speed continued to increase toward the dock. Seconds later, the pilot requested the engine be stopped, and the master pushed the emergency stop button for the main engine.
CCTV footage from the dock showed the Nomadic Milde advancing toward the dock with its port anchor chain across the bulbous bow and leading down its starboard side. The master steered to swing the port quarter of the Nomadic Milde clear of the bow of the Atlantic Venus and, once clear, he steered to starboard in an attempt to avoid contact with the center of the Cornerstone Chemical dock, which contained most of the dock’s piping. At 1858, the bow of the Nomadic Milde struck the upriver section of the Cornerstone Chemical Dock cell 2 at a speed of 6 knots before its bow grounded on the right descending bank. There were no injuries. No product from the broken piping was released into the river or atmosphere, and there was no fire or explosion.
The Nomadic Milde lost its starboard anchor with four shots of anchor chain just before it hit the dock, and its starboard anchor windlass was damaged. The anchor was later recovered. The contact with the Cornerstone dock left an approximate 25-foot gash aft of its port anchor pocket, as well as an indentation and a fracture to the portside shell plating in the vicinity of the No. 5 port wing ballast tank from the contact with the bulbous bow of the Atlantic Venus.
The propeller had numerous indentations and fragments missing from each blade. There was damage to the portside bilge keel, and there were multiple anchor chain abrasion markings at the bulbous bow on the portside hull area, and in the vicinity of the propeller. An estimated 13 gallons of stern tube lube oil were released into the river from a broken propeller hub seal. Damage and repair costs were estimated at between $5.5 and $6 million.
The Atlantic Venus lost its starboard anchor with 9.5 shots of anchor chain, both of which were not recovered. On the remaining chain, there were rotational indentations and deep scratches on the starboard anchor chain links. The starboard anchor chain stopper was damaged. The bulbous bow sustained multiple indentations to the shell plating as well as a weld crack and buckled stringer. Damage and repair costs were estimated at $410,943.
Cornerstone’s marine facility consisted of five cylindrical cells. The damaged cell was capable of receipt/discharge of acrylonitrile, molten sulfur and sulfuric acid. Cell 2, its piping systems, and the structures on it were damaged beyond repair. Additionally, a bridge and walkways between the cells were damaged. Cell 3 was also damaged. Damages estimates to repair the facility were estimated to be approximately $10,943,405.