NTSB published its latest report of an incident during which an incorrect solution to address a main engine start issue led to the contact between an oil tanker and a loading dock in the Port of Corpus Christi. Damage to the vessel was estimated at $550,000, while the estimated property damage to the facility was $7M.
The incident
On March 15, 2021, at 10:18, two pilots from Aransas-Corpus Christi Pilots boarded the Riverside to assist with maneuvering the vessel out of the port. The vessel carried 717,554 barrels of crude oil and was bound for Lisbon, Portugal. The vessel proceeded down the Inner Harbor section of the Corpus Christi Ship Channel at 3.5 knots with tug escorts.
Once the Riverside passed through the Harbor Bridge at 12:00, the tug escorts departed, and pilot 2 took control of the tanker and increased speed to 10.5 knots at a half-ahead bell. Pilot 2 continued outbound, and, about 1238, he became aware from radio transmissions that the tank vessel Nordic Aquarius was preparing to depart the no. 4 loading dock at the Moda Ingleside Energy Center (no. 4 Moda dock), located about 11 miles ahead of the Riverside.
At 1245, pilot 2 was informed by the pilot aboard the Nordic Aquarius that it was departing the no. 4 Moda dock. After slowing to about 6 knots, the Riverside began to sheer to port. At 1258, pilot 2 ordered the rudder hard to starboard to counteract the heading change to port, but the rudder movement had no effect on the vessel’s direction. He then ordered dead slow ahead to increase the flow of water across the rudder, which required restarting the engine in the ahead direction.
The engine failed to start from the bridge. The captain contacted the engine room, and the chief engineer tried to start the engine from the engine control room; the engine again failed to start. Meanwhile, at 1258, the Nordic Aquarius had entered the channel and was proceeding outbound.
Pilot 2 noticed that the captain was focused on adjusting the engine controls and inquired if there was a problem. The captain informed him that they had “lost the engine.” In response to that notification and realizing that the Riverside was heading toward the no. 4 Moda dock, pilot 2 contacted a nearby tug, Honor, which was standing by on the west side of the no. 4 Moda dock, and requested that the tug push on the Riverside’s port bow in an effort to clear the pier.
The tug pushed against the Riverside’s port bow and was able to affect the vessel’s direction back toward the channel, but the tug had to move out of the way to avoid becoming trapped between the pier and the vessel. Pilot 2 ordered dead slow astern, and the chief engineer tried to start the engine astern locally, but it failed to start.
At 13:02, the Riverside’s port bow struck the mooring dolphin and catwalk at the end of the no. 4 Moda dock at 5 knots. The Riverside continued past the pier, and the tug Honor maneuvered to the vessel’s stern, attached a line on the stern, and, with the assistance of the tugs Strength, America, and Courageous, stopped the vessel about 1,600 feet past the no. 4 Moda dock.
After the vessel stopped, the tugs assisted in docking the Riverside at the Flint Hills dock no. 4, a facility next to the Moda Ingleside Energy Center.
Probable cause
NTSB determines that the probable cause of the contact of the tanker Riverside with the Moda Ingleside Energy Center no. 4 loading dock was the ineffective evaluation and incorrect solution for a main engine start issue by the company and shipboard engineers, overlooking the fouling of the main engine’s no. 6 air start actuator valve within the starting air distributor.
Contributing to the casualty was the presence of moisture in and lack of routine drainage of the air start system, which allowed the buildup of hardened grease within the air start actuator valve.
Lessons learned
On vessels with slow-speed diesel propulsion engines, starting and stopping main engines is a critical function for effective maneuverability. The NTSB has investigated multiple casualties involving slow-speed engine pneumatic starting and control systems and, in particular, air actuating valves within the systems.
- Vessel operators should ensure their crews are equipped with the resources and training to execute timely and thorough maintenance and repair on engines. If the root cause of an engine operating issue cannot be determined, it is critical for a chief engineer and vessel owner/operator to have a diesel technician further evaluate and determine the cause of the malfunction.
- Vessel reliability is dependent on the complete resolution of equipment malfunctions and abnormalities when they occur.
Source: Safety4sea
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