After a freighter slammed into the New Orleans Riverwalk, forensic analysis found poor maintenance practices to blame for the disaster.
As the fully loaded bulk carrier Bright Field navigated outbound in the lower Mississippi near downtown New Orleans on its way out to sea on Dec. 14, 1996, it suddenly lost propulsion power.
The 735-ft vessel's main engine tripped due to low lube oil pressure, causing it to slow down as it passed the upriver span of the Crescent City Connection Bridges. As its stern cleared the second bridge, the pilot radioed the Governor Nicholls Lighthouse to warn the moored gambling boat, the Queen of New Orleans, of the impending crash. Hearing the radio traffic, the gambling boat staff quickly evacuated its 637 passengers. Upon seeing the approaching Bright Field, many people panicked. One patron jumped from the second floor of the boat and sustained severe back and leg injuries. Another jumped from the main deck to the pier and also suffered significant injuries.
Striking the shore at a 45° angle, the floating skyscraper slid along the face of the wharf until it was parallel with the structure. When all was said and done, the accident left 66 people injured (three seriously) and caused $15 million in damages to the Riverwalk, adjacent condominiums, and several riverside rooms in the Hilton Hotel.
What allowed the Bright Field to embark on this collision course? An extensive investigation revealed several layers of inadequate man-machine relations. Although electrical systems operated exactly as designed, this case demonstrates the consequences of poor maintenance procedures.
Importance of automation.
To stay competitive, modern ships increasingly rely on automation systems to improve efficiency and cut personnel costs. The worst insult that can befall a ship after sinking is loss of propulsion and maneuvering control.
To help prevent such tragic fates, engineers design redundant power distribution and control architectures to feed and direct equally redundant propulsion and maneuvering machinery. For instance, ships like the Bright Field, owned by Liberian shipping company Cosco, employ redundant hydraulic steering machinery cross-fed by normal and emergency power sources. Port/starboard and high/low cableways convey multiple power and control feeds to the steering machinery to ensure operation regardless of the catastrophe. Circuit breakers feeding the redundant electric steering motors are set in excess of 200% of the locked-rotor current. Even if the stern section completely detached from the rest of the ship and severed all electric power and control lines, manual backup provisions would still allow complete rudder motion, assuming a manned steering compartment and a buoyant stern section.
Despite the precautions and its redundant architecture, the Bright Field's maneuvering machinery still failed. But why?
The investigation.
Coast Guard officials identified several man-machine interface failures in this case. First, the boat was plagued by serious maintenance problems that could have equally affected main engine and maneuvering reliability. We found that the main engine's lube oil was extremely dirty, and the level in the oil sump was marginally low. Furthermore, the previous crew hadn't performed lube-oil replenishing activities prior to the start of the journey. In fact, it was unclear as to when, or if, the lube oil was ever changed.
The secondary lube oil filter downstream of both lube oil pumps (main and secondary) served as a common point of failure in this critical system; dirt-induced flow restrictions in this lube oil filter choked off adequate oil flow and pressure to the main engine. The differential pressure switch located across the filter performed its job and notified the crew of a need to clean the lube oil filter. However, the crew paid no attention to this alarm.
Much was also made of the standby status for the No. 2 lube oil pump, as solid evidence wasn't provided as to whether the No. 2 pump was or wasn't in the standby mode. Given the common choke point and the dirt-induced restriction downstream of the two lube-oil pumps, it's likely this issue is moot: Even if as many as four pumps were simultaneously operating, it's unlikely that sufficient oil would have blasted through the filter restriction to service the engine. However, given what appears to be purposeful activity in the Bright Field's crowded engine room just prior to the accident, it's unlikely the status of the No. 2 lube oil pump would have escaped notice. We believe the No. 2 pump was online and ready, as testified by the crew.
What went wrong.
After the main engine tripped, the crew noticed a drastic reduction in engine vibration, as the bow veered to port. At this point, the pilot (responsible for safely guiding the ship through congested waterways) asked the master (the ship's highest ranking authority responsible for the operation and safety of the ship, crew, and cargo), “Do we have a problem?”
By now, the Bright Field was on its destructive path. The master didn't reply. Instead, he instructed a crewmember to contact the engine control room. The chief engineer responded and asked for control to be transferred back to the engine control room. The crewmember agreed and ended the call. However, he failed to inform the chief engineer of the ship's dire situation.
As the Bright Field continued its slow swing to port, the pilot ordered the master to let go the anchors. At first, the master attempted to relay the order to the carpenter at the anchor detail by handheld radio, but the pilot began to sound the danger signal (five or more short blasts) on the ship's whistle. The deafening blasts prevented any radio communications between the master and carpenter, so the master then tried to relay the order using hand signals from the bridge wing. The carpenter couldn't understand the signals, and thus took no action.
Shortly after the accident, the case was filed in the Eastern District of Louisiana, including actions for personal injuries, destruction of shops and hotel rooms, and damages to the surrounding vessels and riverwalk. More than 5½ years after the incident and about 2,500 motions later, the case is still open. However, undisclosed settlements have been reached in some of the minor claims. Cosco and Clearsky Shipping are hoping that under maritime law, liability will be limited to the value of the ship and its contents (approximately $16 million). However, such limits apply only in cases where the ship is found seaworthy and the crew is void of negligence. Attorneys on both sides are still arguing applicability of maritime law limitations, despite findings that the chief engineers were negligent. The Coast Guard also charged Cosco with six civil charges and fined them more than $800,000.
Because of treacherous currents and twisting bends, the Mississippi River around New Orleans is said to be the most difficult waterway to navigate in the world, with more tonnage of petroleum, chemical, and dry bulk cargoes transiting that stretch of the river than any other port in the United States. Luckily, the Bright Field was carrying corn rather than a flammable product that could have placed the New Orleans Riverwalk collision in the history books as one of the worst marine collisions of all time.
Ruggieri, P.E., is a forensic engineer with General Machine Corp., Washington, D.C.
Photo courtesy of USCG Commander William Marhoffer
