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NTSB: Fatal blast was result of towboat’s poor voyage planning

Mar 26, 2015 03:18 PM
The towboat Shanon E. Settoon burns after striking an underwater pipeline in Louisiana’s Bayou Perot. Investigators said the accident happened because the captain’s bosses didn’t give him adequate navigation information for the waterway.

Courtesy U.S. Coast Guard

The towboat Shanon E. Settoon burns after striking an underwater pipeline in Louisiana’s Bayou Perot. Investigators said the accident happened because the captain’s bosses didn’t give him adequate navigation information for the waterway.

A towboat struck an underwater pipeline off Louisiana in 2013 because a relief captain, who died as a result of the explosion, hadn’t been given enough information about navigation hazards in the area, the National Transportation Safety Board (NTSB) has determined.
 
Shanon E. Settoon ruptured a gas pipeline in Bayou Perot Canal on March 12, 2013. The 47-foot towboat was pushing tank barge SMI 572 with the intention of topping off the barge with crude oil at the Louisiana Delta Oil Co. (LDOC) facility.

While the towboat steered to avoid unspecified obstructions in the water, one of its propellers struck the Chevron Midstream Pipeline at 1744 hours and burst into flames. 

The relief captain, Chad James Breaux Sr., 46, was burned in the fire and died about a month later in a Baton Rouge hospital. Three other crewmembers escaped the fireball.

The probable cause was “the introduction of petroleum gas into the main engines after the vessel struck and ruptured a submerged pipeline due to incomplete navigational information provided to the captain by the vessel company,” the NTSB wrote.

The towboat belonged to Settoon Towing, based in Pierre Part, La. In a statement to Professional Mariner, the company said it disagrees with the NTSB’s findings. Settoon said it provides its captains with all necessary navigation information, and this particular pipeline should have been marked with lighted buoys.

“Neither a voyage plan nor the most up-to-date or well-researched navigation information or any other tool provided to our captains would have allowed them to identify and have knowledge of a submerged, exposed or improperly buried hazardous pipeline in navigable waters,” the company’s statement said. Mariners “have a right to assume that a pipeline is buried below the water bottom.” 

Visibility was 10 miles with winds at 8 knots. The NTSB said the relief captain had contacted a LDOC contractor twice asking for directions into the facility. During one of the phone calls, the vessel’s regular captain, who was not on the boat, joined the conversation. The contractor suggested two options for where to turn.

“The LDOC contractor told him that if he felt uncomfortable with the approach, he could wait until morning,” the investigators wrote. “The captain chose to proceed that evening, and he took the more southeast route in his approach to the LDOC facility. As the tow was inbound, the captain saw two obstructions in the water ahead, and he turned to starboard to avoid them.”

Shanon E. Settoon and the barge passed over the pipeline and eventually pierced it. The crew noticed a disturbance in the water, and the captain asked for help powering the engines down to prevent a spark. Just then, while the crewmembers walked aft, the main engines exploded. 

“Two of the crewmembers retreated to the barge, while the captain — who was badly burned — and another crewmember ended up in the water and made their way to shore,” the report said.

The captain was hospitalized with second- and third-degree burns. The fire continued burning for several days. Inspectors were able to pinpoint the area of initial contact. 

“A survey revealed that the vessel’s portside propeller had struck and penetrated the pipeline,” the investigators wrote. “When the gas reached the surface of the water, it was drawn into the main engines, where it ignited. The explosion caused an intense fire, which was fed by the escaping gas under pressure.”

Shanon E. Settoon was a total loss. The barge was slightly damaged. The report said 1,000 gallons of diesel fuel escaped from the towboat. 

The NTSB noted the challenges of navigating along the Louisiana coastline and the need for precautions. 

“Numerous active or abandoned oil and gas pipelines traverse the Louisiana region,” the report noted. “When installed, the pipelines are surveyed to ensure that they are buried at an appropriate depth. However, over time their coverage can decrease due to storms, shoreline changes, etc., which makes voyage planning challenging and particularly reliant on up-to-date, accurate information. Many pipelines do not appear on standard navigation charts and mariners do not know their exact locations.”

In recent years, Coastal and Marine Operators (CAMO) has initiated various programs to prevent vessels from crashing into or running aground on undersea pipelines and other petroleum infrastructure. CAMO emphasizes voyage planning that carefully considers vessel drafts and tides and the use of updated charts and notices. 

“Given the numerous pipelines in that area that present submerged hazards, and given that the locations of oil and gas facilities may be temporary and subject to change, it is essential that vessel companies provide their operators with up-to-date, well-researched information to ensure safe navigation,” the NTSB wrote. 

Settoon said it has “implemented procedures and instructions in order to address the risk of exposed and improperly buried pipelines, such as facility inspections of new locations, underwater hazard surveys and voyage plan procedures.”

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