A team from U.S. Coast Guard Air Station Elizabeth City, N.C., in an HH-60 Jayhawk helicopter, made a dangerous nighttime rescue of six of the crew who were in a lifeboat near the sinking vessel. Coast Guard rescue swimmer David Foreman spent more than a half-hour in 44Â° water helping the six men into a rescue basket dangling from the helicopter. One other lifeboat was found capsized.
The 22,587-gt Bow Mariner was partially loaded with 3.2 million gallons of industrial ethanol. The tanker made four stops to unload MTBE in New York and New Jersey, before embarking, according to Jerry Crooks, chief of investigations for the Coast Guard Marine Safety Office in Hampton Roads, Va. There were 193,000 gallons of fuel oil and 48,000 gallons of diesel oil on the vessel.
There was more than one explosion onboard the vessel, although the exact number has yet to be determined because of conflicting eyewitness statements, according to Crooks. An Indian-flagged bulk carrier, Dakshineshwar, was 3.6 miles away and launched a lifeboat as part of rescue efforts for the crew. A videotape of the fire before Bow Mariner sank was taken by a crewmember on the Indian vessel, according to Crooks.
Bow Mariner, built in 1982, is owned by Odfjell ASA of Bergen, Norway, and operated by Ceres Hellenic Shipping Enterprises Ltd. of Piraeus, Greece. Although the vessel was Singapore-flagged, that country asked the U.S. Coast Guard to conduct the investigation into the sinking.
The inquest was hampered because four of the surviving crewmembers had refused to speak to the Coast Guard, citing their Fifth Amendment rights not to incriminate themselves. The two men who did talk were in the galley and could not provide any information about the explosions, according to Crooks. The other four men “are key to figuring out what happened onboard that vessel that day,” Crooks said. “We need to know what was happening onboard the ship at the time of the explosion.”
The four men did testify before a grand jury at the Eastern District of Virginia federal court in Newport News in April, after the U.S. Attorney’s office granted them immunity from prosecution. Coast Guard officials had to wait for grand jury proceedings to end before they could see if the four would then talk to them.
Ceres and Odfjell gave the Coast Guard 1,043 pages of documents, including information about the ship’s safety-management system, fire-control plan and its inert-gas-systems manual.
Crooks said his team is analyzing infrared video taken from a Coast Guard C-130 Hercules airplane as the ship sank. In addition, there are 57 hours of video of the sunken vessel on the ocean floor, shot by a remotely operated vehicle (ROV) operated by the salvors.
The ROV was operated by Mystic Viking, a 253-foot diving-support vessel hired by the owner and operator. The bodies of the 18 missing crewmembers have not been located. (The bodies of three crewmembers were recovered at the scene.) The ROV inspection of the ship showed extensive damage to the vessel’s tanks, so officials believe there was no recoverable product still onboard, either in fuel or cargo tanks, according to a Coast Guard press release.
In addition, a remarkable sonar scan of Bow Mariner, sitting on the ocean floor in 264 feet of water, was taken on March 4 by Rude, a 90-foot hydrographic survey vessel operated by the National Oceanic & Atmospheric Administration.
That sonar image provides clues about what might have happened to trigger the explosion, according to Lee Kincaid, deputy executive director for the National Cargo Security Council in Annapolis, Md.
After looking at the sonar image, which was posted on a NOAA website, Kincaid said it appeared that wing tanks on the starboard and port sides were missing, in addition to the No. 2 tanks.
Although Kincaid acknowledged that there were few details available about the incident, he theorized that those tanks may have been empty after discharging MTBE in the New York area.
“It’s got to be an empty tank that exploded,” said Kincaid, who is also a member of the Coast Guard’s Chemical Transportation Advisory Committee. “The question is, what caused those tanks to explode?”
Vapors in the empty tank could have provided the fuel for the explosion, Kincaid said. He said it is possible that there were problems with the vessel’s inert-gas system or that proper inert-gas procedures weren’t followed.
“It indicates to me that the tanks may not have been inerted. Inerted tanks don’t blow up,” he said.
The source of ignition could have been sparks created by repair work or tank cleaning, Kincaid said. “If you’re pushing a high volume of water through a high-pressure nozzle, it will generate static electricity,” he said. “It will actually create a mini electrical storm in the cargo tank.”
That water could have become the source of ignition, if safety procedures were not followed. One precaution is to make sure that the hose is grounded to the hull of the ship.
Kincaid said that most tankers wash out their tanks at sea to avoid wasting time in port. In cleaning, fresh air may be introduced into the tank. If the tank is not properly vapor-free, or if positive inert-gas pressure has not been maintained during the washing, “you’re in the flammable range,” Kincaid said. And a single spark could start a series of explosions.
Although Crooks confirmed Bow Mariner unloaded MTBE, he said he preferred not to say which tanks on the vessel were empty.
Jesse Lewis, spokesman for Ceres and Odfjell could not comment on possible causes for the accident except to say that the two companies were investigating. “We do not know whether tank cleaning was underway,” he said. The two companies were not aware of any problems with the inert-gas system.
Crooks said there was no pattern of inspection violations with Ceres or Odfjell. Based on class survey records and U.S. Coast Guard records, Crooks said, “There is nothing in there that would cause alarm with the inspection or types of deficiencies the vessel has had over the years.”
Another chemical tanker operated by Ceres, Bow Power, was cited on Feb. 27, 2003, by Coast Guard inspectors in Philadelphia for transporting a cargo of industrial ethanol that contained dangerously high levels of oxygen — more than 15 percent, according to Cmdr. Stephan Billian, chief of the inspection and investigation department at the Marine Safety Office Philadelphia.
Inert systems are supposed to keep oxygen levels at less than 8 percent, according to Kincaid.
“The portion of the tank above the cargo, the ullage, was effectively explosive; an ignition source could have initiated an explosion,” Billian said. While the ship was underway, oxygen levels started creeping up, and the inert-gas system was not used correctly to dilute the oxygen with inert gas, Billian said.
The Coast Guard intervened to make sure the problem was taken care of before the vessel could continue with cargo operations.