Officials investigating a Navy submarine's sinking of a tugboat off Los Angeles--killing one crewman--are questioning how a submarine equipped with highly sophisticated listening devices failed to avoid the accident.
The Houston, a nuclear-powered submarine based in San Diego, sank the tug Barcona before dawn Wednesday when it snagged a 1,000-foot steel cable connecting the tugboat to two empty barges. The sub yanked the tugboat backward and into the water about 10 miles southwest of Long Beach. Two crew members survived, but pilot Bryan Ballanger went down with the Barcona in waters 2,500 feet deep.
The accident--apparently without precedent in U.S. naval history--is being investigated by the Navy, the Coast Guard and the National Transportation Safety Board.
The Navy said it will not discuss details of its inquiry. The investigation will cover "what happened, how did it happen and why did it happen," said Petty Officer Vicki Evans, a spokeswoman for the Naval Submarine Base at San Diego.
Asked if the Houston's sensors were capable of detecting the tugboat's tow cable--or of otherwise detecting a tugboat pulling two barges--Evans said only: "That's all part of the investigation."
Navy officials declined to discuss the submarine's sonar capabilities, saying the information is classified. However, it is known that the listening devices are so sensitive as to be able to identify types of vessels by the sounds of their engine.
Several naval experts and retired submarine commanders said Thursday that the freakish mishap is an accident that the submarine, skippered by Capt. John Sohl, should easily have avoided.
"At 12 miles off the coast, he's in training. He's not worrying about (compromising) security," said independent naval expert James Bush, a retired Navy captain and former submarine commander. "He should be worried about safety."
The Houston's passive sonar systems should have picked up the sound of the tugboat from miles away, Bush and other experts said. The submarine should then have raised to periscope depth and sighted the tugboat. A coded series of lights on the tug would signal whether other vessels were being towed.
Ralph Larison, president of Connolly-Pacific Co., a marine contractor that owned the Barcona, said surviving crew members Mike Link and Daniel Rodriguez reported that the lights were operating properly, as were lights on the barges in tow. Despite a gathering fog, the crew members said there was about two miles of visibility when the accident occurred, Larison said.
If the submariners failed to locate the tug visually, naval experts said, they should have been able to detect it by activating a more sensitive sonar system that transmits a sound wave and listens for an echo. This practice is known as "pinging" for the sound that returns to the submarine.
"Pinging is one of the things he should be doing," Bush said.
The Navy fixed the time of the collision at 4:43 a.m., but the Houston did not notify the Coast Guard until 6:40 a.m. There was no immediate explanation for the time lag.
Commissioned in 1982, the Houston is a fast attack submarine of the "Los Angeles" class--an advanced vessel designed to hunt enemy submarines as well as surface vessels.
Evans, the submarine base spokeswoman, called the accident "freakish." The sinking of a boat in such a manner by a Navy submarine is apparently without precedent, Navy spokesmen said.
In various parts of the world, however, there have been at least three incidents since 1987 in which a Navy submarine has become caught in commercial fishing nets. In one case, a fishing boat was towed for three hours by a submarine.
In January of this year, a submarine collided with a fishing vessel on the water's surface. On May 23, the San Diego-based submarine Gurnard hit a reef off the Southern California coast. No one was hurt in the brief grounding, and the Gurnard continued on its way under its own power. That incident, which occurred during routine operations, is still under investigation.
Unlike some fishing crews that were unable to cut their nets loose, the crew of the Barcona had no time to release its tow cable, Larison said. The crew members had no idea what had suddenly jolted their boat backward, he said, and even if they had known, the stern was under water almost instantly and the cable release impossible to reach.
Ballanger was piloting the tugboat while Link and Rodriguez were asleep below deck. Link was jolted awake, but Rodriguez was still asleep. Ballanger went below deck to wake up Rodriguez, then apparently attempted to check the engine room.
Link attempted to radio a distress call but became tangled in radio wires, freeing himself just before the boat sank. Ballanger, 32, married and the father of a 4-year-old son and 2-year-old daughter, apparently never made it out of the Barcona.
Link and Rodriguez managed to climb aboard one of the barges and later saw the Houston surface about 100 yards away. The Houston made no attempt to communicate with the two men, Larison said. Later, a private vessel, the My Way, picked up Link and Rodriguez.
Larison described the Navy as "very cooperative." On Thursday, one end of the Barcona's tow cable was located on the ocean surface. A one-man Navy submarine was trying to locate the Barcona.
"Our main goal," Larison said, "is to try to recover the body."
Times staff writer Melissa Healy in Washington contributed to this story.