Tanker, tender collision cause still a mystery
As the inquiry into the US Coast Guard's worst peacetime disaster drew to a close Saturday, March 22, investigators said they still could not assign blame with any certainty.
A Coast Guard Marine Board of Inquiry, aided by the National Transportation Safety Board (NTSB), finished 39 days of hearings that included more than 10,000 pages of testimony about the Jan. 28 collision between the Coast Guard buoy-tender Blackthorn and the oil tanker Capricorn.
But neither group was willing to say what actually happened that night in Tampa Bay's main shipping channel.
Twenty-three Coast Guardsmen perished as the 180-foot Blackthorn rolled over and sank within minutes after it collided with the 586-foot Capricorn.
The two ships were in the 400-foot-wide channel that leads from Tampa's port to the Gulf of Mexico; the Blackthorn was outbound after four months of drydock and the Capricorn was inbound with a load of oil for a power plant.
When ships pass in a channel, they are supposed to keep to their right, just like cars on a highway, and witnesses aboard the bridges of each ship insist that their vessels were traveling properly.
The captain and pilot aboard the Capricorn testified that the Blackthorn missed a dodleg turn in the channel and steamed across the channel into the tanker's path. The skipper and ensign on the Blackthorn were equally adamant that they were steering correctly but that the Capricorn turned left across the channel into the buoy-tender's path.
The most significant evidence consisted of readings from the course recorder aboard the Capricorn. The course recorder automatically charts changes in a ship's direction and serves much like a "black box" aboard an airliner to tell what happened aboard the craft prior to an acident. The Capricorn had a course recorder but the Blackthorn did not.
According to an expert witness called by the Coast Guard board to interpret the thin ink lines scrawled across the chart paper, the tanker was well into a hard left turn toward the Blackthorn's side of the channel when the accident happened.
That evidence tends to support the Blackthorn's side of the argument, but it is not conclusive. The witness could not mark on the chart exactly where the accident happened. He could only point to three blips in the ink line and say one of them was the impact point.
But the course recorder expert's testimony was contradicted by a damage expert who said the configuration of the wreckage showed the ships must have hit practically headon. If that happened, then the Capricorn could not have been turning hard left at the time of the crash.
Neither the Coast Guard officers nor the NTSB experts considered either evidence conclusive.
"There is a possibility, but a shrinking one, that we won't be able to assign blame in the case," said Rear Adm. Norman Venske, chairman of the inquiry board. "We're going to very carefully go through the facts and get them in order." The process could take a couple of months he said, and the board may reconvene to hear more technical evidence.