A large fuel barge struck and damaged a San Francisco-area bridge fender after the tug captain followed the wrong green light in thick fog, the Coast Guard said.
The 4,100-hp Pacific Wolf was towing the barge Cascades when the accident happened at about 1800 on Jan. 10. A second tug, Delta Deanna, was helping to escort the barge, which was loaded with 2.8 million gallons of heavy fuel oil.
The outbound flotilla was traveling southwest in San Pablo Bay when it approached the Richmond-San Rafael Bridge. The weather had worsened since the vessels departed the ConocoPhillips refinery at Rodeo, said Lt. j.g. Nephtwim Rosario, the Coast Guard investigating officer.
The bridge has three spans. The main span is 1,000 feet wide, fender to fender. On each side of the main span are an east and west auxiliary span. The east auxiliary span is only 484 feet wide. Each of the three spans is marked by an identical green light.
The crew of Pacific Wolf spotted one of the green lights and thought it was the main span, Rosario said. Instead, it was the east span.
“Visibility deteriorated to about a quarter of a nautical mile, and it was misty,” Rosario said. “The fog rolled in thicker than expected. They could see one of the lights. Based on the way they were heading, it looked like it was the main span.”
As the vessels got closer to the bridge, the captain of Pacific Wolf realized that they were following the wrong green light. Because it was too late to correct his direction, he decided it was safer simply to maintain a course that would lead through the narrower east auxiliary span. However, an ebb tide and a 2-knot current made that transit difficult, while the margin of error was less using the auxiliary span.
“That’s the one the master of the Pacific Wolf began using as a last resort — as an evasive maneuver to avoid striking the bridge,” Rosario said.
“Once he realized he was aligned on the wrong marked line, it was too late to transit through the main span,” he said. “He tried to come to port in order to effect that (east span) transit, but the effect of the tide was too great.”
The starboard bow of the barge slammed into the fendering system of the eastern tower, the Coast Guard said. No fuel spilled from the 309-foot, double-hulled barge.
Rosario said water was working against the towing-vessel captain at the moment of the accident. While Pacific Wolf made it through the span, Cascades had too much current pushing on its stern. Just as the vessels reached the bridge, the current also was pushing the barge a bit from its port side.
“The tide had a southwest set to it,” Rosario said. “Because of the southwest set and the current going about 2 knots, there was just too much pull on the barge.”
K-Sea Transportation Partners, based in East Brunswick, N.J., owns the 111-foot Pacific Wolf. K-Sea spokesman Mike Hanson said the company wasn’t sure what caused the accident.
Delta Deanna is owned by Baydelta Maritime of San Francisco. That vessel was on the stern notch of the barge at the time of the bridge transit, Rosario said. The tugs were transporting the fuel barge to Portland, Ore.
The Coast Guard said the collision damaged only the bridge fender and not the structure of the bridge. The 15-year-old barge is equipped with specially reinforced bulkheads and had minimal damage. The barge is 76 feet wide.
Rosario said mariners can see all three green lights when the weather is good. When it’s foggy, sometimes they can only see one light.
Rosario said he had never heard anybody suggest making the three green lights different. The Coast Guard’s investigation was still open in early March.