A tugboat repositioning a barge as part of a bridge reconstruction project in Portsmouth, N.H., partially flooded and listed after a hatch was not dogged down securely, the U.S. Coast Guard said.
Lt. Nathaniel L. Robinson, supervisor of the Marine Safety Detachment Portsmouth, said the Piscataqua River’s 3-knot current pushed Miss Stacy broadside to the flow and water washed over the rail and flooded a compartment on the port side.
The Coast Guard received a call shortly before 1400 on Feb. 21 stating that the square-bow river-style towing vessel had capsized. “When we arrived at the state dock in Portsmouth, we saw that the vessel had not capsized but had a significant port list,” Robinson said. The tug was also pinned against the bridge.
“The tug was in the process of repositioning a deck barge about 8 feet when the incident occurred,” he said. The tug had been hired by a contractor who was removing a support piece on the side of Memorial Bridge. The barge was being used to catch falling debris.
Robinson said the tug was pinned against the bridge for about 20 minutes until a larger tug, Eugenia Moran, arrived and towed Miss Stacy to the state dock. There Robinson and another inspector examined it.
“Surprisingly there was no water in the engine room,” he said. “We started opening deck hatches on the starboard side to make sure there wasn’t any breach of the hull when it was pinned up against the bridge, and there were no penetrations to the hull.”
“We did identify a deck hatch on the port side that was not completely dogged down,” Robinson said. The small storage compartment and air tanks below the hatch were completely filled with water.
The list was exacerbated because the vessel had a cross-connect valve between the port and starboard fuel tanks to make sure they are drawn down evenly. “So when the vessel was pinned underneath the bridge, fuel from the starboard side migrated to the port side,” Robinson said.
The investigation report is awaiting approval in Washington. But Robinson said his conclusion about the cause of the accident was that “it was a combination of the outgoing tide and the effect of what we believe to be downstreaming,” the Venturi suction effect of the water moving around the bridge structure, and the partially secured hatch.
As the tug approached the barge, its stern was shifted sideways, putting the port side perpendicular to the current. Water began washing over the rail and then the tug became wedged against the bridge span.
Robinson said the tug was in danger of capsizing, but the current pushing the vessel against the bridge prevented that from happening.
He said there was no negligence involved. The accident occurred on the third approach to the barge.
“He had made two prior approaches because he wasn’t happy with the way he was setting up,” Robinson said.
Miss Stacy was built in 1966. It is owned by Seaward Marine Corp. of Chesapeake, Va. The company declined to comment.