A Charleston, S.C. pilot maneuvering a tanker passed too close to a bank before a turn on the Cooper River, resulting in an allision and collapse of a 300-foot section of pier at Joint Base Charleston’s Naval Weapons Station, the National Transportation Safety Board said Tuesday.
The 600’x106’ tanker Bow Triumph struck the weapons station Pier B while transiting the Joint Base Charleston Channel just after 4 p.m. on Sept. 5, 2022, A Charleston Branch Pilots Association pilot was navigating the vessel, which sustained significant damage to the bow. The contact resulted in $29.5 million in damages. No pollution or injuries were reported.
After making a right turn onto Range D of the channel, the pilot maneuvered the vessel closer to the left bank as he approached the next turn, a left turn around a bend.
“The maneuver caused the vessel to experience bank effect – when a ship’s bow is pushed away from the bank and the stern is pulled toward the bank while transiting in confined waters,” according to an NTSB summary. “The pilot’s subsequent rudder and engine orders could not overcome the bank effect, and the tanker struck the pier, which was on the opposite side of the river.”
“Hydrodynamic forces reduce rudder effectiveness (squat and shallow water effect) and yaw the bow away from the closest bank and pull the stern in (bank effect),” the report said.
“When maneuvering in shallow waters such as channels, shoaling can reduce the water depth below charted or expected, and therefore exacerbate the forces on a vessel. Bank effect can have an undesired effect on vessels, even for the most experienced shiphandlers. Pilots, masters, and other vessel operators should consider the risks in areas known for shoaling when planning transits.”
The NTSB also is investigating a Jan. 14 contact between the 603’x90’ tanker Hafnia Amessi and Pier B after the tanker attempted the same turn at the bend. That investigation is ongoing.
