Tugs capsized because they were too weak for the task, TSB saysFeb 26, 2016 12:37 PM
A salvor’s crane lifts Lac Manitoba from the St. Lawrence River after the tugboat capsized in June 2015 along with one other tug during a bridge demolition project. Canada’s Transportation Safety Board has concluded that the vessels were not powerful enough for the job in the swift currents.
Two tugboats were capsized by the current of the St. Lawrence River while attempting to maneuver a barge into position because they were underpowered for the job, Transportation Safety Board of Canada (TSB) investigators said.
The June 22, 2015, incidents involved the tugs Lac Manitoba and LCM 131 during an attempt to secure a barge against the Seaway International Bridge at Cornwall, Ontario. In separate instances five hours apart, both tugs were caught in swift currents and overturned. One captain suffered a broken ankle.
In a letter to the vessel operators, a TSB official wrote that “the suitability of the tugs to carry out the operation, given the river conditions, had not been thoroughly assessed.”
The 64-foot Lac Manitoba, powered by two diesel engines with a combined power of 1,000 hp, was attempting to secure the 178-foot steel barge OC 181 to a bridge footing near the Seaway International Bridge. The barge was part of the equipment required in the demolition of the span by American Bridge Co.
Lac Manitoba was upstream of the barge OC 181 and was helping to hold it in position. The barge was anchored to the riverbed by a single spud and had a steel cable secured from its port bow to one of the bridge footings.
At the same time, the tug LCM 131 was pulling another steel cable from the barge that would be used to secure the barge to the bridge footing. At one point during the operations, Lac Manitoba lost power, drifted downriver and collided with the side of the barge. After the collision, the current pinned Lac Manitoba against the barge and the tug listed, downflooded and heeled over onto its side.
The crew of Lac Manitoba was able to safely abandon the vessel into a life raft.
About the same time as the capsizing, the steel cable holding the barge in place broke and the barge pivoted on its spud, allowing the current to carry Lac Manitoba farther downstream.
In the second incident, approximately five hours later, LCM 131 resumed the operation of securing OC 181 to one of the bridge footings. LCM 131, connected to the barge by a towline, was maneuvering around the bow when the current overpowered the tug, pinning it against the hull of the barge. This caused LCM 131 to list, downflood and heel over onto its side. Most of the crew evacuated onto the barge. Television footage of the incident showed one crewman in the water who was picked up shortly afterward. The captain, who was briefly trapped inside, escaped with a broken ankle and was shown being evacuated on a stretcher.
Information obtained by the TSB indicated that on the day of the occurrences, the upstream dam was releasing water and the speed of the current ranged between 5.6 and 7.4 knots. Three days prior, an attempt was made to push the barge toward the bridge using Lac Manitoba, but the tug was unable to carry out this operation. A rescue boat, which was on standby, was used to transfer a cable. Both tugs, while pinned alongside the barge, heeled over in the strong current.
After investigating the incidents, the TSB sent a marine safety information letter on Aug. 28 to American Bridge and main contractors Nadro Marine Services Ltd. and West Front Construction.
“Prior to a vessel undertaking any operations, particularly in the presence of strong currents, the operation should be assessed for safety,” wrote Marc-Andre Poisson, TSB director of marine investigations.
“In these occurrences, the suitability of the tugs to carry out the operation, given the river conditions, had not been thoroughly assessed,” the letter continued. “Furthermore, the risks of using the rescue boat for a purpose other than intended and outside its primary duties were likely not considered.
“Performing a detailed risk assessment to identify and mitigate hazards associated with vessel operations is essential for the safety of crews, vessels and the environment.”
Capt. Bill Nadrofsky, director of operations for Nadro Marine Services, owner of the vessels, said the fundamental cause of the Lac Manitoba incident involved the loss of power on the port side of Lac Manitoba due to wire cable fouling in the port propeller and stalling the engine.
“Any tug, regardless of hp, that gets a cable fouled in their propeller would have met with the same outcome,” Nadrofsky told Professional Mariner.
In addition, Nadrofsky said that equipment selection, including Lac Manitoba, and methodology were based on previous experience on this same job site in 2011, when Nadro Marine provided marine assets for the successful completion of Phase 1 of the International Seaway Bridge replacement.
Stéphane Chevalier, TSB’s investigator in charge, told Professional Mariner that on the Friday prior to the incident Lac Manitoba tried to move the barge by itself and was overpowered by current.
“On Friday (June 19) they called for help and on Monday (June 22) they tried again to relocate the barge,” he said. The investigation showed that with one vessel they could not do the job. They had to reorganize and get LCM 131.
“We believe the first accident was because, for one reason or the other, Lac Manitoba lost power on the Monday afternoon (and) therefore the current slipped it against back against the barge and the vessel rolled over,” Chevalier said.
Video of the capsizing LCM 131 was obtained when a television crew that went to the site for footage of the barge then filmed the incident.