Nickelena Ship Details and Seafarer Feedback

The National Transportation Safety Board (NTSB) has released its findings on the allision between a crane towed by the tugboat 'Nickelena' and the iconic Mackinac Bridge in Michigan. This incident, which occurred in May 2023, resulted in significant damages estimated at $665,000 to the crane and $145,000 to the bridge's underside. The 'Nickelena', typically tasked with transporting barges carrying construction equipment across the Great Lakes, was engaged to tow a barge with a 160-foot boom crane and a 5-foot rooster sheave from Escanaba to a construction site in Sault Ste. Marie. On May 6, during a routine operation that required passage beneath the Mackinac Bridge — a vital suspension bridge linking Michigan's Upper and Lower Peninsulas — the tow line was extended to 500 feet. The captain, who left the bridge to take a rest, intended to return before 2 a.m., the planned transit time under the bridge. At this moment, the National Oceanic and Atmospheric Administration reported no maritime traffic and minimal wind, with the tug moving steadily at eight knots within the navigational channel. The initial contact with the bridge occurred with the stiffening truss situated just below the roadway, approximately 155 feet above water. The crane's securing wires made contact first, resulting in the boom hitting the top chord of the truss. As the barge advanced, the boom was pushed backward, its angle and elevation increasing, eventually impacting the upper diagonal truss at around 183 feet above the water before it collapsed back onto the barge. Eyewitness accounts from the engineer and crew aboard the 'Nickelena' revealed they were unaware of the initial contact until the boom was no longer visible. The investigation indicated that the captain and the barge company management failed to verify bridge clearance, relying solely on assurances from the loading supervisors who claimed everything was adequately secured. The evaluation conducted by the managers suggested an angle for the crane boom between 50 and 60 degrees and an estimated length of 140 feet. However, the Load Moment Indicator on the crane was malfunctioning, and the well-being of the barge’s stability was prioritized over adjusting the boom’s angle for clearance, compounding the situation. According to the NTSB, operators of towing vessels are mandated to have a towing safety management system (TSMS), which should include thorough voyage planning—a protocol that appears to have been inadequately fulfilled by Basic Towing, the vessel’s operating company. While Basic Towing asserted the existence of a TSMS, no documentation proving that a navigation assessment was conducted was discovered, nor was there any action on the captain's part to confirm the safety of the tow. The water level beneath the Mackinac Bridge was reported higher than average, resulting in a clearance of approximately 153 feet rather than the typical 160 feet. However, the boom’s angle was measured at approximately 62 degrees — equating to a height of 162.3 feet, making the boom 10 feet too high to safely transit under the bridge. Incorrect length assessments made by the management were pivotal in this incident. The NTSB report clearly emphasizes that the captain, being accountable for the transit’s safety, neglected to verify the height of the boom and confirm the vertical clearance of the bridge. For further information, you can view the detailed report with images here: https://www.maritime-executive.com/article/ntsb-ineffective-voyage-planning-caused-towed-crane-to-hit-mackinac-bridge.