Transportation Safety Board Finds Lack Of Spotter Led To Crane Barge Collapse
The failure to post a spotter in accordance with written company policy led to the collapse of a crane on the construction barge Carolyn Skaves on February 8, 2022, at a bridge construction site in Norfolk, Va., according to the National Transportation Safety Board in a report released last month. The crane was recovered, but it was declared a total loss of an estimated $2 million; there were no injuries. Diesel fuel from the crane was released into the surrounding water, and an oil sheen about 75 feet by 75 feet was observed.
The barge was spudded down in the Willoughby Bay area on the south side of the Hampton Roads Bridge Tunnel when the crane operator shifted the position of the onboard crawler crane toward the stern, and the crane toppled into the water.
The Carolyn Skaves was a 180-foot-long construction barge built in 2019 and owned by Sterling Equipment. In 2021, Seaward Marine Corporation leased the barge and purchased a Liebherr 1300.1SX model mobile hydraulic lattice boom crawler crane, which was operated from the barge deck.
The crane was affixed to the barge using a centerline cable system that allowed longitudinal (fore and aft) movement of the crane; the cable system, required by OSHA, prevented the crane from moving laterally or rolling off the barge. The centerline cable made of wire rope ran the length of the mat. The cable ends were formed into loops (eyes) that were connected to shackles that were in turn connected to brackets welded on the deck of the barge forward and aft of the mat. The loops were created by securing the cable’s bitter (dead) ends with cable clips (clamps). The centerline cable passed through shackles hanging from loops of wire rope on the underside of the crane, allowing the crane to move along the cable.
The crane operator told investigators that once on board the barge, the four-person work crew members participated in the pre-work risk assessment that focused on crane operations such as swinging the boom and lifting. The discussion did not include shifting the location of the crane. The crane operator and one of the workers then prepared the crane to begin operations to set bridge girders—large 62-foot-long concrete beams, each weighing 22 tons—all day.
After lowering the block to its desired height, the crane operator began moving the crane aft, using the pedals to move each track. The operator told investigators that as he moved the crane aft, he heard a noise on his left and thought the crane’s steps had hung up on something. He quickly looked to his left and right and then looked for the aft stop mark painted on the timber mat near the forward end of his left track. He stated that he saw that he was beyond the stop mark and released the pedals that he used to move the crane aft. He felt the crane was “light in the toes,” meaning he could see the tracks “were starting to come up a little bit,” so he immediately pushed the pedals to move the crane forward. However, the crane continued to travel aft, and he felt the crane “tipping over,” so he opened the cab door and jumped from the crane as it “went over backwards off the barge” into the bay.
After the casualty, investigators found the cable eye that secured the centerline cable to the aft deck shackle and bracket had opened. The bitter (dead) end of the wire rope had slipped through three cable clips and out of the shackle. OSHA regulations required the centerline cable system, which included the method and components used to secure the cable to the barge deck, to be of sufficient strength to keep the crane on the barge.
Written company policy required that a signal person or spotter be used “at any time the crane is traveling,” and the company report noted that the crane operator should have called on one of the deck workers to serve as a spotter (signalman). The report also stated that the centerline cable system was insufficient to keep the crane from falling from the barge; other means to prevent the crane from falling off the barge, such as barricades or stops, were not put in place; and the supervisor was not present at the pre-work risk assessment.
According to the crane operator, the foreman normally would have been on board the barge to lead the risk assessment but was not present because he was scheduled to attend a company meeting ashore. The director learned during his investigation that employees working on the Carolyn Skaves had not always assessed hazards, nor had they always used a spotter for previous crane movements.
Following the casualty, Seaward Marine met with its employees to discuss the lessons learned from the Carolyn Skaves casualty and emphasize the company’s written procedures that
1) before beginning crane operations, a pre-work risk assessment must take place;
2) the supervisor must attend the pre-work risk assessment; and
3) cranes should not be moved without a spotter/signalman. Additionally, Seaward Marine outfitted its crane barges with stops and barricades to construct a “corral” system to prevent movement. New company policy, added following this casualty, required that the corral system be in place when the turnbuckles were disconnected from the crane, including when the crane operator moved the crane forward or aft on the barge.