In one other report on an sad assembly between a crane on a barge and a bridge, the NTSB says that an incorrect estimate of a crane’s growth top led to contact with the Houma Twin Span Bridge final 12 months. On March 6, 2022, the towing vessel Robert Cenac was transiting the Gulf Intracoastal Waterway, pushing the crane barge Mr. Dawg and one other deck barge.
While making an attempt to go beneath the Houma Twin Span Bridge, the crane aboard Mr. Dawg contacted the bridge span. Eastbound car visitors, which is estimated at practically 30,000 car a day, was diminished from two lanes to 1 for 10 days. No accidents or air pollution have been reported. The contact resulted in $1.5 to $2 million in damages to the bridge.
The day earlier than the contact, Sealevel Construction contracted with Al Cenac Towing to constitution the Robert Cenac to tow the crane barge Mr. Dawg and a deck barge from Houma to Clovelly, La. Despite being requested at the very least twice in regards to the top of the crane by the towboat operator earlier than departure, Sealevel didn’t present Al Cenac Towing with a verified crane top.
Without a verified crane growth top, the captain of the Robert Cenac estimated the overall air draft of the tow, assuming the barge spuds to be an ordinary 50 toes excessive after which estimating the portion of the crane growth above the spuds at 10 toes, for a complete air draft of “roughly 60 feet.” However, the raised spuds on the Mr. Dawg had an air draft of about 56 toes, not 50 toes because the captain assumed. The captain was additionally judging the peak at midnight, which most definitely affected his skill to precisely decide the growth’s distance above the spuds.
The NTSB decided the possible explanation for the contact was the tow captain’s incorrect estimate of the crane growth top and his choice to depart earlier than getting a confirmed top from the crane barge proprietor. Contributing to the incident was the crane barge proprietor not offering the correct air draft data to the tow firm.
“Tow operators are required to know the air draft of their vessel and tows and should not make assumptions,” the report mentioned. “As the NTSB has recommended before, tow operators should have a detailed voyage plan with specific information concerning/about all known risks, including calculated overhead clearance limitations for tows. In this case, the captain should have waited to get underway until the exact air draft of the tow was established.”
The NTSB additionally beforehand advisable the Occupational Safety and Health Administration revise laws to handle “the placement and securing of crane booms for transit to and from marine construction and other sites.” OSHA declined to amend the laws.
“When operating in higher risk conditions, operators should ensure that they have the most accurate and objective data before getting underway,” the report mentioned. “Bridges pose a risk to vessels and tows with high air drafts. Owners and operators should develop voyage plans that assess operational risks and hazards, to include air draft relative to bridge vertical clearances along the intended route.”
