NTSB: Crane barge improperly moored before canal breakawayJun 4, 2019 11:59 AM
U.S. Coast Guard photo
After coming free from its moorings, Troy McKinney drifted south on Louisiana’s Harvey Canal for about a half mile. The barge’s transit came to an end when its A-frame crane struck power lines owned by the Entergy Corp.
An unmanned crane barge that broke free and struck high-voltage power lines over a Louisiana canal was not effectively moored, federal investigators have determined.
The 192-foot Troy McKinney was tied up at Chet Morrison Contractors (now called Morrison shipyard) on the Harvey Canal on June 7, 2017. The barge came loose at about 2000 after a towboat and barge passed the dock at nearly 5 knots.
Troy McKinney drifted south for about a half mile until its A-frame crane hit the power lines 124 feet above the canal. The barge was not damaged, but the power lines, owned by Entergy Corp., required $440,000 in repairs.
National Transportation Safety Board (NTSB) investigators focused their attention on the barge’s mooring arrangement. They determined that 18-knot winds from the north and the wake from the passing tow should not have caused the breakaway.
“Neither the prevailing wind conditions nor the speed and wake of the Gail Cecilia tow appeared to be extraordinary circumstances that would have caused a properly moored vessel to break free from its mooring,” the NTSB determined in its accident report.
Troy McKinney arrived at the Morrison shipyard in mid-May for crane washing, blasting and repainting. The barge tied up port side to the yard, with its stern facing north toward the Mississippi River. Two weeks later, the crane boom was raised to allow for the paint work. Its top stood almost 136 feet off the water.
Troy McKinney was initially tied up with five mooring lines. Two connected with another barge to its north, and three connected to shore. The other barge was moved on May 21, leaving just the three shore lines, the NTSB report said. The president of barge owner McKinney Salvage & Heavy Lift of Baton Rouge, La., added a fourth line when he toured the vessel June 1.
Six days later, the barge came loose soon after Gail Cecilia passed with its barge. Video showed Troy McKinney’s stern coming loose from the dock, and soon the rest of the vessel was free and drifting south. It spun 180 degrees along the way and its stern-mounted crane hit the power lines at about 2025.
A diagram from the NTSB report shows the mooring line arrangement for Troy McKinney on June 1, 2017, six days before the accident.
NTSB/Pat Rossi illustration
McKinney Salvage and the shipyard gave conflicting accounts of who was responsible for mooring the barge. McKinney officials said the shipyard had that duty, while the yard said its scope of work did not include mooring, according to the NTSB.
“The shipyard project manager who oversaw work on the Troy McKinney told investigators that the owner was responsible for mooring the barge and that this was ‘fairly typical’ when other vessels moored at the facility,” the NTSB said in its report. “The project manager also stated that vessel owners would occasionally specify (in the contract with the shipyard) that the shipyard would be responsible for the vessel’s mooring.”
Shipyard personnel also produced emails suggesting the scope of work did not include mooring, the report noted.
In any case, the mooring arrangement did not align with best practices cited by the NTSB. The agency’s investigators referenced R.S. Crenshaw’s Naval Shiphandling and Charles F. Chapman’s book, Piloting, Seamanship, and Small Boat Handling.
Crenshaw’s volume notes that spring lines should run parallel to the keel to prevent forward or aft movement, the NTSB report said, and Chapman calls for bow lines that run from a bitt on the vessel as far forward as possible to prevent astern movement. Stern lines, conversely, should extend from an aft bitt to a secure bollard or piling located aft of the vessel to check forward motion.
Troy McKinney was moored with three lines that ran almost perpendicularly from the vessel to the shoreside connections. The fourth line placed by McKinney’s president ran roughly 45 degrees to the vessel’s keel rather than parallel as the research recommends.
“Investigators therefore believe that Troy McKinney’s mooring lines were led from vessel to shore at an angle insufficient to prevent the barge from moving forward, or to the south, as the Gail Cecilia tow passed,” the NTSB said. “Forward and aft movement is best prevented by forward- and aft-leading lines.”
Neither Morrison nor McKinney Salvage responded to emails seeking comment on the NTSB findings.