Impact with lock gate attributed to captain’s ‘sleep inertia’

The captain of a towboat that pushed its lead barge into a Louisiana lock gate was battling “sleep inertia” at the time, according to federal investigators.  

The 2,000-hp Ava Claire entered the Leland Bowman Lock in Intercoastal City, La., with two loaded tank barges on March 22, 2021, at 0519. The 298-foot HFL 439 hit the western gate at 1.2 mph three minutes later, the National Transportation Safety Board (NTSB) said in its incident report. 

The barge sustained minimal damage and the four crewmembers were not hurt. But the steel lock gate needed about $2.5 million in repairs. 

The unidentified captain woke up less than 20 minutes before the impact after sleeping for about 4.5 hours. NTSB investigators believe he was still groggy from waking up.  

“Sleep inertia negatively affects an operator’s performance, vigilance, alertness and decision-making for 30 minutes or more after waking, especially in demanding situations that require high levels of attention and cognitive demand,” the NTSB said in its report. 

“The captain’s sleep inertia, coupled with the challenges presented by the operating environment, would have negatively impacted his ability to safely navigate through the lock,” the agency added. 

Vessel operator General Marine Services of Baton Rouge, La., did not respond to an inquiry. 

Ava Claire and barges HFL 437 and HFL 439 got underway two days earlier from a Valero refinery on the Lower Mississippi River in Norco, La., with a load of naphtha. The vessels were bound for a Valero refinery in Port Arthur, Texas. Leland Bowman Lock is located en route at mile 163W of the Gulf Intracoastal Waterway.

The captain retired for the night at about 0030 on March 22, and he woke up about 4.5 hours later between 0500 and 0515. He came to the wheelhouse soon after waking to relieve the pilot. The pilot offered to guide the vessel through the Leland Bowman Lock, but the captain declined, the report said. 

That decision went counter to General Marine Services’ operations manual that said changes of watch should not occur during a “critical move,” the NTSB said. Such moves include passing under bridges, docking or transiting through locks. 

Ava Claire and its tow made about 5.2 mph as the vessels came within a quarter mile of the lock. Its speed decreased as the tow entered the lock. Soon thereafter, the vessel’s electronic chart system failed. Radio communication with the deck hand calling distances was spotty until the tow was within 250 feet of the western lock gates. 

“The captain said that when the tow was about 200 feet from the gates, he put the engines at full astern,” the report said. “The tow continued to slow but did not fully stop before the starboard bow of the HFL 439 struck gate No. 3 on the northwest side of the lock at 0522.”

The captain helming the tow had more than 30 years of towing experience, and he had locked through the Leland Bowman site numerous times. But this was his first time passing through the locks in Ava Claire, which has less stopping power than the 2,600-hp towboats he’d operated for the previous six years. 

The incident happened before dawn, and the captain admitted lighting within and around the lock affected his depth perception. A tidal current also pushed on the towboat’s stern within the lock chamber. 

“The captain’s limited familiarity with operating the lower-horsepower Ava Claire in the Intracoastal Waterway may have contributed to a misjudgment of the timing and magnitude of the engine commands needed to slow the tow as it entered the Leland Bowman Lock,” the NTSB determined. 

The NTSB noted the company policy against changing the watch before critical maneuvers and said the captain should have known these policies. However, the agency acknowledged the captain’s decision to take the watch might itself have stemmed from impairment caused by sleep inertia.