The 2018 sinking of a duck boat on Missouri's Table Rock Lake that killed 17 people would likely not have occurred if the U.S. Coast Guard had acted on recommendations made after a similar tragedy more than two decades ago, NTSB investigators said Tuesday.

During a teleconferenced meeting of the National Transportation Safety Board ahead of the release of the agency's final report on the accident, investigator Brian Young also said the accident could have been avoided if the operator of the Ride the Ducks attraction had heeded weather warnings of an impending derecho.

"On the day of the accident, the National Weather Service accurately forecasted and issued timely notifications of a severe thunderstorm that would impact the accident location," an abstract of the yet-unpublished final report concluded. "Ride the Ducks did not effectively use all available weather information to monitor the approaching severe weather and assess the risk it posed to its waterborne operations."

About 35 minutes after leaving the dock near the resort town of Branson on July 19, 2018, Stretch Duck 7, a modified World War II-era landing craft known as a DUKW, was seen struggling to make headway through steep waves as it took on water. Of the 31 people aboard, 16 passengers — including nine from the same family — and one of the two crew members aboard drowned.

The National Weather Service has said that winds reached 65 mph on the lake at the time of the accident.

The boat's captain, Kenneth Scott McKee, survived the accident. He was indicted in November 2018 on 17 counts of misconduct, negligence and inattention to duty by a ship's officer. More charges were added to McKee's indictment in June of last year, when two other employees of Ride the Ducks of Branson — its general manager at the time of the accident, Curtis P. Lanham, and operations supervisor, Charles V. Baltzell — were also charged with negligence.

At the NTSB teleconference, investigators reiterated that failing to implement all 22 recommendations the agency made after a previous duck boat sank in Arkansas in 1999, killing 13 people, contributed to the 2018 accident. All but nine of them were ignored, including a key recommendation to add "reserve buoyancy" to the boats, allowing them to stay afloat after taking on water. Among other problems with the design of the vessels, the NTSB said they had insufficient "freeboard" — clearance between the deck and the waterline.

"NTSB investigators found that the accident vessel was originally constructed with a low freeboard, an open hull, and no subdivision or flotation, resulting in a design without adequate reserve buoyancy. Additionally, the NTSB cited previous inaction to address emergency egress on amphibious passenger vessels with fixed canopies which impeded passenger escape from the Stretch Duck 7," investigators concluded.

The NTSB released an April 15 letter it received from Daniel Abel, vice admiral of the Coast Guard, in which the service agreed that canopies and side curtains should be removed from the boats.

NTSB Chairman Robert Sumwalt said duck boats should not be allowed to operate until the agency's recommendations are implemented. As of last year, more than a dozen duck boat tours were operating across the U.S. from California to Maine.

Sumwalt said he was "very optimistic" the Coast Guard was committed to improving small passenger boat safety.

Ripley Entertainment, which operated the now defunct Ride the Ducks of Branson, has settled 31 lawsuits filed by survivors or relatives of those who died, according to The Associated Press.

"We remain dedicated to working with the community of Branson, and continuing our support of all those who were impacted by the accident," company spokeswoman Suzanne Smagala-Potts said.

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