Washington (CNN) Ripley Entertainment and Ride the Ducks Branson are to blame for the 2018 sinking of a duck boat in Missouri that killed 17 people because managers did not relay a severe weather forecast to the vessel's captain, federal investigators concluded Tuesday.

The nearly two-year long National Transportation Safety Board probe found a "systemic problem with the company as a whole," an investigator said at a board meeting Tuesday.

The board decided against specifically naming the captain of the Stretch Duck 7 in its findings of fault.

"You can't know what you don't know," NTSB Chairman Robert Sumwalt said, noting that when the vessel arrived at the shore of Table Rock Lake on July 19, 2018, "it was glassy smooth on that lake."

But while the amphibious vehicle, a World War II-era boat refitted to carry sightseeing passengers, toured the lake, the heavy storms that forecasters warned of arrived. The boat began taking on water due to unusually large waves.

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