The duck boat involved in the accident in Missouri that left 17 sightseers dead was not allowed to operate in water if winds clocked in at 35 mph or waves were higher than 2 feet, according to the vessel’s certificate of inspection that the US Coast Guard has released.

“Vessel shall not be operated waterborne when winds exceed thirty-five (35) miles per hour, and/or the wave height exceeds two (2) feet,” according to the certificate, which was filed Feb. 7, 2017.

The Coast Guard announced it has convened a formal Marine Board of Investigation into the July 19 accident involving a Ride the Ducks of Branson duck boat.

The vessel sank at Table Rock Lake near Branson during a storm.

Video and audio from the boat, recovered by divers, showed that the lake was calm when the boat entered the lake, but the weather suddenly turned violent and within minutes the vessel sank.

The National Transportation Safety Board has said the wind speed at the time of the tragedy was more than 70 mph, just short of hurricane force.

Weather forecasts had warned of an impending storm with winds possibly exceeding 60 mph.

The wave height wasn’t known, but cellphone video shot by passengers on a nearby boat showed waves that appeared to be far greater than 2 feet high.

An email message from the Associated Press seeking comment from Ripley Entertainment, the company that owns Ride the Ducks of Branson, was not returned.

The Coast Guard said the Marine Board of Investigation is its highest level of investigation.

The inquiry will be conducted by a five-member board. No timetable for the probe was released.

“The Coast Guard will conduct a thorough and detailed investigation to identify all potential causal factors associated with this tragedy,” Capt. Wayne Arguin, chairman of the Marine Board of Investigation, said in the news release.

In addition to the weather, the probe will look at regulatory compliance of the boat and crew member duties and qualifications, the Coast Guard said.

The board also will examine whether misconduct, inattention, negligence or willful violation of the law were factors, as well as whether the Coast Guard and other governmental agencies provided adequate oversight.

With Post wires