Updated

The duck boats in Branson, Mo., like the one that capsized in a Missouri lake Thursday, resulting in 17 deaths, are not up to federal safety standards, a private inspector asserted Friday.

Steve Paul, who conducts vehicle inspections for both businesses and consumers, said the exhaust system on the front of the vessels used in Branson may have contributed to Thursday night’s tragedy, FOX 2 in St. Louis reported.

Paul, with Test Drive Technologies, said engines seize up when exhausts take on water and leave only the rudder to steer.

“You have no propulsion and you’re not going to have any bilge, you’re not going to have the pump inside the hull to pump water out of the boat,” Paul said. “It’s a dead stick, dead in the water.”

“You have no propulsion and you’re not going to have any bilge, you’re not going to have the pump inside the hull to pump water out of the boat. It’s a dead stick, dead in the water.”

— Steve Paul, inspector, Test Drive Technologies

Suzanne Smagala with Ripley Entertainment, which owns Ride the Ducks in Branson, said the company was assisting authorities in their investigation of the tragedy. It was the company's only accident in more than 40 years of operation, she said, according to the Associated Press.

Paul, who said he inspected 24 duck boats in Branson last August, said the boats’ exhaust didn’t meet federal regulations.

Department of Transportation regulations prohibit exhausts forward of the passenger compartment, Paul said. To comply with those standards, the exhaust should have been higher than or behind the passengers, he added.

But oversight of the “amphibious” vehicles falls under the jurisdiction of the U.S. Coast Guard, a DOT spokesman told FOX 2.

Paul said the duck boats -- which also operate on land -- shouldn’t be on the road or in the water unless the two agencies invoke a common safety standard. It’s unclear if either agency took any action between last August inspection and Thursday night’s tragedy, he said.

Meanwhile, some 300 mourners gathered in Branson on Friday, one day after the tragedy, for a vigil in memory of the victims. The crowd sang "Amazing Grace," prayed, and held candles in honor of the 17 people who died.

Another 75 people gathered at a separate vigil.

The Associated Press contributed to this report.