In dramatic opening testimony Monday in the federal Ride the Ducks trial, a lawyer for the families of two Hungarian tourists killed in the July 2010 accident said one of the victims lost her life because she took time to throw a life vest to someone already in the water.

"Sixteen-year-old Dora Schwendtner throws her life preserver to Kyle Burkhardt to save his life, and because of the defendants' failures, she lost hers," said Robert Mongeluzzi, a lawyer representing the families of Schwendtner and Szabolcs Prem, 20, the second victim.

The defendants are Ride the Ducks, which operates the amphibious vehicles, and K-Sea Transportation Partners, which owns the tug that pushed a barge into a duck boat carrying Schwendtner, Prem and 33 others.

It was difficult to see details in the video that appears to show Schwendtner's lifesaving action. In it, a passenger wearing a white shirt throws a life vest overboard to Burkhardt, the first mate on the duck boat, who leaped overboard as a barge descended on the smaller vessel. Mongeluzzi said Schwendtner's body was found in the Delaware River wearing a white shirt. The person on the video tossing the life jacket was sitting where Schwendtner sat on the boat.

On July 7, 2010, the captain of the duck boat, Gary Fox, had stopped the boat on the Delaware River after he saw smoke coming from the engine. As the duck vessel waited to be towed to safety, the barge ran over it, pushing it under water. A National Safety Transportation Board investigation found that Matt Devlin, the first mate on the tug, was using his cell phone and laptop as he dealt with a medical emergency involving his son.

Parents of both Hungarian students sat in the first row of the courtroom. Monday was the first time they saw the video that seems to show Schwendtner trying to help Burkhardt.

"Watching the videos and the tape of my daughter dying was horrible," Schwendtner's father, Peter, said through his lawyer and interpreter Peter Ronai.

During the video, Schwendtner's mother, Aniko, dabbed her eyes with a white tissue.

An 1851 maritime law limits liability in some cases to the cost of the vessels involved. Lawyers for Prem, Schwendtner and other passengers must show that Ride the Ducks and K-Sea Transportation Partners can be held liable for more than the $1.8 million value of the boats.

Mongeluzzi, Wayne Meehan, the lawyer for K-Sea, and John Snyder, who represents Ride the Ducks, sparred before U.S. District Judge Thomas O'Neill Jr. over who was at fault in the accident. O'Neill will decide the case in the nonjury trial, which is expected to last about one month.

Meehan said one person deserved blame: Devlin, who is serving a one-year prison sentence for involuntary manslaughter in the case.

Just before he began piloting the tug that day, Devlin learned that his son, who was having minor surgery, had been deprived of oxygen for several minutes. K-Sea policy calls for crew members who have a problem on watch to ask the captain for relief, but Devlin never did that. Instead, he was on the cell phone with his wife and on a laptop computer, researching his son's medical problem.

"Due to his diminished mental state, Devlin did not call the captain," Meehan said. "This accident was solely caused by what I will refer to as Devlin having a meltdown."

But Mongeluzzi said cell-phone use was rampant among K-Sea crew members. He said he will present testimony that the tug's captain, Ben Woods, used his cell phone thousands of times while on watch over many years.

K-Sea never enforced a policy saying that crew members should not use their cell phones on watch, Mongeluzzi said.

"This [accident] is the by-product of years of ineffective and inconsistent policy by K-Sea," he said.

Meehan said the company had clearly communicated the policy to employees.

Luis Fernandez, a deck hand on the tug, testified that he used his cell phone at least once on every watch. Under persistent questioning from Mongeluzzi, Fernandez also said K-Sea had never told him that he was supposed to check on the person on watch - Devlin, in this case - when the tug was in busy areas, such as the Delaware River near Philadelphia.

If Fernandez had checked hourly, he might have learned that Devlin was upset and needed to be relieved from his watch, Mongeluzzi said.

"If they had actually trained them to follow the [K-Sea] manual, the accident would not have occurred," Mongeluzzi said.

Also Monday, Alysia Petchulat, a passenger on the duck boat that day, described the terror of falling into the dark Delaware. She had traveled with her son, Cole, who was 11 at the time, and friends to Philadelphia from Illinois. She testified that Fox, the boat's captain, never told people to don their life jackets. As the barge moved closer, Petchulat grabbed a life vest for Cole and put it over his head.

As passengers realized the barge was going to hit the back of the duck boat, they pushed to get to the front of the vessel, Petchulat said.

"I grabbed him, gave him a bear hug, took a deep breath, and said, 'OK, we are going to do this,' " she said. Just then, the barge "pushed us, and we kind of rolled," Petchulat said.

She tried to hold on to Cole, but he slipped out of her arms. As she struggled in the dark water, she could not tell which way was up. She surfaced but still could not see her son.

"You could feel people underneath, trying to get up," she said. "It felt like Cole was underneath me trying to claw his way up." Moments later, she saw Cole bob up above the surface, safe.