The Hungarian youths killed in last week's Duck-boat crash were each the sole child in their family.

Now their parents have no children, and they want answers.

"They want to find out what really happened," said Peter Ronai, the Hungarian-American lawyer who is representing the families of Dora Schwendtner, 16, and Szabolcs Prem, 20.

To help him with this endeavor, the New York attorney and his law partner/wife, Holly Ronai, hired "catastrophic personal injury" lawyers Bob Mongeluzzi and Drew Duffy on Thursday to represent the families in Philadelphia.

And Mongeluzzi knows who he's going after.

"We intend to proceed ahead against the corporations that we believe caused this catastrophe, which is K-Sea Transportation and Philadelphia Ride the Ducks LLC," he said.

Schwendtner, a thespian at heart who performed for the disabled, and Prem, who learned to speak English at age 5 by watching cartoons, both died in the accident on the Delaware River.

They drowned when a tugboat operated by K-Sea Transportation of New Brunswick, N.J., pushed a 250-foot, city-owned sludge barge into the back of the Ride the Ducks boat filled with 37 passengers, including a contingent from Mosonmagyarovar, Hungary.

The other 35 people survived the crash, which is under investigation by the National Transportation Safety Board.

Ride the Ducks is owned by Herschend Family Entertainment Co., of Norcross, Ga.

Mongeluzzi said his firm, Saltz Mongeluzzi Barrett & Bendesky, has handled about 50 loss-of-life cases, but "the death of a child is a very different thing. It is devastating."

"It is a wound from which no parent can ever fully heal," he added.

Duffy and Mongeluzzi were en route last night to Vienna, Austria, which is a 45-minute drive to Mosonmagyarovar, population 32,000, where the Schwendtners live. The Prem family lives 15 minutes away in the tiny village of Yanos Somorja, population 300, Ronai said.

Mongeluzzi also represented victims in the Pier 34 collapse that killed three women on the Delaware River in May 2000, and in the Tropicana Casino Resort parking-garage collapse, which resulted in four deaths and 24 injuries in October 2003.

Mongeluzzi said families don't think about money in most cases when there's loss of life.

"They want to know how can this happen? Why did it happen? How can we prevent this from happening again?" he said yesterday from his Liberty Place office with a bird's-eye view of the Delaware River.

"Clearly, these families suffered the most devastating of all losses," he said of the Prems and Schwendtners.

Mongeluzzi and Duffy asked the public to contact them if they have any images, videos or information from the day of the crash.

People close to Dora's mother have set up a post-office box for her so that those in Philadelphia can send her correspondence. Anyone can send letters - no money - to Aniko Takacsne, Box 9201-PF 157, Mosonmagyarovar, Hungary.