The city and Coast Guard must impose a moratorium on Ride the Ducks service on the Delaware River because the vessels are potential "death traps," the attorneys representing the families of two victims who drowned in the July 7 Duck-boat accident said yesterday.

The boats' canopies and lack of buoyancy make for a fatal mix, attorneys Bob Mongeluzzi and Holly Ostrov Ronai. said.

They cited a 2002 National Transportation Safety Board report on the Miss Majestic sinking in Lake Hamilton, Ark., that killed 13 people, to support their claims.

The report recommended to the Coast Guard that Duck boats be altered to have sufficient reserve buoyancy and that the canopies be removed.

Once a Duck boat fills with water, it sinks like a bag of rocks, Mongeluzzi said. Meanwhile, the natural buoyancy of passengers traps them against the canopy.

"Now, to me, a vessel that has both of those dangers is a death trap, and it's been proven in Arkansas and now in Philadelphia," Mongeluzzi said.

Thirty-seven people were in Duck boat No. 34 when it stalled in the river and a tug boat pushed a barge into it.

Dora Schwendtner, 16, and Szabolcs Prem, 20, tourists from Hungary, drowned. Ronai and Mongeluzzi represent their families, who will be in the United States "in the near future," Ronai said yesterday.

The Arkansas Duck-boat accident killed 13 people, three of them children. That boat was operated by the now-defunct Land and Lakes Tours Inc.

Changes to make the boat buoyant would have been "easy," but Ride the Ducks seems concerned about money, Ronai said.

A sister company manufactures boats for Ride the Ducks, "but I'm sure it would have cost more money to change the boats," she said. "It really has to be the bottom line we're talking about here."

On its Web site, Ride the Ducks said it's cooperating with the NTSB and that its own inspections "confirmed that our vessels are safe and adhere to a robust set of operating and training standards which meet or exceed U.S. Coast Guard or local standards."

Doug Oliver, a spokesman for Mayor Nutter, said no decision on a moratorium "will be made until we have at least the preliminary reports of the NTSB investigation in hand."