There was an engine fire, and the Ride the Ducks boat stalled out. The watercraft drifted, powerless in the Delaware. The Center City skyline loomed behind them, hazy behind the waves of 103-degree heat, and crew members told the tourists to hang tight - a rescue boat was on the way.
One of the passengers called her husband to tell him what was going on, that the Duck boat was dead in the water - and then suddenly the husband heard a scream. The phone went dead.
It was 2:39 p.m.
On the riverbank near Penn's Landing, Meg Scharpf, a tourist from Phoenix, saw what the husband on the phone could not see - a massive 250-foot barge, pushed by a tugboat and seemingly headed right toward the listless watercraft.
At first, Scharpf said, everyone on the boat appeared from the shore to be relaxed, even laughing. The Arizonan thought to herself there was no way the barge could strike the tourist-packed vessel, but that is exactly what happened. Some on the shore were yelling frantically toward the tug: "There's a boat! There's a boat!"
"There was nothing they could do," Scharpf said. "It was the most horrible thing I've ever seen. Everybody seemed to disappear and then they all started popping up with their life vest on."
Except that many had just a few seconds to get those life vests on - and not everybody made it.
"I pushed my [9-year-old] daughter over the side of the boat and tried to get the life jacket on her and I grabbed her by her hair as the boat rolled over on top of us," said one of the passengers, Kevin Grace, 50, of St. Louis. "It was really chaotic. It was flailing bodies everywhere and water and air bubbles."
Not everyone was as fortunate as Grace and his daughter. Until last night, police divers searched the murky waters and the watercraft - which capsized and sank 50 feet to the river bottom - looking for two passengers not accounted for.
The two were reported to be young tourists from the Hungarian group - a 20-year-old man and a 16-year old girl.
The 35 other passengers and crew were plucked from the fast-moving Delaware current, some by helicopter and some grabbing onto a hose. Ten of the passengers - some visibly shaken - were rushed to Hahnemann University Hospital but none of their injuries were serious. Two declined treatment and the rest had been released by last night. The others were treated at Penn's Landing, many at the Independence Seaport Museum.
City officials said the massive barge that struck the tourist-laden Duck boat, the Resource, was owned by the city but operated by a contractor, K-Sea Transportation. The barge hauls sludge from a biofuels plant in Northeast Philadelphia to a recycling plant in Southwest Philly.
Ride the Ducks, owned by Herschend Family Entertainment Co., of Norcross, Ga., runs similar land-and-water tours across the country and said it had never had an accident of this type before.
Nevertheless, the apparent Philadelphia tragedy is certain to rekindle the debate over the safety of tours using the amphibious vehicles that were developed for World War II.
In 1999, a Duck boat operated by a different company sank rapidly in Lake Hamilton, Ark., as the overhead canopy trapped passengers, 13 of whom died.
Here in Philadelphia, a new Duck-boat disaster may raise fresh questions about the intersection of tourism and industry on the busy and sometimes crowded Delaware - an intersection that may have turned deadly in a matter of seconds yesterday.
"We're doing everything we can to search for the unaccounted for individuals, as well as to find the vessel that has sunk," Mayor Nutter said last night. "We're putting all of our efforts and forces into that on the water and in the air. This is a very serious situation and were going to do everything we can to obviously get to the bottom of it."
Divers searched until 10:30 last night for the two missing passengers, whose names were not released. The city Police Department's marine unit said divers would resume searching at 6 a.m. today.
The search, which focused on the submerged boat, was hampered by poor visibility. Police Commissioner Charles Ramsey said the divers couldn't see far in the murky water. "It's like diving with your eyes closed," he said.
Officials said that the Ride the Ducks vehicles are inspected regularly by the state Public Utility Commission for land use and the Coast Guard for water use, and that there were no problems. In addition, authorities said, all of the Duck boat's permits and licenses were up to date.
Still, there were many questions last night. Coast Guard officials said they have no record of a distress call from the disabled watercraft, even as the barge bore down.
The father of an 18-year-old deckhand on the boat who did not want to be identified by name said last night that "The Duck boat tried to contact the captain of the tugboat and they just ran 'em the hell over . . . There is no reason for anybody to run anybody over on the Delaware River. It's not like there's fog out there!"
The National Transportation Safety Board launched an immediate probe and said it would review radio recordings captured by the Coast Guard to reconstruct what happened. It also plans to interview riders on the Duck boat and perform a sight test to determine whether the tugboat operator could have seen the smaller boat, according to Robert Sumwalt, an NTSB board member.
Nothing seemed amiss at 1:30 p.m., when the Duck boat left from its land base at 6th and Market streets and soon entered the Delaware just to the south of the Ben Franklin Bridge.
Not surprisingly, most of the passengers were tourists visiting Philadelphia at the height of the travel season, just three days after the city's extensive July Fourth activities.
Carol Eberherd, of Wilmington, Del., who works in the Bourse Building near Independence Hall and the site where the Duck boat departs, had urged her niece and two grand-neices who were visiting from North Carolina to take the tour.
"I kept telling them that if you do anything, you've got to do the Ducks tour," Eberherd said. "You've got to do the Ducks. Now I feel guilty."
Apparently it was not long after the Duck boat entered the river that the engine caught fire, forcing the crew to shut down the vessel and call for help. According to the passengers, the crew dropped anchor a few minutes later.
"Then they threw out an anchor and we waited for someone to tow us back," said Grace, from St. Louis, who along with his daughter was in the boat along with a 31-year-old female companion and her 11-year-old son.
"We saw the barge head toward the boat but it happened pretty quickly - we had maybe 45 seconds to put our life jackets on," he said.
Other tourists and day-trippers watched the tugboat and barge approach the stalled watercraft with a mixture of horror and disbelief.
"We saw a lot of people waving and yelling at the boat and we could see that it looked like the barge was heading right for it," said James Scharpf, one of a group of family members touring Penn's Landing before visiting the Liberty Bell.
"It became clear that something was going to happen, and everyone on shore was yelling to the tugboat, 'There's a boat! There's a boat!' "
When the barge struck, the passengers were tossed into the Delaware in an instant.
"I thought for sure half of those people were dead. It was horrible, they all went under," witness Meg Scharpf said. "And then we saw them pop up to the surface, like corks. They all had their vests on. Those life vests saved them."
Still, the rapid current made rescue efforts difficult.
"Everyone had life jackets on, and they were floating, a lot of them were scared, but no one was drowning," James Scharpf said. "We saw a hose laying on the dock and we pulled it over to the edge of the embankment and dangled it down for them to grab.
"They were floating and paddling and really working hard to make it to the shore. The current was strong. We were able to pull six people out of the river."
The incident left all of those involved badly shaken, even though most did not suffer serious injury. Outside Hahnemann, one girl was protected by being wrapped in an American Red Cross blanket, while her mother covered her own face with another blanket.
Down at the river, Sandy Cohen, an older woman visiting from North Carolina, was escorted to a waiting police car. Her husband was still wearing the Duck whistle customers get while on the tour.