The accident happened off Market Street and Columbus Boulevard around 2:40 p.m. Wednesday. The Coast Guard says 37 people were on the boat, including two crew members.
Philadelphia police say the boat had just entered the water south of the Ben Frankin Bridge and was to make a routine loop of the Delaware River when it suffered a small engine fire, rendering the boat helpless.
It was struck about 10 minutes later by a barge used to transport sludge pulled by a private tugboat, then sank.
A woman on the boat, Sandy Cohen, said "A barge went into us. We had engine trouble, so we were just waiting for somebody else to come and tow us." When asked if she had any warning, Cohen said "Not about the barge," then added "Just very briefly."
Bystanders nearby could only watch the collision.
"They didn't blow a horn or anything. The people were trying to get out of the boat, I saw them trying to get out of the boat because they saw the barge coming; the barge just ran over the top of them, it, actually, sunk under," witness Omar Lamoumba said.
"It pretty much ran over that boat, it crushed it into pieces, everybody jumped off the boat. You could tell eveyrbody had life vests," witness Eric Scharpf said.
Witness Tiffany Michaels told Action News: "People on the Duck, from what I could tell, were standing up. It looked like they were in a state of panic, probably thinking 'should I jump or not?' at which point the barge hit the duck from behind. It looked like the duck boat had capsized, the barge plowed over it."
The boat sank and was located around 6:20 p.m. in 40 to 50 feet of water by police using divers and SONAR.
As for the two missing people, Police Commissioner Charles Ramsey said the diver could not see but a few inches in the murky water.
"You cannot see inside [the boat] and it's too dangerous for the diver to try to get in it...you've got to lift it up," Ramsey said.
Hahnemann University Hospital spokeswoman Coleen Cannon says 10 people were taken there after Thursday afternoon's collision between the tourist boat and a barge. The victims included four from Hungary and others visiting from the Midwest.
Cannon says two declined treatment and eight others - three teenagers, three younger children and two adults - were treated for minor injuries. By 8 p.m., Cannon says, all of them had been treated and released.
One crew member from the duck boat was rescued by the ferry that the Delaware River Port Authority was operating on its scheduled route between Philadelphia and Camden, said authority spokesman Ed Kasuba.
The company says everyone onboard is routinely issued life jackets. The people coming to shore could be seen either wearing or carrying flotation devices.
Those rescued were taken to the Seaport Museum which was transformed into a makeshift triage unit.
"People were freezing; we got them clothes, socks, blankets, food, things to drink, and we're starting the emotional support process," Tom Foley of the American Red Cross said.
Survivor Russell Kean may have been freezing, but he took time to thank the rescuers.
"The police and fire did a super job, as well as the Coast Guard; they were there in minutes, all of them," Kean said.
The city Water Department uses the barge to transport sludge from a sewage plant in northeast Philadelphia to a recycling plant down river, said Maura Kennedy, a Nutter spokeswoman.
The barge was directed by a tugboat owned by K-Sea Transportation Partners of East Brunswick, N.J.
A spokeswoman at the company's headquarters in Norcross, Ga., said it would issue a statement when it had more information.
In a brief press conference around 9:00 p.m., the 'Ride the Ducks' company gave a statement concerning the accident.
"I'd like to share with all of you that 'Ride the Ducks' extends our heartfelt feelings to the families of the guests who were on our vehicle today. It is their comfort and wellbeing that is our first priority. We will continue to work with the authorities on the recovery effort," spokesperson for Ride the Ducks, Sharla Feldscher, said.
At a waterfront news conference earlier in the day, Mayor Nutter said authorities were trying to figure out exactly what happened.
"This is a very serious situation, and we are going to do everything we can to get to the bottom of it," he said.
A Coast Guard spokesman, Thomas Peck, said neither craft was in a wrong lane.
It is unclear if the duck boat sent out a distress signal. The Coast Guard says it did receive a distress signal around the time of the collision, but it is not clear if the signal came from the duck boat or some other vessel.
The NTSB will investigate that amongst other issues.
Late Wednesday night, the NTSB held a press conference concerning the incident.
NTSB spokesman Robert Sumwalt said the Coast Guard will be assisting them in the investigation. While Sumwalt told the press, officials had just arrived to Philadelphia and details remained scarce, he did mention they would try to reconstruct the crash by using a variety of resources.
"There are a number of photographs from people on the dock, and possibly, possibly, maybe some occupants from the Duck that would have photographs, as well...we will be interviewing any witnesses we may learn about that may have good photographs that may help us with the investigation," Sumwalt said.
Sumwalt said typically the NTSB performs a '72-hour history' to learn the physical and mental state of the people operating all the vessels involved.
Previous accidents
According to the Associated Press, a duck boat sank at Hot Springs, Ark., on May 1, 1999, killing 13 of the 21 people aboard after its bilge pump failed. The National Transportation Safety Board blamed inadequate maintenance and recommended that duck boats have backup flotation devices.
In June 2002, four people were killed when an amphibious tour boat, the Lady Duck, sank in the Ottawa River near Canada's Parliament.
History of Ride the Ducks
According to the Ride The Ducks website, the company claims to be the nation's largest amphibious tour operator with a fleet of over 90 vehicles, carrying over 1,200,000 guests each year around the United States.
The sightseeing tour begins on the corner of N. 6th and Market Streets next to the Independence Visitor Center. On land, the tour goes through historical Philadelphia, passing by such landmarks as Independence Hall, The Philadelphia Mint, Christ Church and the Betsy Ross House.
The bus then enters the Delaware River at Penn's Landing for sightseeing of the Adventure Aquarium, Battleship New jersey and the Benjamin Franklin Bridge.
The company says that their vehicles are regularly inspected, tested and certified by the United States Coast Guard.
Ride The Ducks was started in 1977 in Branson, Missouri by Bob McDowell. In 2001 Ride The Ducks partnered with the Herschend Family Entertainment in pursuit of a national and international expansion and then in 2003, Ride The Ducks of Philadelphia was opened.
Herschend Family Entertainment also owns Adventure Aquarium in Camden, New Jersey.
In 2004 The Herschend Family Entertainment company, headquartered in Norcross, Georgia, became the sole owner of the company.
The Duck vehicles are based on the classic WWII DUKW amphibious design, first built by General Motors in 1942. Today, Ride The Duck builds their vehicles from the ground up using "the latest in marine design and safety."
