In interviews with NTSB on Friday, the duck boat master said he tried to tell the tow boat guiding the barge to change course, but there was no response.

The fact that others in the area heard his call, which he said he made when the barge was 400 yards away, indicates that the fault more likely lies with the tow boat’s equipment or crew.

The duck boat had shut off its engine and set anchor because it was having engine problems.

When the barge hit the duck boat, the duck boat quickly sank. Two of the passengers were fatally injured. The other thirty-five people on board survived.

The two who died were Hungarian students, 16-year-old Dora Schwendtner and 20-year-old Szabolcs Prem. They were in the U.S. for an faith-based exchange program.

At a press conference Friday night, NTSB board memebr Robert Sumwalt said the master of the boat, a 58-year-old man with the duck boat company for three seasons, told NTSB he found no irregularities during his routine pre-trip inspection.

But the two marine communication tools on board — an airhorn and a VHF radio — were both unsuccessful at catching the attention of the tug boat pushing the barge that collided with the duck boat.

The airhorn didn’t work, although the master said it did when he checked it before the trip. It’s unclear whether the VHF transmitted the message properly since there was no response.

The master said he tried to hail the tug boat operator on a channel meant for boat-to-boat communication. The Coast Guard does not monitor that station.

The master and deckhand told NTSB that after they turned around to head back to the dock, they noticed smoke coming out of the engine. The master described it as “white” and “acrid” smoke, while the deckhand described the smell as similar to “burning rubber.”

The deckhand checked the engine out. There were no flames,  but the master turned off the engine just in case and notified the duck boat dispatcher that they had stopped.

The boat was stopped for five to 10 minutes before the collision with the barge. In that time, another duck boat came by and offered help, but the master or deckhand declined, Sumwalt said.

The master said that when the barge was about 400 yards away, he tried to reach the tug boat operator over the radio and requested that it change course. He said he didn’t receive a response.

It was around that time that either the master or the deckhand told passengers to put on life jackets.

They also interviewed 16 duck boat passengers Friday. Their testimonies were mostly consistent with each others’ accounts and the accounts of the deckhand and master.

“Our investigation at this point is right where it should be. We’ve only been on the ground here for two full days,” Sumwalt said, an answer to the unasked question of why more definitive information couldn’t be made available.

Tomorrow NTSB will interview the five tugboat crew members.

“Our job is to find out what happened. Our goal is to prevent it from ever happening again. It’s a true tragedy of untold proportions,” Sumwalt said.

A U.S. Coast Guard boat circles the site of the accident shortly after 8 a.m. Friday. The boat sank in the Delaware River, only a couple hundred yards off of Penn’s Landing. The river is a busy site for both recreational and commercial use and large freighters like the one in the background are common. The channel is relatively narrow at this point in the river. There isn’t much room for boats to move around.

The salvage company’s barge, being pushed by a tug boat, arrives at the site of the accident. Weeks Marine, the salvage company selected, also salvaged the plane that crashed into the Hudson River last year.

The Philadelphia Police Department’s marine unit makes an attempt to recover the body of one of the duck boat passengers. The strong current pulled his body underneath the barge and police were unable to retrieve it until the barge left at the end of the day. One of the police officers in dry suits later attempted to swim under the barge and retrieve the body.

The duck boat, here being lifted by a crane on the salvage company barge and held by straps that were pulled underneath the hull, broke the surface of the river around 1:30 p.m. Salvaging attempts began at 8:15 a.m.

By the afternoon, dozens of bystanders had gathered at Penn’s Landing to watch the recovery efforts. Person after person expressed shock at the accident.

The duck boat is loaded onto the salvaging barge. It broke the surface around 1:30 p.m., but was not secured on the barge until about 2:50 p.m. A significant amount of water had to be drained from the hull, according to police officers at the scene.

Officials gather at Penn’s Landing to watch recovery efforts Friday afternoon around 2:30 p.m. From left: NTSB public information officer Keith Holloway, board member Dr. Mark Rosekind, board member Robert Sumwalt, a member of the NTSB investigative staff and two officers from the Philadelphia Police Department.

When the salvaging barge left the site around 3 p.m., the trapped body of 20-year-old Szabolcs Prem, one of the duck boat passengers, came up to the surface and began drifting downstream. Bystanders were the first to notice the body, which police are pictured here retrieving. The other deceased passenger, 16-year-old Dora Schwendtner, was found near the Walt Whitman bridge at 4:45 a.m. by a local fisherman.

A salvage company brought the boat out of the water at about 2:45 p.m. and loaded it onto the company’s barge. The company will bring the boat to shore for closer inspection.

From Penn’s Landing,  200 yards from the accident site, the only sign of damage visible was a crushed canopy, but there could be more damage to the side of the boat that couldn’t be seen.

One passenger, 16-year-old Dora Schwendtner, was found at 4:45 a.m. downriver from the accident site. A fisherman found her near the Walt Whitman Bridge on his way out for the day, the Philadelphia Inquirer reported.

The body of the other, 20-year-old Szablcs Prem, was recovered by the Philadelphia Police Department’s marine unit at about 3:10 p.m. It was first spotted around 9 a.m., before his body drifted underneath the salvage company’s barge. The current was too strong for the police to recover the body until after the barge moved.

Both were Hungarian citizens visiting the United States on a church program, the Inquirer reported.

Although the Philadelphia Police Department’s work is almost done, NTSB still has much ahead of it. Board members Robert Sumwalt and newly-approved Dr. Mark Rosekind came to Penn’s Landing around 2:30 p.m. Friday to watch recovery action.

NTSB Lead investigator Tom Roth-rothy spent much of the day onboard a local Coast Guard boat, observing recovery efforts.

Rosekind and Sumwalt spent much of the time in serious talk with local police and Coast Guard officials and were there when the second body was recovered.

NTSB declined to comment until tonight’s press conference at 8 p.m., where they will discuss findings from today’s investigations.

Check back later tonight for a series of photos from today’s work.

But board member Robert Sumwalt, the only one to speak at the press conference, spent more time telling local media that NTSB still has few answers and it will be a long time before some of their most pressing questions are answered.

Thirty-seven people were thrown into the Delaware River Wednesday afternoon when a barge collided with the amphibious duck boat they were on. Thirty-five people were immediately rescued.

The U.S. Coast Guard suspended the search for the two missing people on Thursday night.

When a television reporter asked Sumwalt what he thought about tourists getting mixed up in an accident involving the industry side of the marine sector, Sumwalt’s only response was “It’s tragic.”

At the time of the collision, the duck boat was at a halt on the river, waiting for assistance after a reported engine fire disabled the engine. A tugboat was pulling the barge.

NTSB is taking the lead on the investigation and questions are being deferred to board member Robert Sumwalt and lead investigator Tom Roth-rothy, who are in Philadelphia supervising the investigation team.

Sumwalt said that NTSB expects to have investigators on the scene for seven to 10 days total, meaning they could depart as early as the end of next week.

Investigators will take all of the data and information collected and bring it back to Washington, D.C., where NTSB is headquartered. It will likely take several months to put all the pieces together and determine everything that went wrong Wednesday afternoon.

While on the scene, investigators will be gathering all kinds of information and data on the actual boats involved, their operating procedures, their crew members and their emergency preparedness and response. That will come form actual inspections of the boats, records and equipment and extensive interviews with passengers, crew and first responders and rescuers.

For local coverage of the accident, you can check out the Philadelphia Daily News and Philadelphia Inquirer at www.philly.com. Thursday’s main story on the accident focuses on confusion about why the tug boat was unaware of the duck boat’s presence.

Keep checking back for more updates and some photos of the accident site. Contact reporter Ariel Zirulnick at ariel.zirulnick@news21.com if you have any leads.

Thirty-five of the 37 people on board were rescued. Two are still unaccounted for. The Duck boat is at the bottom of the Delaware River.

The Duck boat was stopped in the shipping channel because of an engine fire that prompted the crew to cease operations, according to the Philadelphia Inquirer. They were waiting for a rescue boat to come get them.

The National Transportation Safety Board has launched an investigation into the accident. Board member Robert Sumwalt will be on the scene, holding regular press conferences.

Keep checking back on the blog for more information as it becomes available and follow reporter Ariel Zirulnick on Twitter at @ariel_news21. If you know anything about this accident or know people who were involved, please contact her at ariel.zirulnick@news21.com.