The tour boat had 37 people aboard when it was struck by a barge being pulled by a tug boat and sank in the Delaware River last week.
Thirteen students and two teachers from Hungary were aboard; two of them drowned.
On Friday, the bodies of 16-year-old Dora Schwendtner and 20-year-old and Szabolcs Prem were recovered from the river.
Jackie Kennedy is youth director of the Marshallton United Methodist Church, which sponsored the group.
She says the departure of the 11 surviving students and the two teachers was bittersweet and emotional.
On Wednesday, Duck 46 stood in for the ill-fated Duck 34 on the Delaware River. Instead of tourists, NTSB investigators were onboard.
The return to the water is part of a larger effort to see how the amphibious craft handles and how visible it is.
As the NTSB ran its tests the Coast Guard set up a safety perimeter.
"What we're going to do is we're going to keep any kind of traffic outside that area so they can conduct their investigation properly," Chief Petty Officer Chad Lawler of the U.S. Coast Guard said.
K-Sea Transportation, the operator of the tugboat involved in last week's collision, says the tug's mate who was in charge at the time has been relieved of duties.
The mate pleaded the 5th amendment, refusing to talk to investigators.
Action News has learned the mate has retained criminal defense attorney Frank DeSimone.
DeSimone declined comment today about his client or the investigation into the deadly mishap.
K-Sea Transportation's statement reads as follow:
K-Sea Transportation continues to fully cooperate with the NTSB investigation into last week's tragic accident on the Delaware. Members of the company completed interviews with NTSB staff yesterday and continue to remain available if needed.
K-Sea has offered counseling to the crewmembers of the Tug Caribbean Sea, and assisted the mate of the Caribbean Sea in retaining independent legal counsel. The mate was relieved of duty and removed from the vessel following the incident. Questions concerning the Mate's interaction with the NTSB should be addressed to his attorney.
K-Sea extends its heartfelt condolences to the family, loved ones and friends of Szabolcs Prem and Dora Schwendtner, and to all those affected by this tragedy.
The Associated Press contributed to this report.