A Ride the Ducks Boat is back in the water Wednesday but tours are not back on.

Instead, the investigation continues on the Duck Boat tragedy as National Transportation Board investigators head into the Delaware River to conduct tests.

Officials are still trying to determine what factors led to the collision between a 250-foot barge and the tourist boat last Wednesday.

Duck 34, which experienced mechanical problems including smoke coming from the engine before deciding to anchor in the water, collided with The Resource barge. The crash caused the duck boat to sink 55 feet into the water.

The accident sent 37 people into the river, injuring 10 passengers and tragically killing two Hungarian tourists.

On Saturday, investigators experienced a roadblock when the tug mate aboard the barge "pleaded the Fifth" and refused to speak with investigators.

Now, it is reported that the mate might have neglected to follow the U.S. Coast Guard's Navigation Center Rules of the Road -- a set of marine regulations, according to the Inquirer.

“The mate didn’t put his only other crew member as a lookout on the deck of the barge,” a representative from the tug mate’s union told NBCPhiladelphia.com.

But according to the representative, the crew only consisted of two active deckhands and their position on the barge was dependent on the type of help the mate needed.

“That isn’t uncommon, out on a two man crew the mate might have needed his crew member to stay on the tug,” said the union official.

Could the collision have been prevented if there were eyes on the deck?

“Although there is a blind spot in front of a barge, at 400 yards the mate would have seen Duck 34 from the upper pilot house,” marine union official, Steve Oravets told the Inky.

For now the tug pilot is off the water, his lawyer Frank DeSimone told the Associated Press.

The NTSB is continuing their investigation with the cooperation of the Coast Guard, Ride the Ducks and K-Sea Transportation (the tug boat company) while important questions still remain unanswered.

As of Wednesday, two members were seen out on a barge on the Delaware showing that precautions are now being taken to monitor trafficking in the waters.

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