One soldier disclosed his vessel's potential speed and suggested it was on a "presence" mission to demonstrate US military power in the Gulf.
Ten US navy soldiers who had entered Iranian waters and were captured by Iran's Revolutionary Guard Corps in January this year, disclosed key information to their captors, said a US navy report.
During interrogation, the captured soldiers divulged the capabilities of their ships, the report said. One soldier disclosed his vessel's potential speed and suggested it was on a "presence" mission to demonstrate US military power in the Gulf.
"It is clear that some, if not all, crew members provided at least some information to interrogators beyond name, rank, service number and date of birth," the report said.
The report did not mention the names, but the Navy last week identified the commander of the boat's task force as Captain Kyle Moses and said he had been relieved of his command.
The incident caused embarrassment to the US, and in May the Navy fired Eric Rasch, commander of the squadron that included the sailors.
The report further said that two people had faced administrative action and it recommended action on six others.
The Navy report blamed the incident on poor planning, leaders who did not properly consider risks, and complacency, a lack of oversight and low morale. The sailors were traveling in two vessels to Bahrain from Kuwait.
At a Thursday news conference, Navy officials acknowledged that the crew and commanders had made serious mistakes.
"Our actions on that day in January and this incident did not live up to our expectations of our Navy," Chief of Naval Operations Admiral John Richardson said. "Big incidents like this are always the result of the accumulation of a number of small problems."
In all, nine Navy personnel -- three of whom were actually on the boats that were meant to head from Kuwait to Bahrain -- have been disciplined or will face disciplinary action.
Iranian media broadcast humiliating images of the US sailors during their detention, showing them kneeling on their boats at gunpoint with their hands on their heads.
But the investigation "found a lack of leadership, a disregard for risk management processes and proper mission-planning standards," US Vice Admiral Chris Aquilino told reporters.
"If the guidance provided ... had been followed, this event could have been prevented."
The US soldiers were apprehended on January 12 this year and freed the following day unconditionally by the Iran authorities.
Problems with the mission
The report said problems had plagued the mission from the beginning.
The boats' captains and crew did not review or follow their planned course from the moment they left port, the report said. They inadvertently went through Saudi Arabian territorial waters before entering Iranian waters off the coast of Iran's Farsi Island in the Gulf, it added.
Near the island, one of the boats had a faulty engine, and the two craft were approached by two IRGC boats, which pointed their weapons.
"I didn't want to start a war with Iran," one of the boat captains told investigators. "My thought at the end of the day was that no one had to die for a misunderstanding."
The Iranians forced the sailors to remove their body armor, kneel, and place their hands behind their heads, and took video and pictures of the crew doing so. At Farsi Island, they interrogated and detained the sailors overnight before releasing them the next day.
Filmed acting happy
The sailors agreed to Iranian demands that they eat and act happy while being filmed in order to be released, and one captain read an apology prepared by the Iranians. They did not know that the US government already had negotiated their unconditional release.
The report faulted the IRGC for violating international norms. The Iranians replaced an American flag on board with an IRGC one, ransacked the vessels, and damaged equipment, the report said.
Iranian Supreme Leader Ayatollah Khamenei awarded medals to IRGC commanders, and Iranian media broadcast videos of the detainees.