Navy probe: US sailors were ill-prepared for Iran encounter

Despite being unsure of their surroundings, the sailors did not adjust their on-board navigation displays to enlarge the purple dot; if they had, they would have seen that it was labeled Farsi Island, a well-known base for the Iran Revolutionary Guard Corps Navy.

"No crewmembers on either (boat) utilized a paper navigational chart in order to plot their exact location or to identify the island they had seen, even though the charts were available" on their boats, known as Riverine Command Boats, the investigation report said.

"Crewmembers lacked navigational awareness, proper communication with higher authority, and appreciation of the threat environment throughout the transit," the report said.

With the Iranians pointing their guns at the U.S. crewmembers, the ranking U.S. sailor decided to try to talk his way out of the predicament.

The investigation concluded that while the boat crews erred in entering Iranian waters, the Iranians violated international law by impeding the boats' "innocent passage," and violated U.S. sovereign immunity by boarding and seizing the boats.

Richardson outlined the investigation's results but declined to go into some details, saying he must avoid being seen as influencing the outcome of disciplinary actions that in some cases have not been completed.

A sailor was said to have failed to uphold the code of conduct standards when he ordered crewmembers to cooperate with the Iranian video production and "acquiesced" in making an Iranian-scripted statement on camera in exchange for the crews' release.