According to the preliminary report, the sailors originally set out from Kuwait for Bahrain but quickly -- and unknowingly -- went off course and headed almost directly for Iran's Farsi Island in the middle of the Persian Gulf.
The report found that several factors may have contributed to the failure:
• The sailors had never made the trip before.
• They had been up most of the night before conducting maintenance on one of the boats that had broken down.
• They had to "cannibalize" parts from a third boat in order to have two working vessels.
• They then experienced problems with their satellite communications gear.
All of this led them to leaving port later than planned.
In addition, they did not conduct a standard operational briefing for themselves prior to setting sail, during which they would have fully reviewed their route and navigation plan.
The approved navigation path would have had them sail in international waters between the Iranian coastline and the eastern side of Farsi Island as they moved south toward Bahrain. Instead, they were significantly off course, sailing on the western side of the island.
The report also indicated that the sailors were not aware of Farsi Island's location. They instead believed a small Saudi island was the navigation feature they were supposed to be sailing around.
As the sailors unknowingly approached the Iranian island, they had already missed one scheduled check-in phone call with their command center, and the command center for some reason did not notice that the tracking equipment on board had them headed for Iranian waters.
Once inside Iranian waters, the boat with the navigation problem broke down again and was then fixed.
But the sailors were quickly surrounded by two initial IRGC boats and didn't immediately understand they were Iranian forces, according to the report. Four more IRGC boats quickly approached and encircled the Americans, blocking their escape path.
At this point, the U.S. personnel decided not to resist, seeing no way out of their situation.
