Two women who were lost at sea for five months had an emergency beacon aboard their sailboat that was never activated, the US coast guard has said.
Spokesman Lt Scott Carr told The Associated Press that their review of the incident and subsequent interviews with the survivors revealed that they had the Emergency Position Indicating Radio Beacon (EPIRB) aboard, but never turned it on.
The device communicates with satellites and sends locations to authorities. It is activated when submerged in water or turned on manually.
During the post-incident debriefing by the coast guard, Jennifer Appel, who was on the sailboat with Tasha Fuiava, was asked if she had the emergency beacon on board. Ms Appel replied she did, and that it was properly registered.
"We asked why during this course of time did they not activate the EPIRB. She had stated they never felt like they were truly in distress, like in a 24-hour period they were going to die," said coast guard spokeswoman Petty Officer 2nd Class Tara Molle.
Lt Carr also said the coast guard made radio contact with a vessel that identified itself as the Sea Nymph in June near Tahiti, and the captain said they were not in distress and expected to make land the next morning. That was after the women reportedly lost their engines and sustained damage to their rigging and mast.
A retired coast guard officer who was responsible for search and rescue operations said that if the women used the emergency beacon, they would have been found.
"If the thing was operational and it was turned on, a signal should have been received very, very quickly that this vessel was in distress," said Phillip R Johnson.
The beacons are solid and built to be suddenly dropped in the ocean.
"Failures are really rare," Johnson said, but added that old and weak batteries also could cause a unit not to work.
It is not clear if the pair had tested it before the journey.
The two women met in late 2016, and within a week of knowing each other decided to take the trip together.
Fuiava had never sailed a day in her life. They planned to take 18 days to get to Tahiti, then travel the South Pacific and return to Hawaii in October.
They were rescued by the US Navy after they were spotted by a Taiwanese fishing vessel 900 miles southeast of Japan.