The two women from Hawaii who say they were lost at sea had an emergency beacon on the ship that was not activated during their roughly five months at sea, a Coast Guard spokeswoman tells CNN.
The mariners, Jennifer Appel and Tasha Fuiava, had "one EPIRB (Emergency Position Indicating Radio Beacon) on board, which was properly registered," Coast Guard Petty Officer 2nd Class Tara Molle told CNN.
The emergency beacon, which is found on many vessels, is used to alert rescue locations around the world in the event of an emergency, "by transmitting a coded message on the 406 MHz distress frequency via satellite and earth stations to the nearest rescue coordination center," according to EPIRB.com.
Molle told CNN that "as far as we know, the EPIRB on their sailboat was working properly. I can't speculate as to why they wouldn't have activated it."
The Associated Press first reported that questions were being asked about certain aspects of their account.
Appel released a response to those questions Tuesday, saying that they had decided not to activate the beacon because, while damaged, the boat was still seaworthy. The women had food and a way of generating fresh water, and thought they could make it to a safe haven to complete repairs, she said.
"EPIRB calls are for people who are in an immediate life threatening scenario," the statement said. "It would be shameful to call on the USCG resources when not in imminent peril and allow someone else to perish because of it."
The statement added that their boat had received significant damage while being towed by the Taiwanese fishing that had initially rescued them, leading to a mayday call to the US Navy ship when they knew it was on the way to retrieve them.
"Had they not been able to locate us, we would have been dead within 24 hours," Appel said earlier, during a news conference on the deck of the ship.
"We did a mayday call for assistance only when it was absolutely necessary and help did arrive because the resources were available. We are grateful for that."
Appel and Fuiava, along with their two dogs, were found last week, drifting about 900 miles southeast of Japan.
The women say their journey was derailed by ferocious storms, multiple shark attacks and a breakdown in vital equipment such as their engine, mast and communication devices.
"We didn't have our hand radio and our radio telephone wasn't working. And also our Iridium (satellite) phone was not working," Appel told CNN. "They're dependent on the antenna, and when the antenna went out everything went out.
After being spotted by a Taiwanese fishing boat, which contacted the US Coast Guard in Guam, the two sailors were rescued by the US Navy and brought to the Japanese island prefecture of Okinawa on the USS Ashland.
Appel told the US Navy that they had survived thanks to two water purifiers, one of which failed, and over a year's worth of food -- mostly dry goods such as oatmeal, pasta and rice on the boat.
To add to the two women's woes, Fuiava was a complete novice, who "started this trip without knowing anything about sailing," saying she "didn't even know what a jib was" before departing.
Storm that never happened?
Further confusion about the two women's story also arose when they claimed to have been battered by a strong storm at the beginning of their months at sea.
The two women say they set out from Hawaii on May 3, and the transcript of their interview with the Navy quotes Appel as saying that "on the first night" they encountered a "force 11 storm," which they battled for the following two nights and three days.
However, Norman Hui, a National Weather Service meteorologist in Honolulu, told CNN there were "no organized storm systems near the Hawaiian Islands on the dates of May 3, 2017 or the few days afterward."
The National Weather Service issued a small craft advisory on May 3 for Alenuihaha and Pailolo channels, warning of "strong east-northeast trade winds." Such an advisory covers winds from 20 to 33 knots (23 to 38 mph). There was no storm warning issued.
Appel told CNN that the Alenuihaha Channel and the area between Maui and the Big Island are "notorious as a dangerous channel -- subject to sudden and vicious weather change."
"It was not a gale warning," she said. "It was a storm warning."
Appel told the Navy that four days after the storm abated, the spreader, a part of the ship's mast and sail apparatus, broke. Towards the end of the first month, they say heavy rainfall disabled the starter on the boat's engine.
The two women claimed they were close to being rescued October 1 when they made contact with officials on Wake Island, a tiny US territory in the middle of the Pacific, after they came within two miles of the shore.
"We actually managed to get a hold of someone. We let them know that we'd been drifting for five months and we needed assistance," Appel said. "And they responded. They said, if we could get to the entrance to the harbor, that they would help us.
"But we were on the north side of the island, and the entrance to the harbor is on the south side of the island, and the swell and the wind were pushing (us) west."
CNN has attempted to contact authorities on the island but has not received a response.
Appel and Fuiava say they learned a lot from their doomed adventure at sea. If they take another trip they say they will take "three of everything" in case of mechanical failures.
CNN's Brandon Miller contributed to this report.