The US Coast Guard has confirmed that two women who said they were lost at sea for five months never activated their emergency beacon, adding to a growing list of inconsistencies that cast doubt on their harrowing tale of survival.

Jennifer Appel and Tasha Fuiava, both from Hawaii, were rescued by the US Navy 900 miles southeast of Japan and recounted how they had survived with a pair of pet dogs on board.

They described a litany of disasters including monster storms, circling sharks, and failing communications equipment, telling how they thought they were going to die.

But, while the seafarers maintain they gave a truthful account of their odyssey, experts have highlighted a series of questions about their account.