Orphans of the Celestial Sea by Mark Fenger

In rescuing three young women from psychotic Draggers, Tom Cain lost two crewmates, his berth on the airship Myrmidon and he very nearly lost his life, but that’s just the beginning of his problems. The four teens recover the abandoned airship Hecate, and flee in her, only to find a stranger named Ishara is stowed away. Ishara has secrets that can save humanity from a slow, painful slide into the depths of madness, but her brain has been scrambled. On a good day she knows where she is and who she is. Orphans of the Celestial Sea is a weekly serial chronicling the adventures of Tom Cain and his misfit crew as they try to unravel the mysteries surrounding their airship Hecate and the plague of psychosis-inducing Mist which is slowly destroying human civilization.