In Ashes Born by Nathan Lowell.
Here is the description from Amazon:
An old friend. A new course
A deadly ship with a secret cargo.
Ishmael Wang returns to Port Newmar but ghosts from his past have followed him. His old shipmate, Phillip Carstairs, offers him the opportunity to track down the man who killed his lover. The catch? He must take command of the Chernyakova, a ship that still stinks of death and haunts Ishmael's nightmares.
Together, Phillip and Ismael begin a journey into unknown reaches of the Deep Dark to bring back the man who killed Greta.
--This is a great story I never want to end!