Undertow by Rachel Ember

In Sihr, a strange world of endless seas, Aron is a penniless orphan fighting for survival, not looking for adventure. He agrees to smuggle forbidden artifacts in exchange for a fresh start in another village, but the rendezvous goes awry. By the night’s end, a magical accident leaves Aron under the compulsion of Zoral, a steely-eyed pirate who seems to be more shadow than man.
Zoral and his crew only have eleven days to rescue their captain from the witches holding her hostage. He doesn’t trust Aron, but he has no choice but to bring him along on the mission.
As the unlikely pair face haunted ships, kraken battles, and the mysteries of ancient cities lost to the rising seas of their world, they discover a connection that runs deeper than magic.

“The queer fantasy romance you’ve been waiting for.”