Pirate. The insult thrown at sailors gone rogue. Or, in some cases, sailors kidnapped from their ships and forced to work on an unregistered ship instead.
James Kirt fits the kidnapped group. His father was the head of a trader's ship, and on James's first trip out to sea with his father, he was kidnapped by pirates. Over ten years later, he's made the very best of his situation, rising through the ranks to captain, and earning the respect of his crew.
When ships start going missing, trade, naval, and pirate, James sets aside the differences between the three types to try and figure out what is going on. He needs help from his crew, and he knows they have been able to handle everything thrown at them so far.
Hopefully solving the mystery of the lost ships is no different.