The Scarlet Blade of the Sea by Celeste Barclay

Danger on the seven seas is no match for what he finds on land…
Keith MacLean set sail for adventure alongside his twin Kyle when they were only boys. Forced from their homes into piracy, Keith’s reputation as the Scarlet Blade precedes him. Keith inherits the Lady Grace from the reformed pirate Rowan MacNeill and is reputed for giving his captives a choice between his sword or sea. Keith anticipates a night of pleasure when he comes ashore in a sleepy village on the Greek Isles. But a chance encounter while on land sets him on a course for unprecedented danger.

Rough waters await a stowaway on a pirate ship…
Serafina Drakos barely knew her father and was raised in the village tavern. Raised among the dregs of society, Serafina faces a certain future that is far too scary to contemplate. Desperate to escape, Serafina chooses a life aboard a pirate ship. But when she’s discovered, her feelings aren’t the only thing tied up. The Scarlet Blade demands order within his crew. When Serafina disobeys, she finds herself over Keith’s knee. A punishment she willingly accepts.