The pirate Devlin / Mark Keating.

Enhanced descriptions from Syndetics:

An injured French officer struggles along a desolate stretch of West African coastline, desperate to hold on to his secret. Alas for him, his tale is soon ended, and violently, but a young pirate recruit, Patrick Devlin, who happens to speak fluent French, comes away from their encounter with a new pair of boots and a treasure map. From there the adventures of the pirate Devlin, his shipmates, and those who wish them dead move forward without restraint, through broadside barrages and subterfuge and brutal encounters on land and at sea, where nothing is as it appears to be at first glance. In these pages readers will meet Blackbeard and his cohorts, Portuguese colonial governors and French commandants, officials of the East India Company and Royal Naval officers, fresh-faced midshipmen and gnarly, scarred, and drunken pirate crewmen. But none of these is as impressive and memorable as the former servant and newly minted pirate captain Patrick Devlin, unless it's the man he once served on board a British man-of-war, a man now sworn to kill him!