Farnol, Jeffery: Black Bartlemy's Treasure (Illustrated). v1. 16th Sep 2009
Classic 1920 swashbuckling tale of pirate adventure from the prolific English author, Jeffrey Farnol.
Martin Conisby is seeking his vengeance on Sir Richard Brandon, who has ruined him, and arranged his sale as a galley slave into long years of torture. He falls in with a group of buccanneers who are seeking the lost treasure hoard of the infamous pirate, Black Bartlemy, and who take service on a ship with Brandon's cousin and daughter Joan. Many adventures follow.
This book has an (even better) sequel, "Martin Conisby's Vengeance", which I shall post shortly.
Note that this is not a children's story, and contains some scenes of fairly gruesome violence.
"tsgreer" posted a version of this book in 2008, but this version has the original illustrations which were missing from that version, and is better formatted.