Given the constraints or lack thereof in your hypothetical, I would have carried out the procedures that have been previously thought up and rehearsed, and taken the pirate ship, captured the pirates and freed the kidnapped mariners, all of the kidnapped mariners. This is what the British, Dutch, Indians and Danes did. However unlike what the poor frustrated Royal Navy men were forced to do, I would not have dropped the pirates off on their home shore but dispatched them to North America so they could forthwith begin their study of colloqueil (sic) and legal English.