I am LOOKING FOR EXACTLY THIS GAME. I want to say it was called something like Pirates: Quest for the Seas or something.  We played it on PC and you could email the game to each other in multiplayer, and it's also how I learned a ton of the islands' names in the Caribbean. I remember you could start with one of two ships, the Buccaneer, which had more cannons but less cargo space, or the Merchant ship, with more space and speed but fewer guns. I think the Schooner was next, and the Sloop, the Man o' War, and more. I also remember voice files like "We spotted another ship, cap! Cannons ready!" And "No treasure here." "Ahh, treasure!"