Check out Fate: Aether Sea, its very much along those lines, right out of the box. Its also PWYW ($4.00) on drivethrurpg, I'm not sure if your need the Fate Accelerated or Fate Core book too, but that's only PWYW ($5.00). You'll probably also want Fate Dice, but they are gorgeous and worth adding to any serious dice-collector's bag

. Fate is a
slightly different beast than D&D or other traditional rpgs, but its not some wild experimental game, either. I like it a lot, and find it pretty easy to run, for the most part. Plus the price is right. (Also, a very good Google Plus community for any questions you have.)
I've played Savage Worlds...it seems like an odd version of 3e D&D with funky dice rolling methods. It kinda looks like you might need to buy at least two settings books to mash up into a Treasure Planet game, and I'm not sure they're both available. (Maybe a more Savage person here might know better.)
I'm not really all that clear from your post what kind of game/rules experience you're looking for. Like, are you interested in a game that's fairly sloppy on tactics but fast on the story...go with Fate. However, if you are looking for a detailed tactical system with squares and lists of weapons and guns and ships and...then maybe take a look at Savage Worlds or one of the other traditional rpg systems already mentioned. If you don't care about traditional rpg structure at all and just want to roll into story...maybe try Uncharted Worlds, which runs on the Apocalypse World Engine. (You'd have to adapt that, because its space opera...but honestly maybe not that much of a stretch.) Could you give some more insight into what kind of game (forgetting the Treasure Planet trappings) that you'd like to see at the table.