I don't think there are any
bareboat operations in
Indonesia, probably due to excessive bureaucracy. I personally didn't see many sailboat charters either. I met an American expat named Don with a
catamaran doing charters. I don't have his contact info but if you call Bali marina and either leave your info or ask for his, you might have some luck. The boat is moored outside and has been there longer than the marina.
Good luck.