This is a Gan Ning only stage. I like it, but at the same time am annoyed how the ship's setting sail work. It sounds like you're just waiting for time to pass for the ships to set sail, but no, you have to defeat specific, unspecified enemies for them to launch, one of them being Zhou Tai who is pretty close to the enemy main camp for most of the stage. So alot of this stage is just solo Gan Ning.