[Jack Stryker]

Well, Isaac, one thing that usually helps is if you examine everything around you and try to interact with everything any way you can.  Like the palm tree, for example.  (Hint! Hint!)  As for getting back to Tamir, you'll have to summon help, as it's too far away for Rosella to swim there herself.  To do that, you'll have to acquire some items; which are hidden good.  Some of those items might need a little tampering with too. (Hint! Hint!) But just keep looking at and interacting with everything you can, and you'll eventually figure it out.