[Ellipsis]

@ Jimwth: The walkthrough was very helpful, thank you!

@ Jimwth & galraen: You're both right, it wasn't difficult at all... I did everything right before, when I marked the nearby point, walked along the coast and found the shipwreck site, except - and I'm embarassed to admit - I missed the pathway in the water. Yeah. After that, everything went as expected: more barrels and chests and princess Aria's body on the boat.

So, thank you all for your replies and sorry for my lack of attention!