South, South East of Ransacked Village in White Orchard is a chest in the water. Its like east of the drowners and behind a rock or underwater hill I suppose. Every time I try to swim around the rock or swim above the rock the game says that Geralt needs a portal or is getting too old for this.

Can you post a screenshot of where you are on the map?

Sounds like a trick or a riddle,if it says that.There must be a special way to get
at the chest.Is there a Telekinesis spell in the game?

How do I take a ss other than from printscreen? Anyways on page 349 of the strategy guide of Deserter Territory: Ravaged Lands, ya look at where Ransacked Village is and then the chest marker that's displayed in the water.

No, just Aard. Add non-steam game to Steam, and choose witcher3.exe, then you can take screenshots etc. with Steam.

I've come across quite a few unreachable chests/boxes/bags/book shelves (not the big ones touching the floor, but the standalone ones part of the way up a wall) in the 100 or so hours I've played so far. (And no, they've not accessible via different angles, jumping on other things, destroying stuff with aard, etc.)

The easy fix I imagine would be for to increase the loot radius (as in, so you can loot things from further away), so here's hoping CDPR do that.

Yes,they haven't made it easy.

I reached that chest by swimming an bit to deeper water, then diving and swim back to the chest. You have to be fast to push "E" the moment the loot sign flashes up, but it is doable...

I too have encountered a half dozen to a dozen things I could not get, sometimes it is multiple barrels stacked in a corner somewhere and you can get all but the one in the back, other times a top shelf thing in someone's house, etc. Ultimately anything that is intended to be attainable should be easy to get to without having to waltz around the map as that just removes one from immersion. This is one thing that I liked about Skyrim, was being able to go into First Person mode, point the cursor at something and you can take it if it is takeable.