I have a disapering texture bug when I get to the carrier.
I enter it through the hole at the side and through the hole in there and dive down throug (yet) another hole, but when I resurface inside the carrier its walls have turned invisible and I can not see where I am suposed to go or what to do. I can see the sky stright up, and a girdle, but not the roof, or deck or what you want to call it. The same with the sides. So I stop here and can not progres any further...
Any sugestions on how to deal with it?

Have you tried restarting the game & seeing if you can reproduce the error?
Done the usual update all your drivers thing?

Looking through web results, apparently it was a known problem. Try setting either the Lighting Quality to Medium or Texture Quality to Low, or enable compressed textures by typing the command 'r_TexNormalMapCompressed 1' at console.

Just press the tilde key .

If that console command works you can have it run every time you start Far Cry.
On my retail copy of Far Cry I create a file called Systemcfgoverride.cfg in the Program Files\Ubisoft\Crytek\Far Cry and save those commands there, one per line.
Here are two lines:
r_FSAA = "1"
r_HDRRendering = "0"