Troubles with silent hunter 5 textures
 

I tried launching the sh 5 on two GPU's - nvidia gtx 770 and gtx 980 and on both I have the same issue - when starting the campain it is ok till Kiel or something like an hour if I am too slow. But when I depart from Kiel on mission or run historical mission some elements inside the sub start flickering - plaques, cyferblats, rivets and other stuff. It starts from few elements but rapidely increases and after 5 mins all the sub is flickering terribly. The strangest thing that it is OK till I reach Kiel. I found nothing about the problem on the internet. sorry if the section is wrong. Please help me

Welcome aboard!
 

SH5 and NVidia cards dont get along too well. Since I have changed my laptop I have flickering textures too, especially on objects sticking above the horizon when the weather is hazy. Never experienced flickering textures inside the sub though.
I haven't played with graphics settings, but in your case I would try adjusting antialising settings within the game and in the Nvidia control panel :hmmm:

I'm running a GTX980Ti Strix and get that flickering on certain things inside the sub but mainly with very rough seas with large waves. It was the same with my previous nVidia graphics card as well. I've never had this issue though in the harbours. Maybe it's just a nVidia thing with SH5 but I have found that having Triple Buffering and Vertical Sync ON give a much smoother result.