OK... I've figured it out. But I have no solution for the problem!
The problem is caused by "NewUIs_TDC_7_2_0_ByTheDarkWraith"
It sounds crazy to me because hundreds of people use it without problems.
I experimented with sobers modlist. Adding one mod after another and testing. As soon as I added "NewUIs_TDC_7_2_0_ByTheDarkWraith" the problem appeared. It also happens when ONLY "NewUIs_TDC_7_2_0_ByTheDarkWraith" is loaded by JSGME.
I took a screenshot from the sub-screws gauges (port, starbord) with sobers mod list loaded (stopping at "NewUIs_TDC_7_2_0_ByTheDarkWraith").... here you see, one screw does not stop turning although "All Stop" is ordered. Only when I select the engineers avatar and order "Standard Propulsion" the gauge loses RPM.
As soon as I order this the engineer answers with "Secure from Battery Charging" .. even when I was at 40m depth for hours... moving forward with 3-4kt by the moving 'Ghost-Screws'
As told in my first posting, no screw-sounds are to hear at the hydro.
Any suggestions?