Some bad news, it seems that the imported ships flag fix doesn't do it after all
I thought I had figured out why german flags don't freeze, but I was wrong. Every flag works in custom missions and in harbour when you start your patrol. So when you load a saved game or start from the harbour, the game loads all the nearby ships correctly, flags working and all. But when time passes and a new ship spawns, problems starts and the flags freeze. So it has something to do with the loading procedure/spawning of the new ships. Probably some .GR2/.dat compatability error. I have now no idea how to fix this, so if somebody wants to try, be my guest
Maybe small ships (fishing boats and torpedo boats) could sail without their flags???
Some good news also. I found one fishing boat lurking in the SH 5 files that wasn't used in the game. I hope that I can bring it in to the game fully working. And it shouldn't cause any flag problems

. Here is a sneak preview: