Looking at the debug.txt I guess I know what happened: “Failed to find ship design [light cruiser_mk1]”
I took a ship design that was already in use, made changes and saved it again. Then it popped up a message saying it was saved under a different name. Then when I clicked the “Load” Button to delete it again. Suddenly I was able to delete all the ship designs, so I though hooray finally I can clean up my list and deleted some.
After clicking “Campaign Mode” to go back, GSB crashed.
Here’s my save if its needed: tyron.at/tmp/tyron.zip
[Edit:]
I was able to fixed my save. But would be really great if you could delete ship designs. I’m aware they are still needed for existing ships, but at least you could hide them from the list. My ship design list consists of 90% garbage designs :<