[Dilust]

I have experienced the same problem. I have installed some ships addon, started a new patrol from harbour and saved near a convoy (note: the convoy was composed by C3 cargos only, no new ships). When I reloaded game crashed.
I tryed uninstalling all mods, and restarting the patrol from harbour again. Waited for a new convoy and retested the procedure (save and reload): this time all works OK.
Maybe this is a problem caused by mods. Or maybe you cannot continue your career after installed a new mod without this problem.
The best way is to save at a certain distance and then approach the convoy.