I know the mission you are deferring to (the convoy escort) on the German side and that was tough but I did manage to complete it somehow, however when I have tried to do it on the English side I feel like I am trying to game the system instead of doing something that makes sense.
I have had my best luck there by heading nearly straight south and coming up nearly behind the convoy. Any direct route to the convoy seems to get you a patrol boat in the face that, at least, I could not destroy. I have yet to beat that mission of the English side and gave up on it after many tries. I haven't started the game up since.
Also I could not figure out how to assist the U-Boat in whatever mission that is, so I can't get past that one either. So yeah, I am stuck. It does seem a bit too hard but I have never played a naval sim before so I don't have a standard to compare it to.
I am a bit disappointed that in a number of the scenarios I am being asked to command multiple ships. I was hoping for more of a first-person PT boat sim experience with most of my time spent at the bridge station or on guns, but there are enough things that I am asked to manage and command, and/or interface and mission design choices that I might as well just play the thing in the 2d map mode and let the AI pilot that ships and fire the guns. Not exactly what I was hoping for.