[Ragtag]

I hade the same problem except i never saw the patrol zone for the carrier up north. The orders says the carrier patrols the Brittish Islands which means the southern patrol area is probably correct. It might be a bug stopping the carrier from showing up or something. I ended up skipping that one and went for Weserübung in Norway.

Magnetic pistol are designed to explode under a ship rather then hitting the side of it. Magnetic pistol does enormous damage to a ship and easily break them in two due to the massive pressure from underneath, lifting the ship litterarly up from the sea level.
Set the torpedo depth to slightly under the bulk of the target. In the early years there was alot of problems with the magnetic pistol making the torpedoes explode premature, especially in rough seas. This was modelled in SH3 if i remember it correctly. I haven't seen any torpedoes go off premature in SH5 yet though.