I typically sink around 10 ships per patrol
Hmmm. Re-check your realism selection options, play through each year and return to base with your boat and crew. I am surprised you have not had white knuckle experiences with escorts and or aircraft or for that matter Q-boats, bad weather, and boat management issues, not to mention identifying neutral ships properly .. played to the fullest this is NOT an arcade game IMHO! this sim maximizes U-boat strategy and tactics
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PS: last night in a storm, dark, pelting rain, high seas, I raised my periscope near the convoy to see the steel hull and bottom paint on an escort that was two meters from shearing it off - and then the concussions ... hot diggety dawg, I dropped my hamburger (dinner) and had to pull off a quick maneuver!!! Dead is dead is the only way to go. Fortunately we are alive and well and tracking that convoy today ...
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DID, no cheats, no shortcuts, no non-historic equipment deviations. Boat and crew safety is integral with my immersion style! Follow the historic events during your patrol:
http://www.uboat.net/today.html