There are many ways to "die" in Silent Hunter... If you're playing stock, I'd recommend
Webster's Better Air Patrols, in that it reduces the number of encounters -BUT- there is a trade-off... the ones that do occur, are more deadly, so you still don't want to be seen by an airplane... When you go to activate it in JSGME, be careful of the folder structure of the mod. Make sure you've got Game Folder / MODS / Webster's Better Air Patrol / Data - there are versions there for SH4 1.4 and 1.5. You also have to watch for extra folders being created if you use Windows archive manager from the Explorer...