There's a ton of info out there about the load game bug. One thing to remember is that the "corruption" carries on to future saves IME. So if saves 1-3 are fine, then save 4 gets corrupted (by saving too close to a ship, the shore, or some other reason), then saves 5-8 will also be corrupted, even if they are saved in "safe" locations. So it's quite possible that one initial bad save corrupted the rest of your saves.
If you're going out on 6 patrols, and get crashed games on 5 of them, that's hard luck!
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