Yes Cueball, I know how how you feel, weeks of virtually nothing then a golden opportunity presents itself and the weather turns against you

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In those conditions I would normally shadow the convoy hoping the weather improves before it got to safety. Or as a last resort, you could infiltrate the convoy submerged, marking out the lanes by the hydrophone, ready the tubes for a snap shot, and take out whatever presents itself. Ok you can't pick your target, but better than nothing, and the evasion will be a bit easier in that weather. It all depends on the philosophy of your current Kaleun.