Alright, first things first.
Yes, this is an Operation Sealion thread.
Yes, I know this has been done to death.
Yes, I've seen the sticky.
I understand that nothing the Germans could've done would've managed to make Sealion a success.
BUT.
Rather than trying to wank the hell out of the Kriegsmarine, I wonder what could screw the Royal Navy up so that Sealion would succeed, not out of the ingenuity of the Kriegsmarine, but out of shitfaced stupidity of the Royal Navy.
I understand that a POD large enough to screw Britain to hell would have to take place sometime during the interwar period.
So, yeah, theres the question: At any point after the 1918 armistace and before, lets say, January 1 of 1942, what could be done to screw up the United Kingdom so bad that a German* invasion, with minimal assistance outside of Italy or (hypothetical collaborating) France could be at least successful enough to seize England?
*I understand that a POD that far back would no doubt either butterfly away the NSDAP or change the NSDAP beyond recognition. Fine, not a problem. As long as it's Fritz doing the swimming across the channel, its all good.