Well I did sneak on Scapa Flow on year 1944, just to bugger those funny brits.
The thing is that you have to go on daylight (Use snorkel, and stay underwater)
And use freecam to spot the subnets and mines.
And stay quiest as possible, you really don't wanna ruin all the preparing that brits did for to spot sneakers, not for U-boat rambo's.
They get sad because that is not challenging at all.
Brits are people too y'know