Sine, cosine, whiz wheels...what did they really do?

[Iron Budokan]

There are a lot of ways to compute attacks on this game, which is fine. But what did the U-boat captains really do? Didn't they pretty much eyeball everything? I know American sub skippers used Whiz Wheels or something like it, and so did the British sub commanders, but did the Germans? I dunno, that's why I'm asking....

Of course it's difficult to do eyeball estimates on the game without input from your other senses you would have while directing a true attack from a conning tower...but did the uboat captains really take the time to do all this trig and stuff for figuring out an attack? Historically, what was it the really did? I seems from my reading they either called out AOB and such from the conning tower or while peeking through a periscope.

I'm not trying to put down the other ways fellows have come up with here on the forums. I use them, too. I just want to know historically what the uboat capts. did....

Thanks!