Nice tutorial! However as gutted pointed out, using the Fast90 or DOK method on a u-boat without using the gyroangle feature is an oversight imo.
All the AOB and lead stuff isn't needed. Just rely on the gyroangle rather than just say "I'm gonna use a 10 degree lead". The gyro shows you why (due to speed) you'd need 10 or 20 or whatever degree lead. Set the scope to 0, set 90 degrees AoB (required for this attack method) and turn the scope back so you're at 000 gyroangle and fire when ships pass center line. Personally I'd also use the meters in 3m 15s divided by 100 for the speed rather than L/T divided by 1.94. 100 is easier to remember than 1.94, way easier math and it doesn't require you to keep your scope still and exposed for the minute or so it takes to cross.
Surely all these various methods "work". The thing about the Fast90 approach I always loved was how quick and easy it is. Reducing math and letting the gyroangle work for you is a big part of that approach for me. Keeping it simple is the key.
