Link
http://www.valoratsea.com/Sclass1.htm
Notice the addition on a rear tube from S-11 onwards and 14 Torpedo's not 12.
The weight and dimensions of the S-Class are more like a Type IX-B Uboat Displacement submerged, Length, Beam and Draft are similar.
Who needs a fancy fleetboat and one of those new electronic slide rules?
Nothing a S-boat, pencil and paper cant handle.
Like to see you fleet boat fellows put YOUR TDC in your pocket when you get back to port. :rotfl: