[Jimbuna]

Yes. The engines came with the superchargers already installed, and so the un-upgraded max speed in SH3 is what the real life boats could do with the supercharged engines. I never take them, precisely for this reason.

II and VIIa didn't have them. VIIb and all later boats came with them. Max speeds for all boats are shown here: http://www.uboat.net/types/index.html

Thanks guys