Create yourself a Mod with "JoneSoft Generic Mod Enabler" (JSGME) for all changes. Do not change any Files direkt in the SH3 installation!
Study this post.
https://www.subsim.com/radioroom/sho...06&postcount=2
Basic.cfg change all availability-dates under [TORPEDO_TYPEx] to 1939-09.
Year=
Month=
PrototypeYear=
PrototypeMonth=
Change also Renown needed:
Renown=0
Flotilla.cfg change like in above Link.
Append all Torpedoes as needed, in all needed Flotillas, in all needed years:
T0_xx0=10
T0_xx1=10
T1_xx0=10
T1_xx1=10
T2_xx0=10
T2_xx1=10
T3_xx0=10
T3_xx1=10
T4_xx0=10
T4_xx1=10
T5_xx0=10
T5_xx1=10
T6_xx0=10
T6_xx1=10
T7_xx0=10
T7_xx1=10
T8_xx0=10
T8_xx1=10
T9_xx0=10
T9_xx1=10
You have to be shure the xx are the same number as under its "Flotilla-Year"-Set and exist only once.
Done. Easy.
HTH