if you are against any SS except KM they are dead if you know how to use your sub
it turned out these SS1 have very good turning force so you can out manuver any SS
and avoid most torpedos (except KM) and you torpedos speed is leathel + you have 4 bow tubes
and 2 steryn tubes

personally i've killed MN SS3 &4 // US SS4 / IJN SS4 (which was the easiest )


edit : just owned 2 KM SS 4 with fast torpedo mode