Gap between target line and real torpedo traject

[aceman10]

Hello everybody,
I'm a newbie on this forum, but i used to modify SH4 for a long time.
also excuse me for my (bad) english,it's not my natural language.

I've got SH4 and U-boot mission 1.5 and i've seen a bug apprearing on the attack map / attack periscope view.
when a torpedo is lauched, his target doesn't follow the redline when the torpedo has to turn, so, on the impact there is a gap of 5-6 meters between the location pointed by the periscope and the real impact location. the torpedo seems to start turning a bit earlier.(on the second phase ), I explain :
first, the torpedo is launched
Second, the torpedo has a linear path
Third, the torpedo turns
fourth, the torpedo has a linear path

The problem appears in the second phase
I've searched the file where torpedo path are stored in order to improve the distance of the second phase but i didn't find him.

Does anyone has the same Problem ?
And where could I find this file ?

Thanks a lot,

Aceman10