Hi Dem!
Well, in FX just one file taken out in data/library: the "torpedoes_g7a-e"...
Torpedo splash is again visible, and at any distance.
In IRAI, i adjusted warship difficulty in data/script/AI/init, like that (because IRAI makes destroyers VERY difficult to escape if not impossible):
############ Difficulty parameters ################
Note: difficulty is in range 0.0 - 1.0 with 0.0 being no difficulty (sensor doesn't exist)
# for non-merchants
VISUAL_DIFFICULTY_MIN = 0.85;
VISUAL_DIFFICULTY_MAX = 1.0;
HYDROPHONE_DIFFICULTY_MIN = 0.60;
HYDROPHONE_DIFFICULTY_MAX = 0.85;
RADAR_DIFFICULTY_MIN = 0.60;
RADAR_DIFFICULTY_MAX = 0.85;
SONAR_DIFFICULTY_MIN = 0.60;
SONAR_DIFFICULTY_MAX = 0.85;
And in RM&A, i deleted the data/scripts/ai/events folder before activating the mod, as per Rongel advice, to bring back old morale boost when sinking merchants ships (as i think any ennemy boat sinked gave crew morale boost in RL).
Hope this help