It would appear that the range for detection of torpedoes, in naval battles, is somewhat broken. From the attached screenshots:
Naval-Air detect - the ship crew can see targets at 10km
Naval-Surface detect - this same crew has the skills to see objects at 1.5km, and even hidden ones at 50m
Naval-Torpedo detect - yet can only see a torp at 10m?
It would appear to be a error in the numbers added as base detection range, and also the values used as multipliers for skill levels.