I know this is a T5 thread, but maybe the rules for MT can be useful for it too.
For MT, sonar was (at least) told about in the Wet Navy design and combat rules, in issues 54 and 60 of the Challenge magazine. I have not read them in deep, but at least there is some mention...
For MT, sonar was (at least) told about in the Wet Navy design and combat rules, in issues 54 and 60 of the Challenge magazine. I have not read them in deep, but at least there is some mention...