Why don't submarines have the ability to flank an opposing surface or submarine ship? I can easily imagine a wolf-pack of subs all firing torps at a target simultaneously. Is there a way around this limitation? I was so discouraged by that fact that I've not checked to see if a wolf-pack of nuclear subs or morays will do what I want (when I gained them later). Anybody know?

Soviet naval doctrine called for subs to support surface assets in this type of role, but that was because Soviet subs were loud, slow, and needed the support of surface ships and aviation to work. American subs have always been more effective when working alone.

The exception is the German wolf pack of WW2. Even there, however, the subs only coordinated with other subs prior to the raids. The attack itself was relatively uncoordinated, preventing any real flanking bonus.

Note that wolf packs were not used against single ships, and were only instituted when the allies started convoying and Germany was unable to sink as many ships.

Wolf packs themselves became substantially less effective as the allies perfected anti-sub tactics, and as technology gave the advantage to the convoys. Better sonar, more and faster destroyers, and most importantly, escort carriers and increased fighter cover from land bases took a horrendous toll on the U-boats after 1942.

This is in Units.txt

I checked the nuclear sub, and it has a unit category of Category UNIT_CATEGORY_UNDERSEA

Meanwhile the Knight unit has
Category UNIT_CATEGORY_FLANKER

Another unit I checke had UNIT_CATEGORY_ATTACKER

So it looks like "Undersea" is a seperate category from "Flanker" or "Attack" or "Defense" or "Ranged"