Have been experimenting with subs... and lo and behold!, subs can indeed use fire control_s brigades (probably others as well). You just need to write it in to the submarine .txt file (allowed_brigades = naval_fire_controll_s).
They can even be built with this brigade pre-attached, as is done with the games's default naval_spotter_s brigade. Yay!!! Afterwards, the sub functions well with the fire control_s brigade attached; when in port, the birgade can de detached, but cannot be re-attached to the sub, so... I don't know if this applies to the naval_spotter_s brigade since this one is game-designed. But, hey, this is really neat... Just thought to share these good news with everyone.
They can even be built with this brigade pre-attached, as is done with the games's default naval_spotter_s brigade. Yay!!! Afterwards, the sub functions well with the fire control_s brigade attached; when in port, the birgade can de detached, but cannot be re-attached to the sub, so... I don't know if this applies to the naval_spotter_s brigade since this one is game-designed. But, hey, this is really neat... Just thought to share these good news with everyone.