@Gen.pixelz:
Can an aircraft carrier fire on a sub or can only destroyers. I’m tryinig to understand if other ships can attack once the sub has started a suprise attack?
If there are no enemy destroyers present and the attacking sub(s) hit during their surprise attack then any defender casualties are immediately removed and won’t roll for defense. If a sub attacks a single carrier and hits, then the carrier is immediately sunk, without firing back.
But if there are remaining defender ships after the subs have fired then they will fire back at the sub, even if there are no friendly destroyers present.
Can an enemy sub see a sub of a different player in the same sector and attack?
An attacking sub may perform a combat move to a SZ occupied by an enemy sub in order to attack. However since both subs have the option to submerge before any combat, the defending sub will always be able to avoid combat.
To attack and destroy enemy subs you need to bring a destroyer, otherwise the sub can always submerge first.