Now think about what you just said for a minute. The Iranian subs are battery-powered. That means underwater speed & endurance are both pretty LOW. A Nimitz-class aircraft carrier doing flight ops is pushing 30 knots through the water — far faster than any battery powered sub can go, even in a sprint.
So what is the tactic? Sit on the bottom like a manned mine. On detecting a US warship coming toward you you rise to periscope depth (if that is how they acquire targets. Then launch torpedoes if in range.
These things are not a serious threat to run down even a merchant ship while submerged.
If the USN suspects that even one slow sub is in the area they will keep the carriers away until its neutralized. The midget subs are hard to detect shallow water. The Norks use them quite a bit and they always seems to evade the ASW assets.