YlAccirding to the rules (which also state you can’t stack ships. Lol) you’re supposed to state which ship was hit.

This means that you would have to say the names of all the ships that just got his. Also, if you were trying to skirt that rule by not saying the names of all the ships underneath, and only saying the name of the top ship, the odds that both if your opponents first guesses that struck would hit the 2 spot ship are pretty low.