Wow, just wow, at the first and third post.
To give some reasoning as to why ship engines cannot be damaged:
Task groups in this game are map objects, not player-operated vehicles like planes and ground vehicles. The task force unit moves all at once; there is no programming currently that would allow, say, one of the DD's to deviate from the rest of the pack. If we have engine damage, that would mean we would need the capability for one ship to fall behind the rest of the pack. There is not that capability, currently.