I don't know if they could afford steel that thick anymore for a ship hull. It'd all have to be imported. Or even they even know how to lay one like that anymore. Besides, all those ships were designed, AFAIK, to let you lift the entire powerplant out the same way it went in. The superstructure is lifted off via shipyard cranes, and the engines come out via cranes as well. Even civilian ships did that a lot back then, when they changed over from coal to oil propulsion. The engines were replaced via cranes.
They've moved to "fast and light", the problem being that as the Cole showed, they're vulnerable when in port. That thing had a pretty massive hole torn through the hull at the waterline, right where the old battleships' anti-torpedo armor is thickest.
That's IF the enemy you want to shoot at is within range of a body of water capable of floating a battleship.
Any time they dock for supplies loading or anything else, they're vulnerable to terrorist rafts.
Then there's Sunburns. The Iowas were designed with a three-level armor on top against aerial bombs:
The Iowa-class incorporate 3 layers of deck armoring. You have from top to bottom the Splinter Deck, the Bomb Deck, and the Main Armor Deck. The bomb deck is 1.5 inches STS plate, the main armor deck is 4.75 inches Class B armor laid on 1.25 inches STS plate and the splinter deck is 0.625 inches STS plate. The bomb deck is designed to detonate general purpose bombs on contact and arm armor piercing bombs so they will explode between the bomb deck and the main armor deck. Within the immune zone, the main armor deck is designed to defeat plunging shells which may penetrate the bomb deck. The splinter deck is designed to contain any fragments and pieces of armor which might be broken off from the main armor deck.
Sunburns approach fast, then pop up and slam down on the deck. Do any of our current ships have anything that'd counter that, really?
