Pretty good. Here's an intersting tidbit, vis-a-vis the Yamato:
In the years prior to WWII, the US Navy had developed an armor plate which provided 25% more protection per inch than older materials of similar weight. The Iowa's armor plate was not as thick as the Yamato's, but was at least as strong with lighter weight.
In addition, the Yamato ws torpedoed by a submarine sometime in 1943. Repairs revealed that the armor belt had seperated fromthe ship's frame. Rather than repair the joints properly, the Japanese merely added another 5,000 tons of armor belt, welded it in place and pretended nothing happened. When struck again at Okinawa, it is entirely possible that the entire section of 'repaired' armor plating promptly fell off, taking the additonal 5,000 tons of armor plating with it. This meant the Yamato had virually no armor protection in that area at all.Had an Iowa and the Yamato slugged it out, the same could be reasonably assumed to happen, leaving the largest battleship in the world with no armor.