Given the large number of variables involved, simply trying to make the case for either ship type winning a one on one match almost doesn't make sense. I personally like to ponder what Yamato might have done had she either:
A) Been deployed to Guadalcanal instead of Kirishima.
B) Actually run into task force 34 in the San Bernardino Strait.
In the case of the former, you would have had the closest thing to a one on one, had the battle unfolded as it did the night USS Washington sank Kirishima. While not an Iowa, the Washington is a fair stand in for one. I submit that had the events of that night unfolded the same with only the swap of Yamato for Kirishima, the outcome might not have been dramatically different, with the exception that South Dakota would have been pummeled even worse than she was. If Washington caught Yamato unaware at the same range as she did the Kirishima, she would have wrecked the big ship's upper works, bridge and directors. It would have been ugly. With no DD's around to finish her off, Yamato might have lived to see another day however.
In the other scenario, had the center force found task force 34 waiting in the strait, it would have been very ugly. Yamato, Kondo, Haruna and Nagato would have faced off against Iowa, New Jersey, Alabama and Washington. Both sides would have had a similar number of destroyers and cruisers. Presumably, Halsey would have included a couple of carriers to support the big ships as well.
I am thinking that the results would have been very similar to what happened at Surigao Strait. Worn down by torpedo attacks, the battleships would have run into four US BB's capping their T. With air support, it seems unlikely that any of the Japanese fleet would have survived. They may have managed to deliver some hits and damage, but likely, it would have been a route.
Got back today. At last a reasonably impartial response. Am working on the numbers now for others, but Guadacanal was what Yamato had been designed for and in fact had been sent, but was too late and turned around.
Yamato was designed to fight multiple Battleships and to take punishment from large shells, Torpedoes dropped from were it's Achilles heel.
Washington had the same radar as Iowa (MK13) albeit not as modern, Washington's Captain, was trained in radar and trained his crew, yet at 7000y and about 76 shots later had only Hit Kirishima 6 times. Kirishima was a WW1 battle cruiser that had been modernized for WW2 but was still not up to the standard of a real Battle ship. Kirishima fired 11 inch guns and its turrets were loaded for shore bombardment.
If Yamato had been in this battle in place of Kirishima, South Dakota would have been wrecked and Washington would have had a fight on its hands.
This is my argument, there are too many variables to say which ship would win between Yamato and Iowa and to say that Iowa would win hands down is just absurd.
Up until 1944 the Americans believed that Yamato was around 45k, so the captain of the Iowa would be working on this knowledge. He would want to close the distance and secure his immunity zone (an estimate at 45k around 25ky to 30ky) as quickly as possible(he has the speed but he does not know it) He has the edge on fire control (but he does not know it) Battleships have a limited amount of ammunition so he is probable not going to start shooting until he is within his immunity zone????. Yamato has been designed to shot a great distance and there is a good chance that its captain is going to start shooting as soon as he feels he has a solution. His first salvo's will more then likely be off (maybe). Now all the big variables start.
The Iowa has STS decaping armour, but the Yamatos shell still weighs 3120lbs,even decapped it is still a devastating weapon and is dangerous in the water near the other ship. The Iowas 2700lbs shell is an excellent projectile, but cannot penetrate the Yamatos vital areas between 25ky and 30ky. The Iowa can hit the Yamato more times than the Yamato can hit the Iowa due to Superior fire control, but the Yamato is designed to take punishment from another Battleship. If the Yamato can hit the Iowa fron 35ky the shell will penetrate the deck and it will do damage to the side armour.
I cannot say which ship would win and I have better things to do then list a whole lot of numbers (but if you want them!)
If these two ships were to stand at 20ky to 25ky and just shoot shells at each other (oh what a sight) It is my belief and this is to answer the Yamato, Iowa debate that, just by weight of shell, subdivision and armour, Yamato would win. Under battle conditions and what was known about ether ship in 1942 to 1944 is a different story.
The HMS Vangaurd, was for the English a well balanced design based on all their experience gained during the wars, but still controlled by budget. If the Iowa was put up against the Vangaurd, then my money would be on the Iowa.
Up until 1944 the Americans believed that Yamato was around 45k, so the captain of the Iowa would be working on this knowledge. He would want to close the distance and secure his immunity zone (an estimate at 45k around 25ky to 30ky) as quickly as possible(he has the speed but he does not know it) He has the edge on fire control (but he does not know it) Battleships have a limited amount of ammunition so he is probable not going to start shooting until he is within his immunity zone????. Yamato has been designed to shot a great distance and there is a good
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