They were the only battleships at Pearl Harbour at the time of the attack, before the North Carolinas and South Dakotas and the big bad Iowas. So how good were they? And the USS Texas, a WW1 dreadnought with 14 inch guns. How would that measure up the the baddies and the battleship world? (probably not well against things like Bismarck or Littorio or Richeliu).
Command and crew quality would have made them a match for LITTORIO; aggressiveness would largely compensate for any design superiority in the Italians's favor, IMHO. BISMARK could, I think, outrun them, while RICHELIEU is, to me, a toss-up. Properly handled, the French could possibly overcome any of them one-on-one, though.
The Pearl Harbor battleships were of the Nevada, Pennsylvania, Colorado, and Tennessee classes. The New Mexicos were (I think) on the West Coast at the time. Arkansas and the New Yorks were in the Atlantic. I am not a fan of the real oldies, and the fact that they were in the Atlantic shows their inferior status in USN thinking. Their armor scheme was not well suited to combat with effective AP shells. Their guns could not reach past around 24,000 yards. The New Mexicos were the most modern units in 1941. However, their bulged hulls were totally unsuited to the Atlantic where their roll behavior effectively halved their potentail firepower. The Tennessees and Colorados hadn't been modernized much. After Pearl Harbor, California, Tennessee, and West Virginia were given the most comprehensive modernizations for any battleships of any nation. The Nevadas and Pennsylvanias were respectable units capable of challenging, if not equaling, the Bismarcks.
The New Mexicos were all in Iceland at the time of Pearl harbor. As Tiornu said, the Standards were quite capable of fighting Bismarck with a chance of winning, they have and IZ of 28,000 to 32,000 yards against her, and Biz has no IZ against the 16" guns and 21,000 to 28,000 yards against the 14" guns. Against Littorio they probably wouldn't do too well, since she has a large IZ against 14" shells, 11,000 - 29,000 yards, and a decent one against the 16" shells, 17,000 - 27,000 yards. While the US ships' belt can be penetrated to 36,000 yards and deck from 34,000, so no IZ.
"IZ" means "immune zone." An IZ is a theoretical range band where the ship's vital spaces are secure from penetrating hits by AP shells. At short range, no practical thickness of belt armor can stop a heavy shell. But as range increases, the shell slows and assumes a higher path to reach the ship, striking the belt at a greater angle. At some point, the range becomes too great for the shell to penetrate the belt. On the other hand, at short ranges, it's impossible for a shell to penetrate even a thin deck--the angle is just so extreme that the shell will skip off. But as the range gets longer, the angle of deck impact becomes more favorable. In fact, at very long ranges, not only does the angle get better, but the shell actually starts to pick up speed again. So at some point, the shell will have the right conditions to penetrate the deck. So here we have Ship A firing at Ship B. Ship A's powerful guns can penetrate B's belt armor out to 20,000 yards--but beyond there, the belt is strong enough to defeat the shell. Ship B has good deck armor, and it's not until the range reaches 30,000 yards that one of A's shells can get through the deck. So in this example, Ship B has an IZ of 20,000-30,000 yards. Some ships are in the unenviable position of having no IZ. Renown, for example--in WWII, her 9in belt armor is no match for modern weapons. Bismarck can put a shell through that armor from more than 35,000 yards away. And Renown's deck armor is a patchwork with some spots given very little protection. Bismarck's shells can get through it from, oh, maybe as close as 22,000 yards. So not only is Renown without any IZ, but she is doubly vulnerable--exposed to both belt penetrations and deck penetrations-- from 22,000 yards out to at least 35,000 yards. Yikes! Please remember that all this is theoretical. There are numerous factors that can affect these figures, and sometimes things happen that you just can't explain. So an IZ is really just an indicator of probabilities, not an absolute value.
Calculations of immune zones can get really complicated, I mentioned the immune zone of vanguard on the vanguard thread, note I calculated the IZ based on different target angles. Belt protection is heavily dependant on the target angle. The immune zones CreepingDeath mentioned assumed a target angle of 0 degrees (Or 90degrees, depending on your perspective, I've been guilty of using both, sometimes in the same sentence.) If the target angle is less then ideal, this will dramatically affect the belt protection.
