
USS MIDWAY & USS IOWA
Interesting size comparison, the Midway is basically the size of Nimitz class carriers. The Iowa was designed to fit through the Canal (barely). It's long length aids with speed, which is the highest maximum of any "real" BB. (Some folks view the Iowa class as battle cruisers, but there is no end to that argument.)
PERSIAN GULF. CIRCA 1987
For historians and history buffs interested in naval history the Battleship / Battlecruiser / Fast Battleship distinction provides fodder for endless debates.
Essentially, the Iowa Class Battleships were designed as Battleships but deployed as Battlecruisers.
Trying to explain the contours of the debate without actually taking sides:
Battlecruisers were first developed and deployed at a time when Battleships were very large, very heavily armed, very heavily armored, and due to the enormous weight of all their guns and armor, very slow. At that time, Cruisers served a different role, they were not nearly as heavily armed nor armored but they were much faster.
Battleships of all navies were generally designed to a standard known as the "Balanced Battleship". This refers to a ship having enough armor to withstand hits from it's own shells. As guns got larger and more powerful it took enormous quantities of steel armor to accomplish that goal which meant that Battleships got heavier and weight retards speed.
The original Battlecruiser concept was to build a ship that essentially:
- Could outrun anything that it couldn't obliterate, and
- Could obliterate anything that it couldn't outrun.
This was accomplished by pairing Battleship sized guns (or sometimes slightly smaller or less of them than a Battleship) with usually more armor than a Cruiser but significantly less than a Battleship).
One function of such ships was to serve as "Cruiser Killers" a role for which Battleships were not well suited since Cruisers could easily outrun Battleships.
In practice, when the Royal Navy and the Imperial German Navy slugged it out off the coast of Jutland in 1916 both navies determined that the total number of big guns brought to the fight was crucial so they sent their Battlecruisers along with their Battleships in order to maximize their total firepower. It did that but it also resulted in a number of Battlecruisers taking magazine hits and exploding.
During the interwar years a succession of international treaties limited and governed Battleship design and construction. The USN completed WWI era Colorado Class in the early 1920's then didn't build a new Battleship until the North Carolina Class in the late 1930's. The Colorado Class ships could only manage 21 kn while the North Carolina Class ships could achieve 28 kn but that was still well below Cruiser speed (about 33 kn). The North Carolina Class (mostly) stuck to the treaty limitations and it simply wasn't possible to build a balanced Battleship with 16" guns that could go much faster than that. Actually, the North Carolina ships were not "balanced Battleships". They had been designed to carry 14" guns and in that iteration they would have been but then the Japanese pulled out of the treaty system and the US invoked an "escalator clause" that permitted the construction of ships with 16" guns. The ships were upgunned to 16" too late in the process to also uparmor them to maintain balance.
Next the USN built the South Dakota Class ships which were still at least theoretically "treaty" ships in that they more-or-less stuck to the treaty limitations. They were a slightly more well armored and otherwise slight improvement on the North Carolina Class but they were a hair slower at 27.5 kn.
By the time the Iowa Class design was finalized they treaty system had completely dissolved so the designers didn't even have to pretend to comply with the treaties. It is an odd situation. The Iowa Class were designed as Balanced Battleships but they were built as something less than that. They were designed to carry 16" guns and have sufficient armor to withstand hits from 16" shells. However, during the design and construction of the Iowa Class, the USN Bureau of Ordinance designed what was called a "Super Heavy Shell" for the 16" guns and the new shell had greater hitting power so by the time the Iowa Class ships were completed they carried guns that their own armor couldn't withstand.
The Montana Class which was the next class after the Iowa Class and was actually authorized but never built would have returned to a Balanced Battleship concept on a larger hull (machinery design was used for the pictured Midway Class Carrier) with 12 instead of nine of the 16" guns and sufficient armor to withstand even the newest 16" shells but that came at a cost in speed as the Montana Class would have returned to the speed of the earlier North Carolina and South Dakota Class ships which would have made them too slow to operate as carrier escorts which is why they were not constructed. The USN realized by then that they didn't need Battleships to slug it out with Japanese and German Battleships, what they needed was carrier escorts. That raises a whole separate question of why the Iowa's were built? A Baltimore Class Heavy Cruiser had more than half the antiaircraft capability on about 20% of the tonnage so there is a credible argument that the USN in 1945 would have been vastly better off if each Iowa Class Battleship had instead been replaced by multiple Baltimore Class Heavy Cruisers which could have been built for the same resources and crewed with the same sailors.