Im not debating that the Iowa Class Battleship was designed to be able to decimate any Japanesse battleship that it came into combat with, but everyone knew that naval warfare had changed and there would be no more "Jutland" battles.  Heck even Jutland was not the climatic battle everyone thought it would be as it ended inclusive with the "victor" England sustaining much more damage and casualities than the "defeated" German high seas fleet.  The Iowa Class battleship was designed to be fast so it could keep pace with the aircract carriers and it was designed to protect the aircraft carrier fleets with the most advanced anti aircraft weapons of the day.  Take a look at the weaponry of the South Dakota class- a class designed to "slug" it out big gun style with another battleship - 9 x 16 in 410mm 45 calibur mark 6 guns, 20 x 5 in 127mm 38 calibur guns.  Compared to the Iowa - 9 x 16 in 406mm 50 calibur mark 7 guns 20 x 5 in 127mm 38 calibur guns 80 x 40mm 56 calibur Bofors anti-aircraft guns  and 49 x 20mm 70 calibur Oerlikon anti-aircraft guns.  Did you not the differences in armorment?  Yes, as expected the main guns were upgraded to much more powerful 50 caliburs, but the South Dakota didn't have any anit-aircraft guns in its original design and the Iowa had every spare inch mounted with an anti-aircraft gun.  Any guesses why?  These guns were not added as an after-thought or they would have put them on the South Dakota's as well.  The difference is the South Dakota's were built to fight the last war WWI and the Iowa's were built to fight in a war where the battleing fleets could not even see each other.  The Iowa was designed in 1938, ordered in 1939, however the first one was not completed until 1943- the design underwent many changes even durring construction to make it a powerful weapon in the new world of naval warefare- a world in which the battleship was a support ship and the aircraft carrier was the capitol ship.  We won the Battle of Midway because we sank all of Japan's capitol ships - they ran like yellow dogs even though they had a support fleet on the way that had battleships including the super-battleships Yamato and Musashi.  This was at a time when the US Pacific Fleet could field no battleships- if the battleship was still a "capitol" ship why not plow head-long into our much smaller fleet with these battleships?  Because they no longer had aircraft support and knew our planes would lay waste to them before they could get close.  The Iowa's were designed to provide massive anti-aircraft suppressive fire and use their massive main guns to finish off damaged ships, bombard shores prior to invasion, sink ships that got too close to the fleet, or ships of opportunity when they were "cut loose" to go on patrols.

There is only one problem with that theory. The South Dakotas were reworked North Carolinas for two reasons.

a. The new compact engines were supposed to give a shorter hull, a shorter thicker belt, and a single stack that improved AAA skyarcs.That last was a major reason for the chosen redesign.  So no the SDs were not designed for WW I. They were designed for WW II with the expectation that they would have to fight aircraft AS DESIGNED.

 

And since people demand sources....

 

Data. 

 

 

 

 

Was to engage and defeat the Japanese Fleet in a surface action, fought near the Home Islands I'd say that you were wrong EarlM....the POINT of ANY battleship was to fight the surface fight against it's brethren in the enemy fleet.

 

The Fleet got faster, the BB's got faster...it has less to do with escorting the Essex's....the fleet got faster and the BB's had to be able to keep up.

 

Pre-war theory, and the Iowas were designed PRE-War...was for the Surface Action Unit to proceed INDEPENDNETLY from the Carriers.  FOR THE CARRIER'S safety....

 

The BB's and the CV's weren't going to be sailing together, so no, the Iowas WEREN'T designed as carrier escorts.  They were designed as surface combatants.  As prime targets for Japanese air attack, from the Mandate Islands, as the Fleet closed on the Japanese core areas, it was absolutely vital they be able to protect themselves from this anticipated Japanese air attack.  The USN did not, and practically could not until 1943, believe that the CV's would provide CAP for aerial protection.  The CV's prime mission was to locate the enemy fleet, the enemy CV's first, and deliver a major air attack to destroy the enemy CV's....not to provide air cover for an invasion or surface group.  Hence the Fast BB's needed and could carry an immense AAA array!

 

Their capacity for Carrier Protection was fortunate, but not their planned goal.  Their immense AA capacity was for self-defense....it also worked out to be handy for carrier screening....the Fast BB's and the Fast CV's weren't not designed to sail together, only the advent of radar, and the CIC allowed the USN to group it CV's together and allowed for defensive aerial coverage.

 

Bottom-Line: the fast BB's, the North Carolina's the SoDak's and the Iowas were designed first and foremost to slug it out with the enemy surface fleet.  Later they became escorts for TF 38, after the USN developed the capacity for coordinated aerial coverage.

You're wrong about the point of the Iowa design and this can be found in dozens of places.  The NC and SD were designed to meet the 35,000t limit and be as good as possible, knowing that there would be major compromises with that tonnage.  The Iowa had to make a 45,000t limit and they wanted a 50 caliber gun and speed overmatch on the Kongos which meant that armor was sacrificed. 

 

"The following information is from "Warships Data #3, USS IOWA (BB-61)" by Cheif Petty Officer Robert F. Sumrall.

Washington Treaty Limitations:

Great Britain: 580,450
U.S.: 500,360
Japan: 301,320
France: 221:170
Italy: 182,000

Captial ship sizes restricted to 35,000 tons and 16-inch guns.

Battleship construction was permitted as long as it replaced a retiring ship.

Battleship reconstruction was permitted, but only to improve against air and underwater attack. The maximum additional displacement of such improvements was 3,000 tons.

The concept of the fast battleship (ncluding the Iowa class) initially was to counter the 26-knot Japanese Kongo class.

The Iowa was to feature a 16-inch 50-calibre gun, originally milled for the cancelled South Dakota class and in storage since 1922.

The Iowa was built to comply with the 1938 battleship treaty that limited tonnage to 45,000 tons.

The Iowas were originally planned to be three ships to counter the three Kongos then believed to be in service. The Iowa class was the first "fast battleship" class to truly be able to catch up with the Japanese battleships.

As envisioned in 1938, the Iowa's armor protection scheme was envisioned with the existing 2,240 lbs AP shell. It was not revised against 2,700 AP shells, as this was considered impractical on 45,000 tons."

 

 

From hazegray.org: 

Concept/Program: The final US battleships to be completed; generally considered to be the best US battleships ever, and among the finest in the world. This design was conceived as functional equivalent of the South Dakota class, but capable of 30+ knots for carrier escort duties, and to oppose the fast Japanese Kongo class ships. Planning initially called for four of these ships, based primarily on the need to counter three Kongos (the 4th had become a training ship). The design was allowed 45,000 tons standard displacement after the Escalator Clause of the London Treaty was invoked, but this limit was far exceeded when the treaties were abandoned.

From Norman Friedman:  "At this point the US designers could continue their combination of heavy weapons and heavy protection; the 18 inch gun was the natural weapon.  Alternatively, 10,000more tons could buy a very fast cruiser-killer, a type first suggested by Admiral A. J. Hepburn...C&R developed both in parallel, but ultimately a variant of the second ebcame the Iowa class."

the NC's, the SoDak's and the Iowas were primarily surface combatants, and designed as such...the USN might have preferred a Montana, UNTIL the tactical reality of the Second WOrld War set in, but they would accept the Fast BB's in the surface fight role.

 

It's true the USN fought the Second World War with restricted weapons, the Fletchers, the Sumners, the Gearings, the Essex class and the fast Battleships were all still follow-ons to the Treaty limited predecessors...the Montana's, the Midways, and the Mitschers were the first UNLIMITED vessels the USN actually got to deploy, or planned to deploy in the case of the Montana's.

 

But that fact doesn't change the fact that they were designed to accomplish certain things, and in the case of the Essex's succeeded and in the case of the Iowas their role was never really fulfilled (surface combat), but they found new roles that they filled nicely (carrier escort).

The carrier escorts were going to be CA's and CL's....in pre-war theory.  The Battle Fleet and the Carriers sailed separately.  The CV's were tasked with finding and destroying Japanese CV's....the "escorts" were to fend off Japanese cruisers.  It was not believed that CV's could withstand aerial attack.  The plan was to find the enemy before he found you and strike him....prior to radar and the development of the CIC, CV-borne a/c could not be expected to repel enemy air attack.  The Iowas were NOT developed as escorts to the Essex class....the escort role was to fend off roving Japanese cruisers, not provide AAA support to the Task Force.

 

Read Friedman's "Design History of US Carriers" and you will discover this...and how the fear of Japanese cruisers drove the development of US carriers in the 1920's and 1930's...it affected armour and armament, and hence displacement and the number of carriers available under the treaty system.  The USN did not envision the CV task force(s) being with the Battle Line and hadn't since the 1920's, from War Games as well as Fleet Problems involving the Saratoga and the Lexington.