Iowa and Alaska Class Conversion Projects

I was browsing Google Books and found a preview of Iowa and Alaska Class Conversion Projects 1942-1962: An Illustrated Technical Reference by Wayne Scarpaci. I thought it was too cool not to share. ;D

http://books.google.com/books?id=L4z8UIRymR4C&printsec=frontcover

Could be an interesting book.

It would seem that the last two Iowa's were of dubious further value to the US Navy but the Alaska's were a huge waste of resources. If converted they would have made "adequate" aircraft carriers which would have been far more useful than as completed. It is also probable that as carriers, with the readily available fittings as used by the Essex class, they may have been in service earlier than caused by the manufacture, fitting and testing of the 12' weapons and supporting equipment. But in reality, other than for the interest of latter day naval enthusiast, the Alaska's were a waste of good steel and building resources

For the proposals to convert to carriers, along with other proposals, please see: http://www.history.navy.mil/photos/albums/s511.htm

Hoo-2b-2day said:

Could be an interesting book.

It would seem that the last two Iowa's were of dubious further value to the US Navy but the Alaska's were a huge waste of resources. If converted they would have made "adequate" aircraft carriers which would have been far more useful than as completed. It is also probable that as carriers, with the readily available fittings as used by the Essex class, they may have been in service earlier than caused by the manufacture, fitting and testing of the 12' weapons and supporting equipment. But in reality, other than for the interest of latter day naval enthusiast, the Alaska's were a waste of good steel and building resources

For the proposals to convert to carriers, along with other proposals, please see: http://www.history.navy.mil/photos/albums/s511.htm

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I believe that you are being overly critical of characterizing the last two Iowa's of "dubious further value to the Navy" and the Alaska's "were a waste of good steel and building resources." It takes three years to build an Iowa-class battleship and an Alaska-class cruiser. With such long lead times, decision makers can only make their best guess to anticipate future needs of the Navy and they can only apply the lessons learned from the last war. The conventional wisdom after World War I at sea was that the next war at sea would be decided by a clash of big gun battleships and cruisers.

Once built and in a post-war period, you need to make a decision whether a ship is of further use as is, can be converted for another purpose, or is obsolete and should be broken up as scrap.

In reply to Tritons comments above:

1. The last two Iowa BB's were not laod down until 6 December 1944 (BB66 Kentucky) and 15 January 1945 (BB65 Illinois) which was well after Aircraft carriers has upsurped battleships as the fleets primary warship. By this time the US navy had all the battleships it needed for the duration of the conflict. Though the Iowas had proved useful as AA escorts this job did not require 16" guns or massive armour. A cruiser of about 8,000 tons with 5" guns could have done the same job. (and the US Navy were working on a design such as this at the end of WW2. As for shore bombardment - 33 knots is a major overkill for this tasks in fact the older battleships were better at this task than the new generation ships.

2.

accidentally hit post so...

2. The Alaska class were not particularly supported with in US navy from conception and seem to have been a result of President Roosevelt's insistence. As oppposed to WW1 battlecruisers which had a speed advantage over contemporary battleships the Alaska large cruisers were designed after the Iowa class battleships which could match them in speed. The US Navy realised that if they could build a 33 knot battleship then so could the other major navies. None of the Alaska class was laid down till after Pearl harbour CB1 Alaska- 17 December 1941 and CB2 Guam 02 February 1942, launched respectively 15 August 1943 and 12 November 1943 by which time air power had replaced gun power as the main offensive arm of the fleet. As for CB3 Hawaii - laid down 20 December 1943.. why?

As in my original post the first two Alaska's would have made adequate aircraft carriers if converted as per the "springstyle" proposals which were considered early enough to have been enacted before the ships had progressed too far. As for CB3, a waste of resources that could have gone into another Essex Class carrier or similar.

The Alaska class were an expensive/resource intensive design which the Baltimore class cruisers (13,600 tons and 8" guns) could undertake the vast majority of the intended tasks (including carrier escort) and a few Iowa battleships could cover the rest.

An intersting note is that in regard to CB3 Hawaii material allotted to this ship was being reallocated to other construction by July 1942.

I would also suspect that a US Navy admiral facing the invasion of Japan in 1945/46 if given the choice of the Alaska class large cruiser or the equivalent number of carriers (whether they were Essex class or converted Alaska's) with 80-90 aircraft each would have unhesitatingly jumped at the latter.

Could be an interesting book.

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The book is amazing!!!

When I ordered it I thought it was a bit expensive but now I think it worths every cent.

As for CB3 Hawaii - laid down 20 December 1943.. why?

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Maybe to keep the skilled shipyard workers occupied and prevent them being drafted to fight.
I believe the same thing happened at Republic Aviation, where a batch of 'unwanted' P-43s were ordered,
to keep the workforce intact until the P-47 was ready for production.
Then of course there were the Horten brothers, continuing work on their 'Amerika Bomber', to keep their workforce away from the russian front.

cheers,
Robin.

Re "Maybe to keep the skilled shipyard workers occupied and prevent them being drafted to fight. I believe the same thing happened at Republic Aviation, where a batch of 'unwanted' P-43s were ordered to keep the workforce intact until the P-47 was ready for production."

This was never a tactic used naval shipyards due to the length of time and expense to build a warship. While a P-43 could be used as temporary equipment for a second line unit a brand new 29,000 ton warship could not be considered in the same light. If it were a matter of keeping the workforce occupied a few destroyers or destroyer escorts would seem far more appropriate. But what I meant was why not another ship such an aircraft carrier, amphibious support ship or submarine depot ship - something more useful to the war effort.

The point I am trying to make is that as large gun armed ships the Alaska's were a waste of resources, had the first two been converted* to aircraft carriers and the third built as a carrier it would have been a far better use of the resources towards the war effort, (*better still all cancelled were and aircraft carriers or amphibious support ships built instead)

The initial proposal to complete the Alaska's as carriers was considered around January 1942**.Had this option been enacted the conversion work would have commenced well before launching these ships. As I mentioned earlier as carriers they would have used weapons and equipment in mass production for the Essex class carriers -for any warship with large guns, such as the Alaska's 12" guns, being unique take longer to design, build and test, the same go's for the mountings. Had the Alaska hulls been completed as carriers it is likely that they would have been combat ready several months earlier than as large cruisers and it is possible that they would have had a more extensive post war service. The limitations caused by being conversions would not have been so severe if employed as antisubmarine carriers as were many Essex class carriers.

**Please see: http://www.history.navy.mil/photos/images/s-file/s511-50c.htm

Interesting discussion, but the book is more concerned with conversion projects for the completed ships.

Thanks for the additional information Hoo-2b-2day.

Did the United States still believe that the Chichibu-class battlecruiser, an improvement of the German "pocket" battleships, was being built for the Imperial Japanese Navy or that the class existed? When was it known that the Chichibu-class battlecruiser did not exist?

Could the US Navy also have been thinking that the Alaska-class might be needed in the Atlantic to take on the "pocket" battleships of the Kriegsmarine?

Re: "Did the United States still believe that the Chichibu-class battlecruiser, an improvement of the German "pocket" battleships, was being built for the Imperial Japanese Navy? When was it known that the Chichibu-class battlecruiser did not exist?"

The Iowa battleships would have been a better answer to any perceived Japanese large cruiser/battlecruiser as well as being able to fulfill the battleship roll, but by mid 1943 it was apparent that the war at sea had moved to an air-power basis and that (except in very unusual circumstances*) aircraft and/or submarines would deal with any surface threat.

*Such as Halsey's actions during the battle of Leyte gulf - which was itself decided by airpower and small ships rather big gun ships.

Could the US Navy also have been thinking that the Alaska-class might be needed in the Atlantic to take on the "pocket" battleships of the Kriegsmarine?

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Doubtful, Graf Spee scuttled 1939 after an action with 3 RN cruisers, two of them 7000ton light cruisers; the other two based in Norway from 1942 for operations in the Arctic. Neither achieved much. Lutzow driven off by two light cruisers in Battle of Barents Sea end of 1942. Don't forget Ultra would tell allies where they were.

Oh, man, a couple of things to point out...

1. The Alaskas were intended to operate independantly of the battlefleet to counter large enemy commerce raiders. While this threat never, in fact, developed, it certainly seemed reasonable in the late 1930s when the ships' characteristics were being mapped out.

2. Ultra intercepts were unknown to the USN until after the war started, and even then only to a select few, certainly nobody in BuShips who would have been responsible for design approval.

3. Even if, and I think the jury will always be hung on this, we want to say that the CB concept was of limited utility durring WWII, John Lehman made an interesting statement durring an interview on reactivating the Iowa class battleships. To paraphrase (I don't have the exact quote handy), he said that even though the Iowas were substantially larger than what was needed the decision was effectivley forced on the Navy because the only other hulls availble, the Des Moines class heavy cruisers were too small. He went on to say that the ideal hulls would have been the Alaska class, but these had been scrapped int eh 1960s.

4. A substantial part of the late start on the last two Iowa class ships was that they had a substantially improved torpedo defense system over the previous 4 ships.

Cheers

Almost forgot, carrier conversions of the Alaskas or even the Iowas? Probably an even bigger waste of resources than the original design. The closest comparason would be the USN CVLs, which were converted cruisers. The ones that actually saw service durring the war were all laid up very shortly thereafter. The two ships of the (IIRC) Saipan class served only a breif time as carriers before being converted to other uses (a command ship and a communications relay vessle). The Achilles heal of the conversions was the uptake trunking which substantially ate into the available hanger space.

My point was that a year before Alaska was laid down (not ordered until Sept 1941) light cruisers had dealt with a German pocket battleship, and did so again in 1942. Baltimores would certainly do the job. But, perhaps wrongly, I had taken the question to apply to 1942, when conversions were being considered, rather than to 1938-40 when initial design requirements were under discussion. There is an interesting page or two discussing the factors deciding the Alaska design in N. Friedman's US Cruisers, which includes reference to "the exploits of the Graf Spee."

Hey Smurf,

That wasn't a shot at your comment, just pointing out that as flawed as the reasoning was in retrospect, the Alaskas really were designed around countering large enemy (read: Japanese) commerce raiders; I don't think the German Navy entered into the thinking of the designers.

The carrier conversion idea was something that was being pushed by Roosevelt in the early stages of the war owing to a miscalculation of:
1. How long it would actually take to redesign existing hulls into carriers & build them
2. How quickly 'keel-up' carriers could be completed once the shipbuilding industry got mobilized.

If you look at the commissioning dates of the CVLs, the first of the bunch entered service about two months after the first Essex class CV, the very ships the CVL was supposed to act as a stopgap for. Also, when you look at the capabilities of the ships side by side, for the extra 16,000 tons of an Essex you get roughly three times the aircraft. Add to that the larger deck made for fewer accidents and the whole CVL idea really doesn't look so hot. Where they would have paid off was IF the plans had already been in place when the Japanese attacked Pearl Harbor And could have been put in place immediately then maybe the USN could have gotten a few of them into service by mid/late 1942. But then again that would have required a Herculean effort on the part of the shipyards right from the off and would they have been able to do that so quickly?

Cheers

Longshour,

In regard to your statements;

Although the ships characteristics were developed in the late 1930’s (mainly prior to WW2) the earliest Alaska CB was not laid down until 17 December 1941, by which time there enough naval warfare had taken place to realise that these ships would be of very limited utility – something much of the US navy realised much earlier. These ships were due to President Roosevelt’s insistence rather than the US navy. The last “Alaska” was not laid down till December 1943 by which time carrier airpower been vindicated and no Japanese equivalents had made any appearance on the field of battle.

In regard to John Lehman’s statement – this is of no relevance to whether or not the Alaska Class ships were built, only of options once they were in existence. Also by the 1960/70’s it would have been better to have built new ships rather than put money and resources into “old hulls” but many WW2 vessels soldiered on to flesh out the Reagan administrations desire for a 600 ship navy – quantity over quality.

The fact that the last 2 Iowa BB’s laid down had improved torpedo defence systems does not mitigate the fact that battleships had been replaced by aircraft carriers as the fleets “capital ships” and the US navy had enough battleships for the tasks allocated to then. As I mentioned previously an 8,000 AA cruiser would make a more appropriate carrier escort and there were sufficient battleships etc for shore bombardment duties. The two ship could be seen as a poor use of available resources, though better than more “Alaska” CB’s.

As to the comparison of conversion of CL hulls with proposed CB & BB hulls - the Cleveland class CL’s were 10,000 tons, 600(wl) x 66 x 20/25 ft with 100,000 shp. In comparison the CB were 29,000 tons, 791 (wl) x 90 x 27/32 ft with 150,000 shp there for had a much larger hull in comparison to the machinery thereby would have had less problems with trunking the uptakes. Please note that even vessels designed as carriers have similar problems. The bigger the ship the easier the engineering work-arounds are for this issue. By the way this is not an Achilles’ heal, (this is a term to describe a critical vulnerability to death or destruction) but a design/operational compromise.

In regard to the conversions of the CL to CVL’s these were considered a success as they gave the US navy a substantial increase in airpower during the critical year of 1943. The Essex class ships started in 1942, (same time as the CVL conversion began) did not begin enter service until late in 1944. It was also expected that based on the experience of 1942 carriers would be sunk, and the rapid conversions of CL hulls mitigated against these expected losses. Comparing the dates of commission without the background information is very misleading.

As for the prompt laying up of most of the CVL’s after WW2, (of which several were recommissioned both in the USN and foreign navies latter), many other warships also were decommissioned as the USN moved to a peace time level of operational ships.
Iowa (Sept. 1948), New Jersey (June 1948), Wisconsin (July 1948), Alaska* (Feb. 1947) Guam* (Feb 1947) *never to be recommissioned. A number of Essex class were also decommissioned during this period. Again your use of information to support your assumptions appears to be misleading.



The conversions of Alaska or Iowa hulls would have resulted in an inferior carrier for the tonnage used than a purpose built ship, such as the Essex class, but due to the nature of naval warfare from 1942, especially in the Pacific, a sub-optimum carrier would have been a more effective warship that either gun armed vessel –especially the Alaska CB’s.

As per my previous post, the Alaska Class CB’s were a poor use of resources, (shipbuilding yards, steel etc) and this was more so with the last laid down, Hawaii, along with the last 2 Iowa’s started. The proposition of converting these hulls to carriers was one option – a better option being to build more useful vessels (Carriers, amphibious assault ships, etc) instead even to the point of in 1942 scrapping the Alaska and Guam on the stocks and using the material to build other ships (i.e. the machinery for Essex class carriers).

Due to its huge industrial capability the USA (alone) was able to expend resources on ships like the Alaska CB’s and still win the war. This does not mean it was a correct decision to build them, nor to commence building the last two Iowa BB’s so late in the war.

Referneces. Battleships: United States Battleships in World War Two. Dublin R & Garzke, W.
• U.S. Aircraft carriers, An Illustrated Design History. Freidman N
• U.S. Cruisers, An Illustrated Design History. Freidman, N
• American Battleships, Carriers and Cruisers. Lenton, H
Plus various web sites

Hoo,

From US Cruisers: An Illustrated Design History:

"The carrier-screening role accounts for the enthusiasm Admiral King showed for the Alaska project. He was first involved in it as commander of Aircraft, Battle Force, i.e., as a carrier force commander. Thus he was a natural proponent of the powerful escort ship. As a member of the General Board he chaired hearings on the characteristics of such ships, and as Cominch/CNO he ordered their construction and resurrected one which had been cancelled, the Hawaii. However, the Alaskas are usually attributed to President Roosevelt and dismissed as an absurdity and as typical of the effects of amateurism in military procurement. It was an easy judgement to make after the fast battleships had been made to join the carrier task forces and after the threat of cruiser attacks on carriers had very largely been discounted. However that future was hardly obvious in 1940-41, and the record strongly suggests that enthusiasm for the big cruiser was not limited to the president."

So, while President Roosevelt was a supporter of the CB project, there was substantial support within the USN for a warship, larger than the existing heavy cruisers and smaller than the fast battleships then under development, to act as a 'cruiser-killer', a term that is used several times in Friedman's book in relation to the Alaska and related programs.

When the Alaska was laid down the US had been at war for 10 days. The bulk of the war experience was from the Atlantic where the Royal Navy had lost 3 fleet carriers, 2 battleships and 1 battlecruisers with a further battleship and battlecruiser being lost in the Pacific. Of those losses only one battleship & one battlecruiser were lost to air attack (both in the Pacific). By far the most deadly weapon in the Atlantic to that point had been the submarine, accounting for 2 carriers and 2 battleships, while the carrier Glorious was sunk by the battlecruisers Scharnhorst & Gneisenau, & the battlecruiser Hood by Bismarck & Prinz Eugen. During the Battle of Matapan, while the Fleet Air Arm did damage a battleship and heavy cruiser, the former escaped and the latter was sunk by torpedoes from surface ships, the remaining 3 Italian warships lost were either to gunfire or torpedoes. The Bismarck chase was similar, the FAA damaged Bismarck, but it was the RN surface fleet that finished the job. The Battle or the River Plate was fought entirely without aircraft doing anything more than the 'traditional' role of spotting the fall of shot for the surface ships. Even with the raid on the Italian fleet at Taranto & the attack on Pearl Harbor, there simply was no empirical evidence that the carrier had beyond any doubt replaced the battleship as the primary weapon of naval warfare. There were theories and beliefs to this extent, yes, but that is hardly sufficient grounds to alter plans for what, after Pearl Harbor, was seen as national survival.

The comment by Lehman was offered as an interesting post script to the story, nothing more, and certainly not as justification for building them.

The fact that the last two Iowas had an improved TDS is not offered as justification for building them only as an explanation of why they were begun so much later than their sisters. Additionally, they were not justified in terms of their shore bombardment utility, this was considered a minor role for the fast battleships and was, until very late int he war, the almost exclusive domain of the old battleships that couldn't keep pace with the carrier force.

The larger hull of the CBs in comparison the the CLs which were converted into the CVLs has very little to do with the uptake problem. The fact that both designs were substantially completed for a vessel that would bring those uptakes through the centerline of the deck amidships is the issue. To get around that you would have to relocate the boilers, which means you would then have to redesign the compartments around and above them. At that point you've gone well beyond converting a hull for another use, you're having to substantially redesign the entire ship. This, not simply their larger size, is why the Essexs did not lose as much hanger deck space to the these necessities. BTW, the term "Achilles' heel" is also used to refer to something that seriously undermines the ability of the thing in question to fulfil it's intended function.

The prompt laying up of large portions of the fleet after the war was largely driven by the massive draw down in the size of the USN after the war, but also by the drastic reduction in funding. The point I was trying to make was that, any way you cut it, these vessels were simply not the equal of a CV, and were yet another example of the Navy making mistakes in trying to predict what weapons they would really need for the coming war. Also, the CVs that were laid up were replaced by units that were completed too late to see service in the war. This saved the Navy from having to pay for costly refits. The CVLs were not replaced in kind, rather the 8 surviving ships of the original class were replaced by the 2 units of the Saipan class which used the same hull form as the Baltimore class cruisers, but were substantially redesigned to make better carriers. Further, the first of Essexs (Essex, Yorktown & Lexington) were in action in August 1943, not late 1944 as you stated, at which time there were an equal number of CVLs in action. Beyond the fact that a one year error is more than misleading, your assertion that the CVL program was a success because it, "...gave the US navy a substantial increase in airpower during the critical year of 1943." is simply wrong. To quote from a 1945 Pacific Fleet Board ship characteristics review, "Their presence in a force containing large carriers provides CAP and other air details without compromising the readiness, launching or landing of complete strikes from the larger ships, but this advantage is not sufficient to to warrant diversion of such tonnage..." The report goes on to cite the small size of the air group, lack of survivability, poor living conditions, inadequate reserve volume for ship & air group control, etc. as grounds for not repeating the CVL program in the future, a verdict that BuAer & BuShips concurred with.

I'd question your assumption that six or, at most, nine more carrier conversions would have been a better use of resources than simply completing those ships to their original designs.

In response to Longshaur lattest comment:

By December 1941 the USN had already observed from the European War that the aircraft carrier was the primary surface fleet unit, even taking into account the Royal Navy's small number of often obsolete carrier aircraft and over the next few months Dec 41 to June 42, this was violently reinforced by firstly the Japanese, then by the USN at Midway. By December 1941 many American naval commanders were firm believers that air-power would be the dominate force in any future naval war and had planned and trained accordingly.

In regard to your comment to relating to fleet actions prior to the Pacific war - these need to be considered in the context of the European war and the forces available. Though it did not appear to have acheived much up to the end of 1941 the FAA was burdened with few and obselte arcraft and carriers that for the most part had small airgroups and complex (therefore slow) aircraft handling requirement. Both the USN and IJN had large carrier airgroups and more efficient airgroup management techniques. The USN had taken on the lessons leant by the FAA and then reveiwed them in light of their carriers, aircraft and techniques - they were confident that US carrier forces could inflict substantial damage againgst opposing forces.

By mid 1942 it was clear that carrier airpower was to dominate the future of the war at sea and by the beginning of 1943 this was confirmed. By this time the first two Alaska's were still at an early stage of construction and were already being considered as "white elephants" so had a low priority in the building programe. This is not 60 years of hind-site it was forseen at that time.

29,000 of a CB or 48,000 tons of a BB are an awefull lot of ship when one considers the main weapons that these ships were to actually use were the 5"/38 cal DP, the 40mm and 20 mm AA guns. By 1943 it had been realised that battleships (and the still building CB's) would basically be AA escorts to the carriers, a task that they did well but could have also been performed by smaller cruisers.

In regard to the CVL no-one ever claimed these ships were the equal of a purpose built aircraft carrier, you appear to miss the concept that they were entirely to provided additional aircraft carriers in a very short time. Their shortcomings were fully accepted due to the need for carriers at sea as soon as possible and due to the accepted limitations they were avaible when the US navy needed. Though tecnically a poor design they gave a lot better service during the war years than many larger vessels. The US navy did not make a mistake with the indeoendence class but acheived an excellent outcome (espescially considering the resources expended to build them.

The Iowa BB's were an excellent design, the Alaska CB's were vey good looking ships but the naval war was dominated not by the big gun but by air-power and even a sub-optimal aircraft carrier (whether it was an Indepencece class CVL or a converted CB or BB) would have been a more effective weapon that any efficiently designed and built BB or CB. Even though the Alaska and Guam were completed as gun ships, the laying down of the Hawaii, Illinios and Kentucky must have been seen as going against the lessons leant by that time.

But (as is the case today) there was at that time people memserised by big ships with big guns irrespective of the operational requirments of their naval forces. At that time (the latter part of WW2) many "battleship" admirals were in desk jobs in Washington and London as they had been usurped in the operational fleets by air-power orientated commanders. This has been put forward as a reason for the late war surge in interest in big gun ships (such as the re-casting of the British Lion class battleships designs in 1944-45) In both fleets the battleship designs finally died when the carrier admirals returned home at the end of the war with their up to date experience and knowledge.

Hoo,

It looks like you posted while I was editing.

By December 1941 carriers had only been used by the RN efectively in the Bismarck chase, the Battle of Matapan, & the strike on Taranto. In both the former operations, the aircraft carrier was playing a supporting role to the conventional battle fleet. Yes, there were many senior officers in the USN who believed carriers were the weapon of the future, but that was not new, it had been proposed as far back as the 1920s and championed by many naval officers ever since. The policy makers, however, did not see sufficient evidence to support this belief, and the Atlantic war hardly did so. What settled the argument was the destruction of the battleship force at Pearl Harbor and Germany's declaration of war, which necessetated a larger naval commitment to the Atlantic than would have been required to fight a Pacific-only war. Also, trying to extrapolate the possible threat of the IJN based on the known operations of the RN has nothing to do with equipment, although in point of fact, the USN had a woefully poor knowledge of both the composition of the Japanese fleet and the particulars of it's ships.

I'm not missing the point of the CVL concept, I'm saying that the concept itself was flawed. The conversions took too long to get in to service to be able to hold the line until the new CVs arived. They both arived at the same time. Adding converted CBs or BBs wouldn't have gained anything practical, and wouyld have delayed the entry of the ships into service. Even if a CLAA would have done the escort job better, you wouldn't have been able to simply stop work on a CB in 1942 and repalce it with a CLAA and still have it in service by the anticipated comletion date of the CB. Nothing about the two types is the same, even the 5" gun turrets and Mk 37 directors were different depending on the type of ship they were being mounted on.

There's a detailed article in this! But, unsupported by detail (thought the support is there with more time) a few comments:
"time is of the essence" A good 1940 decision may be a bad 1942 decision, and not only because the outside world has changed.
The RN took the decision that the carrier was the most important fleet unit in 1942. New small light fleet carriers were built to a new design based on a roomy mercantile style hull. Apart from Vanguard, no further large (>10,000tons) surface units were built, though some planned.
Consider the ships.

Cleveland class CL’s were 10,000 tons, 600(wl) x 66 x 20/25 ft with 100,000 shp. In comparison the CB were 29,000 tons, 791 (wl) x 90 x 27/32 ft with 150,000 shp there for had a much larger hull in comparison to the machinery thereby would have had less problems with trunking the uptakes.

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Essex CV 820'wl x 93 x 27,500tons standard 150,000shp

Clevelands 4 boilers, in line. Machinery about 25% of ship length, boilers about half of that.
Alaska 8 boilers, paired across the ship, so four pairs in line. Machinery about 22%, boilers about half of that.
Essex 8 boilers, 6 in line (2 pairs) about 30%, boiler 3/5 of that.
Looking at the profiles, the ratio of the height of the boilers to the depth of the ship is much smaller in Essex, the purpose built carrier.
Handling the uptakes is a matter of detailed design, not simple substitution.
the Alaskas would need either trunking across the width, or uptakes Saipan style both sides, affecting usable hull width. (Or complete rearrangement of machinery spaces. Whether that is practicable depends on the state of construction reached - see below)

early 1940 Alaska at sketch design stage. In effect we can say "do we want out 800ft ship to carry guns or aircraft?" with no great change in timing thereafter.
End 1941 Alaska laid down. 12 months detailed design work done, and thrown out by conversion to carrier. 12 months more detailed design work makes ship 12 months late. By the time Alaska is laid down, the gun mountings will have been ordered and much design and construction work done on them (they take longer than ships). Cancellation means compensation payments to the gunmakers.
End 1942 much construction work done. What a year before was a detail redesign paper exercise has now become a reconstruction, with redesign parameters set by what material and equipment has been built into the ship, and the costs of using it as-is even though inconveniently placed, removing it (expense and further delay) and replacing etc etc. The alternative is scrap altogether and build new. But it is never as easy as it sounds to use eg machinery from one ship in another of completely different design. Especially true of the expensive items, rather than the relatively cheap plain steel of the hull.
The decisions taken may now look inferior, but the people making them were neither amateurs nor fools, and gave detailed rather than general consideration to factors of time and cost. Doesn't mean it always worked out right, but you may need hindsight for that.
You can see the pressures to continue to build as planned, and the rationale for completing early ships and cancelling later ones.

A very general point in the light of recent suggestions for reorganising or moderating the forum. My experience with naval threads, compared to aircraft threads, is that the naval ones very easily move from discussing ships to discussing strategy, especially if the ships were ones never actually built, and that can send the temperature up.

A very general point in the light of recent suggestions for reorganising or moderating the forum. My experience with naval threads, compared to aircraft threads, is that the naval ones very easily move from discussing ships to discussing strategy, especially if the ships were ones never actually built, and that can send the temperature up.

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I'll stay on alert...

I've had another look at http://www.history.navy.mil/photos/images/s-file/s511-50.jpg Preliminary design for conversion CB1-6 [my emphasis] 3rd January 1942
The Alaska boiler arrangements appear unchanged from those of the gun ship, including the armoured deck above.
It's not at all clear to me how all the uptakes were to exhaust into the single offset funnel while maintaining draught on the boilers, though no substantial redesign of machinery spaces seems to be contemplated, even though little work could have been done on Alaska between 17 Dec 1941 and 3 Jan 1942.
Friedman (US Aircraft carriers p.190) begins "The Alaska conversion was particularly attractive [compared to Clevelands and Baltimores] given the close affinity..[with] the Essex design." He then spends fifteen lines on the snags, concluding "the lengthy delays inherent in such a project made it impractical, and work stopped on 7th January." - about the time (4days) I would expect to be needed to draw up and consider a reasonable preliminary design.
He goes on to say of the Saipan design "the most general adverse comments related to the narrow hanger ... due to the multitude of vent ducts and uptakes."
The only viable alternative IMHO was to cancel the Alaskas and use the slips to build Essex carriers, but the overriding need for carriers rather than gun armed ships had not yet been established by the 1942 carrier battles, and a lot of gun armed ships had been sunk on Dec 7th.

Hey Smurf,

I was trying to avoid turning this into a doctoral disertation, even though my home office now looks like a naval library exploded in it! ;D

Triton asked a while ago

When was it known that the Chichibu-class battlecruiser did not exist?

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http://www.history-on-cdrom.com/id108.htm
FM 30-58 December 21, 1941
War Department, Basic Field Manual, Military Intelligence, Identification of Japanese Naval Vessels
182 page document describing 55 ships/classes including 170 pictures, 73 silhouettes, and 1 line drawing
has Chichibu, or rather Kadekuru

ONI 41-42 November 9, 1942 with supplements through August 1943
Navy Department Division of Naval Intelligence Japanese Naval Vessels
325 page document describing 269 ships/classes including 1,113 aerial/target views, 263 pictures,
150 silhouettes, and 318 line drawings
doesn’t.
Strong indication.

Given the Independence class CVL's carried less aircraft than planned (33 rather than 45 from what i've seen printed), can the expected aircraft capacity of an Alaska or Iowa conversion be said to be accurate?

PMN1 said:

Given the Independence class CVL's carried less aircraft than planned (33 rather than 45 from what I've seen printed), can the expected aircraft capacity of an Alaska or Iowa conversion be said to be accurate?

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They're probably a bit high, but close. One of the difficulties in predicting aircraft capacity is aircraft change more rapidly than ships. I'm at work at the moment so I'm going off of memory here, but IIRC the Independence class air groups were designed around a mix of F4Fs & SBDs. By the time they were commissioned & working up a few TBFs had been added by reducing the number of smaller SBDs, which reduced the total number aircraft, and based on photographic & tabular evidence, 1 NE-1 was carried on each ship in a knocked-down form slung from the overhead in the hanger. When they worked up the F4Fs were replaced by the larger F6Fs, so capacity went down. Somewhere early on there was a decision to replace the SBDs with TBFs, again a larger airframe, so the ships can't carry as many of them. Then another decision was made to delete the strike capacity all together & carry fighters only. The F6F is smaller than the TBF so some capacity was regained.

The experience of the CVLs in service was that their only real value was providing fighter cover for the carrier group without having to lose the strike capability of one of the large carriers to do so. This is the root of the decision to build the two Siapans, to account for war attrition of the Independences and still have enough CVLs to team up with a pair or more of CVs. By the time the CB or BB conversions would have been ready, they would have been superfluous to that role.

After the battles of Coral Sea and Midway, it was recognized that the aircraft carrier was the warship to fight decisive battles in the Pacific. The construction of BB 65 (USS Illinois) and BB 66 (USS Kentucky) was suspended while the Bureau of Ships made a special study in 1942-43 of the feasibility of converting their hulls to fast carriers. A Spring Style carrier configuration was completed in 1942, and design work continued into 1943 for a planned conversion. It was determined that these ships would not carry as many aircraft as an Essex-class carrier, however they would retain the nominal speed of the Iowa-class battleship of 33 knots. Further study showed that several Essex-class carriers could be completed in the time that it would take to complete the conversion, and at significantly less expense. Therefore, the conversion of these hulls to aircraft carriers was abandoned and completion of BB 65 and BB 66 as fast battleships was given low priority.

The armament would have been the same as the Essex-class aircraft carriers--twelve 5 in/38 guns in four twin mounts forward and aft of the island superstructure and four single mounts in gun sponsons on the port side. Six 40-mm quadruple-mounted Bofors guns were planned.

The carrier conversion would have retained the armor box of the Iowa-class battleship below the third deck.

Populsionplant would be identical to the Iowa-class battleship.

Flight deck would have been 864 feet long by 108 feet wide.

Source: Battleships: United States Battleships 1935-1992 by William H. Garzke and Robert O. Dulin, Naval Institute Press, 1995.

Artist and author Wayne Scarpaci designates these ships battle carriers, or CVBB, in his book Iowa Class Battleships and Alaska Class Large Cruisers Conversion Projects. He states that aircraft capacity would be approximately 75.

Triton said:

I was browsing Google Books and found a preview of Iowa and Alaska Class Conversion Projects 1942-1962: An Illustrated Technical Reference by Wayne Scarpaci. I thought it was too cool not to share. ;D

http://books.google.com/books?id=L4z8UIRymR4C&printsec=frontcover

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Thanks for posting this. I was about to post a question about info regarding the BBG proposals, but then I clicked through the link to the book. I didn't realize that the entire book was scannable. I was thinking about modeling one of the BBG designs using the 1/700 Trumpeter Wisconsin. Now if I could just find some Terrier launchers (and missiles) in that scale...

Triton said:

After the battles of Coral Sea and Midway, it was recognized that the aircraft carrier was the warship to fight decisive battles in the Pacific. The construction of BB 65 (USS Illinois) and BB 66 (USS Kentucky) was suspended while the Bureau of Ships made a special study in 1942-43 of the feasibility of converting their hulls to fast carriers. A Spring Style carrier configuration was completed in 1942, and design work continued into 1943 for a planned conversion. It was determined that these ships would not carry as many aircraft as an Essex-class carrier, however they would retain the nominal speed of the Iowa-class battleship of 33 knots. Further study showed that several Essex-class carriers could be completed in the time that it would take to complete the conversion, and at significantly less expense. Therefore, the conversion of these hulls to aircraft carriers was abandoned and completion of BB 65 and BB 66 as fast battleships was given low priority.

The armament would have been the same as the Essex-class aircraft carriers--twelve 5 in/38 guns in four twin mounts forward and aft of the island superstructure and four single mounts in gun sponsons on the port side. Six 40-mm quadruple-mounted Bofors guns were planned.

The carrier conversion would have retained the armor box of the Iowa-class battleship below the third deck.

Populsionplant would be identical to the Iowa-class battleship.

Flight deck would have been 864 feet long by 108 feet wide.

Source: Battleships: United States Battleships 1935-1992 by William H. Garzke and Robert O. Dulin, Naval Institute Press, 1995.

Artist and author Wayne Scarpaci designates these ships battle carriers, or CVBB, in his book Iowa Class Battleships and Alaska Class Large Cruisers Conversion Projects. He states that aircraft capacity would be approximately 75.

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Triton these are interesting :

specular name of one of these converted battleship in carrier was Santa Cruz !

Jschmus said:

Thanks for posting this. I was about to post a question about info regarding the BBG proposals, but then I clicked through the link to the book. I didn't realize that the entire book was scannable. I was thinking about modeling one of the BBG designs using the 1/700 Trumpeter Wisconsin. Now if I could just find some Terrier launchers (and missiles) in that scale...

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I'm having the same problem in 1/350! I've got great drawings of the Talos & Terrier missiles, but I've found nothing on the launchers.

airman said:

specular name of one of these converted battleship in carrier was Santa Cruz !

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Surprising that no US Navy ship has been named for the Battle of Santa Cruz. I wonder if the Sea Control Ship (SCS) or V/STOL Support Ship (VSS) had gone into production, if the members of the class would have been named for famous battles.

Triton said:

Surprising that no US Navy ship has been named for the Battle of Santa Cruz. I wonder if the Sea Control Ship (SCS) or V/STOL Support Ship (VSS) had gone into production, if the members of the class would have been named for famous battles.

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Probably since the next major class of US Navy surface warships were named for battles: the Ticonderoga class (CG-47).

airman said:

Surprising that no US Navy ship has been named for the Battle of Santa Cruz. I wonder if the Sea Control Ship (SCS) or V/STOL Support Ship (VSS) had gone into production, if the members of the class would have been named for famous battles.

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Probably not. The Navy actually has a (often violated) naming convention for ships. In ye olden days it was:

Carriers = battles
Battleships = states
Large Cruisers = territories
Cruisers = cities
Destroyers = famous naval personnel
Submarines = fish

Now it's:

Carriers = politicians
Cruisers = battles
Destroyers = famous naval personnel
SSBNs = states
SSNs = cities

So in the current climate we're not going to see a USS Santa Cruz unless a new generation of cruisers is built.

Cheers

SSNs are now getting state names, starting with USS Virginia (SSN-774).

Back when SCS/VSS was planned, they were still more or less sticking to tradition, though the big carriers had already gone to prominent naval-related people starting with USS Nimitz. I could imagine the Navy giving SCS/VSS escort carrier names, which initially came from bays and sounds but later were taken from WW2 battles, both on land and at sea.

Hello All:

Plse note that the CB1 class were considered such a threat by the USSR postwar that the USSR designed and started construction on a class of 12 ships(!), of the P82 class CB Stalingrad's design expressedly to counter the CB1 class in 1950 (!)......guess the CB1's impressed the Soviet Navy more than most posters on this board.....And plse don't not reply with the usual drivel about that pathetic deathtrap HMS Hood, which was sunk by the 8" guns of the Prinz Eugen a treaty CA, or the grossly underarmed Scharnhorst class... (11" guns on 32,000t bah, USN BB's on 32,000t mounted 16" guns(!) the CB1's mounted 12" on 27,000t)....Make no mistake, the CB1's would have slaughtered either one in damn short order.... the CB1's were powerful and beautiful ships the epitomy of battlecruiser designs..Sorry for all you CB1 haters but that is the way it is.....Best Wayne

Longshaor said:

airman said:

Surprising that no US Navy ship has been named for the Battle of Santa Cruz. I wonder if the Sea Control Ship (SCS) or V/STOL Support Ship (VSS) had gone into production, if the members of the class would have been named for famous battles.

Click to expand...

Probably not. The Navy actually has a (often violated) naming convention for ships. In ye olden days it was:

Carriers = battles
Battleships = states
Large Cruisers = territories
Cruisers = cities
Destroyers = famous naval personnel
Submarines = fish

Now it's:

Carriers = politicians
Cruisers = battles
Destroyers = famous naval personnel
SSBNs = states
SSNs = cities

So in the current climate we're not going to see a USS Santa Cruz unless a new generation of cruisers is built.

Cheers

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thanks for info Longshaor ! B)

From Global Security:

In 1979 the Navy proposed reactivating the Iowa Class under a two-phase program. Under Phase I the battleships would be brought back into service quickly with a minimum of new modifications. This was done, and all four ships rejoined the fleet. The initial plan also envisioned a Phase II, under which the aft turret was to be deleted and a hanger and flight deck added in its place. The hanger would accommodate 12 AV-8B Harrier STOVL jumpjets. The Martin Marietta version for Phase II had a V-shaped flight deck with two ski jumps on the forward edges, on either side of the main superstructure. The flight decks would measure 330 feet by 150 feet. However, by 1984 the plans for these "Battlecarriers" had been dropped.

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Line drawing of Iowa-class aviation conversion circa 1981.

Sources:

http://www.globalsecurity.org/military/systems/ship/bb-61-av.htm
Proceedings July 1981
http://i149.photobucket.com/albums/s60/scifibugc/

"Aircraft Carrier, Converted from BB 61-66 Class"

Preliminary design plan prepared for the General Board as part of an exploration of carrier conversions of warship hulls then under construction.
This plan, dated June 1942, represents the conversion of Iowa class battleship hulls. It would have produced a ship somewhat similar in external appearance to the Essex (CV-9) class, but with lower freeboard, only two aircraft elevators, one catapult, and an 864' long flight deck set well back from the bow.
The drawing bears the handwritten notation, dated 12 June 1942, "This conversion apparently will not materialize."

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The original plan is in the 1939-1944 "Spring Styles Book" held by the Naval Historical Center .

U.S. Naval Historical Center Photograph.

Source: http://www.ijnhonline.org/mission_structure.html