Plan 8-8-8 From Outerspace!

[GaryChildress]

ORIGINAL: MateDow

How was the Japanese AI able to handle a French Indochina? It is an interesting idea, but wasn't sure whether it would work or not.

I'm not sure how the AI will handle a French Indochina. Once I get a beta version I'll test it out. Right now I've halted work while I wait for some booklets to arrive from GHQ. I think I may take a look at their rule books for micro-armor and see if there is anything in the way of weapon stats I could use for WITP in them.

Also I'm not yet sure if I want Kamikazes in the game or not. With a French Indochina I assume that would activate Kamikazes but I may simply not assign any Jap airgroups the Kamikaze ability.

[MateDow]

ORIGINAL: Gary Childress

Also I'm not yet sure if I want Kamikazes in the game or not. With a French Indochina I assume that would activate Kamikazes but I may simply not assign any Jap airgroups the Kamikaze ability.

I don't think that Kamikazes will activate before 1/44, so there shouldn't be any problem if the Japanese crush the French quickly enough.

[dwg]

ORIGINAL: Gary Childress
I'm not sure how the AI will handle a French Indochina. Once I get a beta version I'll test it out.

I'm building a mod with a French Indochina, I haven't gotten further than a few days into it in testing, but any significant air power in Indochina tends to turn the South China Sea into a bloodbath for the Japanese convoys (the SBC Helldivers the French bought IRL, but never deployed, are hell on wheels against unescorted merchant convoys with no air cover), so you may want to think about additional/redeployed Japanese air units.

Without any mods to the AI, the Japanese aren't going to stage any major invasions aimed at Indochina, though there seems to be a taskforce aimed at Tourane in the scenario I've borrowed as a base, which should be Da Babes standard IIRC. I'm not quite certain if that's there by default, I might have put it in as an experiment and forgotten. I relocated the Japanese Indochina garrison en masse to Hainan as the core of an Indochina invasion force, but that's going to need some AI coding to control it properly. There are AI sections that can be used as a model for that, just change the targets to Indochina and use the former garrison as the core of your assault force.

[GaryChildress]

Well the GHQ rulebooks arrived but it doesn't look like they are going to be much of any help with any real weapons data. [:(]

[RevRick]

ORIGINAL: Gridley380

Well, I doubt the US would have had 48 of the line in commission AT ONCE in peacetime with the IJN only having 24 and the RN about the same. I was thinking of 30 in commission (many of them scheduled for retirement as new construction came online) with 18 being built in the 1940's.

Still, there's no reason that absent the depression AND the treaties the USN wouldn't have retired all the dreadnaughts and 'standard' BBs by 1941, replacing them with new construction. I want to see those old girls fight, but I'd also like to see the treaty wiped away (I demand a BB USS Montana!). It seems that the best way is to kill the treaty but keep the depression.

The "old 30" would be the Delaware, Florida, Wyoming, New York, Nevada, Pennsylvania, New Mexico, Tennessee, Colorado, South Dakota, and 'improved South Dakota' classes (the last being three ships built in the late 1920's). These break down pretty well into ten divisions of three ships each (common major caliber and speed in all but one division). The depression halts construction after the improved SD class, which also halts plans to retire the old 12" gunned ships in light of continuing IJN construction.

Well, Here is a quick synopsis of my take on a AltWNT & failed London treaty USN...
RN and IJN similarly increased as well...

BTW - this is by the seat of the pants down and dirty approximations.. not calculated with intense attempt a naval construction or architecture:

Battleships

1941
Two x AltHist Massachussetts class (Massachussetts, Oregon)
Massachussetts- Active PacFlt, Oregon-WorkingUp LantFlt.
40,000 tons, 30 knots. 3 X 3 16" 50 caliber, 20 x 5" 38 caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 48 x 20mm Oerlikon (increased by 1941).
Armor = 7" decks, 12.2" belt, 18" turrets, torpedo bulkheads: 1 x 25mm & 2 x 19mm. 3 seaplanes.

One x AltHist Alabama class: (Alabama, Michigan, Maine, Nebraska)
Alabama-ActivePacFlt, Michigan- workingup LantFlt, Maine & Nebraska-fitting out shipyards.
40,000 tons, 30 knots. 3 X 3 16" 50 caliber, 20 x 5" 38 caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 48 x 20mm Oerlikon (increased by 1941).
Armor = 7" decks, 12.2" belt, 18" turrets, torpedo bulkheads: 1 x 25mm & 2 x 19mm. 3 seaplanes

Two x North Carolina class. North Carolina, New Hampshire (both ActivePacFlt)
40,000 tons, 30 knots. 3 X 3 16" 45 caliber in triple turrets; 20 x 5" 38 caliber DP in twin mounts
AAA = 48 x 40mm Bofors & 48 x 20mm Oerlikon.
Armor = 7" decks, 12" belt, 16" turrets, 1 x 25mm torpedo bulkhead & 2 x 19mm + double bulge each side. 3 planes.

1931-1934
Four AltHist South Dakota class (South Dakota, Indiana, Georgia, Louisiana)
South Dakota, Indiana, Louisianna-ActivePacFlt; Georgia-ActiveLantFlt
43,600 tons; 30 knots
4 X 2 x 16" 50 caliber Mk 3., 20 x 5" 38 caliber DP in four twin mounts each side (post refit)
AAA = 16 (4 x 4) 1.1 machine cannon & 12 x 2 20 mm Oerlikon..
5” AD, 1.5 Splinter, 13.5" belt, 18" turret faces, 1 x 25mm & 2 x 19mm + internal & external torpedo bulges each side. 2 seaplanes

1919-21
Four x modified Colorado class: Colorado, Maryland, Washington, West Virginia
Maryland, West Virginia-ActivePacFlt. Washington-ActiveLantFlt. Colorado-Refit Seattle.
All four modernized in service in 1932-34 Naval Reconstruction Period w/extended bows.
Original electric drive replaced 1932-34 w/ 85,000 hp plant w/alternating boiler & engine rooms).
37,600 tons & 26 knots
4 X 2 16" 45 caliber, 16 x 5” 38 cal DP in twin mounts.
AAA = 16 (4 x 4) 1.1 machine cannon; 8 x 1 20mm Oerlikon; 10 x 1 .50 Cal M2 machine guns.
6" AD, 1.5” Splinter; 13.5" belt, 18" turret faces, three x 19mm torpedo bulkheads + 90# blister.
2 seaplanes.

1916-17
Two modified Tennessee class. Tennessee, California.
Rebuilt identically to Modified Colorado class save for main battery.
Main battery 4 x 3 14” 50 Cal in triple turrets. Elevation increased to 35 degrees.

1915 Four x heavily modified New Mexico class.
35,000 tons, otherwise somewhat modernized as Tennessee: engine plant rebuilt from for orig
1919 South Dakota Design. 65,000 hp. Speed 24 kts. 4th Ship in class – USS Kansas – built with funds from sale of USS Kansas (BB21) to Chile & USS Minnesota (BB22) to Brazil.



1914
Two x modified historic Pennsylvania class. Somewhat modernized as 33,500 tons, 21 knots. 12 x 14" 45 caliber in triple turrets, 10 x 5" 51 caliber in casemates, 8 x 5" 25 caliber AA in unenclosed single mounts, AAA = 16 x 40mm Bofors + 32 x 20mm Oerlikon. 4 seaplanes. 7" decks, 13.5" belt, 18" turret faces, three x 19mm torpedo bulkheads + single bulge each side. Obsolete.

1913
Two x Nevada. Somewhat modernized as 29,000 tons, 21 knots with turbine engines. 10 x 14" 45 caliber in twin turrets superimposed over triple turrets fore & aft, 10 x 5" 51 caliber in casemates, 8 x 5" 25 caliber AA in unenclosed single mounts, AAA =164 x 40mm Bofors + 32 x 20mm Oerlikon. 4 seaplanes. 5.5" decks, 13.5" belt, 18" turret faces, three x 19mm torpedo bulkheads + single bulge each side. Obsolete.


Building: 2 x Alabama, 1 x Iowa, 1 Montana ready in 1942,
2 x Iowa, 1 Montana in 1943,
1 Montana in early 1944. 1 Rhode Island 1944
1 Rhode Island 1945.

Planned Additions:
1942
Four X Iowa Class: Iowa, New Jersey, Wisconsin, Missouri
47,500 tons, 35 knots. 3 X 3 16" 50 caliber, 20 x 5" 38 caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 48 x 20mm Oerlikon (increased by 1941).
Armor = 7" decks, 12.2" belt, 18" turrets, torpedo bulkheads: 1 x 25mm & 2 x 19mm. 4 seaplanes

1942-43
Four X Montana Class: Montana, Kentucky, Illinois, Ohio
67,200 Tons, 30 Kts. 4 x 3 16” 50 Caliber, 20 x 5” 54 Caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 40 x 20mm Oerlikon (both increased by 1941)
Armor = 8.2” decks, 16” Belt, 20” turrets, torpedo bulkheads: 1 x 45mm & 2 x 25mm. 4 Seaplanes.

1943-44
2 x Rhode Island Class: Rhode Island, Delaware
79,200 tons, 28 kts. 8 x 2 18”47 Cal. Mk. 3, 24 x 5” 54 Cal. DP in twin mounts.
AAA: 88 x 40mm Bofors + 48 x 20mm Oerlikon.
Armor = 9.2” Decks, 18.6” Belt, 20.5” turret, 4” Armored bulkhead, 4 torpedo bulkheads total 95mm.

[JuanG]

Some thoughts on the designs...

ORIGINAL: RevRick
Planned Additions:
1942
Four X Iowa Class: Iowa, New Jersey, Wisconsin, Missouri
47,500 tons, 35 knots. 3 X 3 16" 50 caliber, 20 x 5" 38 caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 48 x 20mm Oerlikon (increased by 1941).
Armor = 7" decks, 12.2" belt, 18" turrets, torpedo bulkheads: 1 x 25mm & 2 x 19mm. 4 seaplanes

Where are you getting the power for 3 extra knots on less displacement than Iowa herself, with comparable weapons and armour?

If you want that speed - look at 55-60,000 tons standard for these things (33 -> 35 knots requires ~30% more power than historical Iowa).

1943-44
2 x Rhode Island Class: Rhode Island, Delaware
79,200 tons, 28 kts. 8 x 2 18”47 Cal. Mk. 3, 24 x 5” 54 Cal. DP in twin mounts.
AAA: 88 x 40mm Bofors + 48 x 20mm Oerlikon.
Armor = 9.2” Decks, 18.6” Belt, 20.5” turret, 4” Armored bulkhead, 4 torpedo bulkheads total 95mm.

I presume that is meant to read 4 x 2 18in/47? Because otherwise theres no way you're putting that many turrets and that armour on 80,000 tons.

[RevRick]

ORIGINAL: JuanG

Some thoughts on the designs...

ORIGINAL: RevRick
Planned Additions:
1942
Four X Iowa Class: Iowa, New Jersey, Wisconsin, Missouri
47,500 tons, 35 knots. 3 X 3 16" 50 caliber, 20 x 5" 38 caliber DP in twin mounts.
AAA = 48 x 40mm Bofors + 48 x 20mm Oerlikon (increased by 1941).
Armor = 7" decks, 12.2" belt, 18" turrets, torpedo bulkheads: 1 x 25mm & 2 x 19mm. 4 seaplanes

Where are you getting the power for 3 extra knots on less displacement than Iowa herself, with comparable weapons and armour?

If you want that speed - look at 55-60,000 tons standard for these things (33 -> 35 knots requires ~30% more power than historical Iowa).

1943-44
2 x Rhode Island Class: Rhode Island, Delaware
79,200 tons, 28 kts. 8 x 2 18”47 Cal. Mk. 3, 24 x 5” 54 Cal. DP in twin mounts.
AAA: 88 x 40mm Bofors + 48 x 20mm Oerlikon.
Armor = 9.2” Decks, 18.6” Belt, 20.5” turret, 4” Armored bulkhead, 4 torpedo bulkheads total 95mm.

I presume that is meant to read 4 x 2 18in/47? Because otherwise theres no way you're putting that many turrets and that armour on 80,000 tons.

Yup... and like I said... a lot of this is SWAG... Every time I stick my nose into Springsharp, I wind up with a ship that either capsizes on the first broad side or steams like a 8 oxen hitch pulling a prairie breaker.

To counterbalance...
one of the things I have stipulated in the AltHist is that a lot of R & D went into the Navy during the 1920s to early 30s, and the engineering plants progressed a few years more quickly with the recognition that the IJN was not going to play well with others regarding the WNT, and because Stimson did not shut down the Black Chamber... the RN and USN knew that the IJN was building monsters on the "sly".

BTW - is there anywhere I can find some quick instructions about the meaning of the data in Springsharp. Some of it I can figure out, but block coefficient and meta height are things one just does not run into in Seminary, or as an Elizabethan English major either..

[Cap Mandrake]

ORIGINAL: Gary Childress

That's the B-226 cockpit, is it not?

[GaryChildress]

ORIGINAL: Cap Mandrake

ORIGINAL: Gary Childress

That's the B-226 cockpit, is it not?

Been on a long sabbatical.

Ah Cap Mandrake, you are almost right, however, you'll note the clipboard showing the flight plans on the wall in the top right of the photo. The B-226's clipboard hook was on the right side of the cockpit and therefore would show up in the upper left of this picture. You'll need to brush up on your alternative history knowledge a bit. This is clearly a B-227 cockpit. You'll also note the large circular wigi board in the upper left, above the co-pilot's head (used to make navigation decisions). Clearly an innovation found only in the B-227.

[GaryChildress]

ORIGINAL: RevRick

Yup... and like I said... a lot of this is SWAG...

Plan 8-8-8 utilizes the SWAG method as well. I adhere to it rigorously! [:D]

[RevRick]

How are you doing with Plan 8-8-8? I am still fiddling with the Alt History Grand Unified Pacific Cataclysm scenario (This time with the FAA getting control of their own aircraft in 1930 or so, and not having to put up with RAF interference of budgetary strangulation)

IJN has possible 20 CV, 22 BB, in addition to the rest of the other class ships in the Iron Man fleet combined with the DaBigBabes mess of thips.
RN has 8 CV between 41-45 (most late war), 21 possible BB's
USN has 2 Lex, 2 Wasp (enlarged) 6 YKTN (enlarged 2 completing after 07DEC4) 6 Essex (all after 1941)and
10 Ticos after 1943.
The BB's are listed in post above.

Obviously, when FDR and Whitehall realized that the IJN was not going to play fair during the WNT, along with building some more ships to keep the work force active (and skills active) they also put some construction types to work building some larger ways and drydocks along with the Coulee and Hoover dams, and the TVA. The IJN decided they needed more ways to, and added them to the economy to increase the work force. Other things come into play as well to make "public works" spending more palatable to the Isolationists - IJA atrocities in China are reported a little more, and some of the information about IJN plans as opposed to their announcements creeps into some more perspicacious hands with a sense of national interest and security at heart, etc., etc., etc. (Some willing suspension of disbelief [good old Sci/Fi term] as well as a visiting ROB might have to be invoked since my exploration of the actual personal histories of some of the actors on this stage was suspended by postgraduate work in another rather intensively focused area.)

This time, I have managed to get a few turns into the game without having something pop up which makes me crazy because I missed something in the editing process, etc., etc.

[GaryChildress]

ORIGINAL: RevRick

How are you doing with Plan 8-8-8?

Oh, haven't made a whole lot of progress. I was all gung ho about getting some rule books from GHQ Microarmor a while back to try to get stats for my new tanks and the books came and there was nothing I could use in them. So I sort of set it aside for a while but I think I'll come back to it now. John 3rd PMed me for some ship art recently and that sort of got me back into WITP, thanks for ruining my life again John! [:D]

[GaryChildress]

OK. So I've been doodling around with all kinds of alternative cruiser art. I'm coming to realize that I can just fabricate pretty much anything and everything. So I feel like there is no rhyme or reason to my alternative cruiser designs. I feel like I'm just doodling in vain. What I really need is some sort of idea of what cruisers might have looked like had there been no naval limitation treaties. From there I need to either figure out spring sharp or else see if Juan G's offer to look up a few cruiser designs for me is still good.

So what would cruisers have looked like? So far I have figured that they would probably evolve to the point where the line between cruiser and capital ship begins to fade. Larger guns, larger ships, etc. But there would still be a need for various "in-between" calibers and sizes I would think. The 6" cruiser design became a standard during WWII despite the lack of naval treaties. My hunch is that even though some large cruisers might mount anything from 9"-12", there would still be a plethora of smaller cruiser designs to fill the gaps, everything from 5" AAA to 8", and especially the 6" for the Allies. So how would alternative cruiser design progress? Would the Americans start out with something like the 6" Omaha class, maybe then go to 8", then 10" or 12" and then mix it up with some more 6" designs? Might the Allies develop "pocket battleships" themselves?

Does anyone have any ideas on an alternative building program for cruisers?

[GaryChildress]

I suppose one way to start out is to come up with an idea of what sorts of missions cruisers are designed to undertake. Then from there come up with what characteristics best serve that role.

1. Scouting - for the main battle fleet was a major role for cruisers as originally conceived but with the advent of longer and longer range aircraft, that role seemed to be pretty non-existent during WWII. Far eaiser and less dangerous to use some PBY's or carrier based planes to find the enemy. Although cruiser float planes did play a major role in fleet scouting too.
2. Commerce raiding - was of course a major role the Germans saw in cruisers but, again, with the availability of land based aircraft that role becomes more and more dangerous. Plus submarines are far more efficient at commerce raiding.
3. Trade protection - The British built a lot of puny 6" cruisers to fulfill the role of protecting their far flung assets around the globe. In this respect cruisers were like a cheap substitute when no battleships were available.
4. Shore bombardment - pretty much every warship type filled this role at some point in the war, given the large number of amphibious operations. If cruisers are good for nothing else, they would still be used in pounding the enemy shore lines.
5. Surface combat - Cruisers found themselves engaging in surface combat without the back up of battleships. During the Solomons campaign cruisers often fulfilled the role of "capital ship" in night battles and other engagements where they were the biggest warships either side had available. In this respect they sort of served as a cheaper substitute for battleships, while the big battleships mainly either styed in port where they still looked good or else stayed with the carriers to provide AAA cover.
6. Destroyer leader- Not a very prominent role either for cruisers during WWII, unless I'm mistaken. I don't think there was a whole lot of need for this role. Destroyers were often mixed with larger ships anyway to provide ASW protection for task forces. So having a flotilla flagship was sort of redundant to having the TF flagship.

[GaryChildress]

ORIGINAL: JuanG

Some comments on the new stuff;

Battleships and building schedules
As was mentioned before, spreading out the US builds might make more sense. Personally I would suggest cutting the South Dakota and Lexington classes to 4 ships each, and then build a new class of battleship or battlecruiser in the late 20s or early 30s, based upon one of the many design proposals from the time.

Cruisers and guns
I like the cruiser lineups, apart from the fact that the gun calibers are all over the place. Every nation seems to jump back and forth between 8", 10" and occasionally larger weapons, with no regard for standardization. Likewise, the 'heavy' light cruisers like the Brooklyn and Mogami probably would not have taken shape in this reality, being something of a product of the treaties (though admittedly one that turned out rather well as a nightfighter and bombardment platform). Lastly, the Italian Zara class with a mixed main battery seems like something more appropriate for 1902 than 1942.

I would suggest redoing the cruisers somewhat; in a reality like the one you propose I can see 3 'sizes' of cruisers emerge;
'Escort' cruisers, around the 4000-6000ton mark, with 5-7in guns; intended for convoy duty, warding off destroyers and later in the war maybe AA work.
'Light' cruisers around the 10000ton mark, with 7-10in guns, intended as cruiser hunters, and leaders of smaller cruiser groups.
'Heavy' cruisers around the 14-18000ton mark, with 10-12in guns, intended as general purpose vessels also capable of taking part in the battleline.

Obviously, each nation will build things suited to their requirements, and put their own 'spin' on these categories, such as German raiders, etc.

So for example, with regards to Japan, I might suggest something like this, beginning with Furutaka;

4x CL Furutaka (4x2 8in) ~9500t / 32knts
4x CL Myoko (4x2 9.2in) ~10500t / 34knts
2x CL Chokai (3x3 9.2in) ~12000t / 34knts
2x CA Maya (2x2 12.2in) ~14500t / 34knts
4x CE Agano (4x2 6in) ~6000t / 29knts
4x CL Mogami (3x3 9.2in) ~12000t / 35knts
4x CA Tone (2x2 12.2in) ~15000t / 34knts
2x CE Oyodo (3x3 6in) ~6500t / 30knts
2x CA Kasuga (3x2 12.2in) ~16500t / 34knts

Destroyers
The same applies here, though you're likely to see more variation in gun caliber simply because of the easier logistics. Most likely national design philosophy will determine the majority of things here. However, some general categories I can see arising;

Destroyer 'Leaders', as a replacement to that role being fulfilled by CLs in certain navies historically. Larger than regular DDs by some 25-50% (so 2500-3000t for a 2000t flotilla), possibly with larger caliber weapons or more of them (latter makes more sense to me) and/or more torpedoes.

'Large' Destroyers, built mainly for anti-surface work; high speed (35knts+), heavy gun or torpedo batteries, probably in the 2500-3500t range (think Shimakaze or Sumner historically). Possibly later designs split into torpedo based ones for ASuW, and gun based with DP guns into an AA escort role.

'Fleet' Destroyers, built as an all purpose platform with good range; moderate-high speed (~32knts), decent weaponry possibly with a focus on guns over torpedoes, tonnage 1500-2500t. Probably the first type to mount DP weapons.

'Escort' Destroyers, built for anti-sub and (later) anti-air work; moderate speed (~30knts), mixed weaponry though possibly lighter on the torpedoes. Tonnage around 1000-2000t.

In addition, specialist designs like lighter torpedo destroyers (something of a souped up TB), dedicated ASW escorts, etc. might appear depending on how development goes. Once again, national preferences are a big influence here.

Designs and numbers
Lastly, if you would like any help with estimates/design stuff for any of these, I can help out (from stuff like 'if it has these guns, this protection and this speed, then how heavy is it gonna be' to 'if it needs these guns and this speed but cant exceed x tonnage, how much armour can you put on?'). Let me know here or in PM, I can post examples if needed.

Hmmm. Digging back in my own thread a little I had forgotten about this excellent post. Think I'll do a little dwelling on this and try to come up with some ideas.

[Symon]

ORIGINAL: JuanG
Some comments on the new stuff;

I agree with JuanG completely. In the absence of the Treaty, the cruiser classes everybody knows oh so well, would not have existed. The provenance is protected cruisers and armored cruisers. I think you need to go back and analyze the missions that the various hulls were constructed for, in the period immediately preceding the Treaty, and go from there in a rational way. You want to make a scenario where the Treaty wasn't present, so why are you concerned about Japanese 8" CAs? Was it me, for every Takao you make, I'll make an Alaska. 10k ton, 8" gun cruisers are Treaty artifacts. If you don't have a treaty, you are on your own.

[Terminus]

Also, you're assuming there's no Great Depression, right? Otherwise, where in the cloaca is the money coming from?

[Don Bowen]

ORIGINAL: Terminus

Also, you're assuming there's no Great Depression, right? Otherwise, where in the cloaca is the money coming from?

A cloaca (pron.: /kloʊˈeɪkə/) is the posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts of certain animal species.

Google: a place were the undereducated can try and keep up with Terminus.

[Terminus]

I'm just a guy who's watched Steve Irwin and Mike Rowe on the television...

[GaryChildress]

Yep Terminus, no Great Depression, see the short storyline in the OP. I have the basic tennets of the mod laid out there.

@JWE: Seeing how the Hawkins class CA was the basis for the definition of "heavy cruiser" for the WNT in 1922, it seems like cruiser design for the next 15 years was stuck in a time capsule, unable to really evolve much. The Hawkins had 7.5" guns so I'm thinking I should start out in 1922 with some 8" cruisers and from there start escalating up to maybe 12"-14" just prior to 1940 maybe? As 1940 approaches the early 8-10" cruisers would become 2nd line cruisers, early escort cruisers would probably be scrapped by 1940, there wouldn't be many of them as mass production escort ships will be more of a wartime thing.

I like JuanG's general distinction between "escort", "light" and "heavy" cruiser designs. The only thing I would do for the purposes of fitting them into the designation categories available in WITP would be to give the following designations for the different ships:

1. "Escort" cruiser = "CL": 5-7" guns, 4000-8000 tons, 30-35kts: Duties would primarily be trade protection or convoy duty. would also serve as escort leaders for convoys.
2. "Light" cruiser = "CA": 7-10" guns, 8000-14000 tons, 30-34kts: commerce raiding, light surface combat, also these would include obsolete "heavy" designs originally laid down in the 1920s. As the war progresses some of these might be upgraded for primary AA duties.
3. "Heavy" cruiser = "CB": 10-14" guns, 14000-25000 tons, 27-33kts: general purpose/power projection, capable of operating on it's own, sort of a cheaper, more numerous version of the battleship or battlecruiser. Primary duties would be surface combat, although it will of course evolve with greater and greater AA ability.