WesWorld

Ladies and Gentlemen,

I am looking for inspiration and your help is much appreciated.

It´s been since 1931 that the RSAN laid down a fleet CL in the 8000ts range - the AJAX class. Since then only DLs or special purpose vessels like the CLAA discussed lately were designed and build.

During the South American war the RSAN cruiser force suffered some losses that need to be replaced. Additionally some elderly units are now pretty worn out despite refits or rebuilds and also need to be exchanged for something new.

To RSAn designers (read to me) the question now is what the next generation of fleet CLs should look like? Is the "old-school" 8000ts cruiser with 8 to 12 main guns of 15cm caliber still the way to go? The RSAN is free of any treaty limitation regarding size or numbers. So larger, more powerful units are possible but numbers do matter too. No unit of such new design will be laid down prior to 1937.


Then there is a decision pending what the next class of large cruisers will look like. The last class of treaty compliant CAs has been the HEROs. The RADIANCE class, originally labelled heavy cruiser, came out as a super-cruiser (CCA in RSAN terms). So what should the next generation CA of the RSAN look like? Is an increase in caliber size necessary? The RSAN already fields a successful 25cm gun which could be used. Or is an increase in number of guns more appealing? Realistically semi-automatic guns of medium size caliber that allow a higher rate of fire are not yet in reach for the South Africans. The question also needs to be answered if the RSAN still needs CAs at all SHOULD a new fleet CL be much larger than her predecessors. Would this lead to a merge of both ship classes?

Your input to all these questions is much welcome. Please explain to me what you think and where necessary support your arguments with springsharp, big gun or facehard data.

Thanks a lot,

HoOmAn

From what I have read about the SA war and the need for protecting sealanes I would go with a fast 8" cruiser and heavy DP 120-130mm secondaries to deal with the new Super destroyers coming on line and if necessary to buy time for convoys against heavier raiders.

Not a bad thought.


It depends, I guess, on what jobs you see your CLs and CAs doing. If the CLs job is trade protection against cruisers and armed merchantmen, the classic 6" CL is the way to go. If the CLs job is to protect the battle line against destroyers, something a bit bigger (but still armed with guns in the 6" class) is a good way to go, being able to smother DDs in a hail of very dangerous 6" rounds day or night. Etc.

Of the two, I'd expect the CA to grow more than the CL, if the CAs job is to crush CLs: as the CLs are leaving the Treaty regime, they're getting bigger and better armored, so the guns a CA needs to deal with them need to get bigger.

Okay, but what´s a job for a CA that a CCA, BC or BB can´t do? Is it all about numbers?

I also think that for a CL one mission still is scouting. Radar is coming up in some navies but lacks reliability and range plus it cannot identify what kind of object it detects. Or am I wrong?

I would say the current larger destroyers will morph into scouting ships. Current CLs are too big to effectively scout without detection and attempts at faster and better armed cruisers will make these ships bigger than 8,000 tons. A big destroyer could have the speed to escape serious harm and enough range to scout, a scout will not stand and fight and so needs a lighter armament. 120-130mm guns should suffice and torpedoes may have more impact in forcing an enemy to break off contact.

The Royal Navy currently builds two classes of historical cruisers, a nine gun and a twelve gun class. This is for cheapness and a high-low mix but it should be noted the nine gun ships are still too big for scouting but good for policing and anti-piracy patrols where firepower counts.
The General Belgrano marks the largest a CL can get and the RN pefers a balanced 12 gun ship. Belgrano has fired few full broadsides owing to blast effects and possible overstressing of the hull but having five turrets means more effective spliting of fire to engage multiple targets (albeit with increased demands for better fire-control and extra directors and thus more weight and space).
CLs should be used as general purpose cruisers able to screen larger warships from air and surface targets and for patrolling and 'gunship diplomacy' rather than scouts themselves.

Specialist AA cruisers may be best value for money if conversions of older types rather than new-builds.

CAs seem to have lost a function and seem to be merging into the Super CA class. I agree as CL armament increases the CA should also keep suit but guns much larger than 9in are impractical owing to low RoF over a smaller cruiser with 12 or so 6in guns. Armour is also increasing and this is no bad thing.

I'm against Super CA's and the latest designs for Super-Super CA's. Such ships are costly, rob materials and slip space for capital ships and other smaller vessels. Cost is not an issue in WW to the same extent as the real world but even so numerous smaller CLs or scouts could be produced for the price of one super CA. Although these ships could, theoretically, defeat any CA there is no doubt politicans and Admirals may be inclined to see these ships as battleships and then comes the temptation to use them in the battleline. Thus we have Jutland Mk II situation.

Of course we then have to debate whether the gun or the torpedo is the most effective killer. CLs and scouts are easily disabled by 6in or 8in gunfire. Multiple 6in hits may not pierce the armour but would wreck any topside instruments and smaller armament. CA's with thicker armour are still vulnernable to torpedoes, all CLs carry them and calibres are bigger than the real-world with many navies having 23-24in torpedoes with greater ranges and explosive content. Only one hit would slow a CA or a Super-CA enough to enable a CL to escape or at least escape destruction.

As ever a good high-low mix is best to cover all areas.

Quoted

Originally posted by HoOmAn
Okay, but what´s a job for a CA that a CCA, BC or BB can´t do? Is it all about numbers?

Mostly, it's about numbers. A CCA/BC can certainly do the jobs of a CA, and very effectively, but at a higher price.

Quoted

I also think that for a CL one mission still is scouting. Radar is coming up in some navies but lacks reliability and range plus it cannot identify what kind of object it detects. Or am I wrong?

I tend to agree with Hood here: the big DDs we're seeing are very likely to replace (for most purposes) CL scouts. Certainly that's one role the WW KM sees for it's Lebrect Maas class large destroyers. CLs are larger, more visible, more expensive and generally slower than large DDs, none of which points to their being good scouts. They're somewhat tougher, as long as the opposition isn't firing large-caliber shells, but.....

But don´t those large DDs lack the seakeeping a larger hull provides? it´s not all springsharp statistics here. A 3000ts hull will always be more lively than one of 8000 tons, right?

Also, most large DDs or DL designs I´ve seen yet have a rather small range and when using their higher speeds they´ll burn oil like hell.

Both points also combine, me thinks. The better seakeeping of a cruiser also allows her to keep a higher speed in anything above seastate 3. Wouldn´t that be an argument to consider given the South Atlantic and Indian Ocean theatre the RSAN is engaged in?

Would the developement of larger TTs in the 24" range force designers to include some kind of TDS into cruiser hulls? Reslistically there isn´t enough beam so what else could be done?

I think Hood's right about the roles DDLs and CLs are going in. For Chile, I myself am planning two new cruiser classes for Chile: a 12,000 ton 12x6" cruiser and an esploratori-type ship for scouting. I've been impressed by Alt-Naval's strategy in Greece: nine CLs of around 5,000 tons to be used as scouts, backed by numerous destroyers of various sizes. That works much better in the Med than around Cape Horn, though;

Chile will be using an 8x13cm fleet destroyer for the immediate future. I've toyed with a variety of esploratori designs to be used as scouts, and I've got one running 8x15cm, 36 knots, on 3,000 tons standard... another with 8x13cm, 36 knots, on 2,600t, etc.

As to heavy cruisers, well...

Agreed, cruisers WILL be more seaworthy than an SS-equivalent seaworthy rating DD, and in the Southern Ocean regions that's of some importance. I might well say that a 3000 ton DD with an SS seaboat rating of 1.2 is similar in it's characteristics to a 6000 ton CL with an SS seaboat rating of 1.0, for instance. Note, though, that the destroyer may have a higher speed at which it has the same seaboat rating (the Lebrect Maas class are rated at 1.2 at 35.5 kts, as an example), so it can afford to slow and increase it's seaboat rating for a bit. And, if the seas get TOO rough, there's not likely to be too much fighting anyway, no one can work the guns or get hits with what they can work in too wild a sea.

Again, agreed, most large DDs do not have huge ranges. However, that one I don't regard as a matter of great import: ship scouting is a tactical, not a strategic, thing by the time period we're talking about, I'd expect the RSAN to use aircraft or airships to do long-range strategic scouting.

This is my opinion, though, if the RSAN sees a continuing role for CL scouts, by all means build them.


As far as the large TTs go, there's really nothing the designers can do about them for the cruisers and smaller vessels. There's not enough room to give a cruiser a TDS or worthwhile bulges, so..... keep a close watch for enemy torpedoes! On larger super-cruisers, though, a TDS can be installed, like the KM did with the Blucher class ships. It will help, though it certainly won't be a solution.

Its worth noting that in WWII the only ships that did any scouting were the large and extremely seaworthy County-Class. Destroyers are far too small, especially if you're going to be at sea for a week or more. The greater availablility and utility of aircraft, HFDF and radar also lessens the need for a dedicated scouting ship and strengthens the requirement for a larger ship.

Churning out more ships along the lines of Ajax and Achilles is probably the best option for South Africa. As we get into the early 1940s you start to have massive increases in equipment so ship size increases significantly.

Bharat basically is not building CA's anymore. The CCA concept IMO has taken the niche that IOTL was occupied by the CA. So IMO building CA is a waste, they will be obsolete by the early 1940's.

I think if what you want is scouting, the CL is the way to go instead of the DDL due to the rough seas your ships will be operating.

In my mind there are two kinds of scouting. The first is you know roughly where the enemy is and you want to watch them (eg shadowing or vectored by other means such as aerial recon or radio interception) and the second is where you don't know where the enemy is (eg hunt for the Graf Spee type operations).

The latter requires good range more than speed and for this a CL is likely to be superior but when you know the enemy is close and your following an enemy force the DD scout has more speed to dash to safety and is less visible. Don't forget the smaller destroyer type scout will cruise at economical speeds, only in emergencies and combat will full speed be used.

3000 tons sounds viable, to gain seakeeping simply extend the forecastle deck further back or have a flush deck design.

Here is a quick attempt I've done my taking a G Class destroyer and increasing the freeboard and length and adding extra bunkerage. The results are not too bad (especially seakeeping).

Light Scout, Great Britain Scout Destroyer laid down 1936

Displacement:
2,667 t light; 2,784 t standard; 3,192 t normal; 3,519 t full load

Dimensions: Length overall / water x beam x draught
429.10 ft / 420.00 ft x 34.00 ft x 16.00 ft (normal load)
130.79 m / 128.02 m x 10.36 m x 4.88 m

Armament:
8 - 4.50" / 114 mm guns (4x2 guns), 45.00lbs / 20.41kg shells, 1935 Model
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 2.00lbs / 0.91kg shells, 1922 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
12 - 0.66" / 16.8 mm guns (2x6 guns), 0.14lbs / 0.06kg shells, 1935 Model
Machine guns in deck mounts
on side, all forward, all raised mounts - superfiring
Weight of broadside 370 lbs / 168 kg
Shells per gun, main battery: 250
8 - 24.5" / 622.3 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 0.50" / 13 mm 0.50" / 13 mm
2nd: 0.50" / 13 mm - -
3rd: 0.50" / 13 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 52,254 shp / 38,981 Kw = 34.00 kts
Range 6,000nm at 16.00 kts
Bunker at max displacement = 736 tons

Complement:
212 - 276

Cost:
£1.757 million / $7.027 million

Distribution of weights at normal displacement:
Armament: 47 tons, 1.5 %
Armour: 17 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 17 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,433 tons, 44.9 %
Hull, fittings & equipment: 1,091 tons, 34.2 %
Fuel, ammunition & stores: 525 tons, 16.4 %
Miscellaneous weights: 80 tons, 2.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,274 lbs / 578 Kg = 28.0 x 4.5 " / 114 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.28
Metacentric height 1.5 ft / 0.5 m
Roll period: 11.5 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.75
Seaboat quality (Average = 1.00): 1.91

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.489
Length to Beam Ratio: 12.35 : 1
'Natural speed' for length: 23.05 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 26
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.00 ft / 7.62 m
- Forecastle (20 %): 21.50 ft / 6.55 m
- Mid (42 %): 21.00 ft / 6.40 m
- Quarterdeck (15 %): 21.00 ft / 6.40 m
- Stern: 21.00 ft / 6.40 m
- Average freeboard: 21.44 ft / 6.53 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 159.7 %
- Above water (accommodation/working, high = better): 88.0 %
Waterplane Area: 9,794 Square feet or 910 Square metres
Displacement factor (Displacement / loading): 94 %
Structure weight / hull surface area: 39 lbs/sq ft or 192 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 4.87
- Overall: 0.63
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Excellent seaboat, comfortable, can fire her guns in the heaviest weather


Misc weight includes:

ASDIC
Full load DCs (two racks and four throwers)
4 reload torpedoes and handling gear

Whoa. That's pretty nice as a seaboat rating - I thought the Atlantean K-class was impressive at 1.28. I think that takes the prize of best seaboat destroyer I've ever seen...

Quoted

Originally posted by Hood
Length to Beam Ratio: 12.35 : 1

The limit is 11:1

It was a long shot.

it only needs another 5 foot beam to be legal......

It was a quick design to illustrate a point that such ships are not impossible.

Here is a refined version with a lower quarterdeck to save weight. Now its like a super-Tribal but longer than any real British destroyer.

DNC Proposal for a Scout Cruiser, Great Britain Scout Cruiser laid down 1936

Displacement:
2,417 t light; 2,528 t standard; 2,910 t normal; 3,215 t full load

Dimensions: Length overall / water x beam x draught
409.10 ft / 400.00 ft x 36.50 ft x 15.00 ft (normal load)
124.69 m / 121.92 m x 11.13 m x 4.57 m

Armament:
8 - 4.50" / 114 mm guns (4x2 guns), 45.00lbs / 20.41kg shells, 1935 Model
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 2.00lbs / 0.91kg shells, 1922 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
24 - 0.66" / 16.8 mm guns (4x6 guns), 0.14lbs / 0.06kg shells, 1935 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 371 lbs / 168 kg
Shells per gun, main battery: 250
8 - 24.5" / 622.3 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 0.50" / 13 mm 0.50" / 13 mm
2nd: 0.50" / 13 mm - -
3rd: 0.50" / 13 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,000 shp / 37,300 Kw = 34.01 kts
Range 6,000nm at 16.00 kts
Bunker at max displacement = 687 tons

Complement:
197 - 257

Cost:
£1.637 million / $6.547 million

Distribution of weights at normal displacement:
Armament: 47 tons, 1.6 %
Armour: 17 tons, 0.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 17 tons, 0.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,331 tons, 45.8 %
Hull, fittings & equipment: 921 tons, 31.7 %
Fuel, ammunition & stores: 493 tons, 16.9 %
Miscellaneous weights: 100 tons, 3.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,098 lbs / 498 Kg = 24.1 x 4.5 " / 114 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.33
Metacentric height 1.8 ft / 0.6 m
Roll period: 11.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.58
Seaboat quality (Average = 1.00): 1.43

Hull form characteristics:
Hull has low quarterdeck
and transom stern
Block coefficient: 0.465
Length to Beam Ratio: 10.96 : 1
'Natural speed' for length: 22.76 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.00 ft / 7.62 m
- Forecastle (20 %): 21.50 ft / 6.55 m
- Mid (50 %): 20.00 ft / 6.10 m
- Quarterdeck (15 %): 11.00 ft / 3.35 m (20.00 ft / 6.10 m before break)
- Stern: 11.00 ft / 3.35 m
- Average freeboard: 19.46 ft / 5.93 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.7 %
- Above water (accommodation/working, high = better): 93.7 %
Waterplane Area: 9,799 Square feet or 910 Square metres
Displacement factor (Displacement / loading): 88 %
Structure weight / hull surface area: 40 lbs/sq ft or 195 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.27
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Good seaboat, rides out heavy weather easily

Misc weight includes:

ASDIC
RADAR
Full load DCs (two racks and four throwers)
4 reload torpedoes and handling gear

Quoted

Originally posted by Red Admiral
Its worth noting that in WWII the only ships that did any scouting were the large and extremely seaworthy County-Class.

Sheffield did some scouting for Force H during the Bismarck chase, as I recall

The 8" Heavy Cruiser IMO is obsolete. Especially with such ships as the 10" gunned 12,000ton Villas and the 15x6" gunned 9,000ton Sydneys.

Personally I feel that Light Cruisers (6") should not be larger than 10k, or Heavies (up to 10") larger than 15k. After that you get diminishing returns.

I don't buy into the death of the 8" gunned cruisers, they are more numerous than the so called cruiser killers out there, which can still be mission killed and even sunk with torpedo's. Can they sink a CA? Sure but its going to cost them. Theres always a bigger fish out there, no sence worrying about them.

CCA's only make sence for navy's with a numbers disadvantage and the returns are rarely worth it. As Hrolf said CCA's do the same job CA's/CL's do but at a higher cost. For the price of a Villa I can get a Daedalus class CA and an Island class DDL.

This being said I agree with Gavin/James on this one. CL's would be the cost effective way to go but the odd CA wouldn't hurt either.