WesWorld

[SIZE=3]THE NAVALIST [/SIZE]
- South Africans Official Navy Newspaper -
25th February 1924

Design history of the Cape-class armored cruisers

Prior to 1905 the naval arm of the South African Armed Forced was rather weak. At that time the Royal South African Navy (RSAN) consists of a mix of several ships including a handful pre-dreadnoughts and three armored cruisers of max. 9500ts. The latter were meant to act as second rate battleships and as back up for scouting forces. During the war of 1905 the Japanese proofed the value of this concept as they made good use of their large armored cruisers against the Russian battleline. Their stunning success made South African naval designers think about the value of large cruisers again and with the Naval Novel of 1906 an extended cruiser force of 12 large ACs was envisioned. At a rate of two units per year this should have been achieved until 1912. Financial restrictions soon forced the RSAN to cut back their plans as a new building plan for capital units consumed most of the money.

The British had rendered all battleships obsolete by introducing HMS DREADNOUGHT to the world. Not being caught by surprise the RSAN worked on a similar project and laid down their first all-big-gun battleships in 1905 and 1906 (RSAN QUEEN FALLATIA and RSAN QUEEN ALEXANDRA II) but those were much more expensive than any common battleship before. When it became obvious that in future all major navies of the world would build ships of the new type only, the RSAN had to take steps and the previously mentioned new building plan was introduced in 1908 when RSAN MADAGASCAR was laid down.

So until 1908 the RSAN had laid down four ACs each of which displaced more than 10,000ts. The COLONY-class carried 8 21cm main guns and 10 15cm guns as secondaries while achieving 23kn during trials. However, the technical development questioned the concept of ACs. With HMS INVINCIBLE the british Royal Navy introduced another new type of ship to the world. Details were unknown until the ship reached completion in 1908, leaving the world stunned once again. Suddenly there was a ship with 30,5cm guns that could achieve 25kn. It would be capable of running down any AC and with its superior guns and armor there was little doubt who would win the fight. However, the British – an unlikely opponent - were the only ones to have such ships at first so the RSAN did not follow immediately.

Nevertheless the concept was born to the world and South African naval designers seriously began to think about a response. Thus the GENERAL-class was laid down in 1910. These modern ACs were designed to have a speed in excess of that of the british BCs (speed at trials was ~26,5kn) but were kept smaller and cheaper otherwise. Their 8 21cm guns in four twin mounts would still proof fatal for any other AC or smaller units while their armor of up to 210mm offered a good chance to survive the impact of some heavy shells should the cruiser be challenged by enemy capital units during a mission.

But once again the Royal Navy had been one step ahead. With the laying down of the LION-class in 1909/10 they altered the concept of the former INVINCIBLE- and INDEFIGABLE-classes. Finished in 1912 HMS LION achieved 27,5kn during trials and combined this high speed with tremendous firepower far in excess of what an armored cruiser could hope to stand up against. The concept of the AC was finally rendered obsolete. No longer capable of playing with the big boys they also lacked the speed to keep up with modern light cruisers which soon exceeded 27kn and made for much better scouts. The RSAN answered these developments with their first battlecruisers of the HERTOG-class in 1911 after building a total of 9 ACs of which three survived until the 1920s (RSAN ARGENTINA being used as a cadet training ship while both GENERAL-class units remain active as second-rate BCs in the 2nd Scouting Squadron even though hopelessly outdated).

In the early 1920s things have changed a little bit. While the old concept of a heavy scout in the van is still obsolete the navies of the world feel the need for a capable warship of decent size that fits in between the categories of capital ships and light cruisers. Battleships and battlecruisers became too expensive to have them in large numbers long ago while light cruisers of max. 8,000ts lack the capabilities a modern flag ship needs when stationed in oversea territories or when showing the flag in foreign harbors. Modern technology now makes it possible to build a large and powerful cruiser that can proceed where old AC-designs had to surrender. Those new large cruisers will be fast enough to stay ahead of the vast majority of all capital ships and combine this speed with guns and armor superior to any other warship short of a battleship or battlecruiser. Their larger size compared to light cruisers will also allow them better use of scout planes which are becoming more and more important to enlarge a cruisers sighting range while the ship is acting either as scout, raider or for trade protection.

To keep pace with those developments the RSAN decided to lay down a class of modern large (armored) cruisers in 1923 – the CAPE GOOD HOPE-class of which specifications and a drawing can be seen below.



Cape Good Hope, South African Heavy Cruiser laid down 1923

Displacement:
12.608 t light; 13.183 t standard; 14.422 t normal; 15.355 t full load
Loading submergence 839 tons/feet

Dimensions:
652,89 ft x 69,72 ft x 21,33 ft (normal load)
199,00 m x 21,25 m x 6,50 m

Armament:
8 - 8,27" / 210 mm guns (4 Main turrets x 2 guns, 2 superfiring turrets)
8 - 5,91" / 150 mm guns
16 - 3,46" / 88 mm AA guns
10 - 1,57" / 40 mm guns
10 - 0,79" / 20 mm guns
Weight of broadside 3.437 lbs / 1.559 kg
8 - 21,0" / 533 mm above water torpedoes

Armour:
Belt 5,91" / 150 mm, ends unarmoured
Belts cover 94% of normal area
Main turrets 5,91" / 150 mm, 2nd gun shields 1,57" / 40 mm
AA gun shields 0,98" / 25 mm, Light gun shields 0,59" / 15 mm
Armour deck 1,97" / 50 mm, Conning tower 7,09" / 180 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 92.494 shp / 69.000 Kw = 31,09 kts
Range 11.500nm at 12,00 kts

Complement:
658 - 855

Cost:
£3,592 million / $14,370 million

Distribution of weights at normal displacement:
Armament: 430 tons, 3,0%
Armour: 2.988 tons, 20,7%
Belts: 974 tons, 6,8%, Armament: 854 tons, 5,9%, Armour Deck: 1.070 tons, 7,4%
Conning Tower: 91 tons, 0,6%, Torpedo bulkhead: 0 tons, 0,0%
Machinery: 3.091 tons, 21,4%
Hull, fittings & equipment: 5.979 tons, 41,5%
Fuel, ammunition & stores: 1.813 tons, 12,6%
Miscellaneous weights: 120 tons, 0,8%

Metacentric height 3,2

Remarks:
Hull space for machinery, storage & compartmentation is adequate
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1,06
Shellfire needed to sink: 17.936 lbs / 8.135 Kg = 63,5 x 8,3 " / 210 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2,0
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 71 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0,64
Relative quality as seaboat: 1,20

Hull form characteristics:
Block coefficient: 0,520
Sharpness coefficient: 0,35
Hull speed coefficient 'M': 8,20
'Natural speed' for length: 25,55 kts
Power going to wave formation at top speed: 53 %
Trim: 59
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 93,8%
Relative accommodation and working space: 164,8%
(Average = 100%)
Displacement factor: 113%
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0,97
(Structure weight / hull surface area: 127 lbs / square foot or 620 Kg / square metre)
Relative longitudinal hull strength: 1,28
(for 22,05 ft / 6,72 m average freeboard, freeboard adjustment 5,75 ft)
Relative composite hull strength: 1,00

Very good piece on the development of the armoured cruiser. The General-class maybe capable of 26.5knts on trials, but HMS Invincible made roughly 27knts on trials as well. All the Invincibles were good for 26knts, later falling to 25knts by 1916.

You mention that the Invincible and Indefatigable classes both shared the same role of armoured-cruiser. I can agree about Invincible but Indefatigable was anything but. People often think of Indefatigable as simply a repeat Invincible because of lack of time. However the problem was money and that alone. The leading design studies until the lack of money came home were: 25knt ship with Invincible armour and 12x12" in centreline triples; 25knt ship with 8x12" and 9" main belt.

HMS Lion was something different, and more or less a logical progression from the Indefatigable design studies.

As for the RSAN Cape-class; I believe that this time the RSAN has made a grevious error. Mounting both 210mm and 150mm guns makes no sense and seems to be a thowback to pre-dreadnought designs. I imagine the 150mm guns will be used against destroyers and torpedo boats, but why not use the 210mm guns for this? Just about all the RSAN designs are firepower-light. I'd delete the 150m guns and use 10x210mm guns instead. You still have enough 88mm to be useful against destroyers. Her speed is maybe a tad slow when compared to ANS Apollo.

The drawing of her is very good though, but torpedo bulge? And isn't the 40mm mount aft to close to X turret?

Glad you like my latest news... :o)

Regarding the drawing - there are no bulges. That´s an external belt - at least it should be. ;o) You may be right on the aft 40mm gun but as long as there is no combined sea/air thread blast from the large guns won´t matter. However, it would have been possible to put the 40mm right on her stern further increasing fire arcs but that might interfer with anchor crew and light equipement aft that is not visible on the drawing.

I´m also glad you´ve a different opinion regarding secondaries. That´s what makes things so interesting. The reason why I choosed 15cm guns lies within the text I posted: the roots of those CAs (or ACs) go back to the last true ACs and the latter featured the same guns (21cm, 15cm and 8,8cm). Not having a split second and third battery surely has its advantages but SAE design crews have to learn that lesson yet.

One thing to keep in mind here: At the end of WW1 it was a proven fact that 10,5cm shells lack the punch to stop incoming light combatants such as TBs or DDs with a single hit or two. That´s why the Germans rearmed their CLs, the British used 15,2cm guns as main armament in their light cruisers and why the latest german DDs featured 15cm guns (buying some disadvantages with it). The philosophy behind CA23 is based on this. Build to engage multiple targets her main armament will engage enemy armored/light cruisers while her secondaries will still pack the punch to engage another CL or DD with success. It´s a similar thinking as behind the german real world PBs.

You may have also noticed that Good Hope is using same calibres as Mocambique or my Rosario-class CLs for example. Introducing another mount (10cm, 11cm or whatever) doesn´t make much sense.

Anyway, thanks for your comments.

If I had 52,000 tons of Class A cruisers to play with, I'd probably build something quite similar.

I do agree that the aft 40 is too close to Y turret (not X, X is the one with the catapult).

Did you design her with the latest SpringSharp, or add the fifth battery 'by hand'?

Uh, I forgot to mention that in a footnote! Thanks...

Note: I added fifth battery by hand.

A report from the latest SpringSharp v2.0 would look completely different and as long as we´re still beta testing and things change every day I won´t puplish such a report here.

Excellent article and drawing, as usual.

The design is indeed different, and more of a logical progression of the armored cruiser concept than most of what we see in Wesworld these days. I would assume that the four twins will have a good rate of fire, and that their protection will guarantee they'll be pumping out shells for some time.

The heavy secondary battery seems reasonable to me. As I recall, the pre-dreadnought problems with distinguishing between heavy and medium shell splashes came up when both were being fired at a single target. It seems that the Capes won't have this problem if they're able to engage multiple targets as you suggest.

I'm surprised that you've opted for 1.2 seakeeping - are sea conditions that bad where you're deploying them? I could see some merit in cutting the freeboard a bit and bumping up your powerplant a bit. Maybe you'd have 1.10 at the end - still not bad.

Despite the stated importance of scout planes to the type, I don't see a hangar anywhere - or is there one?

How long, in meters or feet, do your 21 cm turrets work out to?

Hi there...

Those turrets are ~8x6m.

Splash size could be a problem, indeed. However, those 15cm won´t be used if the ship is fighting a single target at some range. Only at short range where centralized firecontroll is not necessary, where RoF and weight of metal thrown against an enemy is more important than anything else (nightfight for example) they´ll be used.

In such a situation naval designers hope to have opted for the perfect solution as no other mount type offers a higher RoF than a single mount. The twins for the main guns are a compromise between weight savings and the nedd for central firecontroll on one hand and high RoF on the other.

I´m pretty sure it will take some time until you´ll see triples on RSAN cruisers and quads are most likely a no-no. Most likely...

Seakeeping is an issue here. You know, I´m not aiming for it in general but these units are designed for long patrols at sea - especially in the South Atlantic (Roaring Forties, Cape Hoorn etc.). Thus I choosed a high freeboard much like the british real world COUNTY-class cruisers.

Regarding floatplanes - you´re right. There´s no hangar yet. Thus only one plane can be carried (on the catapult). Problem is that the RSAN still has no standard floatplanes and the installation of the catapult on C turret is a test. Most likely her aft aft mast will be put further aft later and a catapult will then be placed behind her third funnel. Another option is to change her crane aft and store a plane or two (in a hangar) aft of her third funnel. You may have noticed that she lacks a RF for her main guns aft - unusial for a RSAN design. So some work still ahs to be done.

Thanks for your comments,

HoOmAn

Excellent HoOmAn!

and great background on your development. You've more time than me ; )

I'd question the heavy secondaries aswell but you make good points. I like the drawing, I see a County-Hipper cross with a touch of Tiger ; )

With the way the torps are sited - do you have reloads in that central deckhouse?

Cheers,

I count myself as lucky enough to see her drawing develope somewhat. The final design is breath takingly beautifull.

Nice Drawing, lot more detail than I get into mine!
Just one question though, is there a hanger or just one plane?

Quoted

Originally posted by Red Admiral
Just about all the RSAN designs are firepower-light.

That´s interesting. Do you really think so?

Quoted

Originally posted by alt_naval
With the way the torps are sited - do you have reloads in that central deckhouse?

No there are no additional torpedos but you´re right, there is enough space for at least one reload.

Quoted

Originally posted by Commodore Green
Nice Drawing, lot more detail than I get into mine!
Just one question though, is there a hanger or just one plane?

No, actually not. I couldn´t place it the way I like. I wanted a cat on C turret and a mast in front of it but this left me without space for a hangar.

I may re-design her later. Place a hangar and a cat atop of it (much like on HIPPER) behind her third funnel, move her mast aft, place boats abreast hangar or/and first funnel... Don´t know. It´s really difficult to get it done properly.

Armament


Zitat:
--------------------------------------------------------------------------------
Originally posted by Red Admiral
Just about all the RSAN designs are firepower-light.

--------------------------------------------------------------------------------



"That´s interesting. Do you really think so?"

Well seeing as Italy designs many of its ships with quads, to RA the RSAN would seem armament light.
The bonus to a more modest armament is of corse armor, and I'd pit this design against a cruiser with 4 quads any day of the week.

The twin turret design will have more armor to protect its firepower than a quad turret design. Given the SAE's done its homework on this design, I'm sure those twins will be very accurate.

Quoted

That´s interesting. Do you really think so?

Yes i do think that. On a ship of 13,000t an armament of 8x210mm is fairly poor, even with the secondaries. I have designs (not legal) that have 9x10" guns, 140mm belt,50mm deck and 32knt speed. You'll have already seen those specs for Basilian, i just used a higher BC for her though.

Again exemplifing firepower-light is RSAN Hertog Alexander. Those 8x280mm guns are pityful for a 22,000t ship. She has lots armour, yes, but those guns aren't going to hurt much. Again, I know that i can fit 6x381mm guns onto that displacement, in duples, and with adequate armour and speed.

Other examples are Mocambique, Rosario...

Quoted

Originally posted by Red Admiral
Again exemplifing firepower-light is RSAN Hertog Alexander. Those 8x280mm guns are pityful for a 22,000t ship. She has lots armour, yes, but those guns aren't going to hurt much. Again, I know that i can fit 6x381mm guns onto that displacement, in duples, and with adequate armour and speed.

Other examples are Mocambique, Rosario...

Well, the HERTOGs are a relic in WesWorld. However, they are a copy of real world GOEBEN/MOLTKE - with two less barels but superior layout. For the weight saved they carry a llittle bit more armor, though. Nevertheless, they´re lightly armed for a BC, for sure. I disagree on MOCAMBIQUE and ROSARIO, though.

The 38cm twins on MOCAMBIQUE were state of the art and provide a higher ROF than any other mount (triple or quad). In RW only the Americans used a triple of similar size (14") - all others used twins for good reason (Britain/Japan and Germany). We know that the american triples were good for 1 RPM while the mounts on BADEN achieved 2,5 RPM [Gröner, Breyer]. Further more the triples had their guns in single sleeves. Thus a shell hitting one barrel could render the whole turret useless. So for me there was no other way to go - twins were used. And taking into account the heavy armor those ships were meant to carry there was no weight reserve for a fifth turret (and no deck/hull space either as her drawing clearly shows).

With ROSARIO I build a 8000ts cruiser 15cm guns. Once again twins were choosen for reasons already mentioned. So while aiming for a balanced design featuring relatively heavy armor there was no choice other than to choose 4 turrets. And to be honest - comparing her to RW designs I can think of NO cruiser ever build and of similar size that is superior to her. I´d favor ROSARIO over LEANDER anyday - and that´s the design I had in mind when designing ROSARIO.

Please also note that in WesWorld some cruiser feature mounts they wouldn´t be able to carry without problems in RW. Often hulls don´t have enough beam and depth to carry the triples and quads spring* allows them to carry because it does not take beam into account (may be change with SpringSharp v2.0 later).

Regards,

HoOmAn

Rate of fire for capital ships is never much of a problem until you get down to about 150hm as you have to wait for the shells to fly through the air. The reasoning behind mounting 16x15" guns on Lepanto is thus; opening fire at maximum range. With 16 guns it should be relatively easy to find the range, and then after getting the range, 16 shells in the air at once has got to hit something.

As for any RW cruiser of similar size being superior to Rosario, you're probably correct. I can only think of the larger Belfast, Cleveland and Garibaldi classes that are better light cruisers.

Quoted

Please also note that in WesWorld some cruiser feature mounts they wouldn´t be able to carry without problems in RW. Often hulls don´t have enough beam and depth to carry the triples and quads spring* allows them to carry because it does not take beam into account (may be change with SpringSharp v2.0 later).

I agree. Note that Pisa does not have a 12:1 l:b ratio. Her beam is 2m less than the 5000t larger Cape Good Hope. I expect that that will be the first and only outing for quad 6" turrets. I'm reverting to duples again for later designs.

Quoted

Originally posted by Red Admiral
Rate of fire for capital ships is never much of a problem until you get down to about 150hm as you have to wait for the shells to fly through the air.

I know this theory but I think it is flawed and repeating it over and over again doesn´t make it much better.

Don´t get me wrong, it has some merit to wait for splashes before firing another shot. Advantage is you can get correctures, disadvantage is you can´t make good use of your theoretical ROF because flight time is up to a minute (thus 1 RPM assumed for such gunfights).

However, with firecontrol systems available at the end of WW1 and thereafter it is no longer necessary to wait for splashed. Once you have found the range you can automatically follow your targets movements via a plotting table and calculate corrections for your aiming. This way you no longer have to wait for splashes. Once you have the range you make good use of your maximum ROF.

The Germans used this system quite early and the British adopted something similar. The Germans started shooting half salvos ranging 500m (for example) apart of each other. These half salvos were fired in quick sucsession. Together with their stereooptical rangefinders (the RSAN is using them too) they quickly found the range with this system and then fired at maximum ROF at long as the target gets straddled. Doing so they still used half salvos as the continues stream of metal towards the target is much better this way than firing full salvos at max. ROF (and half salvos mean less stress to the hull of course).

With this system it was not necessary to spot splashes and IIRC german gunfire was quite accurate and effective in most battles. Good training helped, though, as no system can be used with success without.

So while I understand your point I disagree for reasons mentioned.

Regards,

HoOmAn

Quoted

Originally posted by Red Admiral
I expect that (Pisa) will be the first and only outing for quad 6" turrets.

I'm seriously considering using quads for my 1927 Romblon-class CL. One advantage is that when 1937 rolls around, you can swap in doubles of a larger caliber...

Quoted

I'm seriously considering using quads for my 1927 Romblon-class CL. One advantage is that when 1937 rolls around, you can swap in doubles of a larger caliber...

However its not really better to have 8x190mm(7.5") than 16x6" guns. Now in 1947 you could put automatic duple 6" guns there.