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CSS Chickamauga-class Commerce Raider, 1934
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Author:  Charguizard [ February 1st, 2017, 11:43 pm ]
Post subject:  CSS Chickamauga-class Commerce Raider, 1934

Greetings shipbucketeers.
I understand the priority of the community is to draw more Real Designs to fill the archive, however, my first Real Design has proven to be a bit more...challenging than what I anticipated, mostly due to lack of sources, but I'll post that on the appropriate forum once you do a quality check on me!
In the meantime, I'd like to present you some fictional designs I've been working on.
The tabletop and videogame universe of Crimson Skies https://en.wikipedia.org/wiki/Crimson_Skies created by Jordan Weisman and Dave McCoy presents a universe where the United States is dismembered for totally believable and thorough reasons and gives way to a world dominated by gigantic airships (hooray!).
However, it totally disregards the fact that a world where the Washington treaty expires and London never comes around to happening has immense consequences to our dear and loved naval aspect of things.
So bla bla bla, goodbye treaty limitations, take a look at the Confederate States of America Ship, first of class, commerce raider Chickamauga!
[ img ]
B side with fluff:
[ img ]
Internal arrangement (based on Surrey sketches in John Jordan's Warships after Washington ) and blatant confession on all the bits I took here and there to make my life less miserable!
[ img ]

And the obligatory Springsharp report:
[spoiler=CSS Chickamauga 1934]Chickamauga, CSS Cruiser laid down 1933 (Engine 1934)

Displacement:
13.304 t light; 13.821 t standard; 14.881 t normal; 15.729 t full load

Dimensions: Length overall / water x beam x draught
730,34 ft / 725,00 ft x 58,00 ft x 22,00 ft (normal load)
222,61 m / 220,98 m x 17,68 m x 6,71 m

Armament:
6 - 9,20" / 234 mm guns in single mounts, 380,08lbs / 172,40kg shells, 1900 Model
Breech loading guns in turrets (on barbettes)
on centreline, evenly spread, 2 raised mounts
8 - 4,72" / 120 mm guns in single mounts, 52,72lbs / 23,92kg shells, 1926 Model
Dual purpose guns in deck mounts
on side, all amidships
8 - 1,57" / 40,0 mm guns (1x8 guns), 1,95lbs / 0,89kg shells, 1930 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
16 - 0,50" / 12,7 mm guns (4x4 guns), 0,06lbs / 0,03kg shells, 1926 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 2.719 lbs / 1.233 kg
Shells per gun, main battery: 140
16 - 21,0" / 533,4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5,50" / 140 mm 612,00 ft / 186,54 m 7,00 ft / 2,13 m
Ends: 3,00" / 76 mm 42,00 ft / 12,80 m 8,00 ft / 2,44 m
71,00 ft / 21,64 m Unarmoured ends
Upper: 5,00" / 127 mm 235,50 ft / 71,78 m 5,00 ft / 1,52 m
Main Belt covers 130 % of normal length

- Torpedo Bulkhead:
1,50" / 38 mm 235,50 ft / 71,78 m 5,50 ft / 1,68 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4,00" / 102 mm 2,00" / 51 mm 5,25" / 133 mm
2nd: 0,50" / 13 mm - -
4th: 0,50" / 13 mm - -

- Armour deck: 3,75" / 95 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 105.285 shp / 78.542 Kw = 32,45 kts
Range 7.500nm at 14,00 kts
Bunker at max displacement = 1.908 tons

Complement:
673 - 875

Cost:
£5,583 million / $22,332 million

Distribution of weights at normal displacement:
Armament: 347 tons, 2,3 %
Armour: 3.944 tons, 26,5 %
- Belts: 1.241 tons, 8,3 %
- Torpedo bulkhead: 72 tons, 0,5 %
- Armament: 570 tons, 3,8 %
- Armour Deck: 2.061 tons, 13,8 %
- Conning Tower: 0 tons, 0,0 %
Machinery: 3.029 tons, 20,4 %
Hull, fittings & equipment: 5.930 tons, 39,8 %
Fuel, ammunition & stores: 1.577 tons, 10,6 %
Miscellaneous weights: 55 tons, 0,4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
21.581 lbs / 9.789 Kg = 55,4 x 9,2 " / 234 mm shells or 2,4 torpedoes
Stability (Unstable if below 1.00): 1,11
Metacentric height 2,7 ft / 0,8 m
Roll period: 14,8 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0,93
Seaboat quality (Average = 1.00): 1,69

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,563
Length to Beam Ratio: 12,50 : 1
'Natural speed' for length: 26,93 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 42
Bow angle (Positive = bow angles forward): 10,10 degrees
Stern overhang: -3,30 ft / -1,01 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 30,00 ft / 9,14 m
- Forecastle (21 %): 26,00 ft / 7,92 m
- Mid (40 %): 24,00 ft / 7,32 m
- Quarterdeck (20 %): 22,00 ft / 6,71 m
- Stern: 24,00 ft / 7,32 m
- Average freeboard: 24,35 ft / 7,42 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 129,6 %
- Above water (accommodation/working, high = better): 146,7 %
Waterplane Area: 29.706 Square feet or 2.760 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 106 lbs/sq ft or 519 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,95
- Longitudinal: 1,51
- Overall: 1,00
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Camell Laird & Co. proposal for a commerce raiding cruiser of about 15000t.[/spoiler]

Just about everything else is greatly influenced by Hood's Surrey Mod, since both ships share a similar origin and timeframe, so thank you and please point out any crediting issues or nonconformities.
So please, do tell me what you think could be better, what you think is wrong and what is evidently wrong under any circumstances so maybe I can later go ahead and post this on the AU forums.
I appreciate your input.

Author:  JSB [ February 2nd, 2017, 12:46 am ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Hi Welcome, Very nice first ship!

My only thought would be that the singles are a very large waste of weight and the range isn't really great for a raiders?

"Main belt does not fully cover magazines and engineering spaces" is very bad in a Spring sharp report but it looks like you are using the main and ends to cover the main belt? Have you checked it all fits as one main belt, if so I would edit the warning out? .

The 4.7" also don't look like not Deck and Hoist?

Author:  Charguizard [ February 2nd, 2017, 1:07 am ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Many thanks for the compliment!
Now, while I'll try to defend my rationale here, I am very eager to learn from discussion, so I'll just point out how my thought process went.
First, experience dictates that one should design a ship for a requirement and not the other way around, but I really really wanted to model a Furutaka-like device on springsharp and see where it took me.
Indeed I'm using the ends to cover the magazines so I can have a narrower, and lighter, belt on that section while keeping a wider belt protecting the taller boiler and engine rooms.
The one time I tried using one wide belt, I think it didn't work even as I made the belt 6m wide, but in my month or so of using springsharp I usually have a very hard time getting that alert out on anything that's not a Battleship, so I'm not actually sure, but I think the internal arrangement diagram makes it more plausible.
So the excuse is that yeah, it's suboptimal but the singles help me make it narrow and fast!
I'm very interested on the range though, I know the Panzerschiffes had more range, but they ran on diesels and couldn't depend on bases (or rely very much on oilers as it turned out), so I ruled that if Leander made do with 5.700nm then 6.800 would do, however, I could thin some armor to help me with that.

Author:  eltf177 [ February 2nd, 2017, 5:21 pm ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Removing the TDS will probably allow you to fix the belt problem, OTOH a ship this large should have a TDS...

Author:  Thiel [ February 2nd, 2017, 5:36 pm ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

You could just use whatever material they use to armour their airships with.
Whatever it is it's light enough that they could make them immune to 18mm AP shells.

Author:  Colosseum [ February 2nd, 2017, 5:49 pm ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Cool stuff. There's no need to credit individual artists for each part (the use of the template and the Shipbucket watermark implies credit) and anyway some of the pieces you've credited weren't made by those guys. I would remove that bit.

You clearly understand the style; looking forward to some real ships. ;)

Author:  KHT [ February 2nd, 2017, 9:35 pm ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Those turrets look awfully big for being singles... Have a glance at the British parts sheets on the 9.2" guns. The Mk. XII is a single, and mass-wise, I doubt it would be even half as big as yours.
[ img ]
Otherwise, it looks to be a pretty nifty drawing.

Author:  Charguizard [ February 3rd, 2017, 1:22 am ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

Shipbucket spoke, and I listened.
I went back to Springsharp and indeed I was missing quite a bit of belt! I had to reduce the belts from 146 to 140mm, also reduced the barbette armour a bit, and in doing so increased range to 7500 nm. Nowhere near Panzerschiffe territory, but I don't think she needs it (or could somehow attain the 10k nm @ 20 kt with any reasonable mods).
Then I limited the TDS to the engineering spaces to reduce weight.
Anyways, the mods on the drawing to push the turrets outwards would've been so extensive I decided to use some of the loooong belt to cover the prow, so as to prevent damage that could impede the ship from fulfilling its mission.
Maybe the design is not that feasible after all :(
But hey! What does SS know about my superheated double-ended very compact Yarrow triple-drum boilers! And if Mogami could fit 150k hp on a smaller hull, I can fit 110k on a small citadel, right?
...right.
So then I went to NavWeaps and it turns out the 4.7" Mark VIII never did have hoists, so out that goes.
And then I finally trimmed down the turrets a bit, not too much though. Let's say they need more space for increased elevation, bigger faster hoists and larger hydraulic engines to train and elevate faster. Oh, and nice big reliable rammers.
Once again I thank you for your imput, and Thiel, let's not go there or we'll flood the forum with a terrible, pointless discussion!

Author:  Thiel [ February 3rd, 2017, 2:44 am ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

I take it we'll ignore the homing weapons and all the mid-air plane jacking as well :p

Author:  Hood [ February 3rd, 2017, 8:43 am ]
Post subject:  Re: CSS Chickamauga-class Commerce Raider, 1934

I like the looks of this ship, certainly has a touch of the Counties and the early pre-Arethusa light cruiser designs about it.

My comments on the design itself are;
The 9.2in gun turrets are quite large and could probably be made smaller in height and length, if you look at the bridge it can barely see over 'C' turret and I think that would be a hinderance in docking manoeuvres etc.
The bow seems too long, partly this is due to the A,B,C, forward turret layout but the overly large turrets are contributing, trimming even 4-5 pixels off each turret would save you 6-7 feet in length.
The main superstructure block is pretty tight due to the layout but generally it looks ok. I would be tempted to raise the bridge and wheelhouse by another deck, the fire-control directors are too low. They are also hemmed in by the fore-funnel, the funnels look a little bit too big and could probably be trimmed in height and maybe, for the forefunnel, width too.
I would raise the torpedoes a deck, they are too low and no warship ever put torpedoes that low in the deck on top of the armoured deck. I realise space is tight with those 4.7in mount overhangs but I think the aft tubes could be moved up and the fore tubes moved up and back to a position roughly below 'Q' turret's guns.
The aircraft layout is unusual and complicated but ok, I think the Japanese at least tried something similar.

I hope this helps in refining the design.

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