Treaty Cruiser Design Challenge

[reytuerto]

Hi, Shigure!
I want to confirm my participation in your challenge. I will send my candidate in a couple of weeks. Unfortunatelly I dont know how use the Springsharp program. May I use my tabulated data (based on the specs of similar ships) instead of Springsharp? Cheers.

[Keisser]

Unfortunatelly I dont know how use the Springsharp program.

Hey Reytuerto,
Using SpringSharp is optional for this challenge.

[pepembr_mb]

This is my proposal for the Treaty Cruiser Design Challenge. CP-1 Brasil is an Effigham derivative created as an answer to Argentinian Almirante Brown Class Heavy Cruiser. It is the beginning of the end of British influence in Brazilian Navy caused by the presence of an American Mission at Rio de Janeiro. It has British main guns and American secondary armament. Brazilian Navy preference was for more armour instead of guns. It had better armour than County Class cruisers and a 32 knots maximum speed:

[pepembr_mb]

This is SpringSharp prevision:

Brasil, Brazil Heavy Cruiser laid down 1935
DESIGN FAILURE: Overall load weight too much for hull (?)

Displacement:
7.969 t light (?); 8.328 t standard (?); 9.500 t normal; 10.438 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(568,99 ft / 562,00 ft) x 65,62 ft (Bulges 78,74 ft) x (18,96 / 20,41 ft)
(173,43 m / 171,30 m) x 20,00 m (Bulges 24,00 m) x (5,78 / 6,22 m)

Armament:
6 - 8" / 203 mm 45,0 cal guns - 255,24lbs / 115,77kg shells, 150 per gun
Breech loading guns in Coles/Ericsson turret mounts, 1935 Model
2 x 2-gun mounts on centreline, forward deck forward
2 raised mounts
1 x 2-gun mount on centreline, aft evenly spread
1 raised mount
8 - 5,00" / 127 mm 45,0 cal guns - 62,50lbs / 28,35kg shells, 150 per gun
Breech loading guns in deck mounts, 1935 Model
4 x Twin mounts on broadside, center deck
Weight of broadside 2.031 lbs / 921 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6,00" / 152 mm 490,00 ft / 149,35 m 16,56 ft / 5,05 m
Ends: Unarmoured
Main Belt covers 134% of normal length

- Hull Bulges:
3,94" / 100 mm 488,85 ft / 149,00 m 6,56 ft / 2,00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6,00" / 152 mm 2,76" / 70 mm 3,56" / 90 mm

- Armoured deck - multiple decks: 3,00" / 76 mm For and Aft decks

- Conning towers: Forward 6,00" / 152 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 84.124 shp / 62.757 Kw = 32,10 kts
Range 10.000nm at 15,00 kts
Bunker at max displacement = 2.110 tons

Complement:
480 - 625

Cost:
£3,983 million / $15,932 million

Distribution of weights at normal displacement:
Armament: 510 tons, 5,4%
Armour: 3.595 tons, 37,8%
- Belts: 1.911 tons, 20,1%
- Bulges: 467 tons, 4,9%
- Armament: 140 tons, 1,5%
- Armour Deck: 1.019 tons, 10,7%
- Conning Tower: 58 tons, 0,6%
Machinery: 2.390 tons, 25,2%
Hull, fittings & equipment: 1.474 tons, 15,5%
Fuel, ammunition & stores: 1.531 tons, 16,1%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5.577 lbs / 2.530 Kg = 21,8 x 8,0 " / 203 mm shells or 1,7 torpedoes
Stability (Unstable if below 1.00): 1,36
Metacentric height 4,6 ft / 1,4 m
Roll period: 15,5 seconds
Steadiness - As gun platform (Average = 50 %): 88 %
- Recoil effect (Restricted arc if above 1.00): 0,35
Seaboat quality (Average = 1.00): 1,24

Hull form characteristics:
Hull has low quarterdeck ,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,396 / 0,404
Length to Beam Ratio: 7,14 : 1
'Natural speed' for length: 23,71 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 71
Bow angle (Positive = bow angles forward): 15,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 0,00%, 26,08 ft / 7,95 m, 23,16 ft / 7,06 m
- Forward deck: 75,00%, 23,16 ft / 7,06 m, 23,16 ft / 7,06 m
- Aft deck: 0,00%, 23,16 ft / 7,06 m, 23,16 ft / 7,06 m
- Quarter deck: 25,00%, 16,60 ft / 5,06 m, 16,60 ft / 5,06 m
- Average freeboard: 21,52 ft / 6,56 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 98,7%
- Above water (accommodation/working, high = better): 208,1%
Waterplane Area: 22.643 Square feet or 2.104 Square metres
Displacement factor (Displacement / loading): 95%
Structure weight / hull surface area: 48 lbs/sq ft or 236 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,36
- Longitudinal: 0,77
- Overall: 0,39
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

[Karle94]

You need to rework either the SS report or the ship. There is so little hull strength that the ship cant be put to sea, ever. Also, 3 inches of deck armor is WAY too much for a cruiser.

[Keisser]

Breech loading guns in Coles/Ericsson turret mounts, 1935 Model

Ericsson turrets are turrets that you may see on monitors. For later ships, use "In turret on barbette mount".

2 x 2-gun mounts on centreline, forward deck forward
2 raised mounts
1 x 2-gun mount on centreline, aft evenly spread
1 raised mount

All your mounts are raised. Make sure that you have "On deck" mounts in SS.

4 x Twin mounts on broadside, center deck

Broadside mount is a thing you may see on old sail vessels and early ironclads. For something more modern, use casemates/deck mounts.

- Overall: 0,39

To be shorter: should be 1.0 for all ships except destroyers (they should have 0.5-0.6).
Also, you have wide bulges that are not really necessary - they increase water resistance and thus make ship need more H.P. for desired speed.
Still a long way to go

[Charguizard]

That's a thorough analysis Keisser, those tips should resolve the issues with the report.

Pepe, I'd also advice you to spend a little more time with your drawing, you have notorious colour mismatches between some parts and the rest of the ship, like with the directors and secondary guns, and also you have many stray pixels and leftovers strewn around, I can tell you erased the ship's badge because there's still yellow bits left.
Being patient and thorough will always produce a superior drawing.

[rundrewrun99]

My turn to enter the fray!

[erik_t]

She's awfully big-boned for a cruiser in the post-triple-expansion era.

[pepembr_mb]

Breech loading guns in Coles/Ericsson turret mounts, 1935 Model

Ericsson turrets are turrets that you may see on monitors. For later ships, use "In turret on barbette mount".

2 x 2-gun mounts on centreline, forward deck forward
2 raised mounts
1 x 2-gun mount on centreline, aft evenly spread
1 raised mount

All your mounts are raised. Make sure that you have "On deck" mounts in SS.

4 x Twin mounts on broadside, center deck

Broadside mount is a thing you may see on old sail vessels and early ironclads. For something more modern, use casemates/deck mounts.

- Overall: 0,39

To be shorter: should be 1.0 for all ships except destroyers (they should have 0.5-0.6).
Also, you have wide bulges that are not really necessary - they increase water resistance and thus make ship need more H.P. for desired speed.
Still a long way to go

I always put a sort of provisory design to discuss the ideas. After that, I refine the drawing. It's my first personal design here and my first spring board use.