Weekly US and Japan ship design challenge

[bklooste]

Damn posted the wrong comparison ..was against teh 6*18 which was similar tonnage - wil fix.

Note I posted a design as per orignal 150K ( ie no engine power upgrade) and it does about 30.5, Im sure you can tweak the design to get another know knot or even 34 if you drop armour to 8". I wonder how small you can build a 6 * 18" * 34 knots * with 8-9" belt . Is 30K or 35K possible ?

[Iridium]

ORIGINAL: bklooste

Damn posted the wrong comparison ..was against teh 6*18 which was similar tonnage - wil fix.

Note I posted a design as per orignal 150K ( ie no engine power upgrade) and it does about 30.5, Im sure you can tweak the design to get another know knot or even 34 if you drop armour to 8". I wonder how small you can build a 6 * 18" * 34 knots * with 8-9" belt . Is 30K or 35K possible ?

Just hitting 30Kts isn't my idea of a fast CA killer, it can't keep up with CAs or outrun fast BBs. Good call on the armor scheme though, I'd probably redesign the 6 x 18" to have protection against 8" guns and 1000lb bombs if possible.

Revised 6 x18" with Triple mounts instead to save weight.

IJN No.13 +, Japan Battlecruiser laid down 1938

Displacement:
36,541 t light; 38,694 t standard; 41,026 t normal; 42,891 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(894.72 ft / 869.42 ft) x 101.71 ft x (31.17 / 32.26 ft)
(272.71 m / 265.00 m) x 31.00 m x (9.50 / 9.83 m)

Armament:
6 - 18.11" / 460 mm 45.0 cal guns - 3,218.00lbs / 1,459.66kg shells, 100 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
2 x Triple mounts on centreline, evenly spread
12 - 5.51" / 140 mm 50.0 cal guns - 88.63lbs / 40.20kg shells, 150 per gun
Quick firing guns in turret on barbette mounts, 1938 Model
6 x Twin mounts on sides, evenly spread
20 - 3.94" / 100.0 mm 65.0 cal guns - 33.83lbs / 15.35kg shells, 400 per gun
Dual purpose guns in turret on barbette mounts, 1938 Model
10 x Twin mounts on sides, evenly spread
10 raised mounts
48 - 0.98" / 25.0 mm 60.0 cal guns - 0.52lbs / 0.24kg shells, 1,500 per gun
Machine guns in deck mounts, 1938 Model
24 x Twin mounts on sides, evenly spread
Weight of broadside 21,073 lbs / 9,559 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 13.0" / 330 mm 656.17 ft / 200.00 m 8.20 ft / 2.50 m
Ends: 9.45" / 240 mm 196.85 ft / 60.00 m 6.56 ft / 2.00 m
16.40 ft / 5.00 m Unarmoured ends
Main Belt covers 116 % of normal length

- Torpedo Bulkhead:
1.97" / 50 mm 426.51 ft / 130.00 m 9.84 ft / 3.00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 12.6" / 320 mm 7.87" / 200 mm 1.97" / 50 mm
2nd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
4th: 0.20" / 5 mm - -

- Armoured deck - single deck: 4.92" / 125 mm For and Aft decks
Forecastle: 0.98" / 25 mm Quarter deck: 0.98" / 25 mm

- Conning towers: Forward 12.99" / 330 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 228,074 shp / 170,144 Kw = 34.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 4,198 tons

Complement:
1,440 - 1,873

Cost:
£22.757 million / $91.027 million

Distribution of weights at normal displacement:
Armament: 3,296 tons, 8.0 %
Armour: 9,592 tons, 23.4 %
- Belts: 3,294 tons, 8.0 %
- Torpedo bulkhead: 306 tons, 0.7 %
- Armament: 1,129 tons, 2.8 %
- Armour Deck: 4,530 tons, 11.0 %
- Conning Tower: 333 tons, 0.8 %
Machinery: 6,245 tons, 15.2 %
Hull, fittings & equipment: 17,157 tons, 41.8 %
Fuel, ammunition & stores: 4,485 tons, 10.9 %
Miscellaneous weights: 250 tons, 0.6 %
- Hull below water: 250 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
41,712 lbs / 18,920 Kg = 14.0 x 18.1 " / 460 mm shells or 4.8 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 5.2 ft / 1.6 m
Roll period: 18.7 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.93
Seaboat quality (Average = 1.00): 0.97

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and a round stern
Block coefficient (normal/deep): 0.521 / 0.526
Length to Beam Ratio: 8.55 : 1
'Natural speed' for length: 29.49 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 78
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 32.45 ft / 9.89 m, 20.64 ft / 6.29 m
- Forward deck: 30.00 %, 20.64 ft / 6.29 m, 20.64 ft / 6.29 m
- Aft deck: 30.00 %, 20.64 ft / 6.29 m, 20.64 ft / 6.29 m
- Quarter deck: 15.00 %, 20.64 ft / 6.29 m, 20.64 ft / 6.29 m
- Average freeboard: 21.82 ft / 6.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 114.6 %
- Above water (accommodation/working, high = better): 164.0 %
Waterplane Area: 60,064 Square feet or 5,580 Square metres
Displacement factor (Displacement / loading): 102 %
Structure weight / hull surface area: 215 lbs/sq ft or 1,047 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.00
- Longitudinal: 1.14
- Overall: 1.01
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
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[RevRick]

ORIGINAL: bklooste

I kind of enjoyed the last 2 threads so i thought i would start a thread to discuss some alternative scenario designs.

2 ships each week one allied and one Japanese.

The best design will be noted. Bonus points for designs based on real proposals ,cheap / cost effective designs or ones which have springgsharp data ( if they are a bit questionable). The goal is not to rort the system but to build good designs with our 20/20 hind sight . The best option may be not to build it or to build more of an existing class.

Last week we talked about a 6-8K CL design for Japan from the Katori onwards and i think Terminus proposal was best - build no CL.

This week i will cover some Capital ships.


Japan gets 70% allowance from the Washington Naval treaty so has built the Kaga and Tosa.

US:
Rumours are around that Japan has allocated resources for up to 8 Battleships in 37-42. Japan pulled out of the Naval treaty in 35 and unless it joins you can build anything in 38. 4 South Dakotas have just been layed down and the escalator treaty is in effect. What does the US build / do congress is sympathetic to increasing the budget to address the deficient battle line ?

If the SoDaks are already laid down, the NC class is in place, I would assume.
A. Begin at least two Montana class in place of two SoDaks to counter any heavy ships in the IJN battle line.
B. Begin and conclude all six Iowas as quickly as possible, since there should still be a couple of ways clear to lay down an Iowa or two.
C. Begin the Baltimore Class heavies as quickly as possible for CV Escort. Upgrade the Clevelands to a Baltimore Class hull to prevent the problems of overweight by the secondary battery. If some Clevelands are already on the ways, drop the #3 6" Turret to allow for more AA (make them a diminutive Baltimore, so to speak!) Either that, or take that 10K ton hull and put six more twin 5"38 twin mounts on it - 24 total guns with 18 on each broadside PLUS the 40mm Bofors ought to make any attacking air strike a little pessimistic.
D. Immediately begin two more Yorktowns to accompany Hornet into the Fleet. Rename the Ranger to the USS White Elephant, and begin a "reconstruction" project like the USN did to the Frigate Constellation. Rebuild the thing in the guise of repairing it. Bring it up to Wasp Standards, at least. Or better, if Wasp is not too far along in the process, build Wasp and (re)build Ranger is concurrent Yorktowns to the other two added to production.
E. Accelerate the planning for the follow up Essex Class.
F. Modify the New Mexico, Tennessee, and Colorado class to all 5"38 secondary battery.
G. Start building a whole #*&( load of destroyers in as many places as possible.
Claim all of this as a job production scheme to improve the Navy and to put people to work at the same time to spend the country's way out of the Depression! If necessary, add ways to the yards at Philadelphia, Mare Island, and Bremerton! Just putting people to work!!

[Nemo121]

Simple answer: What they should have done, in that situation, is realise that aircraft would make BBs obsolete, go with the carrier mafia within the IJN and build more CVs instead of those BBs.
 
With 90,000 tons to spend one could build 3 x 30,000 ton Akagi-level CVs

[stuman]

ORIGINAL: Shark7

Springsharp is a programme that allows you to design warships for simulation purposes.

You can read up on it better than I can explain it, website is here: http://www.springsharp.com/

Very cool, thx.

[bklooste]

ORIGINAL: Nemo121

Simple answer: What they should have done, in that situation, is realise that aircraft would make BBs obsolete, go with the carrier mafia within the IJN and build more CVs instead of those BBs.

With 90,000 tons to spend one could build 3 x 30,000 ton Akagi-level CVs

the 60-90K is for the Yamato , expanding the ship yard and her turret ship. One issue is since you have the 2 Kaga class battleships the US will ramp up production and you will see Iowas and maybe a Montana in 42. This is good from the allied point of view it gives them more options but can Japan handle these or just go for "mission kills" on the Iowa while loosing your capital ships and rely on air craft.

Obviously building your entire tonage on Soryu class ships is a strong option. Were certainly building some CVs ( see thread how many ships can you build instead of the Yamatos. With 70% Japan starts with more old carriers also but that will come up in a later week) .

Unless we can get a cheapish 16"/18" BC design which is very usefull vs say an Iowa class raid on KB i like something like Terminus/alt naval suggestion of refit some Battleships , take their turrets and make a few cheap fast BBs. for KB escort and make some 12" Cruiser killers ( though lighter weight and with only cruiser armour similar to the german pocket battleships) .

[bklooste]

ORIGINAL: RevRick



If the SoDaks are already laid down, the NC class is in place, I would assume.
A. Begin at least two Montana class in place of two SoDaks to counter any heavy ships in the IJN battle line.
B. Begin and conclude all six Iowas as quickly as possible, since there should still be a couple of ways clear to lay down an Iowa or two.
C. Begin the Baltimore Class heavies as quickly as possible for CV Escort. Upgrade the Clevelands to a Baltimore Class hull to prevent the problems of overweight by the secondary battery. If some Clevelands are already on the ways, drop the #3 6" Turret to allow for more AA (make them a diminutive Baltimore, so to speak!) Either that, or take that 10K ton hull and put six more twin 5"38 twin mounts on it - 24 total guns with 18 on each broadside PLUS the 40mm Bofors ought to make any attacking air strike a little pessimistic.
D. Immediately begin two more Yorktowns to accompany Hornet into the Fleet. Rename the Ranger to the USS White Elephant, and begin a "reconstruction" project like the USN did to the Frigate Constellation. Rebuild the thing in the guise of repairing it. Bring it up to Wasp Standards, at least. Or better, if Wasp is not too far along in the process, build Wasp and (re)build Ranger is concurrent Yorktowns to the other two added to production.
E. Accelerate the planning for the follow up Essex Class.
F. Modify the New Mexico, Tennessee, and Colorado class to all 5"38 secondary battery.
G. Start building a whole #*&( load of destroyers in as many places as possible.
Claim all of this as a job production scheme to improve the Navy and to put people to work at the same time to spend the country's way out of the Depression! If necessary, add ways to the yards at Philadelphia, Mare Island, and Bremerton! Just putting people to work!!

yep like the idea of putting people to work durring the depression it would be an easy argument for congress and give the US some nice hardware to make the early war more interesting. This thread is about the Capital ships so will stay on them.
A.) Sounds ok to build 2 instead. Though in this case i would put the Iowas only 6 months forward. So swap 2 SoDaks for 2 Montanas and 6 month earlier Iowas vs 1 year earlier Iowas and swap 2nd Iowa for a Montana. ??
F) I dont see this justified until we see some air power vs naval or if the ships get a major upgrade ( which is unlikely as we are building Montanas/Iowas ) . We could see this being scheduled starting in mid 41 due to results in Europe.

[Iridium]

Cheapish 12" CA killer:

IJN Zetsubo, Japan Battlecruiser laid down 1938

Displacement:
26,249 t light; 27,457 t standard; 29,362 t normal; 30,886 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(848.24 ft / 820.21 ft) x 82.02 ft x (26.25 / 27.35 ft)
(258.54 m / 250.00 m) x 25.00 m x (8.00 / 8.34 m)

Armament:
8 - 12.01" / 305 mm 45.0 cal guns - 873.08lbs / 396.02kg shells, 140 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
4 x Twin mounts on centreline, evenly spread
2 raised mounts
Aft Main mounts separated by engine room
20 - 3.94" / 100.0 mm 65.0 cal guns - 33.83lbs / 15.35kg shells, 150 per gun
Dual purpose guns in turret on barbette mounts, 1938 Model
10 x Single mounts on sides, evenly spread
48 - 0.98" / 25.0 mm 60.0 cal guns - 0.52lbs / 0.24kg shells, 1,500 per gun
Machine guns in deck mounts, 1938 Model
24 x Twin mounts on sides, evenly spread
Weight of broadside 7,686 lbs / 3,486 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8.66" / 220 mm 590.55 ft / 180.00 m 9.84 ft / 3.00 m
Ends: 6.30" / 160 mm 196.85 ft / 60.00 m 6.56 ft / 2.00 m
32.81 ft / 10.00 m Unarmoured ends
Main Belt covers 111 % of normal length

- Torpedo Bulkhead:
1.97" / 50 mm 524.93 ft / 160.00 m 9.84 ft / 3.00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 8.66" / 220 mm 7.87" / 200 mm 8.66" / 220 mm
2nd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.20" / 5 mm - -

- Armoured deck - single deck: 3.94" / 100 mm For and Aft decks
Forecastle: 1.97" / 50 mm Quarter deck: 1.97" / 50 mm

- Conning towers: Forward 9.84" / 250 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 190,945 shp / 142,445 Kw = 34.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 3,429 tons

Complement:
1,120 - 1,457

Cost:
£13.530 million / $54.121 million

Distribution of weights at normal displacement:
Armament: 1,558 tons, 5.3 %
Armour: 7,703 tons, 26.2 %
- Belts: 2,345 tons, 8.0 %
- Torpedo bulkhead: 376 tons, 1.3 %
- Armament: 1,621 tons, 5.5 %
- Armour Deck: 3,159 tons, 10.8 %
- Conning Tower: 202 tons, 0.7 %
Machinery: 5,229 tons, 17.8 %
Hull, fittings & equipment: 11,760 tons, 40.1 %
Fuel, ammunition & stores: 3,113 tons, 10.6 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
35,022 lbs / 15,886 Kg = 40.5 x 12.0 " / 305 mm shells or 4.3 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 3.8 ft / 1.2 m
Roll period: 17.7 seconds
Steadiness - As gun platform (Average = 50 %): 57 %
- Recoil effect (Restricted arc if above 1.00): 0.68
Seaboat quality (Average = 1.00): 0.92

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and a round stern
Block coefficient (normal/deep): 0.582 / 0.588
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 28.64 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 62
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 31.50 ft / 9.60 m, 20.05 ft / 6.11 m
- Forward deck: 30.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Aft deck: 30.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Quarter deck: 15.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Average freeboard: 21.19 ft / 6.46 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 108.3 %
- Above water (accommodation/working, high = better): 164.9 %
Waterplane Area: 48,381 Square feet or 4,495 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 175 lbs/sq ft or 855 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.16
- Longitudinal: 0.97
- Overall: 1.01
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[Iridium]

Maybe take some old 16" guns and place them on this ship to make it cheaper...smaller engines do make all the difference but sadly make them slightly less able to keep up with fast CV groups.

IJN Ichizen, Japan Battlecruiser laid down 1938

Displacement:
34,167 t light; 36,336 t standard; 38,598 t normal; 40,407 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(930.26 ft / 902.23 ft) x 98.43 ft (Bulges 104.99 ft) x (29.53 / 30.61 ft)
(283.54 m / 275.00 m) x 30.00 m (Bulges 32.00 m) x (9.00 / 9.33 m)

Armament:
8 - 16.14" / 410 mm 45.0 cal guns - 2,120.84lbs / 962.00kg shells, 140 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
4 x Twin mounts on centreline amidships (forward deck)
2 raised mounts
Aft Main mounts separated by engine room
20 - 3.94" / 100.0 mm 65.0 cal guns - 33.83lbs / 15.35kg shells, 150 per gun
Dual purpose guns in turret on barbette mounts, 1938 Model
10 x Single mounts on sides, evenly spread
48 - 0.98" / 25.0 mm 60.0 cal guns - 0.52lbs / 0.24kg shells, 1,500 per gun
Machine guns in deck mounts, 1938 Model
24 x Twin mounts on sides, evenly spread
Weight of broadside 17,668 lbs / 8,014 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8.66" / 220 mm 557.74 ft / 170.00 m 9.84 ft / 3.00 m
Ends: 6.30" / 160 mm 262.47 ft / 80.00 m 6.56 ft / 2.00 m
82.02 ft / 25.00 m Unarmoured ends
Main Belt covers 95 % of normal length

- Torpedo Bulkhead:
1.97" / 50 mm 524.93 ft / 160.00 m 9.84 ft / 3.00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 16.5" / 420 mm 11.8" / 300 mm 16.5" / 420 mm
2nd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.20" / 5 mm - -

- Box over machinery & magazines: 2.95" / 75 mm
Forecastle: 0.98" / 25 mm Quarter deck: 0.98" / 25 mm

- Conning towers: Forward 9.84" / 250 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 131,987 shp / 98,462 Kw = 30.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 4,070 tons

Complement:
1,376 - 1,789

Cost:
£19.057 million / $76.226 million

Distribution of weights at normal displacement:
Armament: 3,059 tons, 7.9 %
Armour: 8,849 tons, 22.9 %
- Belts: 2,384 tons, 6.2 %
- Torpedo bulkhead: 376 tons, 1.0 %
- Armament: 4,283 tons, 11.1 %
- Armour Deck: 1,564 tons, 4.1 %
- Conning Tower: 242 tons, 0.6 %
Machinery: 3,614 tons, 9.4 %
Hull, fittings & equipment: 18,646 tons, 48.3 %
Fuel, ammunition & stores: 4,430 tons, 11.5 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
50,748 lbs / 23,019 Kg = 24.1 x 16.1 " / 410 mm shells or 7.2 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 4.9 ft / 1.5 m
Roll period: 19.8 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.74
Seaboat quality (Average = 1.00): 1.09

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and a round stern
Block coefficient (normal/deep): 0.483 / 0.488
Length to Beam Ratio: 8.59 : 1
'Natural speed' for length: 30.04 kts
Power going to wave formation at top speed: 43 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 31.50 ft / 9.60 m, 20.05 ft / 6.11 m
- Forward deck: 30.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Aft deck: 30.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Quarter deck: 15.00 %, 20.05 ft / 6.11 m, 20.05 ft / 6.11 m
- Average freeboard: 21.19 ft / 6.46 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 89.3 %
- Above water (accommodation/working, high = better): 161.7 %
Waterplane Area: 58,268 Square feet or 5,413 Square metres
Displacement factor (Displacement / loading): 120 %
Structure weight / hull surface area: 235 lbs/sq ft or 1,149 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.09
- Longitudinal: 0.99
- Overall: 1.01
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

[bklooste]

Just hitting 30Kts isn't my idea of a fast CA killer, it can't keep up with CAs or outrun fast BBs. Good call on the armor scheme though, I'd probably redesign the 6 x 18" to have protection against 8" guns and 1000lb bombs if possible.

Revised 6 x18" with Triple mounts instead to save weight.

I agree , I think proof vs 8" gun at 16KYards sounds best so 6" inclined belt.
So what is the lightest hull you can build 6*18 ( 2*3 ) , 6" inclined belt and 34-35 knots in ? ( 1000lb AP bombs is a bonus )

[Iridium]

My current best build with those armor specs...can't recall what the penetration of a 1000lber AP bomb is but I upped the deck armor over the criticals to 100mm instead of a single deck of 75mm.

I've tried to make it smaller than 38k tons but with those armor requirements and the size of the powerplant needed to move the beast... I haven't managed any smaller.

IJN Pocket 18" BB, Japan Battlecruiser laid down 1938

Displacement:
34,161 t light; 36,078 t standard; 38,332 t normal; 40,135 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(947.72 ft / 918.64 ft) x 104.99 ft x (32.81 / 33.86 ft)
(288.87 m / 280.00 m) x 32.00 m x (10.00 / 10.32 m)

Armament:
6 - 18.11" / 460 mm 45.0 cal guns - 3,218.00lbs / 1,459.66kg shells, 100 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
2 x Triple mounts on centreline, evenly spread
20 - 3.94" / 100.0 mm 65.0 cal guns - 33.83lbs / 15.35kg shells, 150 per gun
Dual purpose guns in turret on barbette mounts, 1938 Model
10 x Twin mounts on sides, evenly spread
48 - 0.98" / 25.0 mm 60.0 cal guns - 0.52lbs / 0.24kg shells, 1,500 per gun
Machine guns in deck mounts, 1938 Model
24 x Twin mounts on sides, evenly spread
Weight of broadside 20,010 lbs / 9,076 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6.30" / 160 mm 672.57 ft / 205.00 m 9.84 ft / 3.00 m
Ends: 3.94" / 100 mm 196.85 ft / 60.00 m 6.56 ft / 2.00 m
49.21 ft / 15.00 m Unarmoured ends
Main Belt covers 113 % of normal length

- Torpedo Bulkhead:
1.97" / 50 mm 524.93 ft / 160.00 m 9.84 ft / 3.00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 9.45" / 240 mm 7.87" / 200 mm 9.45" / 240 mm
2nd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.20" / 5 mm - -

- Box over machinery & magazines: 3.94" / 100 mm
Forecastle: 0.98" / 25 mm Quarter deck: 0.98" / 25 mm

- Conning towers: Forward 8.66" / 220 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 205,207 shp / 153,085 Kw = 34.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 4,058 tons

Complement:
1,369 - 1,780

Cost:
£21.162 million / $84.647 million

Distribution of weights at normal displacement:
Armament: 3,089 tons, 8.1 %
Armour: 7,270 tons, 19.0 %
- Belts: 1,878 tons, 4.9 %
- Torpedo bulkhead: 376 tons, 1.0 %
- Armament: 1,799 tons, 4.7 %
- Armour Deck: 3,005 tons, 7.8 %
- Conning Tower: 212 tons, 0.6 %
Machinery: 5,619 tons, 14.7 %
Hull, fittings & equipment: 18,183 tons, 47.4 %
Fuel, ammunition & stores: 4,171 tons, 10.9 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
42,083 lbs / 19,088 Kg = 14.2 x 18.1 " / 460 mm shells or 5.2 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 5.5 ft / 1.7 m
Roll period: 18.8 seconds
Steadiness - As gun platform (Average = 50 %): 87 %
- Recoil effect (Restricted arc if above 1.00): 0.90
Seaboat quality (Average = 1.00): 1.18

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and a round stern
Block coefficient (normal/deep): 0.424 / 0.430
Length to Beam Ratio: 8.75 : 1
'Natural speed' for length: 30.31 kts
Power going to wave formation at top speed: 47 %
Trim (Max stability = 0, Max steadiness = 100): 74
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 33.33 ft / 10.16 m, 21.23 ft / 6.47 m
- Forward deck: 30.00 %, 21.23 ft / 6.47 m, 21.23 ft / 6.47 m
- Aft deck: 30.00 %, 21.23 ft / 6.47 m, 21.23 ft / 6.47 m
- Quarter deck: 15.00 %, 21.23 ft / 6.47 m, 21.23 ft / 6.47 m
- Average freeboard: 22.44 ft / 6.84 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 110.7 %
- Above water (accommodation/working, high = better): 178.1 %
Waterplane Area: 60,298 Square feet or 5,602 Square metres
Displacement factor (Displacement / loading): 108 %
Structure weight / hull surface area: 222 lbs/sq ft or 1,082 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.24
- Overall: 1.01
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

[Iridium]

Well with the 18" 2 x 3 boat I seem to be able to do a couple things. 34kts seems the most reasonable speed without making a massive hull. If I try to make the hull longer and thinner I either run into stability problems or losing too much tonnage to keep the ship from breaking apart.

I'm beginning to think 38k tons is the best one could get for this setup.

[bklooste]

ORIGINAL: Iridium

quote:

IJN Pocket 18" BB, Japan Battlecruiser laid down 1938

Displacement:
34,161 t light; 36,078 t standard; 38,332 t normal; 40,135 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(947.72 ft / 918.64 ft) x 104.99 ft x (32.81 / 33.86 ft)
(288.87 m / 280.00 m) x 32.00 m x (10.00 / 10.32 m)

Armament:
6 - 18.11" / 460 mm 45.0 cal guns - 3,218.00lbs / 1,459.66kg shells, 100 per gun
Breech loading guns in turret on barbette mounts, 1938 Model

I like it .. While 16" guns will make it lighter it wont be able to penetrate US ships without getting very close for which it would need armour be bigger etc..

Pros
- Difficult to kill by ships ,against powerfull ships it can use long range plunging fire and keep them at long range .
- It can also work with the battle line providing the 14"/16" line some power against the excellent US belts.
- KB escort where it can delay any chasers and keep the chasers under dangerous fire.
- Can easilly kill cruisers who cant get away.

Con
-Cost
-Close / Night fighting

[RevRick]

ORIGINAL: bklooste

ORIGINAL: RevRick



If the SoDaks are already laid down, the NC class is in place, I would assume.
A. Begin at least two Montana class in place of two SoDaks to counter any heavy ships in the IJN battle line.
B. Begin and conclude all six Iowas as quickly as possible, since there should still be a couple of ways clear to lay down an Iowa or two.
C. Begin the Baltimore Class heavies as quickly as possible for CV Escort. Upgrade the Clevelands to a Baltimore Class hull to prevent the problems of overweight by the secondary battery. If some Clevelands are already on the ways, drop the #3 6" Turret to allow for more AA (make them a diminutive Baltimore, so to speak!) Either that, or take that 10K ton hull and put six more twin 5"38 twin mounts on it - 24 total guns with 18 on each broadside PLUS the 40mm Bofors ought to make any attacking air strike a little pessimistic.
D. Immediately begin two more Yorktowns to accompany Hornet into the Fleet. Rename the Ranger to the USS White Elephant, and begin a "reconstruction" project like the USN did to the Frigate Constellation. Rebuild the thing in the guise of repairing it. Bring it up to Wasp Standards, at least. Or better, if Wasp is not too far along in the process, build Wasp and (re)build Ranger is concurrent Yorktowns to the other two added to production.
E. Accelerate the planning for the follow up Essex Class.
F. Modify the New Mexico, Tennessee, and Colorado class to all 5"38 secondary battery.
G. Start building a whole #*&( load of destroyers in as many places as possible.
Claim all of this as a job production scheme to improve the Navy and to put people to work at the same time to spend the country's way out of the Depression! If necessary, add ways to the yards at Philadelphia, Mare Island, and Bremerton! Just putting people to work!!

yep like the idea of putting people to work durring the depression it would be an easy argument for congress and give the US some nice hardware to make the early war more interesting. This thread is about the Capital ships so will stay on them.
A.) Sounds ok to build 2 instead. Though in this case i would put the Iowas only 6 months forward. So swap 2 SoDaks for 2 Montanas and 6 month earlier Iowas vs 1 year earlier Iowas and swap 2nd Iowa for a Montana. ??
F) I dont see this justified until we see some air power vs naval or if the ships get a major upgrade ( which is unlikely as we are building Montanas/Iowas ) . We could see this being scheduled starting in mid 41 due to results in Europe.

I didn't make myself clear. If the SoDaks were already laid down, I would assume that they would be completed, or at least off the ways at about 2 years. It is, usually in peace time 7-9 months to commissioning, and 3-4 working up. This makes ships already under construction at the beginning of 1938 in fleet service in late 1940. It also means that as the ways are cleared in late 1939 to early 1940, you begin another two year to launch, and 6-8 months to commissioning cycle with the next set of ships. The USN then begins two Montanas and the first two Iowas (depending on the size of the building ways). The Iowas also took about two years from laying of the Keel to Launching. Assuming at least two ways, if they were of sufficient size to accomodate that hull, then getting the keel laid late 1939, early 40 gives a prospective launch date of the first two Iowas around Dec 1941 to early 1942, with commisioning within six months, and the ships being ready by the end of 42 at the latest. The Montanas would presumably take longer. This would mean a battle line of two North Carolinas, four South Dakotas, and two Montanas by the end of 1942, with two Iowas around for fun and games. This would also probably mean the the North Carolinas would have been completed with the twelve 14"50s being contemplated for their main armament.

[bklooste]

Yep NC would be 14" , I think they could of got the Montanas in between with the Kaga and Tosa out there , asuming a few hassles due to resources going to the Montanas (eg Guns) will put the first Iowa in early 43.

[RevRick]

According to NavWeaps, 71 of the 16/50 Mk 3s were around. That would surely be enough to equip the Montana's. After all, it was a design team error which cause the Mk 7 to be built for the Iowas. They didn't allow enough room for the turret necessary to carry the Mk 3. That would probably not be a problem with a Montana.

[bklooste]

If you prioritise the Montanas to come late 42 , which means they need to be layed down in early 39 or mid 39 at the latest suck in a lot of yearly budget and design that went to the Iowas( as there design was not completed) ......Most of the yard time is not under war time like the Iowas and with the greater tonnage so i would expect at least 40-50% more .

So i think either prioritize Montanas
2 Montanas in late 42
Iowa 22/2/43 Historical
New Jersey 23/5/42

Or Prioritize Iowas
Iowa 22/8/42
New Jersey OR Montana 23/11/42
Misouri -> 29/7/43
Wisconsin 22/10/43
Ohio 2/2/44
New Jersey OR Montana 4/4//44