SDN World 3 Ship Design Thread

[Ryan Thunder]

For some unknowable reason I altogether forgot that submarines were in service during the First World War and thus would be in service now. I will thusly be needing to add destroyers and perhaps a few submarines to my naval ORBAT, if that's okay with Steve...

[Steve]

Are you under your cap, Ryan? If not you need to remove some of your other ships to make space. Not that you'd need to do much. Coastal subs would be like 500-1,000 tons displacement, destroyers, depending on age, from 500 to 1,800 tons.

[Ryan Thunder]

Are you under your cap, Ryan? If not you need to remove some of your other ships to make space.

Well, of course. I meant add the capability, not increase my fleet tonnage.

Not that you'd need to do much. Coastal subs would be like 500-1,000 tons displacement, destroyers, depending on age, from 500 to 1,800 tons.

Ah, thanks. I'll assume the subs are 1000 tons and find something in that ballpark to base it off of. That, and work out a destroyer design...

Springsharp won't help me with subs, will it?

[Steve]

Well, newer subs are creeping toward 1,500 tons I believe. 2,000 tons for the very newest ones being made for oceanic distance.

Also, SpringSharp sucks for destroyers, as has been said in this thread, and doing subs really doesn't work either because it's not designed to emulate subs. There are some tricks that are supposed to help mimic subs but I've found they don't work well.

[Ryan Thunder]

Hmm... after doing some research I came across this motherfucker, which was, frankly, just too amusing to pass up.

[CmdrWilkens]

Speaking of OrBats I'm tentatively 7 kt over my 1.2Mt initial limit but that is with placeholders for a lot of ship sizes. I've done a rough cut on my 1916-build BC/CC and my 1918 BB (Presteza and Veracruz-class respectively) and they are within 1 kt per ship of my stated target.

My plan right now is that once I get all of my surface ships lined up I will edit down in to my Sub force as needed. Since I'm not commissioning any new warships until 1927 I've got some time to make sure it all works out.


I've also got a rough cut of my 1927-series Battleship which will start building after I get my 55 kt+ slipways in place. Yeah its a freakin beast and essentially invulnerable even to the 16"/50 with super heavy APC rounds. Being slightly more specific a couple of rough cuts on the ship places the zone of immunity as between 16 or 17,000 and 32,000 yards. Yeah for super heavy sloped armor.

[Ryan Thunder]

22"/60 guns ahoy?

[Steve]

What are the specs on this vessel?

[CmdrWilkens]

22"/60 guns ahoy?

Sure, if you want the barrels to wear out after 2 firings before getting the range

What are the specs on this vessel?

WIP but I can send you the current SSHIP file, I'm not gonna put it up on the Wiki until I actually lay the first hulls

[Steve]

22"/60 guns ahoy?

Sure, if you want the barrels to wear out after 2 firings before getting the range

What are the specs on this vessel?

WIP but I can send you the current SSHIP file, I'm not gonna put it up on the Wiki until I actually lay the first hulls

Please do so.

[Ma Deuce]

Who came up with that rule? It seems rather optimistic given that deck armor was almost always used as structure by everyone, plating added as latter upgrades excluded of course.

It was a suggestion by fellow hobbyist I know IRL. Of course, optimistic or not my "experiment" does not seem very outlandish when you consider the attributes of the Omaha class. So what in your opinion would be a better rule of thumb? Leave the deck as thick as it's supposed to be and thin out the belt to 1/3 only, or maybe subtract the average thickness of the a backing plate + cement from the belt?

The thickest armor used in this manner on Japanese cruisers was the 145mm thick belt and 65mm thick deck slope over magazines on the Tone class (machinery armor is thinned on all the big Japanese CAs). However some thicker material was supposedly used on Shokaku class and latter Japanese carriers, I’ve never been able to confirm exactly what nor the complete armor layout of the ships in the first place.

Would you happen to have any diagrams of the armor scheme for any of the Japanese cruisers? I've never never been able to find any either online or in the books I own or have had access to.

[Raesene]

Hmm... after doing some research I came across this motherfucker, which was, frankly, just too amusing to pass up.

Tuscany laid down its own Surcoufs in Q2/1925

I'm not sure what I'm going to use them for, they were mostly a 'wouldn't it be cool...'-moment of the naval staff.

Somehow I have my doubts about the capacity to hit ships by 8'' (or in my case, 21cm) gunfire using a submarine as the base.

[Sea Skimmer]

It was a suggestion by fellow hobbyist I know IRL. Of course, optimistic or not my "experiment" does not seem very outlandish when you consider the attributes of the Omaha class. So what in your opinion would be a better rule of thumb? Leave the deck as thick as it's supposed to be and thin out the belt to 1/3 only, or maybe subtract the average thickness of the a backing plate + cement from the belt?

Subtracting 19-25mm for no backing plate would certainly be acceptable for belts. As far as I can tell cement wasn’t typically used on cruisers to mold the backing plate and belt armor together because the tolerances on thin armor are pretty tight. Thick belt plates on battleships meanwhile could easily have 5-10mm variances which were enough of a problem to warrant concrete. Such heavy plates were just way too expensive to reject for such errors, even on treaty ships.

The 1/3rd rule might work out to be valid for thin belt armor used as structure, but I don’t think deck armor should be able to benefit from this. I think we, by which I mean you since this isn’t my game, just need email the creators to ask them if deck armor is being factored into structure or not. If its being completely ignored then the rule could be valid. I haven’t done enough experiments with the new versions to know or not, but with version 1.0 you could make a Jap CA work pretty damn well without such a rule of thumb. However 1.0 also didn’t assign any weight to some features like torpedo tubes (it only assigned them volume) which may have counter balanced over estimations of hull and armor weights.

Would you happen to have any diagrams of the armor scheme for any of the Japanese cruisers? I've never never been able to find any either online or in the books I own or have had access to.

I have a dead tree copy of Japanese Cruisers of the Pacific War which is the only reason I know anything about the subject. It’s pretty much the best naval reference book ever (it really enlightened me to a lot that was relevant not just to Japan) and has multiple cross section and side view armor diagrams of every turbine powered cruiser Japan built. Plus lots of other plans and diagrams of turrets, machinery optical systems and other features like bilg and firefighting pump capacity, as well as information on Jap prewar battle plans and fleet planning.

Luckily though, since the book seems to have gone out of print recently and cost 75 USD new anyway (still more then worth it in an era of 60 dollar computer games!!!!!!!), Google books has an extensive preview available and while I have not looked at the whole thing it does include some of the armor diagrams of the Myoko class. Look at page 89 and 92 for starters for those. I see some of the Takao armor plans on page 127. It looks like they have the first couple full chapters online. Aoba class armor plans can also be found earlier in the book, and the various early CLs.

http://books.google.com/books?id=dP8Yue ... q=&f=false

Tuscany laid down its own Surcoufs in Q2/1925

I'm not sure what I'm going to use them for, they were mostly a 'wouldn't it be cool...'-moment of the naval staff.

Somehow I have my doubts about the capacity to hit ships by 8'' (or in my case, 21cm) gunfire using a submarine as the base.

Well, she did have anti rolling tanks IIRC specifically to make her a slightly more stable gun platform. Also a proper optical rangefinder; and you can catapult the seaplane as a spotter. The idea though seems to have been to make a surprise surfacing at a fairly close range, and rely on the heavy hitting power of the 8in shells to cripple the target with a few quick hits. The target could then be destroyed at leisure, and without the expense or bad politics of a surprise torpedo strike drowning the crew.

Late in WW2 the USN found the Gato class made good enough gun platforms that nine boats were fitted with two 5in guns apiece, plus a proper fire control computer and gun stabilizer gyro to make them dedicated gunboat subs. They didn’t see action owing to atomic bombings, but clearly a decent level of steadiness could be achieved, at least in clam Pacific weather. Just don’t try to shoot it out with cruisers on the surface, as awesome as that book Strike From the Sea is.

The number one problem with big submarines (over 2,000 tons or so surfaced) is that while they can surface fast, they can’t properly crash dive. This doesn’t matter in the 1920s when aircraft are of the 130mph type and have no radar, but it became a steadily greater liability as time went on which is why designs like USS Nautilus were not repeated. Also a big expensive sub can only be in one place at a time which is bad for finding many targets.

[Fingolfin_Noldor]

I'm not sure if this light cruiser is a good idea, but it's my first attempt anyway.

Sparta, Byzantium Cruiser laid down 1925

Displacement:
12,006 t light; 12,940 t standard; 15,120 t normal; 16,863 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(635.23 ft / 606.96 ft) x 78.74 ft x (29.53 / 31.56 ft)
(193.62 m / 185.00 m) x 24.00 m x (9.00 / 9.62 m)

Armament:
9 - 6.00" / 152 mm 53.0 cal guns - 115.77lbs / 52.51kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1925 Model
3 x 3-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
8 - 5.00" / 127 mm 25.0 cal guns - 56.77lbs / 25.75kg shells, 2,000 per gun
Anti-air guns in deck and hoist mounts, 1925 Model
4 x Twin mounts on sides, evenly spread
16 - 1.57" / 40.0 mm 60.0 cal guns - 2.14lbs / 0.97kg shells, 2,000 per gun
Anti-air guns in deck mounts, 1925 Model
4 x 4-gun mounts on sides, evenly spread
24 - 0.79" / 20.0 mm 70.0 cal guns - 0.27lbs / 0.12kg shells, 600 per gun
Anti-air guns in deck mounts, 1925 Model
6 x 4-gun mounts on sides, evenly spread
Weight of broadside 1,537 lbs / 697 kg
Main Torpedoes
6 - 21.0" / 533 mm, 30.00 ft / 9.14 m torpedoes - 1.906 t each, 11.438 t total
In 6 sets of deck mounted carriage/fixed tubes
2nd Torpedoes
6 - 21.0" / 533 mm, 0.00 ft / 0.00 m torpedoes - 0.000 t each, 0.000 t total
In 6 sets of deck mounted carriage/fixed tubes
Mines
6 - 0.00 lbs / 0.00 kg mines + 6 reloads - 0.000 t total
in Above water - Stern racks/rails

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6.00" / 152 mm 330.00 ft / 100.58 m 18.00 ft / 5.49 m
Ends: Unarmoured
Main Belt covers 84 % of normal length
Main Belt inclined 19.00 degrees (positive = in)

- Torpedo Bulkhead - Strengthened structural bulkheads:
3.00" / 76 mm 400.00 ft / 121.92 m 10.00 ft / 3.05 m
Beam between torpedo bulkheads 65.00 ft / 19.81 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 6.00" / 152 mm 6.00" / 152 mm
2nd: 1.00" / 25 mm 1.00" / 25 mm 1.00" / 25 mm
4th: 0.50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 3.00" / 76 mm
Forecastle: 2.00" / 51 mm Quarter deck: 2.00" / 51 mm

- Conning towers: Forward 6.00" / 152 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Electric motors, 4 shafts, 78,238 shp / 58,366 Kw = 31.00 kts
Range 10,000nm at 16.00 kts
Bunker at max displacement = 3,923 tons

Complement:
681 - 886

Cost:
£3.011 million / $12.044 million

Distribution of weights at normal displacement:
Armament: 434 tons, 2.9 %
- Guns: 419 tons, 2.8 %
- Weapons: 14 tons, 0.1 %
Armour: 4,156 tons, 27.5 %
- Belts: 1,554 tons, 10.3 %
- Torpedo bulkhead: 444 tons, 2.9 %
- Armament: 525 tons, 3.5 %
- Armour Deck: 1,554 tons, 10.3 %
- Conning Tower: 79 tons, 0.5 %
Machinery: 2,540 tons, 16.8 %
Hull, fittings & equipment: 4,841 tons, 32.0 %
Fuel, ammunition & stores: 3,113 tons, 20.6 %
Miscellaneous weights: 36 tons, 0.2 %
- On freeboard deck: 36 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
27,399 lbs / 12,428 Kg = 253.7 x 6.0 " / 152 mm shells or 3.1 torpedoes
Stability (Unstable if below 1.00): 1.29
Metacentric height 5.5 ft / 1.7 m
Roll period: 14.0 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.16
Seaboat quality (Average = 1.00): 1.42

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.375 / 0.391
Length to Beam Ratio: 7.71 : 1
'Natural speed' for length: 29.31 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 51
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 13.12 ft / 4.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 26.25 ft / 8.00 m, 26.25 ft / 8.00 m
- Forward deck: 30.00 %, 26.25 ft / 8.00 m, 19.69 ft / 6.00 m
- Aft deck: 30.00 %, 19.69 ft / 6.00 m, 16.40 ft / 5.00 m
- Quarter deck: 15.00 %, 16.40 ft / 5.00 m, 16.40 ft / 5.00 m
- Average freeboard: 21.33 ft / 6.50 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 82.3 %
- Above water (accommodation/working, high = better): 170.5 %
Waterplane Area: 30,050 Square feet or 2,792 Square metres
Displacement factor (Displacement / loading): 142 %
Structure weight / hull surface area: 119 lbs/sq ft or 580 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.93
- Longitudinal: 2.00
- Overall: 1.00
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

[Raesene]

Some illustrations created using Virtual Shipyard (small program I found some time ago on the net)

Details are not perfect as I don't want to spend time pushing around portholes or positioning rafts and light AA. It should be enough to give you a general impression of the looks.

My latest heavy cruiser, the Tevere-class (17 000 ts std; 12x 21cm guns; max speed 33 kts)






Freeboard is not perfect- the ship should have a slope from 8m at the stem to 6m at the stern, but I can't set freeboard for each section separately.

[Ryan Thunder]

any idea where I could get that software?

[Raesene]

any idea where I could get that software?

Unfortunately no, I downloaded it for free about two years ago and the link from then is dead. It is a small program, only about 2.5 MByte

[Ryan Thunder]

any idea where I could get that software?

Unfortunately no, I downloaded it for free about two years ago and the link from then is dead. It is a small program, only about 2.5 MByte

What if you were to put it up on FileSmelt? I'm pretty sure that's legal.

If you don't mind, of course.

[Sea Skimmer]

The guy who made that program goes by the handle Alt Naval, though I have not seen him around for a while now. He was a nice guy and I seriously doubt he’d mind that program being uploaded. His original site was a collection of unbuilt projects, as well as a very well thought out alternative building program for the IJN, but it was on geocities and is now dead. you'll find pictures he did all over the internet on other peoples sites anyway.

[Agent Sorchus]

Skimmer if you have the url of the old site there is a chance that it has been archived at reocities. Just replace the g in the url with r and it should work.

[Ma Deuce]

Here is the revised version of my experimental scout cruiser; only the belt is thinned, though is now only supposed to be 60 mm (I don't know if that's too thick for the belt to be used as structure), plus 40 mm in the bow. Armor is all-around thinner than before, though her vitals should still be well protected against destroyer-caliber gunfire. She's now a half-knot slower as well, though on the other hand I was able to increase the main battery magazine capacity to 1,170 rounds total. Due to her scout role, I've re-oriented her main battery so the superfiring mount is aft, so she can direct the maximum volume of fire against pursuers.

HMMS Binara, Royal Merina Navy Scout Cruiser laid down 1924

Displacement:
6,493 t light; 6,750 t standard; 7,762 t normal; 8,571 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(551.17 ft / 541.34 ft) x 49.21 ft x (20.77 / 22.31 ft)
(168.00 m / 165.00 m) x 15.00 m x (6.33 / 6.80 m)

Armament:
6 - 6.30" / 160 mm 50.0 cal guns - 132.28lbs / 60.00kg shells, 195 per gun
Quick firing guns in deck and hoist mounts, 1924 Model
3 x Twin mounts on centreline ends, majority aft
1 raised mount aft - superfiring
4 - 3.15" / 80.0 mm 50.0 cal guns - 15.43lbs / 7.00kg shells, 360 per gun
Anti-air guns in deck mounts, 1924 Model
4 x Single mounts on centreline, evenly spread
12 - 0.59" / 15.0 mm 90.0 cal guns - 0.18lbs / 0.08kg shells, 3,000 per gun
Machine guns in deck mounts, 1924 Model
6 x Twin mounts on centreline, evenly spread
6 raised mounts
Weight of broadside 858 lbs / 389 kg
Main Torpedoes
8 - 21.7" / 550 mm, 24.61 ft / 7.50 m torpedoes - 1.683 t each, 13.466 t total
In 2 sets of deck mounted side rotating tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 0.79" / 20 mm 459.32 ft / 140.00 m 11.48 ft / 3.50 m
Ends: 0.52" / 13 mm 78.74 ft / 24.00 m 11.48 ft / 3.50 m
3.28 ft / 1.00 m Unarmoured ends
Main Belt covers 131 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.36" / 60 mm 1.57" / 40 mm 2.36" / 60 mm
2nd: 0.98" / 25 mm - -
3rd: 0.39" / 10 mm - -

- Armoured deck - single deck:
For and Aft decks: 1.18" / 30 mm
Forecastle: 0.79" / 20 mm Quarter deck: 1.18" / 30 mm

- Conning towers: Forward 2.36" / 60 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 86,250 shp / 64,342 Kw = 34.45 kts
Range 7,980nm at 15.00 kts
Bunker at max displacement = 1,820 tons

Complement:
413 - 537

Cost:
£2.202 million / $8.808 million

Distribution of weights at normal displacement:
Armament: 230 tons, 3.0 %
- Guns: 203 tons, 2.6 %
- Weapons: 27 tons, 0.3 %
Armour: 647 tons, 8.3 %
- Belts: 180 tons, 2.3 %
- Armament: 51 tons, 0.7 %
- Armour Deck: 396 tons, 5.1 %
- Conning Tower: 20 tons, 0.3 %
Machinery: 2,841 tons, 36.6 %
Hull, fittings & equipment: 2,713 tons, 35.0 %
Fuel, ammunition & stores: 1,268 tons, 16.3 %
Miscellaneous weights: 63 tons, 0.8 %
- On freeboard deck: 63 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5,414 lbs / 2,456 Kg = 43.3 x 6.3 " / 160 mm shells or 0.7 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 2.2 ft / 0.7 m
Roll period: 13.9 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.42
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.491 / 0.505
Length to Beam Ratio: 11.00 : 1
'Natural speed' for length: 26.39 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 60
Bow angle (Positive = bow angles forward): 12.50 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 15.00 %, 29.53 ft / 9.00 m, 22.64 ft / 6.90 m
- Forward deck: 25.00 %, 22.64 ft / 6.90 m, 18.04 ft / 5.50 m
- Aft deck: 45.00 %, 18.04 ft / 5.50 m, 14.76 ft / 4.50 m
- Quarter deck: 15.00 %, 14.76 ft / 4.50 m, 15.42 ft / 4.70 m
- Average freeboard: 18.54 ft / 5.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 129.5 %
- Above water (accommodation/working, high = better): 145.1 %
Waterplane Area: 18,305 Square feet or 1,701 Square metres
Displacement factor (Displacement / loading): 107 %
Structure weight / hull surface area: 86 lbs/sq ft or 420 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.71
- Overall: 1.00
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room

Misc Weight = 50 tons for aircraft, 13 tons for torpedoes

[Lascaris]

Plan 1913A, Cisplatina Enter ship type laid down 1913 (Engine 1914)

Displacement:
27.699 t light; 29.220 t standard; 30.502 t normal; 31.528 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(680,00 ft / 680,00 ft) x 98,00 ft x (30,00 / 30,78 ft)
(207,26 m / 207,26 m) x 29,87 m x (9,14 / 9,38 m)

Armament:
12 - 14,00" / 356 mm 45,0 cal guns - 1.400,00lbs / 635,03kg shells, 86 per gun
Breech loading guns in turret on barbette mounts, 1913 Model
3 x 4-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
20 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Quick firing guns in casemate mounts, 1913 Model
20 x Single mounts on sides, evenly spread
12 - 1,57" / 40,0 mm 60,0 cal guns - 2,14lbs / 0,97kg shells, 600 per gun
Breech loading guns in deck mounts, 1913 Model
6 x Twin mounts on sides, evenly spread
Weight of broadside 18.024 lbs / 8.175 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 14,0" / 356 mm 433,00 ft / 131,98 m 15,38 ft / 4,69 m
Ends: Unarmoured
Main Belt covers 98% of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
2,00" / 51 mm 433,00 ft / 131,98 m 27,22 ft / 8,30 m
Beam between torpedo bulkheads 78,00 ft / 23,77 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 18,0" / 457 mm 5,00" / 127 mm 14,0" / 356 mm
2nd: 3,00" / 76 mm - -
3rd: 0,50" / 13 mm - -

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

- Conning towers: Forward 14,00" / 356 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 74.307 shp / 55.433 Kw = 26,00 kts
Range 8.300nm at 10,00 kts
Bunker at max displacement = 2.308 tons

Complement:
1.153 - 1.500

Cost:
£3,242 million / $12,967 million

Distribution of weights at normal displacement:
Armament: 3.644 tons, 11,9%
- Guns: 3.644 tons, 11,9%
Armour: 9.798 tons, 32,1%
- Belts: 4.006 tons, 13,1%
- Torpedo bulkhead: 872 tons, 2,9%
- Armament: 2.539 tons, 8,3%
- Armour Deck: 2.087 tons, 6,8%
- Conning Tower: 294 tons, 1,0%
Machinery: 2.862 tons, 9,4%
Hull, fittings & equipment: 11.395 tons, 37,4%
Fuel, ammunition & stores: 2.803 tons, 9,2%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
35.985 lbs / 16.323 Kg = 26,2 x 14,0 " / 356 mm shells or 5,8 torpedoes
Stability (Unstable if below 1.00): 1,14
Metacentric height 6,3 ft / 1,9 m
Roll period: 16,5 seconds
Steadiness - As gun platform (Average = 50 %): 54 %
- Recoil effect (Restricted arc if above 1.00): 0,65
Seaboat quality (Average = 1.00): 1,09

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,534 / 0,538
Length to Beam Ratio: 6,94 : 1
'Natural speed' for length: 26,08 kts
Power going to wave formation at top speed: 48 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 24,60 ft / 7,50 m, 20,12 ft / 6,13 m
- Forward deck: 30,00%, 20,12 ft / 6,13 m, 15,65 ft / 4,77 m
- Aft deck: 35,00%, 15,65 ft / 4,77 m, 15,65 ft / 4,77 m
- Quarter deck: 15,00%, 15,65 ft / 4,77 m, 15,65 ft / 4,77 m
- Average freeboard: 17,57 ft / 5,36 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 97,8%
- Above water (accommodation/working, high = better): 126,3%
Waterplane Area: 45.817 Square feet or 4.256 Square metres
Displacement factor (Displacement / loading): 99%
Structure weight / hull surface area: 210 lbs/sq ft or 1.026 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,97
- Longitudinal: 1,32
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room



Plan 1917A, Cisplatina Enter ship type laid down 1917 (Engine 1918)

Displacement:
37.293 t light; 39.500 t standard; 42.115 t normal; 44.207 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(700,00 ft / 700,00 ft) x 108,00 ft x (32,00 / 33,31 ft)
(213,36 m / 213,36 m) x 32,92 m x (9,75 / 10,15 m)

Armament:
12 - 16,00" / 406 mm 45,0 cal guns - 2.099,99lbs / 952,54kg shells, 86 per gun
Breech loading guns in turret on barbette mounts, 1917 Model
3 x 4-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
20 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1920 Model
10 x Single mounts on sides, evenly spread
32 - 1,57" / 40,0 mm 60,0 cal guns - 2,14lbs / 0,97kg shells, 1.600 per gun
Anti-air guns in deck mounts, 1920 Model
8 x Quad mounts on sides, evenly spread
Weight of broadside 26.466 lbs / 12.005 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 14,0" / 356 mm 434,00 ft / 132,28 m 16,12 ft / 4,91 m
Ends: Unarmoured
Main Belt covers 95% of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
2,00" / 51 mm 434,00 ft / 132,28 m 29,98 ft / 9,14 m
Beam between torpedo bulkheads 88,00 ft / 26,82 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 18,0" / 457 mm 5,00" / 127 mm 14,0" / 356 mm
2nd: 2,00" / 51 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 6,00" / 152 mm

- Conning towers: Forward 5,00" / 127 mm, Aft 2,00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 93.229 shp / 69.549 Kw = 26,00 kts
Range 6.000nm at 16,00 kts
Bunker at max displacement = 4.707 tons

Complement:
1.469 - 1.910

Cost:
£7,624 million / $30,497 million

Distribution of weights at normal displacement:
Armament: 5.225 tons, 12,4%
- Guns: 5.225 tons, 12,4%
Armour: 13.604 tons, 32,3%
- Belts: 4.314 tons, 10,2%
- Torpedo bulkhead: 963 tons, 2,3%
- Armament: 3.069 tons, 7,3%
- Armour Deck: 5.076 tons, 12,1%
- Conning Towers: 183 tons, 0,4%
Machinery: 3.363 tons, 8,0%
Hull, fittings & equipment: 15.100 tons, 35,9%
Fuel, ammunition & stores: 4.822 tons, 11,4%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
50.030 lbs / 22.693 Kg = 24,4 x 16,0 " / 406 mm shells or 7,5 torpedoes
Stability (Unstable if below 1.00): 1,17
Metacentric height 7,6 ft / 2,3 m
Roll period: 16,5 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0,72
Seaboat quality (Average = 1.00): 1,07

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,609 / 0,614
Length to Beam Ratio: 6,48 : 1
'Natural speed' for length: 26,46 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 29,41 ft / 8,96 m, 18,72 ft / 5,71 m
- Forward deck: 30,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Aft deck: 35,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Quarter deck: 15,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Average freeboard: 19,58 ft / 5,97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 95,2%
- Above water (accommodation/working, high = better): 135,4%
Waterplane Area: 55.775 Square feet or 5.182 Square metres
Displacement factor (Displacement / loading): 97%
Structure weight / hull surface area: 234 lbs/sq ft or 1.140 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,96
- Longitudinal: 1,41
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

Plan 1917A, Cisplatina Enter ship type laid down 1921 (Engine 1922)

Displacement:
37.502 t light; 39.709 t standard; 42.115 t normal; 44.040 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(700,00 ft / 700,00 ft) x 108,00 ft x (32,00 / 33,21 ft)
(213,36 m / 213,36 m) x 32,92 m x (9,75 / 10,12 m)

Armament:
12 - 16,00" / 406 mm 45,0 cal guns - 2.099,99lbs / 952,54kg shells, 86 per gun
Breech loading guns in turret on barbette mounts, 1921 Model
3 x 4-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
20 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1921 Model
10 x Single mounts on sides, evenly spread
32 - 1,57" / 40,0 mm 60,0 cal guns - 2,14lbs / 0,97kg shells, 1.600 per gun
Anti-air guns in deck mounts, 1921 Model
8 x Quad mounts on sides, evenly spread
Weight of broadside 26.466 lbs / 12.005 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 15,0" / 381 mm 425,00 ft / 129,54 m 16,12 ft / 4,91 m
Ends: Unarmoured
Main Belt covers 93% of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
2,40" / 61 mm 425,00 ft / 129,54 m 29,98 ft / 9,14 m
Beam between torpedo bulkheads 88,00 ft / 26,82 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 18,0" / 457 mm 5,00" / 127 mm 14,0" / 356 mm
2nd: 2,00" / 51 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 6,00" / 152 mm

- Conning towers: Forward 5,00" / 127 mm, Aft 2,00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 93.229 shp / 69.549 Kw = 26,00 kts
Range 6.000nm at 16,00 kts
Bunker at max displacement = 4.331 tons

Complement:
1.469 - 1.910

Cost:
£10,621 million / $42,484 million

Distribution of weights at normal displacement:
Armament: 5.225 tons, 12,4%
- Guns: 5.225 tons, 12,4%
Armour: 14.007 tons, 33,3%
- Belts: 4.548 tons, 10,8%
- Torpedo bulkhead: 1.131 tons, 2,7%
- Armament: 3.069 tons, 7,3%
- Armour Deck: 5.076 tons, 12,1%
- Conning Towers: 183 tons, 0,4%
Machinery: 3.162 tons, 7,5%
Hull, fittings & equipment: 15.107 tons, 35,9%
Fuel, ammunition & stores: 4.613 tons, 11,0%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
51.026 lbs / 23.145 Kg = 24,9 x 16,0 " / 406 mm shells or 8,0 torpedoes
Stability (Unstable if below 1.00): 1,17
Metacentric height 7,5 ft / 2,3 m
Roll period: 16,5 seconds
Steadiness - As gun platform (Average = 50 %): 54 %
- Recoil effect (Restricted arc if above 1.00): 0,72
Seaboat quality (Average = 1.00): 1,07

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,609 / 0,614
Length to Beam Ratio: 6,48 : 1
'Natural speed' for length: 26,46 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 29,41 ft / 8,96 m, 18,72 ft / 5,71 m
- Forward deck: 30,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Aft deck: 35,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Quarter deck: 15,00%, 18,72 ft / 5,71 m, 18,72 ft / 5,71 m
- Average freeboard: 19,58 ft / 5,97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 93,3%
- Above water (accommodation/working, high = better): 135,4%
Waterplane Area: 55.775 Square feet or 5.182 Square metres
Displacement factor (Displacement / loading): 97%
Structure weight / hull surface area: 234 lbs/sq ft or 1.141 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,96
- Longitudinal: 1,42
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room


Plan 1921, Cisplatina Enter ship type laid down 1923 (Engine 1924)

Displacement:
46.285 t light; 48.679 t standard; 51.228 t normal; 53.267 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(780,00 ft / 780,00 ft) x 108,00 ft x (34,00 / 35,08 ft)
(237,74 m / 237,74 m) x 32,92 m x (10,36 / 10,69 m)

Armament:
9 - 17,72" / 450 mm 47,0 cal guns - 2.900,01lbs / 1.315,42kg shells, 86 per gun
Breech loading guns in turret on barbette mounts, 1923 Model
3 x 3-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
20 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1923 Model
10 x Single mounts on sides, evenly spread
32 - 1,57" / 40,0 mm 60,0 cal guns - 2,14lbs / 0,97kg shells, 600 per gun
Anti-air guns in deck mounts, 1923 Model
8 x Quad mounts on sides, evenly spread
Weight of broadside 27.366 lbs / 12.413 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 15,0" / 381 mm 441,00 ft / 134,42 m 16,47 ft / 5,02 m
Ends: Unarmoured
Main Belt covers 87% of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
4,00" / 102 mm 441,00 ft / 134,42 m 31,98 ft / 9,75 m
Beam between torpedo bulkheads 88,00 ft / 26,82 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 18,0" / 457 mm 9,00" / 229 mm 15,0" / 381 mm
2nd: 3,00" / 76 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 8,00" / 203 mm

- Conning towers: Forward 5,00" / 127 mm, Aft 2,00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 117.219 shp / 87.446 Kw = 28,00 kts
Range 6.000nm at 15,00 kts
Bunker at max displacement = 4.588 tons

Complement:
1.702 - 2.213

Cost:
£13,966 million / $55,863 million

Distribution of weights at normal displacement:
Armament: 5.467 tons, 10,7%
- Guns: 5.467 tons, 10,7%
Armour: 19.267 tons, 37,6%
- Belts: 4.854 tons, 9,5%
- Torpedo bulkhead: 2.087 tons, 4,1%
- Armament: 4.147 tons, 8,1%
- Armour Deck: 7.971 tons, 15,6%
- Conning Towers: 208 tons, 0,4%
Machinery: 3.861 tons, 7,5%
Hull, fittings & equipment: 17.690 tons, 34,5%
Fuel, ammunition & stores: 4.943 tons, 9,6%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
65.112 lbs / 29.534 Kg = 23,4 x 17,7 " / 450 mm shells or 10,8 torpedoes
Stability (Unstable if below 1.00): 1,11
Metacentric height 6,9 ft / 2,1 m
Roll period: 17,3 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,75
Seaboat quality (Average = 1.00): 1,02

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0,626 / 0,631
Length to Beam Ratio: 7,22 : 1
'Natural speed' for length: 32,28 kts
Power going to wave formation at top speed: 51 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 28,68 ft / 8,74 m, 23,47 ft / 7,15 m
- Forward deck: 30,00%, 23,47 ft / 7,15 m, 18,25 ft / 5,56 m
- Aft deck: 35,00%, 18,25 ft / 5,56 m, 18,25 ft / 5,56 m
- Quarter deck: 15,00%, 18,25 ft / 5,56 m, 18,25 ft / 5,56 m
- Average freeboard: 20,49 ft / 6,25 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 86,9%
- Above water (accommodation/working, high = better): 143,3%
Waterplane Area: 65.821 Square feet or 6.115 Square metres
Displacement factor (Displacement / loading): 98%
Structure weight / hull surface area: 229 lbs/sq ft or 1.119 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,97
- Longitudinal: 1,22
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

[CmdrWilkens]

So as I mentioned to Steve the zone of invincibility for my proposed 1927/8 series BB (some other factors will play in to when construction will occur) is relatively large even against a pretty heavy shell like the 2,700 lb "super heavy" AP shell fired by the Iowa-class 16"/50.

The data I used is a derivative of some trig calculations and comparison to this reference which itself references "Battleships: United States Battleships 1935-1992."

The critical component is the side armor penetration and the angle of fall. Because the armor on my proposed vessel is sloped this changes the effective angle of incidence and thus the effective width of armor which it must penetrate. The max width is 18.5" sloped at 18 degrees and the reason I claimed 16-17,000 as the beginning of the zone works as such:

For 15,000 yds: Angle of Fall = 9.8 deg, Angle of incidence (Fall+Slope) is 27.8, the Cosecant and a 27.8 degree angle is 1.13, multiplied by the width (18.5") generates an effective width along the angle of incidence of 20.9". The penetrative ability of the AP Mark 8 at this range is 23.04" so it will penetrate

For 20,000 yds: Angle of Fall = 14.9 deg, Angle of Incidence = 32.9, Cosec = 1.19, the effective width = 22.03" against a penetrative ability of 20.04"

So somewhere between 15,000 and 20,000 even the AP Mark 8 will lose the ability to penetrate with side shots.

Now the deck armor is 8" over the fore and aft, single decked with the AP able to penetrate 6.65" at 30,000 and 8.48" at 35,000 yards which would indicate invulnerability to plunging fire under 33-34,000 yards.

All told against a 2,700 lb shell at a muzzle velocity of 2,500 fps my target design would be in zone from (conservatively) 18,000 to 33,000 yards. The conning tower would be invulnerable from roughly 25,000 yards out and the guns and turrets from roughly 20,000 yards out. I'm still tweaking because, again, I may not have the IBP or yard space until 1928 which does change some factors for me.

What I can say is that the 18"/45 with 2940 lb AP shell will be the biggest gun I'm likely to mount as I've figured a firing rate of 1-1.5 rounds/min based off the 46cm/45 guns on the Yamamoto (though NavWeaps states as high as 2 I'm figuring lower). Given I'm actually using a lighter shell this may be conservative but given the age difference I'm betting it isn't too bad.

[Steve]

Is your belt internal, Wilks?

[Sea Skimmer]

Yamato could fire two rounds per minute if the target was nice enough to come within the IIRC 6,000 yards she could reach at the loading angle. This has the actual firing cycle.


In reality heavy gun rates of fire proved to be fairlymeaningless because of the need to wait for the fall of shot before firing again, in addition to problems like errors in drill and misfires and the need to move ammo from more remote parts of the magazines after the ready racks emptied. For the 2,700lb fired by Iowa even at 20,000 yards the time of flight was already nearly 30 seconds, and after that you had to wait for the splashes to rise and someone had to actually think about how they'd landed. Even supposedly fast shooting ships like Bismarck in good conditions actually averaged less then 1 round per minute per gun (see Denmark Straits). Just about anyone could manage this with any gun. So not a big concern unless you intend to fight at close ranges all the time.