WesWorld

Folks,

when I compare posted designs with my own I sometimes get the feeling I´ve made something totally wrong.

Example: deck armor

RSAN South Africa is the SAEs most powerfull warship. It weights 36kts more or less and features eight 38cm L/45 guns. Those guns fire a 780kg (1719lbs) AP shell with a MVo of 800m/s (2624fps). Those variables are quite average for the guns age (designed in 1912) and reflect what I found in my sources about british and german guns of that period.

The exact data of this gun is given below in detail.

When looking at those stats you´ll see that at 15000m (150hm - I like to refer to ranges in hektometer) the gun can penetrate ~48cm of WW1-era vertical (belt) armor (no inclination) and ~8+cm of WW1-type horizontal (deck) armor using a WW1-type shell (ballistic performance 0,9).

I took 150hm as a reference because in 1915 when the ship was laid down no battles beyond 150hm were expected. Thus I choosed to go with an average 8cm of deckarmor in springstyle (reading it as 10cm over engines and magazins and 5cm outside the citadel, not taking into account normal thin decks). I thought this should do to protect the ship against its own guns at all ranges a battle could take place.

Now when I look at most players designs I get the impression I made something completely wrong because in most cases my deck armor seems to be oddly thin. Why is this?

Have I made an error while calculating what is necessary to protect my ships or did I use a gun/shell that is/was inadequate? Are you guys using much heavier shells as reference? What ranges have you used when calculating your deck armor?


Help much appreciated!

HoOmAn

[Players note: the RSAN 38cm L/45 gun used against WW1-type armor using a WW1-type shell]

38cm L/45


Caliber = 38.0 cm (15.0 inch)
Shell weight = 780 kg (1719 lbs)
Muzzle velocity = 800 m/s (2624 fps)

Relative ballistic performance: 0.90

Muzzle energy = 249.6 megajoules = 91977.6 foot-tons

Relative muzzle energy: 0.86

Typical barrel length: 45 calibers


Elevation Range Time Velocity Fall Angle

2.5 deg 5100 meters 7.0 sec 679 m/s 2.8 deg
5.0 deg 9200 meters 13.5 sec 598 m/s 6.1 deg
7.5 deg 12700 meters 19.8 sec 540 m/s 9.8 deg
10.0 deg 15700 meters 25.7 sec 499 m/s 13.6 deg
12.5 deg 18400 meters 31.5 sec 470 m/s 17.7 deg
15.0 deg 20700 meters 37.0 sec 450 m/s 21.7 deg
20.0 deg 24700 meters 47.6 sec 428 m/s 29.6 deg
25.0 deg 27900 meters 57.6 sec 423 m/s 36.6 deg
30.0 deg 30600 meters 67.1 sec 427 m/s 42.8 deg
35.0 deg 32600 meters 76.2 sec 436 m/s 48.1 deg
40.0 deg 34000 meters 84.9 sec 449 m/s 52.8 deg
45.0 deg 34600 meters 93.0 sec 463 m/s 56.9 deg
50.0 deg 34400 meters 100.6 sec 476 m/s 60.7 deg


Armor Penetration - Vertical Belt Armor

(Relative armor quality, 0.83)

Maximum penetration: 89.69 cm


Elevation Range Belt Deck

1.2 deg 2600 meters 80 cm
2.0 deg 4100 meters 75 cm
2.5 deg 5200 meters ... 2 cm
2.9 deg 5800 meters 70 cm
3.9 deg 7500 meters 65 cm
4.6 deg 8700 meters ... 4 cm
5.1 deg 9400 meters 60 cm
6.5 deg 11400 meters 55 cm
6.8 deg 11800 meters ... 6 cm
8.3 deg 13700 meters 50 cm
9.2 deg 14800 meters ... 8 cm
10.5 deg 16300 meters 45 cm
12.0 deg 17800 meters ... 10 cm
13.4 deg 19200 meters 40 cm
15.8 deg 21400 meters ... 12 cm
17.3 deg 22600 meters 35 cm
18.6 deg 23700 meters ... 14 cm
21.0 deg 25400 meters ... 16 cm
23.0 deg 26700 meters 30 cm
23.5 deg 27000 meters ... 18 cm
26.0 deg 28500 meters ... 20 cm
28.5 deg 29900 meters ... 22 cm
31.1 deg 31100 meters ... 24 cm
31.4 deg 31200 meters 25 cm
33.7 deg 32200 meters ... 26 cm
36.4 deg 33100 meters ... 28 cm
39.2 deg 33800 meters ... 30 cm
42.0 deg 34300 meters ... 32 cm
43.3 deg 34500 meters 20 cm
44.9 deg 34600 meters ... 34 cm
47.8 deg 34600 meters ... 36 cm


Maximum range = 34600 meters at 46.3 deg elevation

When I design a ship I usually take an existing design (usually British) and make slight alterations to it. With Atlantis out industrialized by its closest nabour Britain I can only resort to building less hulls but more powerful ships. When it comes to deck armor it usually hinges around the design I am copying but occasionally I will look at other compareable designs and go for the average. On newer designs I tend to design something completely new but I tend to go with the "deck armor is good" appoach. As for shell weight my grasp of the formula behind shell weight vs. armor at a given angle is extremely limited.

My latest designs feature large thicknesses of deck armour. For a BB i get the hull form, speed and firepower i want, then just stick as much armour as possible on the brute. Not much point in putting an 18" belt on something so that is limited. My turret armour hangs about 15/16" because any more hampens stability. This leaves me with 2 choices; put lots of deck armour on, or make the ship smaller.

Of course hindsight creeps in a bit when designing ships. Walter and 17inc both have masses of AAA on their BB's. Mine have thick decks.

Wes, a heavy shell takes more force to accelerate but when it is up to speed it as more interia so it just keeps on going whereas a lighter shell slows quickly. For anti- tank guns this doesn't apply because of the short ranges. Most guns fire sub-calibre rounds creating a very fast projectile which doesn't have the time to slow during its short flight time.

Caracciolo carries 15"/40 Mk I guns firing 1890lb shells. For new ships i would use 15"/40 MK II firing 2060lb shells. This is because designers, having accepted a 15" limit on calibre have tried to make their weapon as powerful as possible...

A thing to bear in mind is that shells don't start hitting belt armour until within 15,000yds. Anything over is probably deck. At 15,000yds range my 15"/40 Mk II can penetrate 16" of belt and 3" of deck. Both values using WW2 armour.

So you simply put as much armour on a beast as possible. You´re not calculating your protection to stand up against special circumstances or certain weapons. This is one way to handle things....

Your MK I is using a shell weighting 860-865kg if I got that right. This sounds quite normal for WW2-type 15" shells when comparing that weight to german, british, french and italian shells. The MK II shell on the other hand surely belongs into the category of "super heavy" and I wonder in which year you will introduce such a shell. Surely not until 1935 or something....?!

I, for example, know very well that a 780kg shell is on the light side for its caliber but it offers the chance for high MVo without getting a muzzle energy to high. 0,86 is what my current 38cm gun achieves and with such a low muzzle velocity barrel wear and dispersion is not a problem. I´m pretty sure a gun like mine with the shell currently used would be very accurate but with this combo I will never be able to penetrate 16" belts or faceplates outside of ~140hm and deck penetration is also lacking if firing against WW2-type armor.
Being aware of these facts I will introduce a heavier shell (855-880kg) one fine day but a 1000kg 38cm shell seems to be out of question.

I don't think that the Mk II 2060lb shell is 'super-heavy'. using Big gun then the shell weight would be around 2250lb. Admittedly it is heavier than normal but only 100lb heavier than the 1950lb carried by the QEs. The Mk II shells introduction should coincide with the comissioning of MM Sicilia with maybe firing trials on Caracciolo for a few months before.

We have both gone the opposite ways with guns. Yours firing light shells quickly and mine firing heavy shells slowly. Both ways work.

I have no set immune zone for my ships. They just carry as much armour as possible. I like ships that are able to take hits and get home. And in the late 1930's i could put some new turbines in and make them faster.

I'd say that we're seeing excessive amounts of deck armor, particularly for the time we're at.

RA illustrates how this happens. Many of us are building 40,000 t ships because it's the biggest we can build - not because they actually need to be that big. Once you've got a certain number of 14" or 15" guns, there's not much to do with that remaining space on the ship except dump armor onto it. In a more realistic setting, we'd put on the armor we need and not make the ship any bigger than it had to be - these things cost money, remember.

Hindsight may be playing a role, since we will have to deal with radar-guided gunfire and mass aerial bombardment in the late thirties or fourties - deck armor is useful at that point. In 1921, not really - the biggest aerial bombs out there might be 500 lbs at most, and radar isn't even a twinkle in some physicist's eye.

As somebody noted - I think Admiral K - thick deck armor will inevitably require a knife fight to end a battleship fight, which has its own implications - close range means a greater need to defend against pesky torpedo-bearing ships, especially if we start seeing weapons like the Long Lance.

Thick deck armor will probably also bring implications for aircraft weapons - torpedo bombers may be considered far more useful than dive bombers.

I've put together designs in the 30,000 - 32,000 t range with 13.8", 14.5", and 15" guns, 13-14" armor, 4" decks and 28 kts speed - designs that I would happily set against any historical opponent of the time, but would likely be shredded at the hands of the monsters inhabiting our world...

J

Hindsight really is a problem here.

in the early 20s where we are no FC doesn´t allow greater ranges than ~150hm. Sure, the guns have greater range but beyond 150hm you can waste all your ammo and achieve little more than nothing.

So obviously nobody needs 6"+ of deck armor, especially because no 16" guns are around and super-heavy 15" shells should not be until the 30s (personal opinion). 4" or 10cm (as single a layer) of deck armor should be enough in 99% of all engagements at least in the 20s.

Cheers,

HoOmAn

PS: What makes me worry is your comment about the Long Lance. I really, really hope we´ll not see them in this world but I fear they will be around some day - and most likely much earlier than in history.

Have you recently had a look at my TT calibre? I am not sure whether Iberia will ever manage to create an actual LL, but the first orogins of that idea are around.

Bernhard

Fiddling around with my BB design after reading comments and on the whole agreeing has led me to reduce deck armour to 6" average. This is no great reduction in armour but i can increase the speed to 28knts. Now i have a design that can catch others, then pulverise them.

In the 1920's we do have rudimentary FC. Nelson even has AA gunnery directors! Nelson deck armour is over 6" thick btw. So with 1920's designs we aren't far wrong.

Heavy torpedos e.g. 24.5" or LL can only be carried by large aeroplanes and this isn't practical at the moment. Heavy bombers at the moment could maybe carry an 18" or 21" torpedo but they are lumbering targets for machine guns and the plethora of 40mm our ships seem to be carrying.

I can´t remember your TT-caliber right now, Lord Arpad, but there is quite a difference between developing a large caliber torpedo (like that 60cm TT the Germans developed late in WW1) and especially a Long Lance with its highly superior speed and range.

RA, you´re right about Nelsons armored deck if you´re referering to it´s thickest parts and I agree that 6" in the mid-20s is not off the track but we´re talking about average thickness here and I´m pretty sure Nelson had not an average thickness of 6".

I just wondered if it is really necessary or a waste of material and thus weight to have such thick decks. Further more springstyle gives "average thickness". So an average thickness of 4" might do, allowing 4,5-6" over machineries and 1,5-3" elsewhere. The problem here are inaccuracies while using springstyle/sharp, though.

Anway, I really think 6" AVERAGE thickness is more than what is really necessary and thus a waste of material and weight but if that´s the way ships are designed in this alternate world I´ll also follow that path. :o)

Regards,

HoOmAn

For the most part my older ships have weaker deck armor than my Melampus class BB's, and even they originally had weaker deck armor but benifited from war experience and got a modification to thier design. Most of my "old lady's" have an average deck of 2.5" to 3.5" so I think despite being weaker designs they seem to be historically accurate for the time they were built.

Quoted

Originally posted by HoOmAn
I can´t remember your TT-caliber right now, Lord Arpad, but there is quite a difference between developing a large caliber torpedo (like that 60cm TT the Germans developed late in WW1) and especially a Long Lance with its highly superior speed and range.

Well, one could be headed in the right direction, but be turned off from it, for some reason or the other.

For the armor deck thickness of Fuso and Nagato, I just looked at Warships1.com (Fuso 0.80”-2.80” instead of 1.3"- 3"; Nagato 1.00”-3.50” in stead of 1.6"- 3"). I thought that if I stuck close to those numbers, I would be all right. I did this since I planned to do the same as the Japanese did historically and give both Fuso and Nagato an extensive modernisation in the 30s (and increase the armor of the deck).

Well, there go all the warship materials I need to build the other ships. :-)

Kaga (BB version) is something different. Originally it was designed with 5x2 16.1" guns, but I simmed it with 4x2 16.1" guns (like Nagato historically) leaving me with an extra 0.15 hull stength for ditching that one turret. This I used for additional armor (Kaga 1.60”-5.60” in stead of 1.3"- 4" BTW).
For future armor deck thickness, I just gradually increase it up to that of the Yamato (the one in the Spring Sharp library).

Big Guns is a nice program but it doesn't set a limit for elevation, which would limit range and deck armor penetration (if you manage to hit a ship at +300 hm). That and you can't really get good data on AAA guns with that (regarding max. altitude).


BTW, would an increase in elevation for your guns require a rebuild or could that be done during a refit ?

Walter

Quoted

Originally posted by Rooijen10

*snip*

Big Guns is a nice program but it doesn't set a limit for elevation, which would limit range and deck armor penetration (if you manage to hit a ship at +300 hm). That and you can't really get good data on AAA guns with that (regarding max. altitude).

*snip*

BTW, would an increase in elevation for your guns require a rebuild or could that be done during a refit ?

Big Gun doesn´t need to limit elevation. The program calculates the capabilities of the gun, not the mount.

As for the gun I presented above my first BBs to carry them have gun houses limiting elecation to a mere 25 degree while later classes can raise their guns up to ~35°. Look at the tables to see what this means for penetration power, range and FC.

The problem of increasing a guns max elevation cannot be easily adressed. How much work has to be done depends on the craddle/mount used, the arrangement of your equipement inside the gun house, the space below and behind the gun and the high of the gun house (turret) and its openings for the barrels.

For this SIM and trying to follow KISS I guess a modification of up to 5° can be done during an extensive refit. To change bulkheads and bunkers is allowed during a refit anyway. Beyond those 5° I think one should rate it as a rebuild because most likely you need to alter the barbets (their height for example), build new gun houses, change your reloading gear etc.
So as a rule of thumb I propose those 5°.

Ciao,

HoOmAn

Can you see what the exact armor penetration for your gun is at 25 degrees ? You can enter 25 as test during the program but it is not given in the list.
Ah well, one will just have to add the extra data himself.

As for your 5 degree rule, I think that would be a good one. It's simple but will do the trick.

Walter

Against WW1-type face-hardened armor using an AP shell with cap the gun achieves

At 25°:

Range: 279hm
Belt: 285,5mm
Deck: 192,3mm

At 30°:

Range: 306hm
Belt: 256,8mm
Deck: 231,6mm

At 35°:

Range: 326hm
Belt: 233,2mm
Deck: 269,8mm

At 40°:

Range: 340hm
Belt: 212,3mm
Deck: 306,6mm


At a range of 152hm the gun can penetrate

Belt: 470,6mm
Deck: 83mm

using the same shells firing them at 9,5°. Such a hit would occure after 24,6secs of flight hitting a vertical belt at an angle of 12,91° and at a speed of 506m/sec.
If we assume the belt is inclined 18° from the vertical (which is quite a lot and can be expected only on the most modern BBs commissioned after WW1) the gun still penetrates 397mm (15,63") - enough for all possible targets.

So even while not being a "super gun" and not using superior (or heavy) shells I think she packs enough power to land a decisive hit at all ranges a battle will happen in a WW1- or 1920s-environment. No need for heavier shells, more muzzle velocity or higher elevation. And once new shells of 850-880kg are introduced to deal with new armor (WW2-type) I doubt much more is necessary once again. No hit was ever achieved against a moving target beyond 270hm (Warning! Hindsight!) and thus a max. elevation of 25° or 35° respectively should do.


I hope this helps,

HoOmAn