Guns and Shells...

[miketr]

The following are default SpringSharp values for weight on various sized shells.

Imperial
1.00" / 25.4 mm gun, 0.50lbs / 0.23kg
2.00" / 50.8 mm gun, 4.00lbs / 1.81kg
3.00" / 76.2 mm gun, 13.50lbs / 6.12kg
4.00" / 102 mm gun, 32.00lbs / 14.51kg
5.00" / 127 mm gun, 62.50lbs / 28.35kg
6.00" / 152 mm gun, 108.00lbs / 48.99kg
7.00" / 178 mm gun, 171.50lbs / 77.79kg
8.00" / 203 mm gun, 256.00lbs / 116.12kg
9.00" / 229 mm gun, 364.50lbs / 165.33kg
10.00" / 254 mm gun, 500.00lbs / 226.80kg
11.00" / 279 mm gun, 665.50lbs / 301.87kg
12.00" / 305 mm gun, 864.00lbs / 391.90kg
13.00" / 330 mm gun, 1,098.50lbs / 498.27kg
14.00" / 356 mm gun, 1,372.00lbs / 622.33kg
15.00" / 381 mm gun, 1,687.50lbs / 765.44kg
16.00" / 406 mm gun, 2,048.00lbs / 928.96kg
17.00" / 432 mm gun, 2,456.50lbs / 1,114.25kg
18.00" / 457 mm gun, 2,916.00lbs / 1,322.68kg
19.00" / 483 mm gun, 3,429.50lbs / 1,555.60kg
20.00" / 508 mm gun, 4,000.00lbs / 1,814.37kg

Metric
0.79" / 20.0 mm gun, 0.24lbs / 0.11kg
0.98" / 25.0 mm gun, 0.48lbs / 0.22kg
1.18" / 30.0 mm gun, 0.82lbs / 0.37kg
1.57" / 40.0 mm gun, 1.95lbs / 0.89kg
1.97" / 50.0 mm gun, 3.81lbs / 1.73kg
2.36" / 60.0 mm gun, 6.59lbs / 2.99kg
2.76" / 70.0 mm gun, 10.47lbs / 4.75kg
2.95" / 75.0 mm gun, 12.87lbs / 5.84kg
3.15" / 80.0 mm gun, 15.62lbs / 7.09kg
3.54" / 90.0 mm gun, 22.24lbs / 10.09kg
3.94" / 100 mm gun, 30.51lbs / 13.84kg
4.13" / 105 mm gun, 35.32lbs / 16.02kg
4.33" / 110 mm gun, 40.61lbs / 18.42kg
4.72" / 120 mm gun, 52.72lbs / 23.92kg
4.92" / 125 mm gun, 59.59lbs / 27.03kg
5.12" / 130 mm gun, 67.03lbs / 30.41kg
5.51" / 140 mm gun, 83.72lbs / 37.98kg
5.91" / 150 mm gun, 102.98lbs / 46.71kg
6.30" / 160 mm gun, 124.98lbs / 56.69kg
6.69" / 170 mm gun, 149.90lbs / 68.00kg
7.09" / 180 mm gun, 177.95lbs / 80.71kg
7.48" / 190 mm gun, 209.28lbs / 94.93kg
7.87" / 200 mm gun, 244.10lbs / 110.72kg
8.27" / 210 mm gun, 282.57lbs / 128.17kg
8.66" / 220 mm gun, 324.89lbs / 147.37kg
9.06" / 230 mm gun, 371.24lbs / 168.39kg
9.45" / 240 mm gun, 421.80lbs / 191.32kg
9.84" / 250 mm gun, 476.75lbs / 216.25kg
10.24" / 260 mm gun, 536.28lbs / 243.25kg
10.63" / 270 mm gun, 600.57lbs / 272.41kg
11.02" / 280 mm gun, 669.80lbs / 303.81kg
11.42" / 290 mm gun, 744.15lbs / 337.54kg
11.81" / 300 mm gun, 823.82lbs / 373.68kg
12.20" / 310 mm gun, 908.98lbs / 412.31kg
12.60" / 320 mm gun, 999.81lbs / 453.51kg
12.99" / 330 mm gun, 1,096.51lbs / 497.37kg
13.39" / 340 mm gun, 1,199.24lbs / 543.97kg
13.78" / 350 mm gun, 1,308.20lbs / 593.39kg
14.17" / 360 mm gun, 1,423.56lbs / 645.72kg
14.57" / 370 mm gun, 1,545.52lbs / 701.04kg
14.96" / 380 mm gun, 1,674.25lbs / 759.43kg
15.35" / 390 mm gun, 1,809.93lbs / 820.97kg
15.75" / 400 mm gun, 1,952.76lbs / 885.76kg
16.14" / 410 mm gun, 2,102.91lbs / 953.86kg
16.54" / 420 mm gun, 2,260.56lbs / 1,025.37kg
16.93" / 430 mm gun, 2,425.91lbs / 1,100.37kg
17.32" / 440 mm gun, 2,599.12lbs / 1,178.94kg
17.72" / 450 mm gun, 2,780.39lbs / 1,261.17kg
18.11" / 460 mm gun, 2,969.90lbs / 1,347.13kg
18.50" / 470 mm gun, 3,167.83lbs / 1,436.91kg
18.90" / 480 mm gun, 3,374.37lbs / 1,530.59kg
19.29" / 490 mm gun, 3,589.69lbs / 1,628.26kg
19.69" / 500 mm gun, 3,813.98lbs / 1,729.99kg
20.08" / 510 mm gun, 4,047.43lbs / 1,835.88kg

Some people have been entering in non default shell weight values no doubt looking to get the performance of a historic weapon.  The historic weapons were all over the place.  This creates TWO problems...

1) Difference in penetration because of heavier shells.
2) Difference in damage because of heavier shells.

The former we can get an answer for out of Naval Armor and Ballistics program; as long as we have someone who can use it that is.  The second depends on whatever system we use / come up with for combat.

SeeKrieg is rather basic and treats all shells of a given size as the same in terms of damage.  Only notes for differneces between AP, SAP and HE.  Does note differences in terms of armor penetration.

I am leaning towards having guns base damage be based off of shell weight... 500 lb AP shell does 50 damage points...  Of course we are going to have ships with large numbers of damage points.

Again talking about heavier than normal shell weights people are all aware of the USN's super heavy shells, the 2,700 lb AP rounds.  A shell nearly as heavy as what springsharp thinks 18" gun would fire; 32% over "normal" springsharp size.  Of course the USN wasn't alone in making over weight shells just perhaps the most well known for doing so.  At anyrate I think we need a tech or perhaps a research rule to reflect larger than normal sized shells.  For every 10% increase in size takes a half year to a max of 40%.  Cost is $0.5 per half.  Any gun of that size can use the heavier shells if the ship is built to use them otherwise the ship needs to undergo a refurbishment  to cover changes to the ammo handling equipement, guns, storage, etc.   

Thoughts?

Michael

[Borys]

Ahoj!
Using shells heavier than SS thinks they are comes at a (small) penalty - the magzine weights go up accordingly. And thus the ship is larger (as it should be).
But is that weight mark-up sufficient to "pay" for the increased effectivenss (if there is any). I suspect not (pire intuition).
If the heavier shells do give some bonus,  then maybe we could pay for it with miscelenous weight, at the rate of "1lb over SS = 1 ton misc. weight"?

As to the USN superheavies - these only make sense if one harbours fantasies of hitting things at over 25K yards, or better - 30K+.

Borys

[maddox]

The only "bonus" heavier shells give in Springsharp is the less shells needed to sink a simular ship compared to "default" weight shells.

The disadvantage is clear too.  Magazine weight goes up or less shells carried for the same weight.

[Borys]

The only "bonus" heavier shells give in Springsharp is the less shells needed to sink a simular ship compared to "default" weight shells.

The disadvantage is clear too.  Magazine weight goes up or less shells carried for the same weight.

Springsharp is one thing. Another is the combat system (if any) used for bang-bang at sea.
Borys

[Korpen]

1) Difference in penetration because of heavier shells.

As you say this is not a major problem, as we got the tools to address it.
To get decent consistency I think it would the easiest to give energy for each gun size. For example: 225MJ muzzle energy for a 38cm/L40 gun.

2) Difference in damage because of heavier shells.

This one I think is quite irrelevant, as all other thing equal a heavier shell will have less payload (smaller cavity). But for armour piercing shells the difference will always be so small I do not think it is worth trying to take into account. Basically If they penetrate and function they will destroy the compartment they hit.

It might be more of any issue for SAP/CPC and HE shells however (who both would make allot more damage if they penetrate*).

*Armour or hull plating, after all a shell that penetrate outside the citadel is still a penetration, granted without the ability to cause system critical damage.

About super heavy shells and very heavy shells, especially when used in L40 guns, is that they give the gun very curved ballistics, resulting in longer flight time and smaller danger zone (the distance the shell travel at altitude were it might strike a ship). In short, lower practical accuracy.

[Korpen]

Further:
I did play around with the different ballistics of 38/40 guns using a ME of 223MJ.
I compared 907kg (BC:12,87 Mv:701m/s) , 820kg (BC:11,63 Mv:738m/s)  and 750kg (BC:10,6 Mv:771m/s) shells, and the difference is rarely significant.
At ranges over 10km there is never any difference exceeding 1cm against vertical protection.
Against vertical protection the difference is relatively larger, with the heaviest shell having about 15% better deck penetration (or 8,1cm vs. 7,1cm at 16km) then the lightest shell. On the other hand the heavier shells got about 1,5 degrees steeper fall.

I used "full perforation" for the above, but have not checked if there is any difference in the functioning of the shells.
My instinct tell me that it is unlikely that it would be significant.

I think the fact that you need larger magazines for the larger shells and charges (SS assumes that the charge weight is about 22% of shell weight) compensates for improved ant-deck ability of the larger shells.

[Borys]

I think the fact that you need larger magazines for the larger shells and charges (SS assumes that the charge weight is about 22% of shell weight) compensates for improved ant-deck ability of the larger shells.

We could leave it that, of course.
I suspect that a heavier shells => heavier gun => stronger recoil => heavier  ship structure and "everything" related with the operation of the guns. Hence my suggestion of the misc. weight.
But I am happy leaving things as they are.

Borys

[Korpen]

I suspect that a heavier shells => heavier gun => stronger recoil => heavier  ship structure and "everything" related with the operation of the guns. Hence my suggestion of the misc. weight.
But I am happy leaving things as they are.

I think you think heavier shell = more powerful gun. But physics tells us that two guns who give equal energy to a shell would have basically identical recoil and stresses.

The only thing that might be heavier would be hoists and shell handling equipment. But the fact that SS increase charge weight while it in the context of our rules should remain the same compensate for that IMO.

[Borys]

Call me stupid, but I think a 100 ton gun firing a 880 kg shell ot 750 m/s will produce a bigger recoil, that 80 ton gun firing a 750 kg shell at 850 m/s.

[Korpen]

Call me stupid, but I think a 100 ton gun firing a 880 kg shell ot 750 m/s will produce a bigger recoil, that 80 ton gun firing a 750 kg shell at 850 m/s.

That it will not by a far shot, considering that the lighter gun in this case got som 10% more ME...
A lighter gun firing a more powerful round = more recoil.

But it should be noted that so far the issue have been about gun of identical weight and power.

[miketr]

1) Difference in penetration because of heavier shells.

As you say this is not a major problem, as we got the tools to address it.
To get decent consistency I think it would the easiest to give energy for each gun size. For example: 225MJ muzzle energy for a 38cm/L40 gun.

Energy is nice but when resolving combat how do you suggest we make use of it?  I was looking for penetration tables.  

2) Difference in damage because of heavier shells.

This one I think is quite irrelevant, as all other thing equal a heavier shell will have less payload (smaller cavity). But for armour piercing shells the difference will always be so small I do not think it is worth trying to take into account. Basically If they penetrate and function they will destroy the compartment they hit.

It might be more of any issue for SAP/CPC and HE shells however (who both would make allot more damage if they penetrate*).

*Armour or hull plating, after all a shell that penetrate outside the citadel is still a penetration, granted without the ability to cause system critical damage.

About super heavy shells and very heavy shells, especially when used in L40 guns, is that they give the gun very curved ballistics, resulting in longer flight time and smaller danger zone (the distance the shell travel at altitude were it might strike a ship). In short, lower practical accuracy.

[/quote]

1) Kinetic energy is important to consider but its not all there is when factoring damage.  Heavier shells were also normally larger shells in terms of length; with larger bursting charges.  If pure Kinetic damage was all there was to it nations would just have kept firing solid shot for AP rounds.

2) As people are fielding L45 and L50 and soon L55 weapons the accuracy of L40's and below isn't an issue with us for much longer.  It is a problem if / when we go to Navalism 4.

Michael

[Korpen]

1) Kinetic energy is important to consider but its not all there is when factoring damage.  Heavier shells were also normally larger shells in terms of length; with larger bursting charges.  If pure Kinetic damage was all there was to it nations would just have kept firing solid shot for AP rounds.

True, but I haven of found any correlation between shell weight and bursting charge for shells of similar calibre. Looking at the historic guns it seems that the pattern is the opposite, the lighter (and earlier) the shell, the larger weight of filler. However for shells of similar generation it seems that the bursting charge is quite constant. For example the UK % Russian ww1 305mm guns had almost identical bursting charges while there was a 20% difference in shell weight.

Apart from there being no real connection between weight of shell and weight of charge, the actual differences are so small in actual terms (1-2kg at most) that I do not find them significant. I simply do not think that a shell functioning with a bursting charge of say 25 kg (38cm shell) will do any more damage then one with a 23kg charge.

2) As people are fielding L45 and L50 and soon L55 weapons the accuracy of L40's and below isn't an issue with us for much longer.  It is a problem if / when we go to Navalism 4.

Well, it does start to be a borderline with the L40 guns with 900kg+ shells IMO.
And those ships are likely to be in service for quite some time.

[Kaiser Kirk]

When considering "Superheavy" shells, they were longer, but also thicker walled, and so do not have the bursting charge one would expect.

Navweaps seems to have it's links mixed up, but looking at the USN 2240 Mk5 AP shells vs. the 2700 mk7 AP shells, the 2700 do have slightly better penetration numbers, but actually have less of a bursting charge.  While they will have more KE, they won't be throwing fragments with quite as much force.

As such, I don't think SH shells should do more damage, simply have a higher penetration number, increasing the likely hood of that damage being internal. That alone is worth an extra tech, as would heavy shells, diving shells, and possibly delay coils.

As for using the Seekrieg penetration, I would rather use BigGun. Once bore size, caliber/MV and shell wieghts are known, penetration can be derived.   So if a player researches a n"/55 caliber with a light shell, it is simple to figure out what that means.  Of course the mods should apply a dispersion penalty at longer ranges...

[miketr]

The decrease in % of bursting charge is rather easy to explain in two parts.

1) Need to create a stronger shell able to penetrate intact
2) Increase in explosive power per weight of explosive

Also I wasn't claiming that a larger shell allowed more relative explosive just more in absolute terms.

Lets look at it another way what is the function of the explosive charge?  Even the HE shells don't have a very large amount of explosive; at least compared to say a torpedo warhead.  The objective is to spread fragments of the shell all over the place.  A larger shell with a larger burst will spread more fragments (perhaps larger fragements but thats pure guess of my own) and IMHO cause more damage.  There was a general trend to increase the size of shells even within the same gun where possible.  UK, US and Germany did this; wouldn't be shocked if the other major naval powers did the same.

The reason I am pushing to wieght of shell to damage is its easy to track.  Otherwise we are going to get a mess in terms of figuring out damage.  You have talked about energy for weapons but I ask again how do you convert that to damage?  Particular are you suggesting we need to know energy at different points?  Like say 5,000 yards, 10,000 yards and in particular after penetrating 300mm of armor, of penetrating 350mm of armor, etc.  All of these bleed energy.

What I am suggesting is that damage is tied to shell size and we create penetration tables.  Shells that penetrate do more damage; ratio to be worked out...

Michael      

[Korpen]

The decrease in % of bursting charge is rather easy to explain in two parts.

1) Need to create a stronger shell able to penetrate intact
2) Increase in explosive power per weight of explosive

Both true, also have a nagging memory of different filling having different weight per volume.

Also I wasn't claiming that a larger shell allowed more relative explosive just more in absolute terms.

I was also talking about absolute terms, a ww1 305mm UK APC Mark Via had 12,4kg of explosives in a 386kg shell, a Russian 1911 APC had 13kg in a 470kg shell and the Germans had 13,6kg in a 405kg shell.

Lets look at it another way what is the function of the explosive charge?  Even the HE shells don't have a very large amount of explosive; at least compared to say a torpedo warhead.  The objective is to spread fragments of the shell all over the place.  A larger shell with a larger burst will spread more fragments (perhaps larger fragements but thats pure guess of my own) and IMHO cause more damage.

Large fragments are a sign of too small a bursting charge. One want the shell to fragment as evenly as possible as that maximises its damage potential. 
But I am not saying that you are correct in theory. But my point is that the actual difference in bursting charges between APC shells in the same calibre (of wildly different weight) is usually insignificant.

There was a general trend to increase the size of shells even within the same gun where possible.  UK, US and Germany did this; wouldn't be shocked if the other major naval powers did the same.

That was usually a absolute increase in power (due to better powers and quality control), which IMO is something else.

The reason I am pushing to wieght of shell to damage is its easy to track.  Otherwise we are going to get a mess in terms of figuring out damage.  You have talked about energy for weapons but I ask again how do you convert that to damage?  Particular are you suggesting we need to know energy at different points?  Like say 5,000 yards, 10,000 yards and in particular after penetrating 300mm of armor, of penetrating 350mm of armor, etc.  All of these bleed energy.

Far too complex, as well as a source for inaccuracies.
As for damages, if the shell function the hit compartment is destroyed, with perhaps some probability for damage to adjacent compartments. If a penetration do not function it would most likely only be damaged instead (perhaps temporary out of action).
I would go with calibre of shells most of the time for "general" damage, as that show more consistency then the weight does.

What I am suggesting is that damage is tied to shell size and we create penetration tables.  Shells that penetrate do more damage; ratio to be worked out...

I am fine with shell size, just do think that diameter is better then weight.