WesWorld

I have just had a conversation with the Empire of Brazil on the differences between SS3.0 and SS2.1 that we thought would be good to raise here.

The Margay class of Destroyers are a seemingly viable design in SS2.1 despite having 50% more main guns on 416 ton lighter and finer hull than the USS Gearings. When simmed in SS3.0 the Margays become a non viable design. So what gives?

My first response was that the improvements in SS3.0 are so far resulting in more realistic designs. It is probably unreasonable to assume that the USS Gearings are so under-gunned and it is possible to make a 9-5" Destroyer on a hull that is 20% smaller and finer than a Gearing.

Then I thought well what about the USS Porter Class ships - Real world ships with 8-5" (albeit not DP) on a Treaty limited Leader sized hull. What would SS3.0 make of these?

From the below I can say that the USS Porter is a possible design under SS3.0 even though the Margays are not. Also the USS Selfridge upgrade with 5-5" DP (2x2, 1x1) and AA upgrades are also possible and that SS3.0 finds that a 6-6" DP (3x2) alternative was not.

USS Porter, United States Destroyer Leader laid down 1933

Displacement:
1,780 t light; 1,871 t standard; 2,187 t normal; 2,440 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(381.04 ft / 372.00 ft) x 36.88 ft x (11.46 / 12.44 ft)
(116.14 m / 113.39 m) x 11.24 m x (3.49 / 3.79 m)

Armament:
8 - 5.00" / 127 mm 38.0 cal guns - 55.00lbs / 24.95kg shells, 100 per gun
Breech loading guns in deck and hoist mounts, 1933 Model
4 x 2-gun mounts on centreline ends, evenly spread
2 raised mounts - superfiring
8 - 1.10" / 27.9 mm 45.0 cal guns - 0.67lbs / 0.30kg shells, 300 per gun
Anti-air guns in deck mounts, 1933 Model
1 x Quad mount on centreline, aft deck aft
1 raised mount
1 x Quad mount on centreline, forward evenly spread
1 double raised mount
2 - 0.50" / 12.7 mm 45.0 cal guns - 0.06lbs / 0.03kg shells, 500 per gun
Machine guns in deck mounts, 1933 Model
2 x Single mounts on sides amidships
2 raised mounts
Weight of broadside 445 lbs / 202 kg
8 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.355 t each, 10.839 t total
In 2 sets of deck mounted centre rotating tubes
8 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.355 t each, 10.839 t total
In 1 sets of deck mounted reloads

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.50" / 13 mm 0.50" / 13 mm -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,695 shp / 37,818 Kw = 33.70 kts
Range 6,500nm at 14.75 kts
Bunker at max displacement = 568 tons

Complement:
159 - 207

Cost:
£1.246 million / $4.984 million

Distribution of weights at normal displacement:
Armament: 131 tons, 6.0 %
- Guns: 110 tons, 5.0 %
- Torpedoes: 22 tons, 1.0 %
Armour: 16 tons, 0.7 %
- Armament: 16 tons, 0.7 %
Machinery: 1,161 tons, 53.1 %
Hull, fittings & equipment: 457 tons, 20.9 %
Fuel, ammunition & stores: 407 tons, 18.6 %
Miscellaneous weights: 15 tons, 0.7 %
- On freeboard deck: 15 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
399 lbs / 181 Kg = 6.4 x 5.0 " / 127 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 1.4 ft / 0.4 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.57
Seaboat quality (Average = 1.00): 0.56

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a round stern
Block coefficient (normal/deep): 0.487 / 0.500
Length to Beam Ratio: 10.09 : 1
'Natural speed' for length: 19.29 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 90
Bow angle (Positive = bow angles forward): 14.00 degrees
Stern overhang: 4.17 ft / 1.27 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 16.80 %, 19.54 ft / 5.96 m, 16.54 ft / 5.04 m
- Forward deck: 20.80 %, 16.54 ft / 5.04 m, 16.54 ft / 5.04 m
- Aft deck: 47.60 %, 9.54 ft / 2.91 m, 9.54 ft / 2.91 m
- Quarter deck: 14.80 %, 9.54 ft / 2.91 m, 9.54 ft / 2.91 m
- Average freeboard: 12.38 ft / 3.77 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 187.2 %
- Above water (accommodation/working, high = better): 96.3 %
Waterplane Area: 9,033 Square feet or 839 Square metres
Displacement factor (Displacement / loading): 65 %
Structure weight / hull surface area: 36 lbs/sq ft or 177 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.49
- Longitudinal: 0.72
- Overall: 0.51
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Caution: Lacks seaworthiness - very limited seakeeping ability

-----------------------------------

USS Selfridge, United States Destroyer Leader laid down 1933

Displacement:
1,784 t light; 1,859 t standard; 2,187 t normal; 2,450 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(381.04 ft / 372.00 ft) x 36.88 ft x (11.46 / 12.48 ft)
(116.14 m / 113.39 m) x 11.24 m x (3.49 / 3.80 m)

Armament:
5 - 5.00" / 127 mm 38.0 cal guns - 55.00lbs / 24.95kg shells, 100 per gun
Dual purpose guns in deck and hoist mounts, 1933 Model
2 x 2-gun mounts on centreline ends, majority forward
1 x Single mount on centreline, aft deck aft
1 raised mount
4 - 1.57" / 40.0 mm 60.0 cal guns - 2.14lbs / 0.97kg shells, 500 per gun
Anti-air guns in deck mount, 1941 Model
1 x Quad mount on centreline, forward deck forward
1 raised mount
4 - 1.57" / 40.0 mm 60.0 cal guns - 2.14lbs / 0.97kg shells, 500 per gun
Anti-air guns in deck mounts, 1933 Model
2 x Twin mounts on sides, aft deck centre
2 raised mounts
6 - 0.79" / 20.0 mm 45.0 cal guns - 0.25lbs / 0.11kg shells, 300 per gun
Anti-air guns in deck mounts, 1933 Model
20 x Single mounts on sides amidships
Weight of broadside 294 lbs / 133 kg
8 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.355 t each, 10.839 t total
In 2 sets of deck mounted centre rotating tubes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.50" / 13 mm 0.50" / 13 mm -
2nd: 0.50" / 13 mm - -
3rd: 0.50" / 13 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,003 shp / 37,303 Kw = 33.59 kts
Range 6,500nm at 15.00 kts
Bunker at max displacement = 591 tons

Complement:
159 - 207

Cost:
£1.188 million / $4.752 million

Distribution of weights at normal displacement:
Armament: 88 tons, 4.0 %
- Guns: 77 tons, 3.5 %
- Torpedoes: 11 tons, 0.5 %
Armour: 13 tons, 0.6 %
- Armament: 13 tons, 0.6 %
Machinery: 1,167 tons, 53.4 %
Hull, fittings & equipment: 441 tons, 20.2 %
Fuel, ammunition & stores: 403 tons, 18.4 %
Miscellaneous weights: 75 tons, 3.4 %
- On freeboard deck: 75 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
441 lbs / 200 Kg = 7.1 x 5.0 " / 127 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.22
Metacentric height 1.6 ft / 0.5 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.30
Seaboat quality (Average = 1.00): 0.59

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a round stern
Block coefficient (normal/deep): 0.487 / 0.501
Length to Beam Ratio: 10.09 : 1
'Natural speed' for length: 19.29 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 85
Bow angle (Positive = bow angles forward): 14.00 degrees
Stern overhang: 4.17 ft / 1.27 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 16.80 %, 19.54 ft / 5.96 m, 16.54 ft / 5.04 m
- Forward deck: 20.80 %, 16.54 ft / 5.04 m, 16.54 ft / 5.04 m
- Aft deck: 47.60 %, 9.54 ft / 2.91 m, 9.54 ft / 2.91 m
- Quarter deck: 14.80 %, 9.54 ft / 2.91 m, 9.54 ft / 2.91 m
- Average freeboard: 12.38 ft / 3.77 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 182.9 %
- Above water (accommodation/working, high = better): 103.9 %
Waterplane Area: 9,033 Square feet or 839 Square metres
Displacement factor (Displacement / loading): 67 %
Structure weight / hull surface area: 34 lbs/sq ft or 166 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.49
- Longitudinal: 0.72
- Overall: 0.51
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Caution: Lacks seaworthiness - very limited seakeeping ability

This is from the SS3.0b2 which will come out next week

Ian

www.springsharp.com

One minor thing. If I read the data on Navweaps correctly about the 5 inch guns, you're probably looking at at least 300 rounds per gun, not 100. The additional rounds will probably drag the design below 0.5 hull strength.

One thing that would make simming destroyers more accurately would be a different calculation of weights for light AA guns. A quad 40mm bofors weighs about 10tons but SS2 only accounts for abouts 0.8tons, a significant. At the moment I assume that the weight per gun is done off a single calculation, inserting an if operator and maybe sticking guns under 75mm with a different calculation (one that takes into account their increased weight) should work.

Re The rounds per gun of a Porter Class: the 100 rpg is taken direct from Friedman's US Destroyers.

Re The new gun weight calculation is as follows:

Step 1 Calculate the average shell weight for a gun of that calibre assuming a barrel length of 45 calibres

shellWeight = Math.Pow(calibre, 3) / 1.9830943211886;

Step 2: Adjust for the actual barrel length in calibres

if (calibreLength < 45)
shellWeight *= (45 - Math.Pow(45 - calLength, 0.5)) / 45;
else if (calLength > 45)
shellWeight *= (45 + Math.Pow(calLength - 45, 0.5)) / 45;

Step 3: Adjust for when the gun was designed

No adjustment if gun design date is after 1890
if (gun design date <= 1890)
shellWeight *= 1 - ((1890  gun design date ) / (100 * 2 / 3));

Step 4: Calculate the weight of unfixed gun including its breach mechanism on the basis of the above average shell weight and the guns calibre, calibre length and the number of barrels carried by the ship.

gunWeight = shellWeight *= (calLength / 812.389434917877 * (1 + Math.Pow(1 / calibre, 2.3297949327695))) * barrels;

Step 5: Calculate mount type adjustment factor based on correlative research

switch (mountType)
{
case 0: //Broadside mount
gunMountWeight = 0.83f;
break;
case 2: //Open barbette
gunMountWeight = 3.33f;
break;
case 4: //Mount on hoist
gunMountWeight = 3.15f;
break;
case 5: //Deck mount
case 6: //Casemate mount
gunMountWeight = 1.08f;
break;
default: //Coles/Ericsson turret or Turret on barbette
gunMountWeight = 3.5f;
break;
}


Step 6: Multiply the mount type adjustment factor by the gun type adjustment factor (also based on correlative research)

switch (gunType)
{
case 0: //muzzle loader
if (Broadside Mount, Deck Mount or Casemate Mount)
gunMountWeight *= 0.9f;
else
gunMountWeight *= 0.98f;
break;
case 2: //QF
if (Broadside Mount, Deck Mount or Casemate Mount)
gunMountWeight *= 1.35f;
break;
case 3: //AA
if (Broadside Mount, Deck Mount or Casemate Mount)
gunMountWeight *= 1.44f;
break;
case 4: //DP
if (Broadside Mount, Deck Mount or Casemate Mount)
gunMountWeight *= 1.57f;
else
gunMountWeight *= 1.1f;
break;
case 5: //Automatic
if (Broadside Mount, Deck Mount or Casemate Mount)
gunMountWeight *= 2.16f;
else
gunMountWeight *= 1.5f;
break;
}

Step 7: The resultant factor is adjusted for the calibre

gunMountWeight += 1 / Math.Pow(calibre,0.313068808543972);

Step 8: The mount weight (other than the armour and the unfixed weight of the guns is calculated by multiplying the weight of the unfixed weigt of the guns from Step 4 by the factor from Step 7

gunMountWeight *= gunWeight;

Step 9: This is further adjusted if the calibre is greater than 10 inches or less than 1 inch
if (calibre > 10)
gunMountWeight *= 1 - (2.1623768599192f * calibre / 100);
else if (calibre < 1)
gunMountWeight = gunWeight; Mount weight assumed to equal the same weight as the guns it carries

Step 10: If the gun mount has more than 1 barrel and has a common cradle then the mount weight is reduced.
gunMountWeight *= weightAdj;

Step 11: Calculate two adjustment factors from the number of barrels wide the mount is
if (mountWidth == 0 || mountWidth == 1 || mountWidth == 2) // 1 Barrel wide
{
f1 = 1.44f;
f2 = 0.609725f;
}
else if (mountWidth == 3 || mountWidth == 4 || mountWidth == 5) // 2 Barrels wide
{
f1 = 1.52f;
f2 = 0.4205f;
}
else if (mountWidth == 6 || mountWidth == 7 || mountWidth == // 3 Barrels wide
{
f1 = 1.64f;
f2 = 0.29f;
}
else if (mountWidth == 9 || mountWidth == 10 || mountWidth == 11) // 4 Barrels wide
{
f1 = 1.80f;
f2 = 0.20f;
}
else if (mountWidth == 12 || mountWidth == 13 || mountWidth == 14) // 5 Barrels wide
{
f1 = 2.00f;
f2 = 0.14f;
}

Step 12: Calculate the diameter of the mount from the factors in Step 11 and its calibre
diameterGun = (f1 * calibre * (1 + Math.Pow(1 / calibre, f2)));

Step 13: Adjust the Diameter if the calibre is less than 12 inches

if (calibre < 12)
diameterGun += 12f / calibre;

Step 14: Further adjust the diameter if the calibre is greater than 1 and the mount has common cradles for multiple barrels

if (calibre > 1 && weightAdj < 1)
diameterGun *= 0.9f;

Step 15: Calculate the gun house height
if (mount == 1) // Coles/Ericsson/Modern Turret or Deck mount on hoist
armGunhouseHeight = Math.Max(7.5f, 0.625f * calibre * 2);
else
armGunhouseHeight = Math.Max(7.5f, 0.625f * calibre);

Step 16: Calculate the gunhouse face armour factor

if (mount == 0 || mount == 6) // Broadside or Casemate
armWeightGunFace = 1f;
else if (mount == 1) // Turret (full)
armWeightGunFace = (float)(Math.PI / 2.0);
else if (mount == 2) // Open barbette
armWeightGunFace = 0f;
else if (armBack == 0) // Open back gunhouse
armWeightGunFace = 1.5f;
else
armWeightGunFace = 0.5f;

Step 17: Calculate the other gun house armour factor and the barbette / hoist armour weight factor

if (mount > 2 && mount < 6) // Turret on barbette or mount
armWeightGunBack = 2.5f;
else
armWeightGunBack = 0f;
if (mount == 2) // open barbette
armWeightGunBottom = 0.6416f;
else if(mount == 3) // Turret on Barbette
armWeightGunBottom = 0.5f;
else if (mount == 4 || mount == 6) // Deck or casemate mount with hoist
armWeightGunBottom = 0.1f;
else
armWeightGunBottom = 0f;

Step 18: Calculate the face armour weight

armWeightGunFace *= (diameterG1 * mountsG1 + diameterG2 * mountsG2) * armGunhouseHeight * armFace * INCH;

Step 19: Adjust this for AA/MG open mounts

if(type == 3 || type == 6 && armBack == 0) // short shield for AA/MG open mounts
armWeightGunFace *= 0.333f;


Step 20; Calculate the other Gun House armour weight
if (mount == 1)
armWeightGunBack = (Math.PI * Math.Pow(diameterG1 / 2, 2) * mountsG1 + Math.PI * Math.Pow(diameterG2 / 2, 2) * mountsG2);
else
{
armWeightGunBack *= (diameterG1 * mountsG1 + diameterG2 * mountsG2) * armGunhouseHeight;
armWeightGunBack += ((Math.PI * Math.Pow(diameterG1 / 2, 2) * mountsG1 + Math.PI * Math.Pow(diameterG2 / 2, 2) * mountsG2) * 0.75);
}
armWeightGunBack *= armBack * INCH;

Step 21: Calculate the Barbette / hoist armour weight from the step 17 barbette/hoist adjustment, the average freeboard of that battery of guns, the super factor or adjustment for raised or below freeboard deck mounts and the same date adjustment as in Step 3.

if(mountAdj > 0.5)
perMountG1 = Math.Min(4, (perMountG1 * mountsG1 + perMountG2 * mountsG2) / (mountsG1 + mountsG2));
else
perMountG1 = Math.Min(5, (perMountG1 * mountsG1 + perMountG2 * mountsG2) / (mountsG1 + mountsG2));
armWeightGunBottom = ((1 -((perMountG1 - 2) / 6)) * ((armBottom * barrels * Math.Pow(calibre, 1.2) * armWeightGunBottom * freeGun / 16 * super * armWeightGunBottom * 2) *Math.Sqrt(dateFactor)));
}
else
armWeightGunFace = armWeightGunBack = armWeightGunBottom = 0f;

Step 22: Add gun Armour weight together

armWeightGun = armWeightGunFace + armWeightGunBack + armWeightGunBottom;


Ian

www.springsharp.com

Urgh! Now I know again why I focused on music and gfx instead of source code back in the good old Amiga 500 time!!!

I&acute;m completely lost.....

Btw, Ian, did you get my email?

Ah, good ol' C++. Been a couple years since I've had to read source code, but I recognize most of that.

I can read it (slowly) if I have to. Never learnt any serious programming, though, so that's my sum ability.

I always hated C++. It seems converse to my thinking pattern. That's probably why I took Visual Basic classes instead of Visual C++ after that first class.

Its C# rather than C++

Ian,

A note on the torpedoes. During my course of digging around for information I found that the weight of the launcher is about 25% the weight of the torpedoes. A simple line in the source code should take care of this. The weight model seems a bit light as well, 21" fish seem to be between 1.4 and 1.8tons