Design Bureau Hong Kong

[Logi]

Yes, I discussed the problem of digging the ship's bow into the waves briefly with Sachmle.

cB increased to 0.456 and the guns are reverted to mount and hoist. Forward guns are completely enclosed whilst the aft guns are completely exposed.

DD22, RRC Hunter laid down 1922

Displacement:
   1,000 t light; 1,079 t standard; 1,154 t normal; 1,214 t full load

Dimensions: Length overall / water x beam x draught
   393.00 ft / 385.00 ft x 33.35 ft x 6.90 ft (normal load)
   119.79 m / 117.35 m x 10.17 m  x 2.10 m

Armament:
      2 - 6.00" / 152 mm guns in single mounts, 128.00lbs / 58.06kg shells, 1922 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all forward, 1 raised mount
      2 - 6.00" / 152 mm guns in single mounts, 128.00lbs / 58.06kg shells, 1922 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all aft, 1 raised mount
   Weight of broadside 512 lbs / 232 kg
   Shells per gun, main battery: 180

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.31" / 8 mm   0.20" / 5 mm      0.20" / 5 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 20,704 shp / 15,445 Kw = 30.30 kts
   Range 3,000nm at 12.00 kts
   Bunker at max displacement = 136 tons

Complement:
   98 - 128

Cost:
   £0.405 million / $1.618 million

Distribution of weights at normal displacement:
   Armament: 54 tons, 4.7 %
   Armour: 2 tons, 0.2 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 2 tons, 0.2 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 486 tons, 42.1 %
   Hull, fittings & equipment: 433 tons, 37.5 %
   Fuel, ammunition & stores: 154 tons, 13.3 %
   Miscellaneous weights: 25 tons, 2.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     316 lbs / 143 Kg = 2.9 x 6.0 " / 152 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.22
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 11.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.79
   Seaboat quality  (Average = 1.00): 0.68

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.456
   Length to Beam Ratio: 11.54 : 1
   'Natural speed' for length: 19.62 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 72
   Bow angle (Positive = bow angles forward): 25.00 degrees
   Stern overhang: 1.01 ft / 0.31 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      15.00 ft / 4.57 m
      - Forecastle (15 %):   14.00 ft / 4.27 m
      - Mid (50 %):      11.00 ft / 3.35 m (8.00 ft / 2.44 m aft of break)
      - Quarterdeck (10 %):   8.00 ft / 2.44 m
      - Stern:      8.00 ft / 2.44 m
      - Average freeboard:   10.54 ft / 3.21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 175.7 %
      - Above water (accommodation/working, high = better): 161.6 %
   Waterplane Area: 8,230 Square feet or 765 Square metres
   Displacement factor (Displacement / loading): 62 %
   Structure weight / hull surface area: 36 lbs/sq ft or 177 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.49
      - Longitudinal: 0.56
      - Overall: 0.50
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Caution: Lacks seaworthiness - very limited seakeeping ability

[Nobody]

NAaB. Penetration vs Vertical belt.

That, might explain it. As far as I know NAab (and FaceHard which it is based on) is only usable for AP rounds. At the very least you would have to choose a cap-less base shell. Also problematic is that the ballistic coefficient which is weight and caliber dependent has to be corrected manually.

[Logi]

That, might explain it. As far as I know NAab (and FaceHard which it is based on) is only usable for AP rounds.

No they have AP and HE rounds for use. The problem is selecting the right one, which caused me some half-hour to do. Granted they do have more AP rounds for use than HE rounds, but I did say most of my shells tested were APC rounds :-\

Also problematic is that the ballistic coefficient which is weight and caliber dependent has to be corrected manually.

I did correct it manually?

[Nobody]

In that case could you tell us (me) what you did exactly?
Which shell/armor did you choose, what was the shell (body) weight and initially velocity and most importantly how did you correct the BC? (calculation please, because while I know I have to correct it, I wouldn't know how)

[Logi]

BC = Mass / ( Diameter Squared x form I); Or you can use BC = SD / form I, which in effect gives the formula above.

Reverse calculating the Cb of the 6" shell (using the 1933 version of the USA 6" though other 6" shell prove to all have the same ballistic co-efficient), concludes that Cb is ~0.345.

The Cb is the Drag Co-efficient of the shell. The shell's drag should not differ that much from the original 6" shell so large variations should be watched for.

This gets down to a Cd calculation. Cd = 2Fd / ( p x v^2 x A).

P is mass density and can be calculated easily enough.
V is the speed of the object relative to the fluid. I would suppose the speed is the muzzle velocity relative to the speed of the air, which we will say is 0.
A is the reference area and should not be a great change over the reference area of the original 6" shell.
This is the same with Fd, the drag force.

Hence looking simply we can gather that the different in drag co-efficient would be minimal, and due to the way physics is, only a slight bit lower.

Alternatively we can look at this this way, P and A will remain the same. V will be higher. A higher V will mean a lower Cb.

Hence we shall assume instead of a 0.345 Cb, we shall use a 0.32 Cb. The lowest Cb accounts for the longer shell length which in would result in a slight lower drag co-efficient (curious isn't it?). Hence we calculate form I now.

form I; Cb/Cg. Cg is the model projectile, in this case the G1 model, and has a number ~0.5191.

0.32/0.5191 = a form I of ~0.62

Now that we have all the numbers needed, we jump back to the original formula, BC = Mass / (Diameter^2 x  form I).

The Mass of the projectile is 128lb, the Diameter is 6". Thus:

BC = 128 / (36 x 0.62) or BC = ~5.735

I used:
Belt - 12" German new KC 'n/A" ('New Type') (1928-36) for 'Pocket BB' turrets only with 12" wood + 2" High Tensile Steel Post WW1 Backing
Deck - German Krupp "High-%" Nickel-steel. (1894-1918)

I used a few APC shells but all are from the USA, I think I used: Avg. 1921-1935 A.C.D. APC Shot (2-3% Ex. D filler) ('Midvale Army 1921') the most.

I told you the shell body weight? You don't need to know the inital velocity for the ballistics tab?

You calculate Muzzle Velocity simply. You use P3D's ME = 0.04 x L X D^3 formula to calculating the muzzle energy.

For example, for the 6"/62 gun, it produces: ME = 0.04 x 62 x 6^3 or ME = 535.68 million lb.ft^2/s^2

With that you go to the Ballistic.zip file that P3D gave out and fill in the details (the default gun there is the 15"/52) including caliber. Then you simply adjust the muzzle velocity until you get the file to say the muzzle energy you calculated earlier.

For example, for the 6"/62 gun firing a shell weighting 128lb, you have a muzzle velocity of 881.815 m/s or ~2893.1 fps

Then you just plug the numbers in: You have muzzle velocity and ballistic co-efficient, that is all you need for calculations via the Ballistic tab in NAaB.

---------

You notice that the calculation of Cb, which is the crucial point of the calculations for Ballistic Co-efficient were under-approximated. Should the real number be calculated for V, I expect V to be higher, thus Cb to be lower. A lower Cb also means a higher BC. Higher BC means better penetration of the belt due to increased travel distance and kinetic energy.

[P3D]

You could also base it on the 155 mm NATO guns which fire a 100 lbs HE (does anyone have more data about it?) which might have a ~17% filler and very thin walls. However the combination of large filler and high shell weight is impossible. Even if you fire a 4 caliber long solid (iron) cylinder (no filler at all!) its weight would hardly exceed 89 kg.

NATO shells are not relevant IMHO , about 30+ years of metallurgy is needed to develop strong but affordable cast steel that allows thin walls.

Perhaps it should also be noted that explosives usually has a density of ~1, compared to ~7.8 for steel.

[Nobody]

You could also base it on the 155 mm NATO guns which fire a 100 lbs HE (does anyone have more data about it?) which might have a ~17% filler and very thin walls. However the combination of large filler and high shell weight is impossible. Even if you fire a 4 caliber long solid (iron) cylinder (no filler at all!) its weight would hardly exceed 89 kg.

NATO shells are not relevant IMHO , about 30+ years of metallurgy is needed to develop strong but affordable cast steel that allows thin walls.

True, but wasn't a 100 lb 155 mm already in use during WW2? Technically it seems to be similar to the (much smaller) mine shells.

[P3D]

True, but wasn't a 100 lb 155 mm already in use during WW2? Technically it seems to be similar to the (much smaller) mine shells.

Have no idea about WW2 army shell weights.

BTW, looking over Navweaps, this is the heaviest 6" HE projectile I could find, at 132lbs/60kg.

http://navweaps.com/Weapons/WNBR_6-50_mkN5.htm

[Logi]

A larger version of the Bombardier. Added a TBD, probably wouldn't work with space constrains...

Randell, RRC Port Assault Ship laid down 1920 (Engine 1916)

Displacement:
   1,000 t light; 1,041 t standard; 1,154 t normal; 1,245 t full load

Dimensions: Length overall / water x beam x draught
   300.00 ft / 300.00 ft x 38.20 ft x 7.50 ft (normal load)
   91.44 m / 91.44 m x 11.64 m  x 2.29 m

Armament:
      1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Quick firing gun in deck mount
     on centreline forward
      2 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Quick firing guns in deck mounts
     on side, all forward
      2 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Breech loading guns in deck mounts
     on side, all aft
   Weight of broadside 177 lbs / 80 kg
   Shells per gun, main battery: 150

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.00" / 51 mm   273.00 ft / 83.21 m   10.00 ft / 3.05 m
   Ends:   Unarmoured
     Main Belt covers 140 % of normal length

   - Torpedo Bulkhead:
      1.00" / 25 mm   247.00 ft / 75.29 m   7.50 ft / 2.29 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.50" / 38 mm         -               -
   2nd:   1.50" / 38 mm         -               -
   3rd:   1.50" / 38 mm         -               -

   - Conning tower: 2.00" / 51 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 4,619 shp / 3,446 Kw = 20.00 kts
   Range 4,000nm at 12.00 kts
   Bunker at max displacement = 204 tons

Complement:
   98 - 128

Cost:
   £0.184 million / $0.734 million

Distribution of weights at normal displacement:
   Armament: 22 tons, 1.9 %
   Armour: 307 tons, 26.6 %
      - Belts: 217 tons, 18.8 %
      - Torpedo bulkhead: 69 tons, 5.9 %
      - Armament: 17 tons, 1.5 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 5 tons, 0.4 %
   Machinery: 172 tons, 14.9 %
   Hull, fittings & equipment: 474 tons, 41.1 %
   Fuel, ammunition & stores: 154 tons, 13.3 %
   Miscellaneous weights: 25 tons, 2.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2,872 lbs / 1,303 Kg = 81.3 x 4.1 " / 105 mm shells or 1.3 torpedoes
   Stability (Unstable if below 1.00): 1.46
   Metacentric height 2.3 ft / 0.7 m
   Roll period: 10.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.08
   Seaboat quality  (Average = 1.00): 1.25

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.470
   Length to Beam Ratio: 7.85 : 1
   'Natural speed' for length: 17.32 kts
   Power going to wave formation at top speed: 48 %
   Trim (Max stability = 0, Max steadiness = 100): 56
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      11.00 ft / 3.35 m
      - Forecastle (20 %):   10.00 ft / 3.05 m
      - Mid (50 %):      10.00 ft / 3.05 m
      - Quarterdeck (15 %):   10.00 ft / 3.05 m
      - Stern:      10.00 ft / 3.05 m
      - Average freeboard:   10.08 ft / 3.07 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 139.9 %
      - Above water (accommodation/working, high = better): 138.1 %
   Waterplane Area: 7,107 Square feet or 660 Square metres
   Displacement factor (Displacement / loading): 135 %
   Structure weight / hull surface area: 47 lbs/sq ft or 232 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.98
      - Longitudinal: 1.16
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

So removed of the TBD...

Randell, RRC Port Assault Ship laid down 1920 (Engine 1916)

Displacement:
   1,000 t light; 1,041 t standard; 1,154 t normal; 1,244 t full load

Dimensions: Length overall / water x beam x draught
   330.00 ft / 330.00 ft x 33.00 ft x 7.50 ft (normal load)
   100.58 m / 100.58 m x 10.06 m  x 2.29 m

Armament:
      1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Quick firing gun in deck mount
     on centreline forward
      2 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Quick firing guns in deck mounts
     on side, all forward
      2 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1920 Model
     Breech loading guns in deck mounts
     on side, all aft
   Weight of broadside 177 lbs / 80 kg
   Shells per gun, main battery: 150

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.00" / 51 mm   170.00 ft / 51.82 m   10.00 ft / 3.05 m
   Ends:   Unarmoured
     Main Belt covers 79 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.00" / 51 mm   1.00" / 25 mm            -
   2nd:   2.00" / 51 mm   1.00" / 25 mm            -
   3rd:   2.00" / 51 mm   1.00" / 25 mm            -

   - Conning tower: 2.00" / 51 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 4,410 shp / 3,290 Kw = 20.00 kts
   Range 4,000nm at 12.00 kts
   Bunker at max displacement = 204 tons

Complement:
   98 - 128

Cost:
   £0.181 million / $0.724 million

Distribution of weights at normal displacement:
   Armament: 22 tons, 1.9 %
   Armour: 172 tons, 14.9 %
      - Belts: 147 tons, 12.7 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 21 tons, 1.8 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 5 tons, 0.4 %
   Machinery: 164 tons, 14.2 %
   Hull, fittings & equipment: 481 tons, 41.7 %
   Fuel, ammunition & stores: 154 tons, 13.3 %
   Miscellaneous weights: 160 tons, 13.9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2,246 lbs / 1,019 Kg = 63.6 x 4.1 " / 105 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.23
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 11.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.14
   Seaboat quality  (Average = 1.00): 1.32

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.495
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 18.17 kts
   Power going to wave formation at top speed: 43 %
   Trim (Max stability = 0, Max steadiness = 100): 53
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      11.00 ft / 3.35 m
      - Forecastle (20 %):   10.00 ft / 3.05 m
      - Mid (50 %):      10.00 ft / 3.05 m
      - Quarterdeck (15 %):   10.00 ft / 3.05 m
      - Stern:      10.00 ft / 3.05 m
      - Average freeboard:   10.08 ft / 3.07 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 77.0 %
      - Above water (accommodation/working, high = better): 134.8 %
   Waterplane Area: 6,933 Square feet or 644 Square metres
   Displacement factor (Displacement / loading): 138 %
   Structure weight / hull surface area: 47 lbs/sq ft or 227 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.03
      - Longitudinal: 0.98
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Misc Weight (160t):
25t FCS System/Director
30t (15t of Extra Landing Craft / Assault Ship)
80t 80 Short-ranged Landing Craft (320 troops)
25t Construction Reserve

[Logi]

Considering the most effective method of fighting the required ships while keeping usable firepower and tonnage lower, an ugly ship as created.

Battery arrangement is level - level - half-raised - raised.
Torpedoes is behind/on the superstructure, all centerline.

DK Brown's rule of thumb on freeboard pegs it at 22.13 ft at the bow, which this ship has above. (Does that even apply to cruisers?)

CL20, RRC Light Cruiser laid down 1920 (Engine 1916)

Displacement:
   4,000 t light; 4,189 t standard; 4,627 t normal; 4,977 t full load

Dimensions: Length overall / water x beam x draught
   405.00 ft / 405.00 ft x 45.00 ft x 17.70 ft (normal load)
   123.44 m / 123.44 m x 13.72 m  x 5.39 m

Armament:
      8 - 6.00" / 152 mm guns (4x2 guns), 108.00lbs / 48.99kg shells, 1920 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all forward, 2 raised mounts - superfiring
   Weight of broadside 864 lbs / 392 kg
   Shells per gun, main battery: 200
   9 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.00" / 76 mm   309.00 ft / 94.18 m   12.00 ft / 3.66 m
   Ends:   Unarmoured
     Main Belt covers 117 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.00" / 51 mm   1.00" / 25 mm      1.00" / 25 mm

   - Armour deck: 1.00" / 25 mm, Conning tower: 3.00" / 76 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 36,429 shp / 27,176 Kw = 28.00 kts
   Range 7,000nm at 12.00 kts
   Bunker at max displacement = 788 tons

Complement:
   279 - 364

Cost:
   £0.995 million / $3.978 million

Distribution of weights at normal displacement:
   Armament: 108 tons, 2.3 %
   Armour: 745 tons, 16.1 %
      - Belts: 455 tons, 9.8 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 46 tons, 1.0 %
      - Armour Deck: 225 tons, 4.9 %
      - Conning Tower: 18 tons, 0.4 %
   Machinery: 1,357 tons, 29.3 %
   Hull, fittings & equipment: 1,648 tons, 35.6 %
   Fuel, ammunition & stores: 626 tons, 13.5 %
   Miscellaneous weights: 143 tons, 3.1 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,746 lbs / 1,699 Kg = 34.7 x 6.0 " / 152 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 1.8 ft / 0.6 m
   Roll period: 14.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.502
   Length to Beam Ratio: 9.00 : 1
   'Natural speed' for length: 20.12 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      23.00 ft / 7.01 m
      - Forecastle (20 %):   19.00 ft / 5.79 m
      - Mid (50 %):      17.00 ft / 5.18 m (13.00 ft / 3.96 m aft of break)
      - Quarterdeck (15 %):   12.00 ft / 3.66 m
      - Stern:      13.00 ft / 3.96 m
      - Average freeboard:   15.77 ft / 4.81 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 117.1 %
      - Above water (accommodation/working, high = better): 82.4 %
   Waterplane Area: 12,165 Square feet or 1,130 Square metres
   Displacement factor (Displacement / loading): 104 %
   Structure weight / hull surface area: 79 lbs/sq ft or 384 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.92
      - Longitudinal: 2.02
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped

Misc Weight: 143 tons
100 t - Fire Control
25 t - Radar
18 t - 2 Torpedo Reloads (18 21" torpedoes)

[Carthaginian]

Not a bad little cruiser...
Does need some kind of AAA, though- at least a few 20-25mm machineguns.
Aside from that, it's a bit slow, but very economical. Who cares if something 3 knots faster runs you down if you outnumber him 2:1.

[Logi]

Added four twin MG emplacements. Should make it a least appealing target for aircraft even if not very effective.

CL20, RRC Light Cruiser laid down 1920 (Engine 1916)

Displacement:
   4,000 t light; 4,189 t standard; 4,627 t normal; 4,977 t full load

Dimensions: Length overall / water x beam x draught
   405.00 ft / 405.00 ft x 45.00 ft x 17.70 ft (normal load)
   123.44 m / 123.44 m x 13.72 m  x 5.39 m

Armament:
      8 - 6.00" / 152 mm guns (4x2 guns), 108.00lbs / 48.99kg shells, 1920 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all forward, 2 raised mounts - superfiring
      8 - 0.98" / 25.0 mm guns (4x2 guns), 0.48lbs / 0.22kg shells, 1920 Model
     Machine guns in deck mounts
     on side, evenly spread
   Weight of broadside 868 lbs / 394 kg
   Shells per gun, main battery: 200
   9 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.00" / 76 mm   309.00 ft / 94.18 m   12.00 ft / 3.66 m
   Ends:   Unarmoured
     Main Belt covers 117 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.00" / 51 mm   1.00" / 25 mm      1.00" / 25 mm

   - Armour deck: 1.00" / 25 mm, Conning tower: 3.00" / 76 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 36,430 shp / 27,177 Kw = 28.00 kts
   Range 7,000nm at 12.00 kts
   Bunker at max displacement = 788 tons

Complement:
   279 - 364

Cost:
   £0.995 million / $3.982 million

Distribution of weights at normal displacement:
   Armament: 108 tons, 2.3 %
   Armour: 745 tons, 16.1 %
      - Belts: 455 tons, 9.8 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 46 tons, 1.0 %
      - Armour Deck: 225 tons, 4.9 %
      - Conning Tower: 18 tons, 0.4 %
   Machinery: 1,357 tons, 29.3 %
   Hull, fittings & equipment: 1,646 tons, 35.6 %
   Fuel, ammunition & stores: 627 tons, 13.6 %
   Miscellaneous weights: 143 tons, 3.1 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,741 lbs / 1,697 Kg = 34.6 x 6.0 " / 152 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 1.8 ft / 0.6 m
   Roll period: 14.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.502
   Length to Beam Ratio: 9.00 : 1
   'Natural speed' for length: 20.12 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      23.00 ft / 7.01 m
      - Forecastle (20 %):   19.00 ft / 5.79 m
      - Mid (50 %):      17.00 ft / 5.18 m (13.00 ft / 3.96 m aft of break)
      - Quarterdeck (15 %):   12.00 ft / 3.66 m
      - Stern:      12.50 ft / 3.81 m
      - Average freeboard:   15.73 ft / 4.80 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 117.2 %
      - Above water (accommodation/working, high = better): 82.4 %
   Waterplane Area: 12,165 Square feet or 1,130 Square metres
   Displacement factor (Displacement / loading): 104 %
   Structure weight / hull surface area: 79 lbs/sq ft or 384 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.92
      - Longitudinal: 2.01
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped

Misc Weight: 143 tons
100 t - Fire Control
25 t - Radar
18 t - 2 Torpedo Reloads (18 21" torpedoes)

[Carthaginian]

I genuinely like her. She's cheap, well-armed, and not slow (even if not fast).
Makes for a really good little vessel for the RRC... and one that can be gotten to sea in only 16 months total, including workips.

[Jefgte]

I agree with Cart.

For better seaboat quality... you can test to increase lenght & beam  - reduce draught.


Jef

[Guinness]

I think she probably draws a little bit too much, but in general the seakeeping is fine given here expected theater of operations. A little bit less freeboard is a fine compromise to get a ship such as this on this tonnage.