Laksmanavati designs

[The Rock Doctor]

Redo of the armored cruiser.  Can't believe I missed the coal.

Anyway, the weight savings let me cut down the size AND implement super-heavy 260mm guns, so yay.  It frees up a bit of tonnage in the 1928 program so I'll tinker with that and post an update later.

Enter ship name, Enter country Enter ship type laid down 1928

Displacement:
   19,495 t light; 20,491 t standard; 21,556 t normal; 22,409 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (600.39 ft / 590.55 ft) x 85.30 ft x (27.23 / 28.08 ft)
   (183.00 m / 180.00 m) x 26.00 m  x (8.30 / 8.56 m)

Armament:
      8 - 10.24" / 260 mm 45.0 cal guns - 648.16lbs / 294.00kg shells, 100 per gun
     Breech loading guns in turret on barbette mounts, 1928 Model
     2 x 2-gun mounts on centreline, forward evenly spread
      1 raised mount
     2 x 2-gun mounts on centreline, aft evenly spread
      1 raised mount
      12 - 6.50" / 165 mm 45.0 cal guns - 138.23lbs / 62.70kg shells, 250 per gun
     Breech loading guns in deck and hoist mounts, 1928 Model
     6 x 2-gun mounts on sides, evenly spread
      8 - 2.36" / 60.0 mm 45.0 cal guns - 6.65lbs / 3.02kg shells, 1,500 per gun
     Anti-air guns in deck mounts, 1928 Model
     8 x Single mounts on sides amidships
      8 raised mounts
      12 - 0.47" / 12.0 mm 90.0 cal guns - 0.06lbs / 0.03kg shells, 4,000 per gun
     Machine guns in deck mounts, 1928 Model
     6 x Twin mounts on sides, evenly spread
      6 raised mounts
      Weight of broadside 6,898 lbs / 3,129 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   10.2" / 260 mm   383.86 ft / 117.00 m   11.81 ft / 3.60 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead:
      1.38" / 35 mm   383.86 ft / 117.00 m   25.46 ft / 7.76 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   12.2" / 310 mm   8.27" / 210 mm      10.2" / 260 mm
   2nd:   2.36" / 60 mm   1.38" / 35 mm      1.38" / 35 mm
   4th:   0.79" / 20 mm         -               -
   5th:   0.59" / 15 mm         -               -

   - Armoured deck - multiple decks: 4.33" / 110 mm For and Aft decks
   Forecastle: 3.35" / 85 mm  Quarter deck: 4.33" / 110 mm

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 100,536 shp / 75,000 Kw = 29.15 kts
   Range 12,000nm at 10.00 kts
   Bunker at max displacement = 1,918 tons

Complement:
   889 - 1,156

Cost:
   £6.432 million / $25.728 million

Distribution of weights at normal displacement:
   Armament: 1,437 tons, 6.7 %
   Armour: 7,044 tons, 32.7 %
      - Belts: 1,989 tons, 9.2 %
      - Torpedo bulkhead: 498 tons, 2.3 %
      - Armament: 1,736 tons, 8.1 %
      - Armour Deck: 2,782 tons, 12.9 %
      - Conning Tower: 39 tons, 0.2 %
   Machinery: 3,130 tons, 14.5 %
   Hull, fittings & equipment: 7,338 tons, 34.0 %
   Fuel, ammunition & stores: 2,061 tons, 9.6 %
   Miscellaneous weights: 545 tons, 2.5 %
      - On freeboard deck: 195 tons
      - Above deck: 350 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     32,040 lbs / 14,533 Kg = 59.7 x 10.2 " / 260 mm shells or 5.0 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 4.6 ft / 1.4 m
   Roll period: 16.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.64
   Seaboat quality  (Average = 1.00): 1.11

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.550 / 0.554
   Length to Beam Ratio: 6.92 : 1
   'Natural speed' for length: 24.30 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 54
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 4.92 ft / 1.50 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  27.89 ft / 8.50 m,  22.97 ft / 7.00 m
      - Forward deck:   30.00 %,  22.97 ft / 7.00 m,  22.97 ft / 7.00 m
      - Aft deck:   35.00 %,  22.97 ft / 7.00 m,  22.97 ft / 7.00 m
      - Quarter deck:   15.00 %,  22.97 ft / 7.00 m,  22.97 ft / 7.00 m
      - Average freeboard:      23.36 ft / 7.12 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94.7 %
      - Above water (accommodation/working, high = better): 173.0 %
   Waterplane Area: 35,156 Square feet or 3,266 Square metres
   Displacement factor (Displacement / loading): 112 %
   Structure weight / hull surface area: 154 lbs/sq ft or 752 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 1.97
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

[Jefgte]

It looks good except that the 1928 ships can and should carry enhanced hydrophone packages rather than just the basic fit.

1500T, Laksamanavati DD1928 laid down 1928

Displacement:
   1 500 t light; 1 571 t standard; 1 806 t normal; 1 995 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (384,40 ft / 380,58 ft) x 32,81 ft x (12,66 / 13,52 ft)
   (117,16 m / 116,00 m) x 10,00 m  x (3,86 / 4,12 m)

Armament:
      5 - 4,33" / 110 mm 45,0 cal guns - 40,96lbs / 18,58kg shells, 250 per gun
     Quick firing guns in deck mounts, 1928 Model
     5 x Single mounts on centreline ends, majority aft
      2 raised mounts - superfiring
      4 - 2,36" / 60,0 mm 45,0 cal guns - 6,66lbs / 3,02kg shells, 400 per gun
     Anti-air guns in deck mounts, 1928 Model
     4 x Single mounts on side ends, evenly spread
      12 - 0,47" / 12,0 mm 45,0 cal guns - 0,04lbs / 0,02kg shells, 1 000 per gun
     Machine guns in deck mounts, 1928 Model
     6 x 2-gun mounts on side ends, majority forward
      6 raised mounts
      Weight of broadside 232 lbs / 105 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,98" / 25 mm         -               -
   2nd:   0,39" / 10 mm         -               -
   3rd:   0,39" / 10 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 35 200 shp / 26 259 Kw = 32,50 kts
   Range 12 000nm at 10,00 kts
   Bunker at max displacement = 424 tons

Complement:
   138 - 180

Cost:
   £0,730 million / $2,921 million

Distribution of weights at normal displacement:
   Armament: 42 tons, 2,3 %
      - Guns: 42 tons, 2,3 %
   Armour: 17 tons, 1,0 %
      - Armament: 17 tons, 1,0 %
   Machinery: 909 tons, 50,3 %
   Hull, fittings & equipment: 430 tons, 23,8 %
   Fuel, ammunition & stores: 306 tons, 17,0 %
   Miscellaneous weights: 101 tons, 5,6 %
      - Hull above water: 8 tons
      - On freeboard deck: 64 tons
      - Above deck: 29 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     469 lbs / 213 Kg = 11,5 x 4,3 " / 110 mm shells or 0,3 torpedoes
   Stability (Unstable if below 1.00): 1,17
   Metacentric height 1,3 ft / 0,4 m
   Roll period: 12,3 seconds
   Steadiness   - As gun platform (Average = 50 %): 80 %
         - Recoil effect (Restricted arc if above 1.00): 0,28
   Seaboat quality  (Average = 1.00): 1,16

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0,400 / 0,414
   Length to Beam Ratio: 11,60 : 1
   'Natural speed' for length: 19,51 kts
   Power going to wave formation at top speed: 61 %
   Trim (Max stability = 0, Max steadiness = 100): 69
   Bow angle (Positive = bow angles forward): 10,00 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 %,  21,65 ft / 6,60 m,  18,04 ft / 5,50 m
      - Forward deck:   30,00 %,  18,04 ft / 5,50 m,  16,73 ft / 5,10 m
      - Aft deck:   35,00 %,  8,86 ft / 2,70 m,  8,86 ft / 2,70 m
      - Quarter deck:   15,00 %,  8,86 ft / 2,70 m,  9,51 ft / 2,90 m
      - Average freeboard:      13,59 ft / 4,14 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 170,4 %
      - Above water (accommodation/working, high = better): 135,7 %
   Waterplane Area: 7 686 Square feet or 714 Square metres
   Displacement factor (Displacement / loading): 75 %
   Structure weight / hull surface area: 30 lbs/sq ft or 149 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,50
      - Longitudinal: 1,29
      - Overall: 0,55
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

AD
25t for LR wireless
4t for 1918 fire control
OD
36t for 4x3TTx533
15t for Enhanced Hydrophone
5t for 50 ASW depth charges
8t reserved
AW
8t for engines additionnal ventillation

Trial Speed:33kts
Bonus:0.5

[The Rock Doctor]

Thanks, Jef.  Hope you have some fun sinking and being sunk by these ships.

[Kaiser Kirk]

Redo of the armored cruiser.  Can't believe I missed the coal.

Anyway, the weight savings let me cut down the size AND implement super-heavy 260mm guns, so yay.  It frees up a bit of tonnage in the 1928 program so I'll tinker with that and post an update later.

I like the 260s better, the bigger shell will give more punch. My modeling for the Parthian 255L47 with an overweight shell..about the 260 wt,  lends me to think it can punch through cruiser armor in visual range.

It's interesting to see these, since I recently went through deciding the successor to the 1920 Zemaka class, and wound up upscaling to the Dahae class.
Looks like I made the right choice, as these would beat the 1928 update to the Zemakas, but not the Dahea being built.
Oddly it's a case of the 1920 Zemaka being a similar battery, less armor but  faster than the Laks AC...  those +2 knots could have bought a fair bit of protection.

[Jeremy]

In preparation for taking over Laksmanavati, I made some minor changes to the 1928 minesweeper/sloop from upthread:

- Removed the 60mm/45 AA gun. (I drew the ship and was finding it difficult to fit the gun)
- Changed the 12mm/90 MG to 12.7mm/90 and moved them from "Above" to "On" the deck (12mm was weird to me)
- Removed all gun armor (It was only splinter protection and seemed unnecessary for a coastal minesweeper / sub-chaser)
- Replaced generic ASW munitions with 1x stern rack and a total of 25x 195kg DC
- Moved some of the miscellaneous weights to different locations
- Removed the "Mines or deck cargo" weight
- Increased speed to 17 kt
- Changed Trim from 25 to 50
- Reduced range from 3000 nm to 1000 nm (3000 nm seemed excessive)
- Reduced the displacement by about 40 t (due to cutting weight)

Do those changes make sense? I'm still learning how to use SS effectively.

AMc-28, Laksmanavati Coastal Minesweeper laid down 1928

Displacement:
   228 t light; 238 t standard; 245 t normal; 251 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (121.89 ft / 114.83 ft) x 21.98 ft x (7.87 / 7.99 ft)
   (37.15 m / 35.00 m) x 6.70 m  x (2.40 / 2.44 m)

Armament:
      1 - 4.33" / 110 mm 45.0 cal gun - 40.96lbs / 18.58kg shells, 200 per gun
     Quick firing gun in deck mount, 1928 Model
     1 x Single mount on centreline, forward deck forward
      4 - 0.50" / 12.7 mm 90.0 cal guns - 0.07lbs / 0.03kg shells, 4,000 per gun
     Machine guns in deck mount, 1928 Model
     1 x Single mount on centreline, aft deck aft
      Weight of broadside 41 lbs / 19 kg

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 1,436 shp / 1,071 Kw = 17.00 kts
   Range 1,000nm at 10.00 kts (Range with geared drive bonus: 1,100 nm)
   Bunker at max displacement = 13 tons

Complement:
   30 - 40

Cost:
   £0.062 million / $0.250 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 3.1 %
      - Guns: 8 tons, 3.1 %
   Machinery: 45 tons, 18.2 %
   Hull, fittings & equipment: 110 tons, 44.7 %
   Fuel, ammunition & stores: 17 tons, 7.0 %
   Miscellaneous weights: 66 tons, 26.9 %
      - Hull below water: 15 tons
      - On freeboard deck: 51 tons

Fittings:
-15 t:  Enhanced hydrophone package (BW)
-1 t: 1x DC racks + 5x 195kg DC (QD)
-25 t:  1x Paravane (QD)
-4 t: 20x 195kg DC reloads (AD)
-10 t: Weight reserve (AD)
-1 t:  1918 fire control (FD)
-1 t:  Spotlight (FD)
-10 t:  Weight reserve (FD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     530 lbs / 240 Kg = 13.1 x 4.3 " / 110 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.00
   Metacentric height 0.5 ft / 0.2 m
   Roll period: 12.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.37
   Seaboat quality  (Average = 1.00): 2.00

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.432 / 0.435
   Length to Beam Ratio: 5.22 : 1
   'Natural speed' for length: 10.72 kts
   Power going to wave formation at top speed: 70 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.94 ft / 1.20 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  17.72 ft / 5.40 m,  15.75 ft / 4.80 m
      - Forward deck:   40.00 %,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Aft deck:   25.00 %,  7.87 ft / 2.40 m,  7.87 ft / 2.40 m
      - Quarter deck:   15.00 %,  7.87 ft / 2.40 m,  7.87 ft / 2.40 m
      - Average freeboard:      12.76 ft / 3.89 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 76.2 %
      - Above water (accommodation/working, high = better): 128.2 %
   Waterplane Area: 1,587 Square feet or 147 Square metres
   Displacement factor (Displacement / loading): 139 %
   Structure weight / hull surface area: 28 lbs/sq ft or 135 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.68
      - Longitudinal: 27.11
      - Overall: 0.99
   Caution: Hull subject to strain in open-sea
   Excellent machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[Jefgte]

Welcome aboard Jeremy

This SS is a good approach.
There are some minor adjustments to be made in the misc weight.

Laksmanavati is a good start but "Empires" are free...
Check with our Kaiser.


Jef, from Byzantine Empire.

[Jeremy]

This SS is a good approach.
There are some minor adjustments to be made in the misc weight.

How would you recommend changing them?

[The Rock Doctor]

Welcome to the board.

One comment on the design - the trim gives you 100% steadiness, which is great for gunnery, but also only 1.00 stability, which puts the ship at risk of capsizing if she takes on any kind of list at all.  Consider adjusting the trim "left" until you get stability in the 1.05-1.10 range.

[Jefgte]

How would you recommend changing them?

Ship equipment is governed by RULES so all SS designs have the same constraints.
EX:
"1915 ASW
1t per ASW Paravane : <=25knots..."

https://www.navalism.org/index.php/topic,7032.0.html

[Jeremy]

Ship equipment is governed by RULES so all SS designs have the same constraints.
EX:
"1915 ASW
1t per ASW Paravane : <=25knots..."

I based my "25 t:  1x Paravane (QD)" off the "25 t:  Sweeping gear (FD)" in the original design, although I couldn't actually find that in the rules (or any minesweeping gear). I just changed it to specifically mean a paravane (although I should have specified 2x instead of 1x).

Would explosive ASW paravanes be much different in weight than minesweeping paravanes? I don't want or need the ASW version. (I won't complain about saving 23 t of weight :))

[Jeremy]

One comment on the design - the trim gives you 100% steadiness, which is great for gunnery, but also only 1.00 stability, which puts the ship at risk of capsizing if she takes on any kind of list at all.  Consider adjusting the trim "left" until you get stability in the 1.05-1.10 range.

Why is 1.05 that much better than 1.0? Stability is one of (many) performance numbers in SS that I don't know how to relate to the real world.

Looking at the SS code, it will warn about capsizing if Metacentric height is ≤ 0 or the Stability is ≤ 0.995. Metacentric height I can understand, but I don't understand why a stability of 1.05 is that much better than a 1.0.

I don't doubt that you are correct but I am hoping someone can help me understand the Stability number better.

Thanks

[TacCovert4]

So steadiness is roll rate and periodization.  That's going to affect gunnery precision.  Stability needs to be 1.0 on a ship regardless.  If you're at a 1.0 Stability undamaged, anything that reduces it, like a torpedo hit, is more likely to put the ship capsizing. 

70 steadiness is where you reach the good gun platform arena.  My recommendation is to adjust trim down to 70, as that trim will add Stability.   This design may have greater than 70 steadiness no matter what, but you can probably significantly improve Stability, which would mean water taken on has less effect on the ship staying upright.

[Jeremy]

So steadiness is roll rate and periodization.  That's going to affect gunnery precision.  Stability needs to be 1.0 on a ship regardless.  If you're at a 1.0 Stability undamaged, anything that reduces it, like a torpedo hit, is more likely to put the ship capsizing. 

70 steadiness is where you reach the good gun platform arena.  My recommendation is to adjust trim down to 70, as that trim will add Stability.  This design may have greater than 70 steadiness no matter what, but you can probably significantly improve Stability, which would mean water taken on has less effect on the ship staying upright.

That's very helpful. Thanks.

[Jefgte]

Tac is right.
1.0 is the minimum for stability with no safety margin.
If you increase to 1.1 you increase the safety margin.

[The Rock Doctor]

Ships 1