Casemates Gunboat

[Jefgte]

Here is a study about a Gunboat with all guns in casemates, (ala Monitor)
Perhaps interresting to protect BB from Torpedoboats


3000T , Peru Squadron CasematesGunboat laid down 1914

Displacement:
   3 000 t light; 3 135 t standard; 3 542 t normal; 3 868 t full load

Dimensions: Length overall / water x beam x draught
   387.14 ft / 387.14 ft x 49.21 ft x 12.40 ft (normal load)
   118.00 m / 118.00 m x 15.00 m  x 3.78 m

Armament:
      2 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1914 Model
     Breech loading guns in casemate mounts
     on centreline ends, evenly spread
      10 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1914 Model
     Breech loading guns in casemate mounts
     on side, evenly spread
      4 - 2.00" / 50.8 mm guns in single mounts, 4.00lbs / 1.81kg shells, 1914 Model
     Breech loading guns in deck mounts
     on side, evenly spread, all raised mounts
      4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1914 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 649 lbs / 294 kg
   Shells per gun, main battery: 150
   4 - 18.0" / 457 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.15" / 80 mm   262.47 ft / 80.00 m   8.01 ft / 2.44 m
   Ends:   1.57" / 40 mm     98.43 ft / 30.00 m   8.01 ft / 2.44 m
     26.25 ft / 8.00 m Unarmoured ends
     Main Belt covers 104 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.57" / 40 mm         -               -
   2nd:   1.57" / 40 mm         -               -
   3rd:   0.79" / 20 mm         -               -
   4th:   0.50" / 13 mm         -               -

   - Armour deck: 1.18" / 30 mm, Conning tower: 3.94" / 100 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 21 000 shp / 15 666 Kw = 25.12 kts
   Range 7 000nm at 12.00 kts
   Bunker at max displacement = 734 tons

Complement:
   229 - 298

Cost:
   £0.364 million / $1.458 million

Distribution of weights at normal displacement:
   Armament: 81 tons, 2.3 %
   Armour: 682 tons, 19.3 %
      - Belts: 326 tons, 9.2 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 53 tons, 1.5 %
      - Armour Deck: 284 tons, 8.0 %
      - Conning Tower: 20 tons, 0.6 %
   Machinery: 809 tons, 22.8 %
   Hull, fittings & equipment: 1 318 tons, 37.2 %
   Fuel, ammunition & stores: 542 tons, 15.3 %
   Miscellaneous weights: 110 tons, 3.1 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     4 887 lbs / 2 217 Kg = 92.7 x 4.7 " / 120 mm shells or 1.0 torpedoes
   Stability (Unstable if below 1.00): 1.30
   Metacentric height 2.8 ft / 0.8 m
   Roll period: 12.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.15
   Seaboat quality  (Average = 1.00): 1.18

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.525
   Length to Beam Ratio: 7.87 : 1
   'Natural speed' for length: 19.68 kts
   Power going to wave formation at top speed: 57 %
   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:      24.28 ft / 7.40 m
      - Forecastle (18 %):   17.72 ft / 5.40 m
      - Mid (50 %):      14.44 ft / 4.40 m
      - Quarterdeck (16 %):   14.44 ft / 4.40 m
      - Stern:      14.44 ft / 4.40 m
      - Average freeboard:   16.02 ft / 4.88 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 103.7 %
      - Above water (accommodation/working, high = better): 164.6 %
   Waterplane Area: 12 989 Square feet or 1 207 Square metres
   Displacement factor (Displacement / loading): 116 %
   Structure weight / hull surface area: 68 lbs/sq ft or 331 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.64
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform

[Sachmle]

To narrow field of fire. To east to find a spot w/ limited arcs of fire.

[P3D]

You mean CSS Virginia.

[Sachmle]

You mean CSS Virginia.

Well, that too. And thank you for not calling her Merrimack.  ;)

[Jefgte]

yes... Virginia


;)

[Borys]

There is an even better setting then "casemattes" avaliable in SS. It is "broadside".
Borys

[Sachmle]

Broadside? What, is someone planning on building Gloire or Warrior 20yrs late?

[Jefgte]

...to protect BB from Torpedoboats


Jef  ;)

[Borys]

We are going retro!
Borys

[khymerion]

Nothing completely wrong with going retro...  if its done right.

Just because 'reality' moved one direction due to everyone going with it IRL doesn't mean that it has to follow the exact same course in an alternate world...

[P3D]

Casemate gun armor cover only the area around the gun port/casemate turret itself. If you want to cover the area between the guns, you need to add upper belt.
In this particular case, 53 tons of casemate armor is 4.5 tons each gun, say 10,000lbs, or 160sqft at 60ls/sqft (1.5" plate) - 20ft long section  by 8' deck height. And the guns are vulnerable to splinters from above and below, and in between.

[Jefgte]

This one, is able to protect a BB from a squadron DD attack

I imagine Protector with 4 rangefinders to engage 4 DDs
Each rangefinder conduct 4x120mmQF


Protector - 24.8kts, Peru Casemate gun boat laid down 1915

Displacement:
   3 600 t light; 3 759 t standard; 4 189 t normal; 4 532 t full load

Dimensions: Length overall / water x beam x draught
   390.42 ft / 390.42 ft x 45.93 ft x 14.73 ft (normal load)
   119.00 m / 119.00 m x 14.00 m  x 4.49 m

Armament:
      16 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1915 Model
     Quick firing guns in casemate mounts
     on side, evenly spread
      2 - 2.00" / 50.8 mm guns in single mounts, 4.00lbs / 1.81kg shells, 1915 Model
     Quick firing guns in deck mounts
     on centreline, all amidships, all raised mounts - superfiring
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1915 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 852 lbs / 386 kg
   Shells per gun, main battery: 160
   6 - 21.0" / 533 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.15" / 80 mm   249.34 ft / 76.00 m   8.01 ft / 2.44 m
   Ends:   1.18" / 30 mm   118.11 ft / 36.00 m   8.01 ft / 2.44 m
     22.97 ft / 7.00 m Unarmoured ends
   Upper:   3.15" / 80 mm   249.34 ft / 76.00 m   12.01 ft / 3.66 m
     Main Belt covers 98 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   3.15" / 80 mm         -               -
   2nd:   0.79" / 20 mm         -               -
   3rd:   0.50" / 13 mm         -               -

   - Armour deck: 1.18" / 30 mm, Conning tower: 3.15" / 80 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 22 000 shp / 16 412 Kw = 24.82 kts
   Range 7 000nm at 12.00 kts
   Bunker at max displacement = 773 tons

Complement:
   259 - 338

Cost:
   £0.483 million / $1.932 million

Distribution of weights at normal displacement:
   Armament: 106 tons, 2.5 %
   Armour: 1 136 tons, 27.1 %
      - Belts: 709 tons, 16.9 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 134 tons, 3.2 %
      - Armour Deck: 275 tons, 6.6 %
      - Conning Tower: 18 tons, 0.4 %
   Machinery: 833 tons, 19.9 %
   Hull, fittings & equipment: 1 344 tons, 32.1 %
   Fuel, ammunition & stores: 589 tons, 14.1 %
   Miscellaneous weights: 180 tons, 4.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5 683 lbs / 2 578 Kg = 107.8 x 4.7 " / 120 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.18
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 13.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.24
   Seaboat quality  (Average = 1.00): 1.17

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.555
   Length to Beam Ratio: 8.50 : 1
   'Natural speed' for length: 19.76 kts
   Power going to wave formation at top speed: 57 %
   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:      20.34 ft / 6.20 m
      - Forecastle (18 %):   17.06 ft / 5.20 m
      - Mid (40 %):      13.78 ft / 4.20 m
      - Quarterdeck (18 %):   13.78 ft / 4.20 m
      - Stern:      13.78 ft / 4.20 m
      - Average freeboard:   14.95 ft / 4.56 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 89.4 %
      - Above water (accommodation/working, high = better): 102.1 %
   Waterplane Area: 12 574 Square feet or 1 168 Square metres
   Displacement factor (Displacement / loading): 109 %
   Structure weight / hull surface area: 68 lbs/sq ft or 334 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.53
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform

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

Protector-27kts, Peru Casemate gun boat laid down 1915

Displacement:
   4 600 t light; 4 781 t standard; 5 279 t normal; 5 677 t full load

Dimensions: Length overall / water x beam x draught
   439.63 ft / 439.63 ft x 45.93 ft x 15.91 ft (normal load)
   134.00 m / 134.00 m x 14.00 m  x 4.85 m

Armament:
      16 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1915 Model
     Quick firing guns in casemate mounts
     on side, evenly spread
      2 - 2.00" / 50.8 mm guns in single mounts, 4.00lbs / 1.81kg shells, 1915 Model
     Quick firing guns in deck mounts
     on centreline, all amidships, all raised mounts - superfiring
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1915 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 852 lbs / 386 kg
   Shells per gun, main battery: 160
   6 - 21.0" / 533 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.15" / 80 mm   288.71 ft / 88.00 m   8.01 ft / 2.44 m
   Ends:   1.18" / 30 mm   118.11 ft / 36.00 m   8.01 ft / 2.44 m
     32.81 ft / 10.00 m Unarmoured ends
   Upper:   3.15" / 80 mm   288.71 ft / 88.00 m   13.65 ft / 4.16 m
     Main Belt covers 101 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   3.15" / 80 mm         -               -
   2nd:   0.79" / 20 mm         -               -
   3rd:   0.50" / 13 mm         -               -

   - Armour deck: 1.18" / 30 mm, Conning tower: 3.15" / 80 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 34 000 shp / 25 364 Kw = 27.06 kts
   Range 7 000nm at 12.00 kts
   Bunker at max displacement = 896 tons

Complement:
   309 - 402

Cost:
   £0.626 million / $2.506 million

Distribution of weights at normal displacement:
   Armament: 106 tons, 2.0 %
   Armour: 1 335 tons, 25.3 %
      - Belts: 865 tons, 16.4 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 134 tons, 2.5 %
      - Armour Deck: 315 tons, 6.0 %
      - Conning Tower: 21 tons, 0.4 %
   Machinery: 1 288 tons, 24.4 %
   Hull, fittings & equipment: 1 670 tons, 31.6 %
   Fuel, ammunition & stores: 679 tons, 12.9 %
   Miscellaneous weights: 200 tons, 3.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     6 376 lbs / 2 892 Kg = 120.9 x 4.7 " / 120 mm shells or 1.1 torpedoes
   Stability (Unstable if below 1.00): 1.16
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 13.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.25
   Seaboat quality  (Average = 1.00): 1.18

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.575
   Length to Beam Ratio: 9.57 : 1
   'Natural speed' for length: 20.97 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 59
   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:      21.65 ft / 6.60 m
      - Forecastle (18 %):   18.37 ft / 5.60 m
      - Mid (40 %):      15.09 ft / 4.60 m
      - Quarterdeck (18 %):   15.09 ft / 4.60 m
      - Stern:      15.09 ft / 4.60 m
      - Average freeboard:   16.26 ft / 4.96 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 99.3 %
      - Above water (accommodation/working, high = better): 110.8 %
   Waterplane Area: 14 427 Square feet or 1 340 Square metres
   Displacement factor (Displacement / loading): 106 %
   Structure weight / hull surface area: 70 lbs/sq ft or 344 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.50
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform