Minesweeper

[ledeper]

Whale-class, Baltic-Confederation Minesweeper laid down 1911

Displacement:
   771 t light; 797 t standard; 820 t normal; 838 t full load

Dimensions: Length overall / water x beam x draught
   231,23 ft / 229,66 ft x 32,81 ft x 6,56 ft (normal load)
   70,48 m / 70,00 m x 10,00 m  x 2,00 m

Armament:
      2 - 4,00" / 102 mm guns in single mounts, 32,00lbs / 14,51kg shells, 1911 Model
     Quick firing guns in deck mounts
     on centreline ends, evenly spread
      2 - 3,46" / 88,0 mm guns in single mounts, 20,79lbs / 9,43kg shells, 1911 Model
     Breech loading guns in deck mounts
     on side, all amidships
   Weight of broadside 106 lbs / 48 kg
   Shells per gun, main battery: 150

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2,00" / 51 mm   149,28 ft / 45,50 m   6,87 ft / 2,09 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length
     Main belt does not fully cover magazines and engineering spaces

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1,00" / 25 mm   1,00" / 25 mm            -

   - Conning tower: 2,00" / 51 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 1 shaft, 2.915 ihp / 2.175 Kw = 18,00 kts
   Range 700nm at 10,00 kts
   Bunker at max displacement = 41 tons (100% coal)

Complement:
   76 - 99

Cost:
   £0,065 million / $0,261 million

Distribution of weights at normal displacement:
   Armament: 13 tons, 1,6 %
   Armour: 99 tons, 12,0 %
      - Belts: 89 tons, 10,8 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 6 tons, 0,8 %
      - Armour Deck: 0 tons, 0,0 %
      - Conning Tower: 4 tons, 0,5 %
   Machinery: 194 tons, 23,6 %
   Hull, fittings & equipment: 316 tons, 38,5 %
   Fuel, ammunition & stores: 49 tons, 6,0 %
   Miscellaneous weights: 150 tons, 18,3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1.122 lbs / 509 Kg = 35,1 x 4,0 " / 102 mm shells or 0,5 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 %): 67 %
         - Recoil effect (Restricted arc if above 1.00): 0,10
   Seaboat quality  (Average = 1.00): 1,34

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,580
   Length to Beam Ratio: 7,00 : 1
   'Natural speed' for length: 15,15 kts
   Power going to wave formation at top speed: 54 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      17,98 ft / 5,48 m
      - Forecastle (20 %):   10,60 ft / 3,23 m
      - Mid (50 %):      10,60 ft / 3,23 m
      - Quarterdeck (15 %):   10,60 ft / 3,23 m
      - Stern:      10,60 ft / 3,23 m
      - Average freeboard:   11,19 ft / 3,41 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 109,2 %
      - Above water (accommodation/working, high = better): 140,1 %
   Waterplane Area: 5.276 Square feet or 490 Square metres
   Displacement factor (Displacement / loading): 111 %
   Structure weight / hull surface area: 40 lbs/sq ft or 198 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,93
      - Longitudinal: 2,01
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Good seaboat, rides out heavy weather easily

[The Rock Doctor]

I don't think the armor belt really adds anything to the design, since the main threat is underwater explosions.  I'd suggest eliminating the belt, reducing the armament, and increasing the operating range with the weight saved.

[Borys]

Ahoj!
What Rock said, exactly.
Borys

[ledeper]

Whale-class, Baltic-Confederation Minesweeper laid down 1911

Displacement:
   616 t light; 635 t standard; 672 t normal; 702 t full load

Dimensions: Length overall / water x beam x draught
   231,23 ft / 229,66 ft x 32,81 ft x 6,56 ft (normal load)
   70,48 m / 70,00 m x 10,00 m  x 2,00 m

Armament:
      2 - 4,00" / 102 mm guns in single mounts, 32,00lbs / 14,51kg shells, 1911 Model
     Quick firing guns in deck mounts
     on centreline, all forward, 1 raised mount
   Weight of broadside 64 lbs / 29 kg
   Shells per gun, main battery: 150

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1,00" / 25 mm   1,00" / 25 mm            -

   - Conning tower: 2,00" / 51 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 1 shaft, 2.438 ihp / 1.818 Kw = 18,00 kts
   Range 1.500nm at 10,00 kts
   Bunker at max displacement = 68 tons (100% coal)

Complement:
   65 - 85

Cost:
   £0,051 million / $0,204 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 1,2 %
   Armour: 9 tons, 1,4 %
      - Belts: 0 tons, 0,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 6 tons, 0,9 %
      - Armour Deck: 0 tons, 0,0 %
      - Conning Tower: 3 tons, 0,5 %
   Machinery: 162 tons, 24,1 %
   Hull, fittings & equipment: 287 tons, 42,6 %
   Fuel, ammunition & stores: 56 tons, 8,4 %
   Miscellaneous weights: 150 tons, 22,3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     913 lbs / 414 Kg = 28,5 x 4,0 " / 102 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,18
   Metacentric height 1,3 ft / 0,4 m
   Roll period: 12,2 seconds
   Steadiness   - As gun platform (Average = 50 %): 74 %
         - Recoil effect (Restricted arc if above 1.00): 0,08
   Seaboat quality  (Average = 1.00): 1,49

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,476
   Length to Beam Ratio: 7,00 : 1
   'Natural speed' for length: 15,15 kts
   Power going to wave formation at top speed: 51 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      17,98 ft / 5,48 m
      - Forecastle (20 %):   10,60 ft / 3,23 m
      - Mid (50 %):      10,60 ft / 3,23 m
      - Quarterdeck (15 %):   10,60 ft / 3,23 m
      - Stern:      10,60 ft / 3,23 m
      - Average freeboard:   11,19 ft / 3,41 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 111,7 %
      - Above water (accommodation/working, high = better): 146,0 %
   Waterplane Area: 4.703 Square feet or 437 Square metres
   Displacement factor (Displacement / loading): 123 %
   Structure weight / hull surface area: 40 lbs/sq ft or 195 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,92
      - Longitudinal: 2,18
      - 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

[Borys]

Make the range 2500 - even for Baltic work 1500 is not enough.
Borys