Icebreakers

[The Rock Doctor]

These are needed in parts of the Baltic, at least.

Some but not all icebreakers have a forward-directed shaft and propeller.

All icebreakers have a 25mm belt, equally above and below the waterline, for the full extent of the ship.  As a result, they are paid for at full cost like a warship.

A portion of the miscellaneous weight allowance goes to towing rig, salvage pumps, and pumps necessary to adjust the trim of the ship.  I'll break these out specifically later.  All would have long-range wireless at this point.

[The Rock Doctor]

Aland Class Icebreaker

Aland, I-1, laid down 1889, preserved as museum ship 1922

Enter ship name, Enter country Enter ship type laid down 1889

Displacement:
   1,179 t light; 1,209 t standard; 1,494 t normal; 1,723 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (165.50 ft / 157.48 ft) x 36.09 ft x (16.73 / 18.75 ft)
   (50.44 m / 48.00 m) x 11.00 m  x (5.10 / 5.71 m)

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm   102.36 ft / 31.20 m   7.22 ft / 2.20 m
   Ends:   0.98" / 25 mm     55.09 ft / 16.79 m   7.22 ft / 2.20 m
     Main Belt covers 100 % of normal length

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 3 shafts, 1,073 ihp / 800 Kw = 12.24 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 514 tons (100% coal)

Complement:
   119 - 156

Cost:
   £0.070 million / $0.282 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Armour: 48 tons, 3.2 %
      - Belts: 48 tons, 3.2 %
   Machinery: 208 tons, 13.9 %
   Hull, fittings & equipment: 773 tons, 51.7 %
   Fuel, ammunition & stores: 315 tons, 21.1 %
   Miscellaneous weights: 150 tons, 10.0 %
      - On freeboard deck: 150 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,080 lbs / 1,397 Kg = 29.0 x 6 " / 152 mm shells or 1.6 torpedoes
   Stability (Unstable if below 1.00): 1.45
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 10.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.50

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a round stern
   Block coefficient (normal/deep): 0.550 / 0.566
   Length to Beam Ratio: 4.36 : 1
   'Natural speed' for length: 12.55 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 47
   Bow angle (Positive = bow angles forward): 30.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  8.20 ft / 2.50 m,  9.84 ft / 3.00 m
      - Forward deck:   30.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  9.84 ft / 3.00 m
      - Average freeboard:      8.52 ft / 2.60 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 46.6 %
      - Above water (accommodation/working, high = better): 52.1 %
   Waterplane Area: 3,966 Square feet or 368 Square metres
   Displacement factor (Displacement / loading): 243 %
   Structure weight / hull surface area: 121 lbs/sq ft or 593 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 2.15
      - Longitudinal: 9.77
      - Overall: 2.50
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, rides out heavy weather easily

[The Rock Doctor]

Bornholm Class Icebreaker

Just ignore the main belt warning; the end belts are just as big.

There are two shafts - 1,500 kw aft, and 1,035 kw facing forward.  Actual top speed is more like 13 knots.

Bornholm, I-2, laid down 1897, scrapped 1922

Enter ship name, Enter country Enter ship type laid down 1897

Displacement:
   1,535 t light; 1,572 t standard; 1,835 t normal; 2,046 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (202.28 ft / 190.29 ft) x 41.99 ft x (16.08 / 17.46 ft)
   (61.66 m / 58.00 m) x 12.80 m  x (4.90 / 5.32 m)

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm   123.69 ft / 37.70 m   7.78 ft / 2.37 m
   Ends:   0.98" / 25 mm     66.57 ft / 20.29 m   7.78 ft / 2.37 m
     Main Belt covers 100 % of normal length
     Main belt does not fully cover magazines and engineering spaces

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 2 shafts, 3,398 ihp / 2,535 Kw = 16.22 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 474 tons (100% coal)

Complement:
   139 - 182

Cost:
   £0.140 million / $0.561 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Armour: 62 tons, 3.4 %
      - Belts: 62 tons, 3.4 %
   Machinery: 618 tons, 33.7 %
   Hull, fittings & equipment: 555 tons, 30.2 %
   Fuel, ammunition & stores: 300 tons, 16.4 %
   Miscellaneous weights: 300 tons, 16.3 %
      - On freeboard deck: 300 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,932 lbs / 876 Kg = 17.9 x 6 " / 152 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.47
   Metacentric height 2.6 ft / 0.8 m
   Roll period: 10.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.56

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a round stern
   Block coefficient (normal/deep): 0.500 / 0.513
   Length to Beam Ratio: 4.53 : 1
   'Natural speed' for length: 13.79 kts
   Power going to wave formation at top speed: 61 %
   Trim (Max stability = 0, Max steadiness = 100): 45
   Bow angle (Positive = bow angles forward): 30.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  15.09 ft / 4.60 m,  13.12 ft / 4.00 m
      - Forward deck:   30.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Aft deck:   35.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  15.09 ft / 4.60 m
      - Average freeboard:      13.43 ft / 4.09 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 109.6 %
      - Above water (accommodation/working, high = better): 95.7 %
   Waterplane Area: 5,324 Square feet or 495 Square metres
   Displacement factor (Displacement / loading): 115 %
   Structure weight / hull surface area: 63 lbs/sq ft or 309 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.03
      - Longitudinal: 5.82
      - Overall: 1.23
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, rides out heavy weather easily

[The Rock Doctor]

Sjalland Class Icebreaker

Sjalland, I-3, laid down 1899, scrapped 1930
Fyn, I-4, laid down 1900, scrapped 1930

Enter ship name, Enter country Enter ship type laid down 1899

Displacement:
   780 t light; 800 t standard; 987 t normal; 1,137 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (148.11 ft / 137.80 ft) x 33.96 ft x (14.76 / 16.45 ft)
   (45.15 m / 42.00 m) x 10.35 m  x (4.50 / 5.01 m)

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm     89.57 ft / 27.30 m   6.99 ft / 2.13 m
   Ends:   0.98" / 25 mm     48.20 ft / 14.69 m   6.99 ft / 2.13 m
     Main Belt covers 100 % of normal length

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 2 shafts, 1,341 ihp / 1,000 Kw = 13.65 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 337 tons (100% coal)

Complement:
   87 - 114

Cost:
   £0.061 million / $0.243 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Armour: 41 tons, 4.2 %
      - Belts: 41 tons, 4.2 %
   Machinery: 239 tons, 24.3 %
   Hull, fittings & equipment: 299 tons, 30.3 %
   Fuel, ammunition & stores: 207 tons, 21.0 %
   Miscellaneous weights: 200 tons, 20.3 %
      - On freeboard deck: 200 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,595 lbs / 723 Kg = 14.8 x 6 " / 152 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.39
   Metacentric height 1.8 ft / 0.5 m
   Roll period: 10.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 2.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a round stern
   Block coefficient (normal/deep): 0.500 / 0.517
   Length to Beam Ratio: 4.06 : 1
   'Natural speed' for length: 11.74 kts
   Power going to wave formation at top speed: 62 %
   Trim (Max stability = 0, Max steadiness = 100): 35
   Bow angle (Positive = bow angles forward): 25.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  15.09 ft / 4.60 m,  13.12 ft / 4.00 m
      - Forward deck:   30.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Aft deck:   35.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  15.09 ft / 4.60 m
      - Average freeboard:      13.43 ft / 4.09 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 79.5 %
      - Above water (accommodation/working, high = better): 89.6 %
   Waterplane Area: 3,118 Square feet or 290 Square metres
   Displacement factor (Displacement / loading): 137 %
   Structure weight / hull surface area: 50 lbs/sq ft or 246 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 12.21
      - Overall: 1.24
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, rides out heavy weather easily

[The Rock Doctor]

Oland Class Icebreaker

Aft-facing shaft has 1,800 kw, the forward-facing shaft has 1,200 kw.  Again, the end belt provides the same coverage as the main belt, so that warning can be ignored.

Oland, I-5, scrapped 1932
Gotland, I-6

Enter ship name, Enter country Enter ship type laid down 1904

Displacement:
   1,563 t light; 1,600 t standard; 1,835 t normal; 2,024 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (202.28 ft / 190.29 ft) x 41.99 ft x (16.08 / 17.32 ft)
   (61.66 m / 58.00 m) x 12.80 m  x (4.90 / 5.28 m)

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm   123.69 ft / 37.70 m   7.78 ft / 2.37 m
   Ends:   0.98" / 25 mm     66.57 ft / 20.29 m   7.78 ft / 2.37 m
     Main Belt covers 100 % of normal length
     Main belt does not fully cover magazines and engineering spaces

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 4,021 ihp / 3,000 Kw = 16.89 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 424 tons (100% coal)

Complement:
   139 - 182

Cost:
   £0.137 million / $0.550 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Armour: 62 tons, 3.4 %
      - Belts: 62 tons, 3.4 %
   Machinery: 591 tons, 32.2 %
   Hull, fittings & equipment: 509 tons, 27.8 %
   Fuel, ammunition & stores: 272 tons, 14.8 %
   Miscellaneous weights: 400 tons, 21.8 %
      - On freeboard deck: 400 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2,001 lbs / 908 Kg = 18.5 x 6 " / 152 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.32
   Metacentric height 2.2 ft / 0.7 m
   Roll period: 11.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.39

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a round stern
   Block coefficient (normal/deep): 0.500 / 0.512
   Length to Beam Ratio: 4.53 : 1
   'Natural speed' for length: 13.79 kts
   Power going to wave formation at top speed: 63 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 30.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  15.09 ft / 4.60 m,  13.12 ft / 4.00 m
      - Forward deck:   30.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Aft deck:   35.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  15.09 ft / 4.60 m
      - Average freeboard:      13.43 ft / 4.09 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 105.0 %
      - Above water (accommodation/working, high = better): 95.7 %
   Waterplane Area: 5,324 Square feet or 495 Square metres
   Displacement factor (Displacement / loading): 112 %
   Structure weight / hull surface area: 58 lbs/sq ft or 284 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.97
      - Longitudinal: 5.50
      - Overall: 1.16
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[The Rock Doctor]

Helgoland Class Icebreaker

The Union's icebreaker fleet is getting a little long in the tooth, so a new class will be built to replace the oldest units.

Like the rest of the icebreaker fleet, the Helgoland and sisters will be operated by the Coast Guard.  There is a light armament for inspection and law enforcement duties, some towing capability, and a working space that can accommodate wreck survivors.

I have modelled light belts to protect against single-year ice, and added a fair bit of below-water miscellaneous weight to represent hull bracing, extra subdivision, and all that jazz.

That said, the class will be built to mercantile standards.

Helgoland, laid down 1921
Falster, laid down 1922
Zealand, laid down 1922
Funen, laid down 1923

Enter ship name, Enter country Enter ship type laid down 1921

Displacement:
   1,785 t light; 1,825 t standard; 1,983 t normal; 2,110 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (204.30 ft / 196.85 ft) x 39.37 ft x (13.78 / 14.52 ft)
   (62.27 m / 60.00 m) x 12.00 m  x (4.20 / 4.43 m)

Armament:
      2 - 1.97" / 50.0 mm 45.0 cal guns - 3.85lbs / 1.74kg shells, 150 per gun
     Quick firing guns in deck mounts, 1921 Model
     2 x Single mounts on centreline, evenly spread
      2 raised mounts
      2 - 0.39" / 10.0 mm 45.0 cal guns - 0.03lbs / 0.01kg shells, 4,000 per gun
     Machine guns in deck mounts, 1921 Model
     2 x Single mounts on sides, forward deck aft
      2 raised mounts
      Weight of broadside 8 lbs / 4 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.59" / 15 mm   144.36 ft / 44.00 m   5.91 ft / 1.80 m
   Ends:   0.98" / 25 mm     52.49 ft / 16.00 m   5.91 ft / 1.80 m
     Main Belt covers 113 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.12" / 3 mm            -

Machinery:
   Coal and oil fired boilers, complex reciprocating steam engines,
   Direct drive, 3 shafts, 6,703 ihp / 5,000 Kw = 18.63 kts
   Range 4,000nm at 10.00 kts
   Bunker at max displacement = 284 tons (90% coal)

Complement:
   148 - 193

Cost:
   £0.312 million / $1.249 million

Distribution of weights at normal displacement:
   Armament: 2 tons, 0.1 %
      - Guns: 2 tons, 0.1 %
   Armour: 36 tons, 1.8 %
      - Belts: 34 tons, 1.7 %
      - Armament: 2 tons, 0.1 %
   Machinery: 427 tons, 21.5 %
   Hull, fittings & equipment: 695 tons, 35.1 %
   Fuel, ammunition & stores: 198 tons, 10.0 %
   Miscellaneous weights: 625 tons, 31.5 %
      - Hull below water: 200 tons
      - Hull above water: 100 tons
      - On freeboard deck: 300 tons
      - Above deck: 25 tons

Fittings:
-25 t:  L/R wireless (AD)
-100 t:  Emergency accommodations (FD)
-150 t:  Towing rig (FD)
-150 t:  Weight reserve (FD/AW)
-200 t:  Hull reinforcement and pumps (BW)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,008 lbs / 1,364 Kg = 788.6 x 2.0 " / 50 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.19
   Metacentric height 1.7 ft / 0.5 m
   Roll period: 12.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 78 %
         - Recoil effect (Restricted arc if above 1.00): 0.01
   Seaboat quality  (Average = 1.00): 1.44

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.656
   Length to Beam Ratio: 5.00 : 1
   'Natural speed' for length: 14.03 kts
   Power going to wave formation at top speed: 69 %
   Trim (Max stability = 0, Max steadiness = 100): 54
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  23.62 ft / 7.20 m,  19.69 ft / 6.00 m
      - Forward deck:   40.00 %,  19.69 ft / 6.00 m,  19.69 ft / 6.00 m
      - Aft deck:   25.00 %,  11.81 ft / 3.60 m,  11.81 ft / 3.60 m
      - Quarter deck:   15.00 %,  11.81 ft / 3.60 m,  11.81 ft / 3.60 m
      - Average freeboard:      16.85 ft / 5.14 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 87.1 %
      - Above water (accommodation/working, high = better): 127.3 %
   Waterplane Area: 5,937 Square feet or 552 Square metres
   Displacement factor (Displacement / loading): 131 %
   Structure weight / hull surface area: 65 lbs/sq ft or 316 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.08
      - Longitudinal: 9.49
      - Overall: 1.34
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

12.61 kts astern from single forward-facing 1,000 kw shaft
18.63 kts ahead from two 2,500 kw shafts

[The Rock Doctor]

RL-1 Class River Icebreaker

The Union's northeastern frontier includes extensive waterways on rivers such as the Neva and lakes such as Ladoga.  These freeze over in winter, which naturally brings waterborne activity to a stop for months each year.

However, there might be circumstances where one wants to enable river traffic early (or later) than the shipping season would normally allow.  This might include freeing ships stuck in an early freeze or, in the event of a war with the Northern Kingdom or Golden Horde, eliminating the ability of ground forces to cross frozen rivers.

So the Union's going to build a few small armed/armored icebreakers for service in the northeast.  Even if not dealing in militarily necessary activities, they can support civilian operations in the Baltic and inland northeast.

The armament is defensive, and mainly about fending off airplanes, infantry or cavalry.

The bow and stern are armored against heavy ice; the rest of the hull is strengthened against ice and small-arms fire, with the upper belt representing a proper box around the machinery and ammunition stowage.

RL-1, laid down 1923
RL-2, laid down 1923
RL-3, laid down 1924
RL-4, laid down 1924

Enter ship name, Enter country Enter ship type laid down 1923

Displacement:
   204 t light; 211 t standard; 215 t normal; 218 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (149.82 ft / 144.36 ft) x 26.25 ft x (3.61 / 3.65 ft)
   (45.66 m / 44.00 m) x 8.00 m  x (1.10 / 1.11 m)

Armament:
      1 - 1.97" / 50.0 mm 45.0 cal gun - 3.85lbs / 1.74kg shells, 250 per gun
     Quick firing gun in deck mount, 1923 Model
     1 x Single mount on centreline, forward deck centre
      1 - 1.97" / 50.0 mm 45.0 cal gun - 3.86lbs / 1.75kg shells, 250 per gun
     Anti-air gun in deck mount, 1923 Model
     1 x Single mount on centreline, aft deck centre
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.11lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1923 Model
     2 x Single mounts on sides amidships
      2 raised mounts
     2 x Single mounts on centreline, evenly spread
      2 raised mounts
      Weight of broadside 8 lbs / 4 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.79" / 20 mm     93.83 ft / 28.60 m   3.94 ft / 1.20 m
   Ends:   1.97" / 50 mm     50.49 ft / 15.39 m   5.91 ft / 1.80 m
   Upper:   0.79" / 20 mm     32.81 ft / 10.00 m   3.94 ft / 1.20 m
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.57" / 40 mm   0.79" / 20 mm            -
   3rd:   0.98" / 25 mm   0.79" / 20 mm            -
   4th:   0.39" / 10 mm         -               -

   - Box over machinery & magazines:
   0.79" / 20 mm
   Forecastle: 0.00" / 0 mm  Quarter deck: 0.79" / 20 mm

   - Conning towers: Forward 0.79" / 20 mm, Aft 0.00" / 0 mm

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 470 shp / 350 Kw = 13.21 kts
   Range 500nm at 10.00 kts
   Bunker at max displacement = 7 tons

Complement:
   27 - 36

Cost:
   £0.029 million / $0.116 million

Distribution of weights at normal displacement:
   Armament: 2 tons, 1.0 %
      - Guns: 2 tons, 1.0 %
   Armour: 78 tons, 36.1 %
      - Belts: 41 tons, 19.2 %
      - Armament: 12 tons, 5.5 %
      - Armour Deck: 24 tons, 11.1 %
      - Conning Tower: 1 tons, 0.3 %
   Machinery: 16 tons, 7.3 %
   Hull, fittings & equipment: 93 tons, 43.3 %
   Fuel, ammunition & stores: 10 tons, 4.9 %
   Miscellaneous weights: 16 tons, 7.4 %
      - Hull below water: 5 tons
      - On freeboard deck: 7 tons
      - Above deck: 4 tons

Fittings:
-4 t:  Fire control, spotlights and stuff (AD)
-7 t:  Weight reserve and/or deck cargo (FD)
-5 t:  Diesel engines (BW)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,291 lbs / 585 Kg = 338.4 x 2.0 " / 50 mm shells or 1.7 torpedoes
   Stability (Unstable if below 1.00): 1.36
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 10.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.02
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.550 / 0.552
   Length to Beam Ratio: 5.50 : 1
   'Natural speed' for length: 12.01 kts
   Power going to wave formation at top speed: 49 %
   Trim (Max stability = 0, Max steadiness = 100): 70
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 1.64 ft / 0.50 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   25.00 %,  10.50 ft / 3.20 m,  7.87 ft / 2.40 m
      - Forward deck:   25.00 %,  7.87 ft / 2.40 m,  5.91 ft / 1.80 m
      - Aft deck:   35.00 %,  5.91 ft / 1.80 m,  5.91 ft / 1.80 m
      - Quarter deck:   15.00 %,  5.91 ft / 1.80 m,  5.91 ft / 1.80 m
      - Average freeboard:      6.91 ft / 2.11 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 31.3 %
      - Above water (accommodation/working, high = better): 117.8 %
   Waterplane Area: 2,644 Square feet or 246 Square metres
   Displacement factor (Displacement / loading): 164 %
   Structure weight / hull surface area: 28 lbs/sq ft or 136 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.50
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

[The Rock Doctor]

Falster Class Icebreaker

A small icebreaker that would replace the 1899 vintage Sjalland class, because it's about time.

The hull dimensions are quite chonky but appear to reflect historical practice, even the L:B ratio.

The armament is minimal and reflects the expectation that she'll never leave the Baltic, which is a Union Lake in theory.  Some fittings allow for limited rescue and salvage work if somebody else is in trouble.

The hull protection pushes this out of mercantile territory and into milspec but what can you do.

The machinery is diesel-electric, which historically became preferred as WW2 came around.  Should mean it's responsive in icy waters.  There are the two main props aft, which allows for 15.4 knots on 1,500 kw.  The forward prop is 500 kw for 11.8 knots, but it turns out the primary purpose of that engine is not ship propulsion.  Rather, it's supposed to pull fresh-broken ice from under the bow and send it aft, and in doing so create a pull that weakens the unbroken ice directly ahead of what broke.  Or this is what I read, anyway.

Places where I'd normally sketch...uh...railings...are instead solid gunwales, since people want to move around and man their stations without getting soaked by cold seawater splooshing around.

Falster, laid down 1929
Hiiumaa, laid down 1929

Enter ship name, Enter country Enter ship type laid down 1929

Displacement:
   748 t light; 767 t standard; 807 t normal; 839 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (139.16 ft / 131.23 ft) x 32.81 ft x (13.12 / 13.51 ft)
   (42.42 m / 40.00 m) x 10.00 m  x (4.00 / 4.12 m)

Armament:
      1 - 2.95" / 75.0 mm 45.0 cal gun - 12.98lbs / 5.89kg shells, 250 per gun
     Quick firing gun in deck mount, 1929 Model
     1 x Single mount on centreline, forward deck centre
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 5,000 per gun
     Machine guns in deck mounts, 1929 Model
     2 x Single mounts on sides, forward deck aft
      2 raised mounts
     1 x Twin mount on centreline, aft deck centre
      1 raised mount
      Weight of broadside 13 lbs / 6 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.79" / 20 mm     85.30 ft / 26.00 m   5.91 ft / 1.80 m
   Ends:   1.57" / 40 mm     45.90 ft / 13.99 m   5.91 ft / 1.80 m
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.59" / 15 mm            -
   3rd:   0.59" / 15 mm         -               -

Machinery:
   Diesel Internal combustion generators,
   Electric motors, 3 shafts, 2,681 shp / 2,000 Kw = 16.42 kts
   Range 3,000nm at 10.00 kts
   Bunker at max displacement = 72 tons

Complement:
   75 - 98

Cost:
   £0.154 million / $0.617 million

Distribution of weights at normal displacement:
   Armament: 3 tons, 0.4 %
   Armour: 41 tons, 5.0 %
      - Belts: 34 tons, 4.3 %
      - Armament: 6 tons, 0.8 %
   Machinery: 82 tons, 10.2 %
   Hull, fittings & equipment: 262 tons, 32.5 %
   Fuel, ammunition & stores: 59 tons, 7.3 %
   Miscellaneous weights: 360 tons, 44.6 %
      - Hull below water: 110 tons
      - Hull above water: 100 tons
      - On freeboard deck: 50 tons
      - Above deck: 100 tons

Fittings:
-45 t:  D-E machinery (BW)
-20 t:  Hull bracing (BW)
-45 t:  40 t water ballast and pumps to move it between tanks (BW)
-100 t:  Crew amenities and extra accommodation space for survivors (AW)
-50 t:  Towing rig (FD)
-25 t:  L/R wireless (AD)
-10 t:  Nightfighting doodads (AD)
-25 t:  Huelsmeyer Device (AD)
-40 t:  Weight reserve (AD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,597 lbs / 724 Kg = 124.1 x 3.0 " / 75 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.14
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 12.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.02
   Seaboat quality  (Average = 1.00): 1.30

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.505
   Length to Beam Ratio: 4.00 : 1
   'Natural speed' for length: 11.46 kts
   Power going to wave formation at top speed: 72 %
   Trim (Max stability = 0, Max steadiness = 100): 46
   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 %,  17.06 ft / 5.20 m,  14.11 ft / 4.30 m
      - Forward deck:   30.00 %,  14.11 ft / 4.30 m,  13.12 ft / 4.00 m
      - Aft deck:   35.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Average freeboard:      13.70 ft / 4.18 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 63.6 %
      - Above water (accommodation/working, high = better): 97.3 %
   Waterplane Area: 2,869 Square feet or 267 Square metres
   Displacement factor (Displacement / loading): 141 %
   Structure weight / hull surface area: 47 lbs/sq ft or 232 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.92
      - Longitudinal: 13.93
      - Overall: 1.21
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is adequate
   Good seaboat, rides out heavy weather easily

45 BW for machinery + 20 structural reinforcement + 45 ballast and pumps
11.8 knots on forward 500 kw shaft, 15.4 knots on two main shafts (1500kw)

[The Rock Doctor]

Saaremaa Class Icebreaker


A relatively heavy icebreaker.

As with preceding classes, it has a minimal armament and a fairly extensive search-and-rescue capability.  There is no ASW capability because the Baltic is supposed to be a Union pond and also because scraping against ice isn't healthy for hydrophones.  Outside the Baltic you just shouldn't be trying to torpedo my icebreaker.

In winter, it would usually be a bit of overkill for typical Baltic conditions, but it would have the power to overcome atypical conditions from a cold winter and thicker-than-usual single-year ice.  The protective scheme notionally includes extensive underwater protection and heavier waterline belts than in preceding classes.  Stability is also high, facilitating movement of ballast water and tolerance of topside ice build-up.  Freeboard and seakeeping should be up to all but the worst sea conditions.

In summer, it'd be available to do research functions in the southern hemisphere, perhaps up to the Antarctic coast.  This explains the large fuel capacity and the relatively high-speed (allowing 15 kts at half power when cruising).  It also explains the presence of a plane, catapult, and hanger:  For a range of scouting, surveying and search/rescue functions.  In this scenario, the extra accommodation for search-and-rescue is available for scientific and extra support personnel, there's a fair bit of stores and cargo capacity, and there are some extra facilities to keep everybody safe, warm, and non-mutinous on extended sorties on the open ocean.

As with previous classes, the sim overstates the speed.  Two props totaling 5,000 kw provide a top speed of 18 knots; half-power allows cruising at 15 knots.  The third shaft is forward and provides 1,000 kw for breaking and clearing ice from the bow.


Saaremaa, laid down 1930

Enter ship name, Enter country Enter ship type laid down 1930

Displacement:
   3,287 t light; 3,367 t standard; 3,645 t normal; 3,867 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (289.81 ft / 278.87 ft) x 55.77 ft x (16.40 / 17.15 ft)
   (88.33 m / 85.00 m) x 17.00 m  x (5.00 / 5.23 m)

Armament:
      1 - 2.95" / 75.0 mm 45.0 cal gun - 12.98lbs / 5.89kg shells, 250 per gun
     Dual purpose gun in deck mount, 1930 Model
     1 x Single mount on centreline, forward deck centre
      1 raised mount
      2 - 1.97" / 50.0 mm 60.0 cal guns - 4.18lbs / 1.89kg shells, 1,000 per gun
     Anti-air guns in deck mounts, 1930 Model
     2 x Single mounts on sides, forward deck aft
      2 raised mounts
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1930 Model
     2 x Twin mounts on sides, forward deck centre
      2 raised mounts
      Weight of broadside 22 lbs / 10 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm   181.27 ft / 55.25 m   7.87 ft / 2.40 m
   Ends:   1.97" / 50 mm     97.57 ft / 29.74 m   11.81 ft / 3.60 m
     Main Belt covers 100% of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      0.59" / 15 mm   181.27 ft / 55.25 m   14.44 ft / 4.40 m
   Beam between torpedo bulkheads 42.65 ft / 13.00 m

   - Hull void:
      0.98" / 25 mm   278.87 ft / 85.00 m   14.44 ft / 4.40 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.12" / 3 mm            -
   2nd:   0.59" / 15 mm   0.12" / 3 mm            -
   3rd:   0.59" / 15 mm         -               -

Machinery:
   Diesel Internal combustion motors,
   Electric cruising motors plus geared drives, 3 shafts, 8,043 shp / 6,000 Kw = 18.87 kts
   18.04 kts with 5000 kw actual top speed on two shafts
   15.11 kts at 2500 kw
   Front shaft for ice clearing is 1,000 Kw
   Range 10,000nm at 10.00 kts
   Bunker at max displacement = 500 tons

Complement:
   233 - 304

Cost:
   £0.630 million / $2.520 million

Distribution of weights at normal displacement:
   Armament: 6 tons, 0.2%
      - Guns: 6 tons, 0.2%
   Armour: 355 tons, 9.7%
      - Belts: 147 tons, 4.0%
      - Torpedo bulkhead: 57 tons, 1.6%
      - Void: 147 tons, 4.0%
      - Armament: 4 tons, 0.1%
   Machinery: 244 tons, 6.7%
   Hull, fittings & equipment: 1,233 tons, 33.8%
   Fuel, ammunition & stores: 358 tons, 9.8%
   Miscellaneous weights: 1,449 tons, 39.8%
      - Hull below water: 549 tons
      - Hull above water: 400 tons
      - On freeboard deck: 300 tons
      - Above deck: 200 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     10,807 lbs / 4,902 Kg = 839.6 x 3.0 " / 75 mm shells or 2.9 torpedoes
   Stability (Unstable if below 1.00): 1.42
   Metacentric height 3.8 ft / 1.2 m
   Roll period: 12.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.01
   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): 0.500 / 0.507
   Length to Beam Ratio: 5.00 : 1
   'Natural speed' for length: 16.70 kts
   Power going to wave formation at top speed: 57 %
   Trim (Max stability = 0, Max steadiness = 100): 35
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 5.91 ft / 1.80 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00%,  28.54 ft / 8.70 m,  23.62 ft / 7.20 m
      - Forward deck:   30.00%,  23.62 ft / 7.20 m,  23.62 ft / 7.20 m
      - Aft deck:   35.00%,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Quarter deck:   15.00%,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Average freeboard:      20.08 ft / 6.12 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 67.6%
      - Above water (accommodation/working, high = better): 164.2%
   Waterplane Area: 10,363 Square feet or 963 Square metres
   Displacement factor (Displacement / loading): 158%
   Structure weight / hull surface area: 73 lbs/sq ft or 356 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 5.03
      - Overall: 1.13
   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

134 t D-E machinery BW