Coastal-patrol and mine boat

[ledeper]

Lake-Class,  Coastal-patrol and mine boat laid down 1913

Displacement:
   323 t light; 341 t standard; 380 t normal; 411 t full load

Dimensions: Length overall / water x beam x draught
   182,76 ft / 180,45 ft x 29,53 ft x 4,92 ft (normal load)
   55,71 m / 55,00 m x 9,00 m  x 1,50 m

Armament:
      2 - 4,00" / 102 mm guns in single mounts, 32,00lbs / 14,51kg shells, 1913 Model
     Quick firing guns in deck mounts
     on centreline, all forward, 1 raised mount
      2 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,89kg shells, 1913 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 68 lbs / 31 kg
   Shells per gun, main battery: 250

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 1 shaft, 1.987 shp / 1.483 Kw = 18,00 kts
   Range 3.500nm at 10,00 kts
   Bunker at max displacement = 71 tons

Complement:
   42 - 55

Cost:
   £0,032 million / $0,128 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 2,2 %
   Machinery: 78 tons, 20,5 %
   Hull, fittings & equipment: 187 tons, 49,2 %
   Fuel, ammunition & stores: 57 tons, 14,9 %
   Miscellaneous weights: 50 tons, 13,2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     776 lbs / 352 Kg = 24,2 x 4,0 " / 102 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,23
   Metacentric height 1,2 ft / 0,4 m
   Roll period: 11,5 seconds
   Steadiness   - As gun platform (Average = 50 %): 57 %
         - Recoil effect (Restricted arc if above 1.00): 0,12
   Seaboat quality  (Average = 1.00): 1,15

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,507
   Length to Beam Ratio: 6,11 : 1
   'Natural speed' for length: 13,43 kts
   Power going to wave formation at top speed: 59 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13,12 ft / 4,00 m
      - Forecastle (20 %):   10,30 ft / 3,14 m
      - Mid (50 %):      10,30 ft / 3,14 m
      - Quarterdeck (15 %):   10,30 ft / 3,14 m
      - Stern:      10,30 ft / 3,14 m
      - Average freeboard:   10,53 ft / 3,21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 99,5 %
      - Above water (accommodation/working, high = better): 160,7 %
   Waterplane Area: 3.439 Square feet or 320 Square metres
   Displacement factor (Displacement / loading): 139 %
   Structure weight / hull surface area: 36 lbs/sq ft or 175 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,88
      - Longitudinal: 3,30
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

[Borys]

Overgunned. IMO the largest guns such a ship should hope for is an 88.

Borys

[Korpen]

Overgunned. IMO the largest guns such a ship should hope for is an 88.

Borys

Well, granted it is a later ship, but the Arholma class (http://sv.wikipedia.org/wiki/HMS_Landsort_(54) ) had two 10cm guns, and is pretty identical in size.
A fairly heavy armament makes sense as the Baltic's lack any other ships suitable for inshore work, and to protect trade along the Baltic costs.

[Borys]

Seems a lot for such small ships.
Germans in WWI had 3x8,8/2x10,5cm minesweepers with 500-530 tonnes load.
The follow up class, however, of slightly larger size, was downgrded to 2x8,8cm.
Borys

[ledeper]

Lake-Class, Baltic Confederation  Coastal-patrol and mine boat  laid down 1914

Displacement:
   302 t light; 313 t standard; 348 t normal; 377 t full load

Dimensions: Length overall / water x beam x draught
   182,52 ft / 180,45 ft x 29,53 ft x 4,92 ft (normal load)
   55,63 m / 55,00 m x 9,00 m  x 1,50 m

Armament:
      2 - 3,46" / 88,0 mm guns in single mounts, 20,79lbs / 9,43kg shells, 1914 Model
     Quick firing guns in deck mounts
     on centreline ends, evenly spread, 1 raised mount
      2 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,89kg shells, 1914 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 45 lbs / 21 kg
   Shells per gun, main battery: 150

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 1 shaft, 1.831 shp / 1.366 Kw = 18,00 kts
   Range 3.500nm at 10,00 kts
   Bunker at max displacement = 63 tons

Complement:
   39 - 52

Cost:
   £0,032 million / $0,128 million

Distribution of weights at normal displacement:
   Armament: 6 tons, 1,6 %
   Machinery: 71 tons, 20,2 %
   Hull, fittings & equipment: 176 tons, 50,5 %
   Fuel, ammunition & stores: 46 tons, 13,3 %
   Miscellaneous weights: 50 tons, 14,4 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     766 lbs / 348 Kg = 36,8 x 3,5 " / 88 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,21
   Metacentric height 1,1 ft / 0,3 m
   Roll period: 11,6 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0,08
   Seaboat quality  (Average = 1.00): 1,22

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,465
   Length to Beam Ratio: 6,11 : 1
   'Natural speed' for length: 13,43 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 9,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13,12 ft / 4,00 m
      - Forecastle (20 %):   10,30 ft / 3,14 m
      - Mid (50 %):      10,30 ft / 3,14 m
      - Quarterdeck (15 %):   10,30 ft / 3,14 m
      - Stern:      10,30 ft / 3,14 m
      - Average freeboard:   10,53 ft / 3,21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94,3 %
      - Above water (accommodation/working, high = better): 165,4 %
   Waterplane Area: 3.288 Square feet or 305 Square metres
   Displacement factor (Displacement / loading): 147 %
   Structure weight / hull surface area: 35 lbs/sq ft or 170 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,87
      - Longitudinal: 3,44
      - 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

[Korpen]

Seems a lot for such small ships.
Germans in WWI had 3x8,8/2x10,5cm minesweepers with 500-530 tonnes load.
The follow up class, however, of slightly larger size, was downgrded to 2x8,8cm.
Borys

Sure it is a heavy armament, but seems resonable for a ship that will do allot of gunboat work. :)

[Borys]

Still, I like the second version better.
I'd prefer to see a 600 tonnes vessel for gunboat work.

Borys

[Korpen]

Still, I like the second version better.
I'd prefer to see a 600 tonnes vessel for gunboat work.

Borys

I prefer the first one; two 88s are insufficient if one looks at what ships Russia has for costal works.
Also considering that I do not see them as high sea ships, I think the smaller size is better (more economical).

[ledeper]

Will be build after specs in proposal no 1.
Plan is building at least 20 in the coming years

[Sachmle]

Lake-Class,  Coastal-patrol and mine boat laid down 1913

Engine year is 1912.

[ledeper]

Lake-Class, Baltic Confederation Coastal-patrol and mine boat laid down 1913 (Engine 1912)

Displacement:
   361 t light; 379 t standard; 424 t normal; 460 t full load

Dimensions: Length overall / water x beam x draught
   182,76 ft / 180,45 ft x 29,53 ft x 4,92 ft (normal load)
   55,71 m / 55,00 m x 9,00 m  x 1,50 m

Armament:
      2 - 4,00" / 102 mm guns in single mounts, 32,00lbs / 14,51kg shells, 1913 Model
     Quick firing guns in deck mounts
     on centreline, all forward, 1 raised mount
      2 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,89kg shells, 1913 Model
     Breech loading guns in deck mounts
     on side, all amidships
   Weight of broadside 68 lbs / 31 kg
   Shells per gun, main battery: 250

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 1 shaft, 2.208 shp / 1.647 Kw = 18,00 kts
   Range 3.500nm at 10,00 kts
   Bunker at max displacement = 81 tons

Complement:
   46 - 60

Cost:
   £0,035 million / $0,140 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 2,0 %
   Machinery: 88 tons, 20,8 %
   Hull, fittings & equipment: 194 tons, 45,9 %
   Fuel, ammunition & stores: 63 tons, 14,9 %
   Miscellaneous weights: 70 tons, 16,5 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     799 lbs / 362 Kg = 25,0 x 4,0 " / 102 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,23
   Metacentric height 1,2 ft / 0,4 m
   Roll period: 11,4 seconds
   Steadiness   - As gun platform (Average = 50 %): 54 %
         - Recoil effect (Restricted arc if above 1.00): 0,11
   Seaboat quality  (Average = 1.00): 1,07

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,566
   Length to Beam Ratio: 6,11 : 1
   'Natural speed' for length: 13,43 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13,12 ft / 4,00 m
      - Forecastle (20 %):   10,30 ft / 3,14 m
      - Mid (50 %):      10,30 ft / 3,14 m
      - Quarterdeck (15 %):   10,30 ft / 3,14 m
      - Stern:      10,30 ft / 3,14 m
      - Average freeboard:   10,53 ft / 3,21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 102,0 %
      - Above water (accommodation/working, high = better): 156,6 %
   Waterplane Area: 3.671 Square feet or 341 Square metres
   Displacement factor (Displacement / loading): 135 %
   Structure weight / hull surface area: 36 lbs/sq ft or 173 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,88
      - Longitudinal: 3,08
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

W/L 10t
Mines 50t
Sweeping gear 10t

[Sachmle]

If it's just for coastal work it should be relatively easy to support w/ a couple of DDs or a small CL, so I'd cut the second 4" and add more mine weight.

[Korpen]

If it's just for coastal work it should be relatively easy to support w/ a couple of DDs or a small CL, so I'd cut the second 4" and add more mine weight.

Not really, as allot of areas are to narrow for cruisers to operate in, it was tricky enogh to run destroyers at full speed down passages were you had less then 3m clearance to the granite walls on each side. Costal work in much of the baltics mean operations in archipelagos, and this puts allot of limits on the size of the ships. Also, it would seem like a bad idea to have ships with significantly less firepower then that posessed by the russian ships (their most likley opponent).

[P3D]

Not really, as allot of areas are to narrow for cruisers to operate in, it was tricky enogh to run destroyers at full speed down passages were you had less then 3m clearance to the granite walls on each side. Costal work in much of the baltics mean operations in archipelagos, and this puts allot of limits on the size of the ships. Also, it would seem like a bad idea to have ships with significantly less firepower then that posessed by the russian ships (their most likley opponent).

This ship is wider than some destroyers.
The mine load is minimal.

[Korpen]

This ship is wider than some destroyers.
The mine load is minimal.

Well in fact the destroyers i was thinking of were the post-war ones (J11 and forward), with beams between 9 and 12m and speeds of 35kts or more.
The scandinavian costline is a pretty unique area of operations.