Minendampfer 1917

[Sachmle]

With only 1 (YES 1!) minelayer in service it was decided that more were needed. First up is the big momma defensive barrage minelayer. She carries 600(!) mines.

Ersatz Albatross, Brandenburg Minendampfer laid down 1917 (Engine 1916)

Displacement:
   2,000 t light; 2,062 t standard; 2,434 t normal; 2,732 t full load

Dimensions: Length overall / water x beam x draught
   339.57 ft / 331.36 ft x 42.65 ft x 12.01 ft (normal load)
   103.50 m / 101.00 m x 13.00 m  x 3.66 m

Armament:
      4 - 4.13" / 105 mm guns in single mounts, 35.27lbs / 16.00kg shells, 1905 Model
     Quick firing guns in deck mounts with hoists
     on side ends, evenly spread
      1 - 1.97" / 50.0 mm guns in single mounts, 3.86lbs / 1.75kg shells, 1917 Model
     Anti-aircraft gun in deck mount
     on centreline amidships, 1 raised gun
      2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1917 Model
     Anti-aircraft guns in deck mounts
     on side, all aft, all raised mounts - superfiring
      4 - 0.30" / 7.7 mm guns in single mounts, 0.02lbs / 0.01kg shells, 1917 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 148 lbs / 67 kg
   Shells per gun, main battery: 150

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm   0.39" / 10 mm      0.98" / 25 mm

   - Armour deck: 0.79" / 20 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 3 shafts, 7,000 ihp / 5,222 Kw = 19.97 kts
   Range 8,000nm at 10.00 kts
   Bunker at max displacement = 670 tons (100% coal)

Complement:
   173 - 225

Cost:
   £0.272 million / $1.088 million

Distribution of weights at normal displacement:
   Armament: 19 tons, 0.8 %
   Armour: 145 tons, 6.0 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 8 tons, 0.3 %
      - Armour Deck: 137 tons, 5.6 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 458 tons, 18.8 %
   Hull, fittings & equipment: 729 tons, 30.0 %
   Fuel, ammunition & stores: 434 tons, 17.8 %
   Miscellaneous weights: 650 tons, 26.7 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2,732 lbs / 1,239 Kg = 77.3 x 4.1 " / 105 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.15
   Metacentric height 1.8 ft / 0.6 m
   Roll period: 13.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.08
   Seaboat quality  (Average = 1.00): 1.32

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.502
   Length to Beam Ratio: 7.77 : 1
   'Natural speed' for length: 18.20 kts
   Power going to wave formation at top speed: 49 %
   Trim (Max stability = 0, Max steadiness = 100): 53
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 8.20 ft / 2.50 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      16.01 ft / 4.88 m
      - Forecastle (20 %):   16.01 ft / 4.88 m
      - Mid (30 %):      16.01 ft / 4.88 m (8.01 ft / 2.44 m aft of break)
      - Quarterdeck (15 %):   8.01 ft / 2.44 m
      - Stern:      8.01 ft / 2.44 m
      - Average freeboard:   10.41 ft / 3.17 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 96.3 %
      - Above water (accommodation/working, high = better): 95.9 %
   Waterplane Area: 9,433 Square feet or 876 Square metres
   Displacement factor (Displacement / loading): 131 %
   Structure weight / hull surface area: 54 lbs/sq ft or 264 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.98
      - Longitudinal: 1.14
      - 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
   Good seaboat, rides out heavy weather easily

600t - 600 mines
25t - LR W/T
25t - Sehendes Auge

[Guinness]

Hmm. Seems like an all your eggs in one basket sort of ship.

Just to see, I hacked at the last Confederate sloop to see what I might make out of her. For the same tonnage, these can ship 676 mines. Or in other figurings, 6 of these can ship 678 mines. Of course, they won't have other niceties like a long range wireless set, but maybe you could do a "leader" version.

At any rate, it's just an idea to illustrate my point, which is at this low speed, I wonder if a bunch of small ships couldn't do the same job as one large one, but give more flexibility (and give you either something to build in otherwise lightly used type 0 slips and dds, or give you something you can build in a hurry).

So, sorry in advance for the threadjack with my own SS:

Sloop based Minelayer, CSA Sloop laid down 1917 (Engine 1916)

Displacement:
   334 t light; 344 t standard; 423 t normal; 486 t full load

Dimensions: Length overall / water x beam x draught
   195.00 ft / 185.00 ft x 20.50 ft x 6.60 ft (normal load)
   59.44 m / 56.39 m x 6.25 m  x 2.01 m

Armament:
     1 - 3.50" / 88.9 mm guns in single mounts, 20.00lbs / 9.07kg shells, 1917 Model
     Quick firing gun in deck mounts
     on centreline, evenly spread
     2 - 1.00" / 25.4 mm guns (1x2 guns), 0.50lbs / 0.23kg shells, 1917 Model
     Anti-aircraft guns in deck mount
     on centreline amidships, all raised guns - superfiring
     4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1917 Model
     Breech loading guns in deck mounts
     on side, evenly spread, 2 raised mounts
   Weight of broadside 21 lbs / 10 kg
   Shells per gun, main battery: 125

Armour:
  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.25" / 6 mm         -               -
   3rd:   0.25" / 6 mm         -               -
   5th:   0.25" / 6 mm         -               -

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 2 shafts, 2,000 shp / 1,492 Kw = 18.00 kts
   Range 8,000nm at 10.00 kts
   Bunker at max displacement = 142 tons

Complement:
   46 - 60

Cost:
   £0.045 million / $0.178 million

Distribution of weights at normal displacement:
   Armament: 3 tons, 0.7 %
   Armour: 1 tons, 0.2 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 1 tons, 0.2 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 75 tons, 17.6 %
   Hull, fittings & equipment: 143 tons, 33.7 %
   Fuel, ammunition & stores: 89 tons, 21.0 %
   Miscellaneous weights: 113 tons, 26.7 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     616 lbs / 279 Kg = 28.7 x 3.5 " / 89 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 0.5 ft / 0.2 m
   Roll period: 11.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.09
   Seaboat quality  (Average = 1.00): 1.53

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.591
   Length to Beam Ratio: 9.02 : 1
   'Natural speed' for length: 13.60 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 40
   Bow angle (Positive = bow angles forward): 18.45 degrees
   Stern overhang: 5.00 ft / 1.52 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      15.00 ft / 4.57 m
      - Forecastle (10 %):   14.50 ft / 4.42 m
      - Mid (30 %):      14.00 ft / 4.27 m (6.00 ft / 1.83 m aft of break)
      - Quarterdeck (10 %):   7.00 ft / 2.13 m
      - Stern:      8.00 ft / 2.44 m
      - Average freeboard:   8.97 ft / 2.73 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 91.8 %
      - Above water (accommodation/working, high = better): 96.1 %
   Waterplane Area: 2,751 Square feet or 256 Square metres
   Displacement factor (Displacement / loading): 148 %
   Structure weight / hull surface area: 28 lbs/sq ft or 137 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.89
      - Longitudinal: 2.83
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

113 mines (113 tons)

[Sachmle]

Thread jack is fine. The Albatross is the big, stay in Brandenburg waters, mine the piss out of everything, defensive ship. For offensive mine laying in far away places I'm working on a smaller design w/ around 100-150 mines each. So far I'm in the 500t range. Any need for a fast minelayer will be met by the kleiner kreuzers, most of which carry 35-50 mines each.

[Korpen]

I do not think there really is all that much need for a dedicated minelayer for defensive minelaying. That is a function that can be carried out by auxiliary ships, such as any form of cargo ship that can take deck cargo. It is cheaper, and such ships are more likely to be immediately available pretty much everywhere (at a naval port).

[The Bushranger]

Oh, that might be the practical way, but will the folks at KM HQ agree? :p

And you'd have more minelayers, if it weren't for those meddling Swiss! *shakes fist*

[Desertfox]

Mwuhahahaha!!! If I recall correctly, it was the Germans who couldn't keep their noses out of other people's business... ;) Now they find themselves fighting those they sougth to defend...