First crack at a fleet minesweeper/minelayer

[Sachmle]

As the subject states this is the NUS's first try at a minewarfare vessel, so I'm sure there's plenty wrong with it.

M-100 Class, NUS Minewarfare vessel laid down 1911 (Engine 1909)

Displacement:
   1,000 t light; 1,030 t standard; 1,401 t normal; 1,698 t full load

Dimensions: Length overall / water x beam x draught
   233.44 ft / 230.00 ft x 28.00 ft x 15.00 ft (normal load)
   71.15 m / 70.10 m x 8.53 m  x 4.57 m

Armament:
      1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1905 Model
     Quick firing gun in deck mount
     on centreline forward, 1 raised gun
      4 - 1.00" / 25.4 mm guns in single mounts, 0.50lbs / 0.23kg shells, 1906 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 16 lbs / 7 kg
   Shells per gun, main battery: 200

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm         -               -

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 7,506 shp / 5,599 Kw = 21.33 kts
   Range 6,600nm at 12.00 kts
   Bunker at max displacement = 668 tons (90% coal)

Complement:
   113 - 148

Cost:
   £0.089 million / $0.355 million

Distribution of weights at normal displacement:
   Armament: 2 tons, 0.1 %
   Armour: 2 tons, 0.1 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 2 tons, 0.1 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 372 tons, 26.5 %
   Hull, fittings & equipment: 425 tons, 30.3 %
   Fuel, ammunition & stores: 401 tons, 28.6 %
   Miscellaneous weights: 200 tons, 14.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,541 lbs / 699 Kg = 114.1 x 3.0 " / 76 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.14
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 12.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.04
   Seaboat quality  (Average = 1.00): 1.94

Hull form characteristics:
   Hull has raised forecastle, rise forward of midbreak
   Block coefficient: 0.508
   Length to Beam Ratio: 8.21 : 1
   'Natural speed' for length: 15.17 kts
   Power going to wave formation at top speed: 62 %
   Trim (Max stability = 0, Max steadiness = 100): 36
   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:      19.50 ft / 5.94 m
      - Forecastle (15 %):   19.00 ft / 5.79 m (18.50 ft / 5.64 m aft of break)
      - Mid (50 %):      18.00 ft / 5.49 m (10.00 ft / 3.05 m aft of break)
      - Quarterdeck (15 %):   10.00 ft / 3.05 m
      - Stern:      10.00 ft / 3.05 m
      - Average freeboard:   14.27 ft / 4.35 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 103.0 %
      - Above water (accommodation/working, high = better): 99.0 %
   Waterplane Area: 4,159 Square feet or 386 Square metres
   Displacement factor (Displacement / loading): 146 %
   Structure weight / hull surface area: 41 lbs/sq ft or 199 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.81
      - Longitudinal: 6.59
      - 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
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Misc weight for minesweeping equipment/mines and weight reserve.

[Borys]

Ahoj!
Nice patrol vessel.
My suggestions:
- there is no need for speed, so go with VTE
- add second shaft
- main gun 4 inches, and more shells - 250-300

Borys

[Korpen]

Ahoj!
Nice patrol vessel.
My suggestions:
- there is no need for speed, so go with VTE
- add second shaft
- main gun 4 inches, and more shells - 250-300

Borys

On speed; It really depends, for sweeping, were there is a great amount of steaming at low speed, VTE engines might be better.
But considering her size, range and speed I suspect that she is to be able to carry out offensive mining operations as well, and then speed is very useful.
As a primary minesweeper I think se is a bit too large, as that is often very dangerous duty, and increased size does not give much increased capacity.

[The Rock Doctor]

I'm inclined to keep sweeping and laying in different vessels entirely, really.

[P3D]

1000t is on the heavy side for a minesweeper, even if ocean-going. 500t should offer you adequate seakeeping for transits. The draught OTOH is excessive, this ship cannot operate in shallow water at all.

[Korpen]

I'm inclined to keep sweeping and laying in different vessels entirely, really.

I agree that minelayers should not be used as sweepers.
But sweepers can make good minelayers for defensive fields.

[Sachmle]

The draught OTOH is excessive, this ship cannot operate in shallow water at all.

Concidering the only ships I have than can operate in water shallower than 15' are my DDs and water that shallow is probably close to shore, where no DD should ever be, what's wrong w/ the draught?

[Borys]

I took a closer look at the German amphibious landing in the Baltic in 1917. With draught like that you woud barely get to the action in the Kassar Wiek :)

Geman coastal battleships, which had their daught INCREASED during a refit, couldn't get into it either :)

There are places in this world with 10 foot depth. And mines usually are laid in not very deep water. But in your geostrategic situation it is not that important. Although I'd recommend a class of 500 tonne boats with smaller draught, and use this ship as patrol ship/minelayer.

Borys

Borys