WesWorld

A possible German destroyer design for 1936. This design doesn't use the autoloading 128mm that's been undergoing testing since the fall of 1934, using instead a "normal" manually-loaded twin mounting.


Z-250, German Destroyer laid down 1936

Displacement:
2,094 t light; 2,211 t standard; 2,410 t normal; 2,569 t full load

Dimensions: Length overall / water x beam x draught
393.14 ft / 377.30 ft x 37.73 ft x 13.94 ft (normal load)
119.83 m / 115.00 m x 11.50 m x 4.25 m

Armament:
6 - 5.04" / 128 mm guns (3x2 guns), 63.99lbs / 29.02kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on centreline, all aft, all raised mounts - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
16 - 0.79" / 20.0 mm guns (4x4 guns), 0.24lbs / 0.11kg shells, 1936 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 400 lbs / 182 kg
Shells per gun, main battery: 300
8 - 23.6" / 600 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.79" / 20 mm 0.39" / 10 mm -

- Conning tower: 2.76" / 70 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,283 shp / 37,511 Kw = 35.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 358 tons

Complement:
171 - 223

Cost:
£1.491 million / $5.966 million

Distribution of weights at normal displacement:
Armament: 50 tons, 2.1 %
Armour: 40 tons, 1.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 29 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 11 tons, 0.4 %
Machinery: 1,197 tons, 49.7 %
Hull, fittings & equipment: 758 tons, 31.4 %
Fuel, ammunition & stores: 316 tons, 13.1 %
Miscellaneous weights: 50 tons, 2.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
686 lbs / 311 Kg = 10.7 x 5.0 " / 128 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.28
Metacentric height 1.8 ft / 0.6 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.48
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.425
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 22.38 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.61 ft / 7.50 m
- Forecastle (20 %): 17.06 ft / 5.20 m
- Mid (50 %): 16.40 ft / 5.00 m
- Quarterdeck (15 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 17.24 ft / 5.25 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 180.0 %
- Above water (accommodation/working, high = better): 87.0 %
Waterplane Area: 9,247 Square feet or 859 Square metres
Displacement factor (Displacement / loading): 73 %
Structure weight / hull surface area: 40 lbs/sq ft or 197 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.34
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

10 tons reserved for depth charges and rails

40 tons reserved for mines and future growth

Do the Germans have plans to change these "normal" 128mm guns for the autoloading 128mm in the future or will the ships of this class keep the original guns?

It still seems so odd that, due to the treaty, Wesworld German DD's above 1,600 tons don't use the 5.9" gun!

This class, if built, isn't really designed with changing out the turrets in mind. If the bugs in the autoloading systems get worked out, they'd probably be installed in a different class of destroyers.

The reason Germany isn't going to a 15cm gun for it's smaller destroyers (below the Maas class ships) is that we don't yet have a DP 15cm mounting. The Maas class is big enough to carry 4 88mms to fill the need for heavy AA, a ship in the 2000-2200 ton range isn't. WW Germany is, if anything, over-estimating the effectiveness of aircraft vs destroyers, as opposed to RL Germany which under-estimated the effectiveness of the threat (I suspect the difference is partly due to having had Nordmark as a hostile nation during the Great War, putting Nordish aircraft in range of my ships more of the time).

Also, the 12.8cm gun, while it's not as good against larger ships, is actually better at shooting up destroyers and freighters: it fires faster than the 15cm gun, and the shells carry more explosive. The Germany cruiser subs, if built, might well be redesigned to carry 12.8cm guns vs the 15cm guns they were designed with.

Quoted

Originally posted by Hrolf Hakonson
WW Germany is, if anything, over-estimating the effectiveness of aircraft vs destroyers, as opposed to RL Germany which under-estimated the effectiveness of the threat

So Germany should listen to news from the war in South America carefully. There might be something to learn about air strikes against ships in the near future.... Ships at sea, that is. What an air strike against a naval base can achieve has already been shown, right?

Yep, Germany will be watching to see if there are any cases of ships at sea attacked by aircraft.

Germany may not build any DDs of this class, it's possible I'll just build more Maas class vessels. The problem there is that they need Type 2 slips, which I don't have as many of as I have Type 1s.

I'd say Atlantis is in the same boat, though many nations rely on heavier AA suites on their vessels anyway. As Hoo says, events in SA will vindicate what is currently seen as overdoing things.

Ultimately several Atlantean vessels are in dire need of upgrades to their AA armaments anyway.

A touch larger version, to get 1000 nm more range.


Z-250, German Destroyer laid down 1937

Displacement:
2,179 t light; 2,299 t standard; 2,552 t normal; 2,754 t full load

Dimensions: Length overall / water x beam x draught
393.14 ft / 377.30 ft x 37.73 ft x 14.76 ft (normal load)
119.83 m / 115.00 m x 11.50 m x 4.50 m

Armament:
6 - 5.04" / 128 mm guns (3x2 guns), 63.99lbs / 29.03kg shells, 1937 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on centreline, all aft, all raised mounts - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
16 - 0.79" / 20.0 mm guns (4x4 guns), 0.24lbs / 0.11kg shells, 1937 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 400 lbs / 182 kg
Shells per gun, main battery: 300
8 - 23.6" / 600 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.79" / 20 mm 0.39" / 10 mm -
4th: 0.39" / 10 mm - -

- Conning tower: 2.76" / 70 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 52,164 shp / 38,915 Kw = 35.00 kts
Range 5,000nm at 15.00 kts
Bunker at max displacement = 455 tons

Complement:
179 - 233

Cost:
£1.607 million / $6.428 million

Distribution of weights at normal displacement:
Armament: 50 tons, 2.0 %
Armour: 41 tons, 1.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 29 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 11 tons, 0.4 %
Machinery: 1,260 tons, 49.4 %
Hull, fittings & equipment: 779 tons, 30.5 %
Fuel, ammunition & stores: 373 tons, 14.6 %
Miscellaneous weights: 50 tons, 2.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
707 lbs / 321 Kg = 11.1 x 5.0 " / 128 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 1.6 ft / 0.5 m
Roll period: 12.4 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.54
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.425
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 22.38 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 59
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.61 ft / 7.50 m
- Forecastle (20 %): 16.73 ft / 5.10 m
- Mid (50 %): 16.73 ft / 5.10 m
- Quarterdeck (15 %): 16.73 ft / 5.10 m
- Stern: 16.73 ft / 5.10 m
- Average freeboard: 17.36 ft / 5.29 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 177.9 %
- Above water (accommodation/working, high = better): 84.0 %
Waterplane Area: 9,247 Square feet or 859 Square metres
Displacement factor (Displacement / loading): 75 %
Structure weight / hull surface area: 41 lbs/sq ft or 199 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.43
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

10 tons reserved for depth charges and rails

40 tons reserved for mines and future growth