WesWorld

For some time there has been a requirement for a Destroyer that can make the Den Helder-Matadi or Matadi-Batavia run at fleet (15kts) speeds. This range would also allow deeper escorting of fleet units into the Pacific or Indian ocean. This was unattainable under the old Class A DDs, but may shortly be an option.

I've tried 3 variants- a 34kt 8x125mm, a 36kt 5x125mm in deck mounts, and settled on the middle, 35kt, 6x125mm as the best balance.

However, a persistent problem is the necessary bunkerage is at that borderline of 19-20%. Unfortunately I've forgotten if 17 or 19% seemed the cap, with some outliers like Graf Spee, but these are right at 905tons and 20.0%.

Now I can substitute 52 tons of miscellaneous weight for 600nm of fuel and hit that 19%, or go further down that route if thought needed, but I thought I would toss it up for comments/debate.

Z74, Netherlands Heavy Destroyer laid down 1935

Displacement:
2,526 t light; 2,656 t standard; 3,159 t normal; 3,561 t full load

Dimensions: Length overall / water x beam x draught
522.48 ft / 508.53 ft x 45.60 ft x 11.35 ft (normal load)
159.25 m / 155.00 m x 13.90 m x 3.46 m

Armament:
6 - 4.92" / 125 mm guns (3x2 guns), 59.52lbs / 27.00kg shells, 1926 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority forward, 1 raised mount - superfiring
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.94lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.95lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
12 - 0.91" / 23.0 mm guns (6x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 385 lbs / 175 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: 0.79" / 20 mm 0.20" / 5 mm 0.20" / 5 mm
2nd: 0.39" / 10 mm 0.83" / 21 mm -
3rd: 0.39" / 10 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 51,890 shp / 38,710 Kw = 35.00 kts
Range 8,500nm at 15.00 kts
Bunker at max displacement = 905 tons

Complement:
209 - 273

Cost:
£1.670 million / $6.679 million

Distribution of weights at normal displacement:
Armament: 48 tons, 1.5 %
Armour: 15 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 0.4 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 4 tons, 0.1 %
Machinery: 1,422 tons, 45.0 %
Hull, fittings & equipment: 906 tons, 28.7 %
Fuel, ammunition & stores: 633 tons, 20.0 %
Miscellaneous weights: 135 tons, 4.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,130 lbs / 513 Kg = 19.0 x 4.9 " / 125 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.37
Metacentric height 2.7 ft / 0.8 m
Roll period: 11.7 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.24
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.420
Length to Beam Ratio: 11.15 : 1
'Natural speed' for length: 25.78 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 67
Bow angle (Positive = bow angles forward): 23.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.13 ft / 7.66 m
- Forecastle (20 %): 15.78 ft / 4.81 m
- Mid (50 %): 15.78 ft / 4.81 m
- Quarterdeck (15 %): 15.78 ft / 4.81 m
- Stern: 15.78 ft / 4.81 m
- Average freeboard: 16.53 ft / 5.04 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 163.0 %
- Above water (accommodation/working, high = better): 150.9 %
Waterplane Area: 15,010 Square feet or 1,394 Square metres
Displacement factor (Displacement / loading): 91 %
Structure weight / hull surface area: 38 lbs/sq ft or 187 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 0.76
- Overall: 0.52
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Designed as a long-range destroyer for deep ocean escort.

That´s an aweful long DD.... She has a very heavy AA suit but lacks adequate armore on her main guns. 20mm front with 5mm sides is hardly more than weather protection...

Have to agree with HOo, that's a LONG DD, it's even longer than my Maas class ships. 23mm???? Since when did the Dutch use that caliber? I'm thinking there's 1 more caliber of light AA than is needed: with the 23mms, there's not a lot of need for the 13.7mms....

Length : Wasn't able to achieve the design goals on 120m, so it grew. Edit: I tinkered some and got the length down, still over 120m. See below

Armor : The mount armor is intended to be a HE resistant shield from the front, and enclosed for weather proofing. I could up it to 25/20/20 without issue I think.

23mm: The Dutch started using 23mm Madsens in 1934. As older ships get refitted, the 20mm suites will be replaced with 23mm.

The 4x 13.2mm MGs are a standard mount at the superstructure corners, ostensibly to give sentries something to shoot with in port security matters, but frankly don't have a viable combat purpose, but a bunch of older Dutch vessels had 13mm MGs, so I've been sticking them on virtually every design as a deliberate useless feature retained due to past practice .

Opinions on how to approach the fuel %? Keep it as is, using 20% as cut off? Use miscellaneous weight for bunkerage over X%?

13.2mm can be usefull vs. small fast attack craft.

Ok, tried for a shorter version, with heavier mount armor.

SA is correct, and I suppose in the islands of the Indies that could be a use, but I think the AA suite would be brought into action for that.

Z74, Netherlands Heavy Destroyer laid down 1935

Displacement:
2,517 t light; 2,647 t standard; 3,139 t normal; 3,532 t full load

Dimensions: Length overall / water x beam x draught
460.00 ft / 446.19 ft x 40.68 ft x 12.80 ft (normal load)
140.21 m / 136.00 m x 12.40 m x 3.90 m

Armament:
6 - 4.92" / 125 mm guns (3x2 guns), 59.52lbs / 27.00kg shells, 1926 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority forward, 1 raised mount - superfiring
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.94lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.95lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
12 - 0.91" / 23.0 mm guns (6x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 385 lbs / 175 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: 0.98" / 25 mm 0.79" / 20 mm 0.79" / 20 mm
2nd: 0.39" / 10 mm 0.83" / 21 mm -
3rd: 0.39" / 10 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 56,354 shp / 42,040 Kw = 35.00 kts
Range 8,500nm at 15.00 kts
Bunker at max displacement = 885 tons

Complement:
209 - 272

Cost:
£1.725 million / $6.900 million

Distribution of weights at normal displacement:
Armament: 48 tons, 1.5 %
Armour: 25 tons, 0.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 21 tons, 0.7 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 4 tons, 0.1 %
Machinery: 1,502 tons, 47.8 %
Hull, fittings & equipment: 827 tons, 26.3 %
Fuel, ammunition & stores: 622 tons, 19.8 %
Miscellaneous weights: 115 tons, 3.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
898 lbs / 407 Kg = 15.1 x 4.9 " / 125 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.30
Metacentric height 2.1 ft / 0.6 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.36
Seaboat quality (Average = 1.00): 1.03

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.473
Length to Beam Ratio: 10.97 : 1
'Natural speed' for length: 24.01 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 23.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.80 ft / 7.56 m
- Forecastle (20 %): 20.14 ft / 6.14 m (15.49 ft / 4.72 m aft of break)
- Mid (50 %): 15.49 ft / 4.72 m
- Quarterdeck (15 %): 15.49 ft / 4.72 m
- Stern: 15.49 ft / 4.72 m
- Average freeboard: 16.79 ft / 5.12 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 171.5 %
- Above water (accommodation/working, high = better): 106.6 %
Waterplane Area: 12,270 Square feet or 1,140 Square metres
Displacement factor (Displacement / loading): 84 %
Structure weight / hull surface area: 38 lbs/sq ft or 184 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.17
- Overall: 0.54
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

Designed as a long-range destroyer for deep ocean escort.

Reduce the speed to around 33/34knts. In a seaway (say SS4 waves ~5ft, quite normal) any destroyer isn't going to be going over 30knts. This rapidly decreases with taller waves. By SS6 limited to around 20knts. The reduction in machinery will save considerable weight and volume - or allow for a more seaworthy hullform.

The freeboard is fine but you'll probably want the step further forward to accomodate the two banks of torpedoes on the same level.

Range should be fine as it currently stands. The best way around the problem is to adopt refuelling at sea, either from the merchies you're escorting or from larger warships.

Armament is fine. The midships 40mm guns might interfere with the torpedo training. Maybe use Hazemeyer twin mountings instead? As well as the Madsen 23mm there is the OTO-Madsen gun developed over the past few years. Using a 25x150 cartridge to fire to 240g round at 1000m/s. Gas operated and water cooled. Normal use is a twin mounting.

As I indicated, a 8x125mm, 34 kts version was considered, I opted for the 35kts for a couple of reasons-
a) The current Z53 class is 35kts
b) while the design has been expanded to allow deep ocean escort, most of the likely combat areas have inland seas and are close to land.
c) If heavy ships increase to 32-33kts as expected, 33-34 is very little margin. I want 36, I just can't manage it and the other parameters.

Still, the 8x125mm/34kts is quite attractive for the firepower.

For the range- the midsea refueling is what we do now for DDs, while the sloops are optimized for a more economical speed. I'd like to have something free of that operational restriction.

I can move the step- which is actually meant to represent a smooth rise towards the bow, forward, but with 75% of the extra-long hull behind that I would think I'd be good with 102m at normal freeboard?

For the 40mm quads, I was thinking of the raised platforms you see amidships on British DDs, which should keep the torpedo arcs clear below. the 21tons other, as per my standard, is the Hazemaijer gear weight.
Your OTO-Madsen sounds good and like something I can transition to later as threat levels continue to rise.

Ok, so this is a 8x125mm / 34kt version, with the step moved forward slightly. I'm not sold on slowing down through, but still considering the options.

Z74, Netherlands Heavy Destroyer laid down 1935

Displacement:
2,331 t light; 2,475 t standard; 2,950 t normal; 3,330 t full load

Dimensions: Length overall / water x beam x draught
460.00 ft / 446.19 ft x 40.68 ft x 11.98 ft (normal load)
140.21 m / 136.00 m x 12.40 m x 3.65 m

Armament:
8 - 4.92" / 125 mm guns (4x2 guns), 59.52lbs / 27.00kg shells, 1926 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.94lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
12 - 0.91" / 23.0 mm guns (6x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 496 lbs / 225 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: 0.98" / 25 mm 0.79" / 20 mm 0.79" / 20 mm
2nd: 0.39" / 10 mm 0.83" / 21 mm -

- Conning tower: 0.79" / 20 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 48,280 shp / 36,017 Kw = 34.00 kts
Range 8,500nm at 15.00 kts
Bunker at max displacement = 855 tons

Complement:
199 - 260

Cost:
£1.604 million / $6.415 million

Distribution of weights at normal displacement:
Armament: 62 tons, 2.1 %
Armour: 31 tons, 1.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 27 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.1 %
Machinery: 1,295 tons, 43.9 %
Hull, fittings & equipment: 818 tons, 27.7 %
Fuel, ammunition & stores: 619 tons, 21.0 %
Miscellaneous weights: 125 tons, 4.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
930 lbs / 422 Kg = 15.6 x 4.9 " / 125 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.24
Metacentric height 1.9 ft / 0.6 m
Roll period: 12.3 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.53
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.475
Length to Beam Ratio: 10.97 : 1
'Natural speed' for length: 24.01 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 23.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.80 ft / 7.56 m
- Forecastle (15 %): 20.14 ft / 6.14 m (15.49 ft / 4.72 m aft of break)
- Mid (50 %): 15.49 ft / 4.72 m
- Quarterdeck (15 %): 15.49 ft / 4.72 m
- Stern: 15.49 ft / 4.72 m
- Average freeboard: 16.46 ft / 5.02 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.1 %
- Above water (accommodation/working, high = better): 112.2 %
Waterplane Area: 12,292 Square feet or 1,142 Square metres
Displacement factor (Displacement / loading): 87 %
Structure weight / hull surface area: 38 lbs/sq ft or 187 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.08
- Overall: 0.54
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

Designed as a long-range destroyer for deep ocean escort.