Diverging from my standing theme

[Valles]

DD-1920, Maori Destroyer laid down 1916

Displacement:
   500 t light; 518 t standard; 601 t normal; 667 t full load

Dimensions: Length overall / water x beam x draught
   227.24 ft / 219.82 ft x 26.25 ft x 7.87 ft (normal load)
   69.26 m / 67.00 m x 8.00 m  x 2.40 m

Armament:
      2 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, majority forward
      1 - 1.38" / 35.0 mm guns in single mounts, 1.32lbs / 0.60kg shells, 1916 Model
     Anti-aircraft gun in deck mount
     on side amidships, 1 raised gun
   Weight of broadside 67 lbs / 31 kg
   Shells per gun, main battery: 150
   6 - 20.7" / 525 mm above water torpedoes

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

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 16,380 shp / 12,219 Kw = 29.00 kts
   Range 3,000nm at 14.00 kts
   Bunker at max displacement = 149 tons

Complement:
   59 - 78

Cost:
   £0.110 million / $0.438 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 1.3 %
   Armour: 3 tons, 0.5 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 3 tons, 0.5 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 306 tons, 51.0 %
   Hull, fittings & equipment: 154 tons, 25.6 %
   Fuel, ammunition & stores: 100 tons, 16.7 %
   Miscellaneous weights: 30 tons, 5.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     141 lbs / 64 Kg = 4.6 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.12
   Metacentric height 0.8 ft / 0.3 m
   Roll period: 12.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 30 %
         - Recoil effect (Restricted arc if above 1.00): 0.18
   Seaboat quality  (Average = 1.00): 0.23

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.463
   Length to Beam Ratio: 8.38 : 1
   'Natural speed' for length: 14.83 kts
   Power going to wave formation at top speed: 74 %
   Trim (Max stability = 0, Max steadiness = 100): 79
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      9.84 ft / 3.00 m
      - Forecastle (15 %):   8.20 ft / 2.50 m
      - Mid (50 %):      8.20 ft / 2.50 m
      - Quarterdeck (15 %):   8.20 ft / 2.50 m
      - Stern:      8.20 ft / 2.50 m
      - Average freeboard:   8.30 ft / 2.53 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 179.9 %
      - Above water (accommodation/working, high = better): 30.1 %
   Waterplane Area: 3,720 Square feet or 346 Square metres
   Displacement factor (Displacement / loading): 46 %
   Structure weight / hull surface area: 27 lbs/sq ft or 129 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.55
      - Longitudinal: 1.11
      - Overall: 0.59
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor
   Caution: Lacks seaworthiness - very limited seakeeping ability



A significant divergence from my destroyer designs to date, intended as a response to shifting needs.

[Sachmle]

HOLY S%@T!! A Maori ship that goes faster than 25kts!!!! But, you still have a cross-sectional of 0.55, so some strength left over to squeeze some more...something out of it. Your gun layout is funny..but I think it's just from changing things around on the guns page w/o updating the mounts page. Since you've only got 2 guns it really shouldn't say "Centerline ends, majority forward" Unless you still have 3 mounts listed. Same with the AA gun being "On side, amidships" instead of centerline amidships. Probably won't really change anything, well the extra mount may but I doubt it.

[Valles]

Hmmm... Buffing freeboard 0.3m across most of the hull and adding a slight upsweep to the bow nets me an 8% steadiness improvement and a 0.13 boost to seakeeping, both things the design desperately needs...

DD-1920, Maori Destroyer laid down 1916

Displacement:
   500 t light; 518 t standard; 601 t normal; 667 t full load

Dimensions: Length overall / water x beam x draught
   227.38 ft / 219.82 ft x 26.25 ft x 7.87 ft (normal load)
   69.31 m / 67.00 m x 8.00 m  x 2.40 m

Armament:
     2 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, majority forward
     2 - 1.38" / 35.0 mm guns in single mounts, 1.32lbs / 0.60kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, all amidships
   Weight of broadside 69 lbs / 31 kg
   Shells per gun, main battery: 150
   6 - 20.7" / 525 mm above water torpedoes

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

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 16,380 shp / 12,219 Kw = 29.00 kts
   Range 3,000nm at 14.00 kts
   Bunker at max displacement = 149 tons

Complement:
   59 - 78

Cost:
   £0.110 million / $0.439 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 1.3 %
   Armour: 3 tons, 0.5 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 3 tons, 0.5 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 306 tons, 50.9 %
   Hull, fittings & equipment: 154 tons, 25.6 %
   Fuel, ammunition & stores: 101 tons, 16.8 %
   Miscellaneous weights: 30 tons, 5.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     142 lbs / 64 Kg = 4.6 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.8 ft / 0.2 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 38 %
         - Recoil effect (Restricted arc if above 1.00): 0.22
   Seaboat quality  (Average = 1.00): 0.36

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.463
   Length to Beam Ratio: 8.38 : 1
   'Natural speed' for length: 14.83 kts
   Power going to wave formation at top speed: 74 %
   Trim (Max stability = 0, Max steadiness = 100): 79
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      11.48 ft / 3.50 m
      - Forecastle (15 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.19 ft / 2.80 m
      - Quarterdeck (15 %):   9.19 ft / 2.80 m
      - Stern:      9.19 ft / 2.80 m
      - Average freeboard:   9.50 ft / 2.90 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 180.0 %
      - Above water (accommodation/working, high = better): 34.3 %
   Waterplane Area: 3,720 Square feet or 346 Square metres
   Displacement factor (Displacement / loading): 46 %
   Structure weight / hull surface area: 25 lbs/sq ft or 121 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.40
      - Overall: 0.55
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor
   Caution: Lacks seaworthiness - very limited seakeeping ability

[Valles]

Alternately, sacrifice a bit of the extra seakeeping and one torpedo set for an additional 100mm.

DD-1920, Maori Destroyer laid down 1916

Displacement:
   500 t light; 521 t standard; 604 t normal; 670 t full load

Dimensions: Length overall / water x beam x draught
   227.38 ft / 219.82 ft x 26.25 ft x 7.87 ft (normal load)
   69.31 m / 67.00 m x 8.00 m  x 2.40 m

Armament:
      3 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline, evenly spread
     Aft Main mounts separated by engine room
      1 - 1.38" / 35.0 mm guns in single mounts, 1.32lbs / 0.60kg shells, 1916 Model
     Anti-aircraft gun in a deck mount with hoist
     on centreline amidships
   Weight of broadside 101 lbs / 46 kg
   Shells per gun, main battery: 150
   3 - 20.7" / 525 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.39" / 10 mm   0.39" / 10 mm            -
   2nd:   0.39" / 10 mm   0.39" / 10 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 16,450 shp / 12,272 Kw = 29.00 kts
   Range 3,000nm at 14.00 kts
   Bunker at max displacement = 149 tons

Complement:
   60 - 79

Cost:
   £0.114 million / $0.455 million

Distribution of weights at normal displacement:
   Armament: 12 tons, 1.9 %
   Armour: 4 tons, 0.6 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 4 tons, 0.6 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 302 tons, 50.0 %
   Hull, fittings & equipment: 155 tons, 25.6 %
   Fuel, ammunition & stores: 104 tons, 17.2 %
   Miscellaneous weights: 28 tons, 4.6 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     134 lbs / 61 Kg = 4.4 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.8 ft / 0.2 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 40 %
         - Recoil effect (Restricted arc if above 1.00): 0.31
   Seaboat quality  (Average = 1.00): 0.34

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.465
   Length to Beam Ratio: 8.38 : 1
   'Natural speed' for length: 14.83 kts
   Power going to wave formation at top speed: 74 %
   Trim (Max stability = 0, Max steadiness = 100): 91
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      11.48 ft / 3.50 m
      - Forecastle (15 %):   9.84 ft / 3.00 m
      - Mid (50 %):      8.53 ft / 2.60 m
      - Quarterdeck (15 %):   8.53 ft / 2.60 m
      - Stern:      8.53 ft / 2.60 m
      - Average freeboard:   9.06 ft / 2.76 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 181.3 %
      - Above water (accommodation/working, high = better): 68.4 %
   Waterplane Area: 3,727 Square feet or 346 Square metres
   Displacement factor (Displacement / loading): 45 %
   Structure weight / hull surface area: 26 lbs/sq ft or 126 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.23
      - Overall: 0.54
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Caution: Lacks seaworthiness - very limited seakeeping ability

[Valles]

...hm. Deepen the hull a bit and shear off a touch of freeboard, and I can get an extra knot out of her.

Though certainly the crew won't enjoy the experience any.

DD-1920, Maori Destroyer laid down 1916

Displacement:
   500 t light; 521 t standard; 603 t normal; 669 t full load

Dimensions: Length overall / water x beam x draught
   227.27 ft / 219.82 ft x 22.97 ft x 9.19 ft (normal load)
   69.27 m / 67.00 m x 7.00 m  x 2.80 m

Armament:
      3 - 3.94" / 100 mm guns in single mounts, 33.07lbs / 15.00kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline, evenly spread
     Aft Main mounts separated by engine room
      1 - 1.38" / 35.0 mm guns in single mounts, 1.32lbs / 0.60kg shells, 1916 Model
     Anti-aircraft gun in a deck mount with hoist
     on centreline amidships
   Weight of broadside 101 lbs / 46 kg
   Shells per gun, main battery: 150
   3 - 20.7" / 525 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.39" / 10 mm   0.39" / 10 mm            -
   2nd:   0.39" / 10 mm   0.39" / 10 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 18,429 shp / 13,748 Kw = 30.00 kts
   Range 3,000nm at 14.00 kts
   Bunker at max displacement = 148 tons

Complement:
   60 - 79

Cost:
   £0.115 million / $0.461 million

Distribution of weights at normal displacement:
   Armament: 12 tons, 1.9 %
   Armour: 4 tons, 0.6 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 4 tons, 0.6 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 308 tons, 51.2 %
   Hull, fittings & equipment: 148 tons, 24.6 %
   Fuel, ammunition & stores: 103 tons, 17.1 %
   Miscellaneous weights: 28 tons, 4.6 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     117 lbs / 53 Kg = 3.8 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.7 ft / 0.2 m
   Roll period: 11.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 32 %
         - Recoil effect (Restricted arc if above 1.00): 0.42
   Seaboat quality  (Average = 1.00): 0.27

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.455
   Length to Beam Ratio: 9.57 : 1
   'Natural speed' for length: 14.83 kts
   Power going to wave formation at top speed: 74 %
   Trim (Max stability = 0, Max steadiness = 100): 76
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      10.17 ft / 3.10 m
      - Forecastle (15 %):   9.19 ft / 2.80 m
      - Mid (50 %):      8.20 ft / 2.50 m
      - Quarterdeck (15 %):   8.20 ft / 2.50 m
      - Stern:      8.20 ft / 2.50 m
      - Average freeboard:   8.58 ft / 2.62 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 184.9 %
      - Above water (accommodation/working, high = better): 52.3 %
   Waterplane Area: 3,233 Square feet or 300 Square metres
   Displacement factor (Displacement / loading): 40 %
   Structure weight / hull surface area: 25 lbs/sq ft or 123 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.40
      - Overall: 0.55
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Caution: Lacks seaworthiness - very limited seakeeping ability

[Laertes]

Given the low range on her, the discomfort might not be such an issue. 3000@14kn is nine days cruising, unless you're fond of oilers.

[mentat]

  I'm no expert on DDs - but freeboard of just 8.5' seems pretty low to me - I'd have thought 11' - 12' - anyone have historical data on this ??

And beam too narrow??

[Guinness]

I've done a lot of work on historic destroyer freeboards:

http://www.navalism.org/index.php?topic=4588.0

[Blooded]

I think they are great examples of what Navalism Light DDs should look like, especially on the light tonnage. #3 is my favorite, a great escort. Not sure if they are the best for Maori needs but they would suit the confines of the Baltic or coastal regions well. I would do a bit different but I am taking notes!  ;)

[Valles]

They're not exactly what I'd call 'fleet boats', no. Their design priorities are a six-month build time and a measure of combat cost-effectiveness. Other factors - like suitability for the open South Pacific - necessarily go by the wayside to feed those twin beasts.

Ultimately, they're essentially a 'Need hulls! Now!' design, the bare-bones needed for their mission.

[Jefgte]

NUS made some studies about the max 70m DDs (in the same time of the CTB200 study)
& If I remember well, they were 550t - 10% heavier than Maoria projects.

10% heavier could resolve some of your difficult choices.


Jef

[Valles]

Probably one or two, at least. But that would also put it over the maximum cut-off for a build-time of under six months, per the rules, effectively making construction take the full year rather than one half. If I'm going to be tying up a dock for that long, I might as well go for a full-featured design like the thousand-tonners I've been building before this.

[P3D]

I'd consider building a 70m+ version (current rules like long destroyers) if you have adequate number of 120m slipways compared to the number you want to build.