Next generation DD from Design Bureau Hamburg

[ledeper]

Dd 43-, Enter country Enter ship type laid down 1920

Displacement:
   1.410 t light; 1.516 t standard; 1.942 t normal; 2.283 t full load

Dimensions: Length overall / water x beam x draught
   390,03 ft / 387,14 ft x 42,16 ft x 11,32 ft (normal load)
   118,88 m / 118,00 m x 12,85 m  x 3,45 m

Armament:
      8 - 4,92" / 125 mm guns (4x2 guns), 59,59lbs / 27,03kg shells, 1920 Model
     Quick firing guns in deck mounts
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,88kg shells, 1920 Model
     Anti-aircraft guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 485 lbs / 220 kg
   Shells per gun, main battery: 250
   2 - 19,7" / 500 mm above water torpedoes

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 25.664 shp / 19.145 Kw = 29,75 kts
   Range 9.500nm at 14,00 kts
   Bunker at max displacement = 767 tons

Complement:
   146 - 190

Cost:
   £0,501 million / $2,003 million

Distribution of weights at normal displacement:
   Armament: 61 tons, 3,1 %
   Machinery: 798 tons, 41,1 %
   Hull, fittings & equipment: 476 tons, 24,5 %
   Fuel, ammunition & stores: 533 tons, 27,4 %
   Miscellaneous weights: 75 tons, 3,9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     704 lbs / 319 Kg = 11,8 x 4,9 " / 125 mm shells or 0,4 torpedoes
   Stability (Unstable if below 1.00): 1,90
   Metacentric height 3,8 ft / 1,2 m
   Roll period: 9,0 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0,11
   Seaboat quality  (Average = 1.00): 0,99

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,368
   Length to Beam Ratio: 9,18 : 1
   'Natural speed' for length: 19,68 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   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:      16,40 ft / 5,00 m
      - Forecastle (10 %):   11,48 ft / 3,50 m
      - Mid (50 %):      11,48 ft / 3,50 m
      - Quarterdeck (15 %):   11,48 ft / 3,50 m
      - Stern:      11,48 ft / 3,50 m
      - Average freeboard:   11,68 ft / 3,56 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 162,3 %
      - Above water (accommodation/working, high = better): 137,5 %
   Waterplane Area: 9.916 Square feet or 921 Square metres
   Displacement factor (Displacement / loading): 83 %
   Structure weight / hull surface area: 33 lbs/sq ft or 161 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,50
      - Longitudinal: 0,72
      - Overall: 0,52
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is excellent
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Trial Speed: 30 knts
Range at max speed: 1300 Nm.
Torpedoes:20 tns 4 reloads
L/R W/L 25 tns
Reserve  : 30 tns   

[miketr]

AA guns in casements?  Also I would halve the number of main guns and put them in mount and hoist.  Increase size to get some more speed too.

Michael

[P3D]

Slow. I'd expect pretty one-sided encounters with enemy light cruisers.

[Tanthalas]

Way to slow, CLs & CAs are making 30+ knots hell my 1500 ton DD is making 33 (for operating with 30+ knot CLs & CAs).  I think a runin with any of the 30+ knot CLs would make for a bad day for these.

[The Rock Doctor]

BC is too low.

[TexanCowboy]

4 reloads per tube? :o.

[ctwaterman]

More Tubes Less Reloads.
And what everyone else said and maybe some depth charges

Charles

[maddox]

Buying a few Italian 5" twin mount and hoists , and using the standard French 37mm AA mounts, as well the heavy CSA 21 torpedo's, I get this.

Anti-DD43, French  Contre-torpilleur laid down 1920

Displacement:
   1.499 t light; 1.583 t standard; 1.915 t normal; 2.181 t full load

Dimensions: Length overall / water x beam x draught
   393,70 ft / 393,70 ft x 32,81 ft x 9,84 ft (normal load)
   120,00 m / 120,00 m x 10,00 m  x 3,00 m

Armament:
     8 - 5,00" / 127 mm guns (4x2 guns), 55,12lbs / 25,00kg shells, 1920 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
     4 - 1,46" / 37,0 mm guns, 1,55lbs / 0,70kg shells, 1920 Model
     Quick firing guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 447 lbs / 203 kg
   Shells per gun, main battery: 180
   8 - 21,0" / 533,4 mm above water torpedoes

Armour:
  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,50" / 13 mm   0,50" / 13 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 30.507 shp / 22.758 Kw = 30,75 kts
  Trial speed 31.5 kts
   Range 6.200nm at 15,00 kts
   Bunker at max displacement = 598 tons

Complement:
   144 - 188

Cost:
   £0,536 million / $2,142 million

Distribution of weights at normal displacement:
   Armament: 63 tons, 3,3%
   Armour: 14 tons, 0,7%
      - Belts: 0 tons, 0,0%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 14 tons, 0,7%
      - Armour Deck: 0 tons, 0,0%
      - Conning Tower: 0 tons, 0,0%
   Machinery: 864 tons, 45,1%
   Hull, fittings & equipment: 517 tons, 27,0%
   Fuel, ammunition & stores: 416 tons, 21,7%
   Miscellaneous weights: 41 tons, 2,1%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     472 lbs / 214 Kg = 7,5 x 5,0 " / 127 mm shells or 0,3 torpedoes
   Stability (Unstable if below 1.00): 1,22
   Metacentric height 1,4 ft / 0,4 m
   Roll period: 11,8 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0,80
   Seaboat quality  (Average = 1.00): 1,03

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0,527
   Length to Beam Ratio: 12,00 : 1
   'Natural speed' for length: 19,84 kts
   Power going to wave formation at top speed: 61 %
   Trim (Max stability = 0, Max steadiness = 100): 69
   Bow angle (Positive = bow angles forward): -5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      21,33 ft / 6,50 m
      - Forecastle (30%):   16,40 ft / 5,00 m (11,48 ft / 3,50 m aft of break)
      - Mid (50%):      11,48 ft / 3,50 m
      - Quarterdeck (10%):   11,15 ft / 3,40 m
      - Stern:      10,83 ft / 3,30 m
      - Average freeboard:   13,44 ft / 4,10 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 173,4%
      - Above water (accommodation/working, high = better): 76,1%
   Waterplane Area: 8.824 Square feet or 820 Square metres
   Displacement factor (Displacement / loading): 71%
   Structure weight / hull surface area: 33 lbs/sq ft or 161 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,51
      - Longitudinal: 0,87
      - Overall: 0,54
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform


16 ton torpedo's
25 tons Fire control

Keeping it purely French, I get this

Anti-DD43 Big Gun, French  Contre-torpilleur laid down 1920

Displacement:
   1.500 t light; 1.595 t standard; 1.929 t normal; 2.196 t full load

Dimensions: Length overall / water x beam x draught
   393,70 ft / 393,70 ft x 32,81 ft x 9,84 ft (normal load)
   120,00 m / 120,00 m x 10,00 m  x 3,00 m

Armament:
     6 - 5,51" / 140 mm guns in single mounts, 92,59lbs / 42,00kg shells, 1920 Model
     Quick firing guns in deck mounts
     on centreline, evenly spread, 3 raised mounts
     4 - 1,46" / 37,0 mm guns in single mounts, 1,55lbs / 0,70kg shells, 1920 Model
     Quick firing guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 562 lbs / 255 kg
   Shells per gun, main battery: 180
   8 - 21,0" / 533,4 mm above water torpedoes

Armour:
  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,50" / 13 mm   0,50" / 13 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 33.961 shp / 25.335 Kw = 31,50 kts
 Trial speed 32 kts
   Range 6.200nm at 15,00 kts
   Bunker at max displacement = 601 tons

Complement:
   145 - 189

Cost:
   £0,554 million / $2,215 million

Distribution of weights at normal displacement:
   Armament: 64 tons, 3,3%
   Armour: 14 tons, 0,7%
      - Belts: 0 tons, 0,0%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 14 tons, 0,7%
      - Armour Deck: 0 tons, 0,0%
      - Conning Tower: 0 tons, 0,0%
   Machinery: 917 tons, 47,5%
   Hull, fittings & equipment: 465 tons, 24,1%
   Fuel, ammunition & stores: 429 tons, 22,2%
   Miscellaneous weights: 41 tons, 2,1%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     467 lbs / 212 Kg = 5,6 x 5,5 " / 140 mm shells or 0,3 torpedoes
   Stability (Unstable if below 1.00): 1,48
   Metacentric height 1,8 ft / 0,6 m
   Roll period: 10,2 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0,41
   Seaboat quality  (Average = 1.00): 1,07

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0,531
   Length to Beam Ratio: 12,00 : 1
   'Natural speed' for length: 19,84 kts
   Power going to wave formation at top speed: 63 %
   Trim (Max stability = 0, Max steadiness = 100): 66
   Bow angle (Positive = bow angles forward): -5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      21,33 ft / 6,50 m
      - Forecastle (30%):   16,40 ft / 5,00 m (11,48 ft / 3,50 m aft of break)
      - Mid (50%):      11,48 ft / 3,50 m
      - Quarterdeck (10%):   11,15 ft / 3,40 m
      - Stern:      10,83 ft / 3,30 m
      - Average freeboard:   13,44 ft / 4,10 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 181,7%
      - Above water (accommodation/working, high = better): 75,8%
   Waterplane Area: 8.856 Square feet or 823 Square metres
   Displacement factor (Displacement / loading): 66%
   Structure weight / hull surface area: 29 lbs/sq ft or 144 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,50
      - Longitudinal: 0,90
      - Overall: 0,53
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform


12 ton torpedo's
25 tons Fire control

[Guinness]

IMHO: every boat in this thread is too slow and has too many guns. If you're going to build something with 8 120 or 127mm guns but only 31ish knots on 1500 tons, you might as well dispense with the torpedoes. Despite their heavy gun battery, these boats are unlikely to ever get close enough to something worth killing with those torpedoes to use them. Their lack of speed will make maneuvering them relative to a main body formation for offensive operations difficult or impossible.

They might be useful for screening against the other guy's DDs, in which case they could be even slower. If you don't care to armor such a ship, you might as well build them to the 1.0 overall strength rules and have them make something like 27 knots.

By rule, twin mounts, even on DDs, need hoists.

Oh, and they all have too much freeboard but you already knew I was going to say that.

[maddox]

This better?

Speedo, XXXX Contre-torpilleur  laid down 1920

Displacement:
   1.495 t light; 1.562 t standard; 1.771 t normal; 1.938 t full load

Dimensions: Length overall / water x beam x draught
   393,70 ft / 393,70 ft x 32,81 ft x 10,66 ft (normal load)
   120,00 m / 120,00 m x 10,00 m  x 3,25 m

Armament:
      5 - 5,00" / 127 mm guns in single mounts, 55,12lbs / 25,00kg shells, 1920 Model
     Quick firing guns in deck mounts
     on centreline, evenly spread, 2 raised mounts
      2 - 1,46" / 37,0 mm guns in single mounts, 1,55lbs / 0,70kg shells, 1920 Model
     Anti-aircraft guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 279 lbs / 126 kg
   Shells per gun, main battery: 200
   9 - 21,0" / 533,4 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1,50" / 38 mm   1,00" / 25 mm            -
   2nd:   0,50" / 13 mm   0,50" / 13 mm            -

   - Conning tower: 3,00" / 76 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 43.323 shp / 32.319 Kw = 34,20 kts
   Trial speed 35 kts
   Range 3.500nm at 16,00 kts
   Bunker at max displacement = 376 tons

Complement:
   136 - 177

Cost:
   £0,530 million / $2,118 million

Distribution of weights at normal displacement:
   Armament: 39 tons, 2,2%
   Armour: 34 tons, 1,9%
      - Belts: 0 tons, 0,0%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 24 tons, 1,4%
      - Armour Deck: 0 tons, 0,0%
      - Conning Tower: 9 tons, 0,5%
   Machinery: 990 tons, 55,9%
   Hull, fittings & equipment: 389 tons, 22,0%
   Fuel, ammunition & stores: 276 tons, 15,6%
   Miscellaneous weights: 43 tons, 2,4%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     318 lbs / 144 Kg = 5,1 x 5,0 " / 127 mm shells or 0,2 torpedoes
   Stability (Unstable if below 1.00): 1,49
   Metacentric height 1,9 ft / 0,6 m
   Roll period: 10,1 seconds
   Steadiness   - As gun platform (Average = 50 %): 43 %
         - Recoil effect (Restricted arc if above 1.00): 0,15
   Seaboat quality  (Average = 1.00): 0,52

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,450
   Length to Beam Ratio: 12,00 : 1
   'Natural speed' for length: 19,84 kts
   Power going to wave formation at top speed: 64 %
   Trim (Max stability = 0, Max steadiness = 100): 70
   Bow angle (Positive = bow angles forward): -5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13,12 ft / 4,00 m
      - Forecastle (20%):   9,84 ft / 3,00 m
      - Mid (50%):      9,84 ft / 3,00 m
      - Quarterdeck (15%):   9,84 ft / 3,00 m
      - Stern:      9,84 ft / 3,00 m
      - Average freeboard:   10,10 ft / 3,08 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 200,2%
      - Above water (accommodation/working, high = better): 59,0%
   Waterplane Area: 8.239 Square feet or 765 Square metres
   Displacement factor (Displacement / loading): 52%
   Structure weight / hull surface area: 30 lbs/sq ft or 146 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,51
      - Longitudinal: 0,51
      - Overall: 0,51
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is cramped
   Caution: Lacks seaworthiness - very limited seakeeping ability

3 tripple torpdo mounts
25 ton FC

[Guinness]

I think that's a much more capable offensive unit, yes. 1.5" armor on the mounts is pretty thick for a DD (at least compared to OTL), but it works. Certainly a division or more of these could present quite a problem for the enemy.

[ledeper]

I have the feeling/notion that I have to chose between speed and a high seaworthiness,since these Dd has to operate in the Northern Atlantic all year round,so the emphasis is put on to the sea keeping aspect,and the qustion is :how low can you go in the question of sea-keeping?below 70 or even lower?
All criticism is welcome,so dont hold back :) ;D ;D

[maddox]

I prefer a good seakeeping, but that's mostly the result crew comfort, high freeboard means a lot of space above waterline for the crew.

French DD's will stay around >1.0 seakeeping. North sea, North Atlantic, deep South Ptlantic, long ranged Pacific missions... enough reasons for good seakeeping.

[Guinness]

Well, I think that table I posted in Naval Discussion is a good place to start. For N. Sea service the RN was quite concerned with seakeeping, but considered the S-Class and V&W classes particularly good seaboats. Their SS seakeeping number was .39 and .62. So the mean of that is about .5. Both classes did 33.3 knots on realistic trial conditions. The RN expected that it's DDs would have to slow down some in heavy seas.

I think it might be better to concentrate on average freeboard than seakeeping when designing DDs and TBs. Something between 3 and 3.7 meters average freeboard is probably perfectly reasonable. Seakeeping suffers in SS as speed goes up, of course.

I think Maddox has hit on what really dictated freeboard in OTL designs: adequate space (deck space, and to a certain extent, volume).

I don't think that the crew necessarily benefits from having extra deck headroom, however, and there are certain drawbacks in reality to high decks structurally. So I think it best to pick a standard deck height (something between 7.5 and 8 feet, I've been using 2.4 meters lately). That plus maybe a little bit sets your freeboard around the start of the quarterdeck, and if you are using the conventional raised forecastle, double that is likely the height of your forecastle deckline. Add a little more at the stem for some sheer, and you are more or less done.

As I noted in the other thread, the RN added just slightly to what we'd consider freeboard as their boats grew, but I believe that was to provide sufficient hull depth structurally as their boats got longer, and not really for any other reason. When they needed more space, they'd sometimes just extend the forecastle further aft.

[miketr]

I favor something simple like double whatever SS reports as a ships Sea Keeping for TB/DD type ships.

Michael