Destroyer rules

[Desertfox]

If it has a cross-sectional coefficient less than one, it is classified as a destroyer.

Thats going to cripple all of my Light Cruiser designs, all of which have BCs below 1.00. 

These are the rules we have at Wesworld and they have worked out pretty well. Note that they allow BCs below 1.00 for ships under 6,000 tons. Perhaps we could have something similar like:

<1,000t =0.50+ BC
1,000-2,000t =0.75+ BC
>2,000t =1.00+ BC

Design Rules for Gentlemen             

Point 1: Hull strength.
a) Relative composite hull strength should not drop below 1.00 except for the light fast combattants (<6000 tons; >24kn)
b) Relative cross-sectional hull strength of light fast combattants should not drop below 0.50
c) In general, light fast combattants smaller than 4000 tons can have a minimum relative composite hull strength of 0.50 as long as it does not cross the limit as given in point 1b.
d) (not sure about this one; do remember that we discussed this bit.) In general, light fast combattants between 4000 tons and 6000 tons can have a minimum relative composite hull strength of 0.75

Point 2: Length:Beam ratio.
(as currently proposed)
a) Ships of 8000 tons and smaller => maximum 12:1
b) Ships bigger than 8000 tons => maximum 10:1

Point 5: Block Coefficient
No bc less than 0.38 is allowed. Only small high speed planing or semi-planing hulls are allowed to have a bc  smaller than that.

[Borys]

Thats going to cripple all of my Light Cruiser designs, all of which have BCs below 1.00. 

Interestingly,  I don't think anybody else has.

A destroyer is a small, flimsy small thing designed to deliver torpedos. Thus a "small fast combatant". A cruiser is more solid, for gun fights.
Either one or the other.

Borys

[Desertfox]

Probably because no one else has a need for fast (25-27kt) light (<2,000t) cruisers. For the NSN those ships are critical as Destroyer Leaders.

[Borys]

Ahoj!
LOL!
EVERYBODY needs fast small cruisers. This is what the Habsburgs are using. Would be even better with 1909 powerplant.

Kaiserlch-Keoniglich Kriegsmarine Kleiner Kreuzer 1904


SMS Uhlan Mod, Austria Klein Kreuzer laid down 1903 (Engine 1908)

Displacement:
2 375 t light; 2 457 t standard; 2 770 t normal; 3 021 t full load

Dimensions: Length overall / water x beam x draught
360,89 ft / 360,89 ft x 39,37 ft x 16,40 ft (normal load)
110,00 m / 110,00 m x 12,00 m x 5,00 m

Armament:
7 - 3,94" / 100 mm guns in single mounts, 33,07lbs / 15,00kg shells, 1903 Model
Breech loading guns in deck mounts with hoists
on side, evenly spread
Pair fore, pair (non crossdecking) amidships, pair aft, singelton aft. Usually 5 guns can be brought to same bearing
4 - 1,46" / 37,0 mm guns in single mounts, 1,55lbs / 0,70kg shells, 1903 Model
Quick firing guns in deck mounts
on side, all amidships
2 - 0,43" / 11,0 mm guns in single mounts, 0,04lbs / 0,02kg shells, 1903 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 238 lbs / 108 kg
Shells per gun, main battery: 200
4 - 14,0" / 356 mm above water torpedoes

Armour:

- Armour deck: 1,24" / 32 mm

Machinery:
Coal fired boilers, steam turbines,
Direct drive, 2 shafts, 21 295 shp / 15 886 Kw = 26,50 kts
Range 5 000nm at 10,00 kts
Bunker at max displacement = 564 tons (100% coal)

Complement:
190 - 248

Cost:
£0,271 million / $1,083 million

Distribution of weights at normal displacement:
Armament: 27 tons, 1,0%
Armour: 203 tons, 7,3%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 0 tons, 0,0%
- Armour Deck: 203 tons, 7,3%
- Conning Tower: 0 tons, 0,0%
Machinery: 1 175 tons, 42,4%
Hull, fittings & equipment: 945 tons, 34,1%
Fuel, ammunition & stores: 395 tons, 14,3%
Miscellaneous weights: 25 tons, 0,9%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1 663 lbs / 754 Kg = 54,5 x 3,9 " / 100 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,39
Metacentric height 2,2 ft / 0,7 m
Roll period: 11,1 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,19
Seaboat quality (Average = 1.00): 1,24

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,416
Length to Beam Ratio: 9,17 : 1
'Natural speed' for length: 19,00 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 57
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20,41 ft / 6,22 m
- Forecastle (20%): 12,99 ft / 3,96 m
- Mid (50%): 12,99 ft / 3,96 m
- Quarterdeck (15%): 12,99 ft / 3,96 m
- Stern: 12,99 ft / 3,96 m
- Average freeboard: 13,59 ft / 4,14 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 146,2%
- Above water (accommodation/working, high = better): 105,1%
Waterplane Area: 8 834 Square feet or 821 Square metres
Displacement factor (Displacement / loading): 98%
Structure weight / hull surface area: 61 lbs/sq ft or 296 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,92
- Longitudinal: 2,01
- Overall: 1,00
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
Good seaboat, rides out heavy weather easily
********************************


With 1909 Engine and 10% oil I put 4x6 inch on her.

Borys

[Desertfox]

Since we never had detailed rules on this I have been using the Wesworld ones, and still think we should use them, as they have worked fine for a long time.

For comparision the NSN Pegasus and Jaguar class LCs:

NSS Pegasus, New Switzerland Light Cruiser laid down 1902 (Engine 1907)

Displacement:
   1,603 t light; 1,673 t standard; 1,929 t normal; 2,133 t full load

Dimensions: Length overall / water x beam x draught
   270.00 ft / 270.00 ft x 25.00 ft x 20.00 ft (normal load)
   82.30 m / 82.30 m x 7.62 m  x 6.10 m

Armament:
      2 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1902 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
      2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1902 Model
     Quick firing guns in deck mounts
     on side, all amidships
      2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1902 Model
     Quick firing guns in deck mounts
     on centreline, evenly spread
      4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1902 Model
     Breech loading guns in deck mounts
     on side, evenly spread
   Weight of broadside 344 lbs / 156 kg
   Shells per gun, main battery: 150
   4 - 19.7" / 500.38 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.50" / 13 mm         -               -
   2nd:   0.20" / 5 mm         -               -

   - Armour deck: 1.20" / 30 mm, Conning tower: 2.00" / 51 mm

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 2 shafts, 22,079 shp / 16,471 Kw = 27.00 kts
   Range 5,900nm at 9.00 kts
   Bunker at max displacement = 460 tons (100% coal)

Complement:
   145 - 189

Cost:
   £0.233 million / $0.934 million

Distribution of weights at normal displacement:
   Armament: 43 tons, 2.2 %
   Armour: 111 tons, 5.7 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 4 tons, 0.2 %
      - Armour Deck: 100 tons, 5.2 %
      - Conning Tower: 7 tons, 0.3 %
   Machinery: 1,008 tons, 52.3 %
   Hull, fittings & equipment: 441 tons, 22.9 %
   Fuel, ammunition & stores: 325 tons, 16.9 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     422 lbs / 191 Kg = 3.9 x 6.0 " / 152 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.26
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 10.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.72
   Seaboat quality  (Average = 1.00): 1.60

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.500
   Length to Beam Ratio: 10.80 : 1
   'Natural speed' for length: 16.43 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 44
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      17.00 ft / 5.18 m
      - Forecastle (20 %):   14.00 ft / 4.27 m
      - Mid (50 %):      14.00 ft / 4.27 m
      - Quarterdeck (15 %):   14.00 ft / 4.27 m
      - Stern:      14.00 ft / 4.27 m
      - Average freeboard:   14.24 ft / 4.34 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 185.9 %
      - Above water (accommodation/working, high = better): 53.0 %
   Waterplane Area: 4,497 Square feet or 418 Square metres
   Displacement factor (Displacement / loading): 60 %
   Structure weight / hull surface area: 33 lbs/sq ft or 160 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.56
      - Longitudinal: 5.24
      - Overall: 0.70
   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
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather


***


NSS Panther, New Switzerland Light Cruiser laid down 1904 (Engine 1908)

Displacement:
   1,950 t light; 2,049 t standard; 2,583 t normal; 3,009 t full load

Dimensions: Length overall / water x beam x draught
   350.00 ft / 350.00 ft x 35.00 ft x 15.70 ft (normal load)
   106.68 m / 106.68 m x 10.67 m  x 4.79 m

Armament:
      5 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1904 Model
     Breech loading guns in deck mounts
     on centreline, evenly spread, 3 raised mounts
      8 - 1.57" / 40.0 mm guns (4x2 guns), 1.95lbs / 0.88kg shells, 1904 Model
     Quick firing guns in deck mounts
     on side, evenly spread
      4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1904 Model
     Breech loading guns in deck mounts
     on side, evenly spread
   Weight of broadside 556 lbs / 252 kg
   Shells per gun, main battery: 150
   4 - 20.0" / 508 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.00" / 51 mm         -               -

   - Armour deck: 2.00" / 51 mm, Conning tower: 2.00" / 51 mm

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 2 shafts, 16,559 shp / 12,353 Kw = 25.00 kts
   Range 9,110nm at 10.00 kts
   Bunker at max displacement = 960 tons (100% coal)

Complement:
   180 - 235

Cost:
   £0.251 million / $1.006 million

Distribution of weights at normal displacement:
   Armament: 69 tons, 2.7 %
   Armour: 337 tons, 13.1 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 35 tons, 1.4 %
      - Armour Deck: 294 tons, 11.4 %
      - Conning Tower: 8 tons, 0.3 %
   Machinery: 891 tons, 34.5 %
   Hull, fittings & equipment: 627 tons, 24.3 %
   Fuel, ammunition & stores: 632 tons, 24.5 %
   Miscellaneous weights: 25 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,380 lbs / 626 Kg = 12.8 x 6.0 " / 152 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.52
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 10.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.36
   Seaboat quality  (Average = 1.00): 1.54

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.470
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 18.71 kts
   Power going to wave formation at top speed: 55 %
   Trim (Max stability = 0, Max steadiness = 100): 46
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      17.00 ft / 5.18 m
      - Forecastle (20 %):   14.00 ft / 4.27 m
      - Mid (50 %):      14.00 ft / 4.27 m
      - Quarterdeck (15 %):   12.00 ft / 3.66 m
      - Stern:      12.00 ft / 3.66 m
      - Average freeboard:   13.59 ft / 4.14 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 133.5 %
      - Above water (accommodation/working, high = better): 90.1 %
   Waterplane Area: 7,947 Square feet or 738 Square metres
   Displacement factor (Displacement / loading): 94 %
   Structure weight / hull surface area: 41 lbs/sq ft or 201 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.64
      - Longitudinal: 1.64
      - Overall: 0.71
   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
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[Ithekro]

Those are actually a little light even for Wesworld rules.

- Cross-sectional: should be 0.75
If not then the  - Overall: should be 0.75 for such light fast vessels...other that the much lighter destroyers.  Below that you start risking some serious structural problems, and probbably lower than average hull life expectancy.

[Desertfox]

Both of them fit WW rules being under 2,000 tons.

Id say any ship faster than 24kts and smaller than 2,000 tons should be allowed overall strength of 0.75, ships faster than 24kts and smaller than 3,000 tons allowed 0.90. While we're at it no transome sterns until say 1915? and then only on ships 30+ kts.

[P3D]

I see no reason at all to change the rules.
You have to allow 0.5 hull strength to even approach historical 2000t destroyer designs.

If you want hull strength below 1.00 and speeds above 25-27kts, you are limited in size to what your destroyer tech allows. If you want something bigger, you must have a hull strength of 1.00.

[Desertfox]

So we are going to have knee jerk ships? In which a 700 ton ship is twice as good as an 800 ton one?

Why not an incremental system in which if you have 500 ton destroyers, you are allowed 0.75 up to 1,000 ton ships and 0.9 up to 1,500 ton. With 1,000 ton DDs it would be 0.75 to 2,000 tons, and 0.9 to 3,000 tons?

[P3D]

If your technology is not advanced enough to have a light powerplant for a 800t ship  then yes. Of course, you can develop the necessary technologies. And the lack of historical precendence for the existance of <2000t fast scout cruisers shows that the simplification of the rules is justified.

Otherwise we would have 2000t "destroyers" with 32 knots speed, 5x5" guns and 4000nm@15kts endurance in 1910.

[Ithekro]

Question:  Grandfathered ships and the design lineage of same.  Looking at the majority of the Swiss fleet, most of the faster ships don't fit into these rules. (or many of the other rules for that matter)  However they did fit (I suppose) into the previous set of rules?

What happens to these vessels and their future kin, if one follows a design style (Fischer ships it seems...fast, fairly weak hulled, heavily armed in many cases)?

[P3D]

There was only one nation that did use weak hulled ships larger than destroyers.
Operating experience with those ships showed that they are weak structurally, and need much more frequent repairs. It does not have much effect on their readiness, but naval architects are inclined not to use such a weak hulls as previously.

So their lineage is a dead end.

[Borys]

Ahoj!
In other words:
- no more under 1,0 hull strength cruisers
- no more (unresearched) turbo-electric destroyers and cruisers
- no (more) transom sterns

Borys

[Ithekro]

Well that's that I suppose.

Grandfathered ships stay as something like design experiments (flawed but servicable)

New vessels need to follow the rules.  If we find the rules don't function as intended later, then they will probably be ammended, if the change is not for abuse, but because it follows a logical historical pattern.