Norse Ship Designs 1913+

[Khryses]

Hearsay had it that a certain degree of slow seakeeping was fine in a DD - and that some ships had been designed and built with a Seakeeping well below 0.9. That being said, I'm fine with taking care of my brave lads over long sea voyages!

I also checked and confirmed the shell weight and ensured these weren't classed as heavy:

As a practical matter, shells between 60 and 95kg are heavy and the ROF will slowly decrease as the crew gets tired.  Power assist will delay this. Hoists are highly recommended.

Shells over 90kg are difficult to handle and are slow to handload. Power hoists and ramming with a turret is recommended.

Bearing these tips in mind, I'm happy to present Snekkja mk3.

Any further useful input? Not sure how many rounds of design we usually do for these.

Snekkja, Norse Destroyer  laid down 1916

Displacement:
   1,500 t light; 1,588 t standard; 1,846 t normal; 2,052 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (401.90 ft / 393.70 ft) x 32.81 ft x (12.47 / 13.38 ft)
   (122.50 m / 120.00 m) x 10.00 m  x (3.80 / 4.08 m)

Armament:
      2 - 6.10" / 155 mm 50.0 cal guns - 120.29lbs / 54.56kg shells, 180 per gun
     Quick firing guns in deck mounts, 1916 Model
     2 x Single mounts on centreline, forward evenly spread
      1 raised mount
      2 - 6.10" / 155 mm 50.0 cal guns - 120.29lbs / 54.56kg shells, 180 per gun
     Quick firing guns in deck mounts, 1916 Model
     2 x Single mounts on centreline, aft evenly spread
      1 raised mount
      12 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1916 Model
     12 x Single mounts on sides, evenly spread
      Weight of broadside 483 lbs / 219 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm         -               -
   2nd:   1.18" / 30 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 31,939 shp / 23,826 Kw = 32.43 kts
   Range 5,000nm at 14.00 kts
   Bunker at max displacement = 465 tons

Complement:
   140 - 183

Cost:
   £0.342 million / $1.368 million

Distribution of weights at normal displacement:
   Armament: 92 tons, 5.0 %
      - Guns: 92 tons, 5.0 %
   Armour: 13 tons, 0.7 %
      - Armament: 13 tons, 0.7 %
   Machinery: 934 tons, 50.6 %
   Hull, fittings & equipment: 389 tons, 21.1 %
   Fuel, ammunition & stores: 346 tons, 18.8 %
   Miscellaneous weights: 71 tons, 3.8 %
      - Hull above water: 24 tons
      - On freeboard deck: 39 tons
      - Above deck: 8 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     410 lbs / 186 Kg = 3.6 x 6.1 " / 155 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.26
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 11.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.49
   Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.401 / 0.416
   Length to Beam Ratio: 12.00 : 1
   'Natural speed' for length: 19.84 kts
   Power going to wave formation at top speed: 59 %
   Trim (Max stability = 0, Max steadiness = 100): 68
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  18.37 ft / 5.60 m,  16.40 ft / 5.00 m
      - Forward deck:   30.00 %,  16.40 ft / 5.00 m,  12.47 ft / 3.80 m
      - Aft deck:   35.00 %,  8.86 ft / 2.70 m,  8.86 ft / 2.70 m
      - Quarter deck:   15.00 %,  8.86 ft / 2.70 m,  8.86 ft / 2.70 m
      - Average freeboard:      12.20 ft / 3.72 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 179.3 %
      - Above water (accommodation/working, high = better): 123.8 %
   Waterplane Area: 7,957 Square feet or 739 Square metres
   Displacement factor (Displacement / loading): 68 %
   Structure weight / hull surface area: 31 lbs/sq ft or 153 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 0.87
      - Overall: 0.53
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

Misc Weight:
-- 36t 4 x 3 21" Torpedos in swivel mounts, centreline
-- 7t 1912 FC (split between above water and above deck)
-- 3t Night Fighting Equipment
-- 25t Long Range Wireless (between hull above water and above deck)

[TacCovert4]

I think its going to be a much to lively platform for 155's and the crew is likey to get worn out quickly schlepping those rounds about. Sure, the 155 is going to end anythign sort of a 1500t can in one hit, but getting that hit might prove more challenging than with a smaller gun that can fire faster for longer. Also, the design does not have great seakeeping, so its theoretically fast speed will degrade much faster in a seaway than a comprible boat with higher seakeeping. I'd drop down to something in the 120-130mm range (I think you have such a gun available) and turn the reserve into more freeboard.

We've both played around with the larger-caliber guns on DDs.  And I think you've settled on a shorter 140, while I at least temporarily ditched the 150 in favor of a ferociously rapid twin 100 and then a balanced 130. 

However, in the case of this particular class, the big gun is growing on me.  The North Sea and the Baltic is a lot different.  Ranges are fairly short, targets fairly fleeting, visibility is often utterly crap.  Having a gun where 1 hit kills are possible, and 1 hit cripples are likely, sort of makes sense in this particular set of weather conditions. 

To make a comparison, a balanced DD gun is like having a 9mm.  Good capacity, good follow up shots, etc. etc.  Going with the 'maximum' DD gun is like having a Desert Eagle, short barreled 500 Magnum, etc.  Sure you lose capacity.  Sure your follow up shots are slower.  Sure your comparative accuracy is going to tank outside of 10 yards.  But if you run into the latter in a back alley at night, it's going to be very ugly.

[The Rock Doctor]

I have a different preference for main guns, which is fine.

I feel like the class would benefit from some tonnage allocated to ASW capabilities, though.

[TacCovert4]

True.  It's more of a 'DD Leader' or 'Torpedo Boat/Destroyer Destroyer'.  I guess it's going to be a question of whether K will be going a route with subchasers and fleet destroyers, or going the route of trying to make all of them balanced.

Overall, there aren't really all that many submarines worldwide.  I mean I don't think any nation has more than 40, and WW1 Germany had something along the lines of 5 times that during its most successful times.

[Khryses]

Taking advantage of some new/upcoming research and the new ASW rules, the Skeid-class destroyer - a shorter legged vessel designed to operate mainly in small independent divisions in friendly territorial waters (and to keep an eye out for unwelcome submarines in same).

Skeid, Norse Destroyer laid down 1917

Displacement:
   1,500 t light; 1,604 t standard; 1,678 t normal; 1,738 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (401.70 ft / 393.70 ft) x 32.81 ft x (11.97 / 12.24 ft)
   (122.44 m / 120.00 m) x 10.00 m  x (3.65 / 3.73 m)

Armament:
      6 - 6.10" / 155 mm 50.0 cal guns - 120.29lbs / 54.56kg shells, 170 per gun
     Breech loading guns in deck mounts, 1917 Model
     2 x Twin mounts on centreline, forward evenly spread
      1 raised mount
     1 x Twin mount on centreline, aft deck centre
      8 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1917 Model
     8 x Single mounts on sides, evenly spread
      Weight of broadside 723 lbs / 328 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 36,369 shp / 27,131 Kw = 34.06 kts
   Range 3,000nm at 10.00 kts
   Bunker at max displacement = 135 tons

Complement:
   130 - 170

Cost:
   £0.390 million / $1.561 million

Distribution of weights at normal displacement:
   Armament: 102 tons, 6.1 %
      - Guns: 102 tons, 6.1 %
   Armour: 10 tons, 0.6 %
      - Armament: 10 tons, 0.6 %
   Machinery: 885 tons, 52.8 %
   Hull, fittings & equipment: 435 tons, 25.9 %
   Fuel, ammunition & stores: 179 tons, 10.6 %
   Miscellaneous weights: 67 tons, 4.0 %
      - Hull below water: 10 tons
      - Hull above water: 6 tons
      - On freeboard deck: 44 tons
      - Above deck: 7 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     336 lbs / 153 Kg = 3.0 x 6.1 " / 155 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.16
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 12.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.80
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.380 / 0.385
   Length to Beam Ratio: 12.00 : 1
   'Natural speed' for length: 19.84 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 71
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  16.40 ft / 5.00 m,  13.45 ft / 4.10 m
      - Forward deck:   30.00 %,  13.45 ft / 4.10 m,  11.81 ft / 3.60 m
      - Aft deck:   35.00 %,  11.81 ft / 3.60 m,  11.81 ft / 3.60 m
      - Quarter deck:   15.00 %,  11.81 ft / 3.60 m,  11.81 ft / 3.60 m
      - Average freeboard:      12.62 ft / 3.85 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 194.4 %
      - Above water (accommodation/working, high = better): 140.1 %
   Waterplane Area: 7,846 Square feet or 729 Square metres
   Displacement factor (Displacement / loading): 54 %
   Structure weight / hull surface area: 34 lbs/sq ft or 167 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.06
      - Overall: 0.54
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

8t - 80 90kg depth charges, rails inc.
10t - FC
3t - Night Fighting Equipment
36t - 4 x 3 21" Torpedos in swivel mounts, centreline
5t hydrophones (basic)
2t - 2 ASW Twin Kites
1t - 10 ASW harpoons + locker
2t - 120m2 Electro-contact mined nets

[Desertfox]

Your BC is below 0.38, also twin 155mm mounts without mount and hoist won't have good RoF.

[The Rock Doctor]

Foxy beat me to it.

[Khryses]

Fixed up the BC. On RoF, the rounds aren't classed as "heavy" (being under 60kg) so I'd expect it to take a good few minutes before RoF begins to slow.

And if the destroyer is in a sustained gunnery duel for 30+ minutes and is still fit to continue the engagement (neither ship having taken heavy enough damage to withdraw) I'll accept the slowing RoF and keep the longer range and heavier rounds that make it less likely to be the Skeid taking the crippling hits.

Since fixing the BC meant losing the 1.22 Seakeeping, I managed to coax top speed above 34 kn.

[snip]

155 twins on a 1500t DD are going to be not-fun to use. Looking at the difficulties the KM had with the much larger Z classes armed with 150s, I dont think these weapons are going to be very serviceable at all. I think the range is also far to low for a 1916 design, you dont have a lot of wiggle room for high speed operation.

Also, I think that 3 twin 155 mounts plus four tripple tubes all on centerline is very tight for only 120m. Finding historical contemporaries is difficult, but the trend Im seeing is that most destoryers in this size range have only a pair of tube groups (typicly quads). I'd be skeptical about it all fitting with room for the uptakes and such for the massive engines.

[Desertfox]

Looking at the Fubiki and Porter classes, it should barely fit... Both have 1 less mount on 4-9m less length. It'll be cramped but doable, especially if the TT are moved to side mounted like the four stackers or dropped down to 3 mounts. The Pilums also have nearly the same issues.