WesWorld

A design possibly to be laid down later in the year.


Z-300, German Destroyer laid down 1934

Displacement:
1,995 t light; 2,097 t standard; 2,319 t normal; 2,497 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(408.60 ft / 393.70 ft) x 37.40 ft x (13.12 / 13.78 ft)
(124.54 m / 120.00 m) x 11.40 m x (4.00 / 4.20 m)

Armament:
6 - 5.04" / 128 mm 45.0 cal guns - 61.73lbs / 28.00kg shells, 240 per gun
Dual purpose guns in deck and hoist mounts , 1934 Model
3 x Twin mounts on centreline ends, majority forward
1 raised mount - superfiring
8 - 1.46" / 37.0 mm 83.0 cal guns - 1.77lbs / 0.80kg shells, 450 per gun
Anti-air guns in deck mounts , 1928 Model
2 x Twin mounts on centreline, aft evenly spread
2 raised mounts
2 x Twin mounts on sides, evenly spread
16 - 0.79" / 20.0 mm 89.0 cal guns - 0.28lbs / 0.13kg shells, 900 per gun
Machine guns in deck mounts , 1934 Model
4 x 2 row quad mounts on sides, evenly spread
2 raised mounts
Weight of broadside 389 lbs / 389 kg
8 - 23.6" / 600 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -

- Conning tower: 2.76" / 70 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 42,354 shp / 31,596 Kw = 34.00 kts
Range 4,500nm at 15.00 kts
Bunker at max displacement = 400 tons

Complement:
166 - 217

Cost:
£1.270 million / $5.080 million

Distribution of weights at normal displacement:
Armament: 97 tons, 4.2 %
Armour: 45 tons, 1.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 34 tons, 1.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 10 tons, 0.4 %
Machinery: 1,065 tons, 45.9 %
Hull, fittings & equipment: 718 tons, 31.0 %
Fuel, ammunition & stores: 324 tons, 14.0 %
Miscellaneous weights: 120 tons, 5.2 %
- Hull below water: 120 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
715 lbs / 324 Kg = 11.2 x 5.0 " / 128 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.23
Metacentric height 1.7 ft / 0.5 m
Roll period: 12.1 seconds
Steadiness - As gun platform (Average = 50 %): 52 %
- Recoil effect (Restricted arc if above 1.00): 0.49
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has a flush deck,
a normal bow and small transom stern
Block coefficient (normal/deep): 0.420 / 0.431
Length to Beam Ratio: 10.53 : 1
'Natural speed' for length: 22.79 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 22.97 ft / 7.00 m, 15.58 ft / 4.75 m
- Forward deck: 30.00 %, 15.58 ft / 4.75 m, 15.58 ft / 4.75 m
- Aft deck: 35.00 %, 15.58 ft / 4.75 m, 15.58 ft / 4.75 m
- Quarter deck: 15.00 %, 15.58 ft / 4.75 m, 15.58 ft / 4.75 m
- Average freeboard: 16.17 ft / 4.93 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 170.6 %
- Above water (accommodation/working, high = better): 89.7 %
Waterplane Area: 9,530 Square feet or 885 Square metres
Displacement factor (Displacement / loading): 78 %
Structure weight / hull surface area: 39 lbs/sq ft or 191 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.73
- Overall: 0.57
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

10 tons for DC racks and charges

30 tons reserved for mine rails, mines, and future growth


80 tons for autoloading 12.8 cm guns.

Autoloading guns? I understand power ramming etc. to be wildly spread in WW but autoloading is a bit more than that, right?

It's the same thing, basically, as what the Russian are doing with their 130mms. When everything's working right (and it may not be for a while) there's no manual interaction with the shell in the upper part of the mount (down inside the mount the shell has to get loaded into the system manually). The shell comes up into the mount and drops into the fuzing tray, where the fuze is set, then it's flipped into the loading tray and rammed (since the gun is based on the German 12.8 cm/45, the round is a 1-piece round).

You're most likely better off in putting some men into the system. It most likely won't be mechanically reliable enough for moving the shell from the handling room, rotating it, onto fuzing tray, onto loading tray, ramming, and then ejecting the cartridge. I put some considerable thought into the process for that 152/53DP gun. I reckoned that the best thing to do would be to have men loading the trays. So a hoist that brings up the shell horizontally. This is then placed on to the fuzing tray, rolled/moved onto the loading tray and then rammed. The cartridge is then ejected on the opposite side.

40tons is a lot of weight for the system. It probably wouldn't weigh much more than 10tons but space in the turret and development time more important.

It's not 40 tons per turret, it's 80 tons for 3 turrets, so 26.667 etc tons per turret (I ran the design with 3 guns per turret then kicked the 3rd gun out to use for the weight of the system). Yeah, the mechanisms themselves won't add that much weight, but the extra weight is there to cover the larger turrets needed and the mechanisms.

There's provision for manual intervention in the system, but the idea is to keep it to (ideally) none and to a minimum when it must happen. The fixed rounds are 108 pounds apiece, so by preference the crew won't be involved directly after the round gets onto the ammunition hoists.

Conceptually it works like this: the round comes up vertically (shell first) on the ammunition hoist and at the top of the cycle is moved to the fuze setter and is fuzed appropriately. Once that's done, the rounds slides out (case first) onto the loading tray. The loading tray, now loaded, matches the angle of the ramming tray and dumps the round onto the ramming tray after the previous round fires, where the rammer rams it home. Ejection takes place on the other side. This allows all-angle loading, which increases rate of fire. Fixed-angle loading would be simpler, removing the step of matching the angle of the ramming tray but slows rate of fire for most angles since it will take longer to point the barrel then to point the loading tray.

In manual operation, the round can be move to the fuzing station manually, then either moved to the loading tray manually or the loading tray can be skipped entirely and the round dropped onto the ramming tray.

Krupp was demonstrating a prototype gun during the test-off between them and Rheinmetall in 1933, and there's now (in 1934) another mounting undergoing testing at Krupp's Meppen range. But of course those are on land, not at sea, so the sea-trials are likely to show more problems that they haven't seen yet. I doubt the system will be ready for prime-time for a couple years or more, but at least with a one-piece round I won't have to deal with the additional issues auto-loading separate rounds brings.

How does ship movements influence the siystem (jamming?)?

Quite considerably. You need quite tight tolerances for parts of the operation but the flexing of the ship could (and most likely will) cause jams in these parts. This was the problem with the KGV class. You could just build a stiffer ship. Another easier alternative is to put a man in the system as he isn't effected by the movement.

The current generation of automatic weapons seem to be more about reducing crew numbers than increasing firepower.

Quoted

(I ran the design with 3 guns per turret then kicked the 3rd gun out to use for the weight of the system). Yeah, the mechanisms themselves won't add that much weight, but the extra weight is there to cover the larger turrets needed and the mechanisms

...is that it automatically gives you a 50% increase in ammunition supply, to support the increased firing rate.

For this type of weapon there probably won't be any increased firing rate. They'll probably max out around 20rpm but be able to sustain that rate.

I think what he meant was that siming as triples gives you additional weight for an extra 150 (or whatever you sim) shells for the twin mount once you kick out the third gun.

Exactly. Mine doesn't have an increased ammo supply, I'm figuring on a rate of fire of 16 rpm or so, which is certainly well within the capability of a manually loaded weapon of this size. The advantage is mostly in consistency: the mechanisms don't get tired and slow down, which is important for firing rounds when you're having to calculate the lead in advance.

Quoted

Originally posted by thesmilingassassin
I think what he meant was that siming as triples gives you additional weight for an extra 150 (or whatever you sim) shells for the twin mount once you kick out the third gun.

My point was that the extra capacity isn't needed as the automatic version won't fire much faster than a manual/power assist version.

An alternative way to get the same testing, at less cost and in less time: refit the lead ship of the Z-203 class of destroyers, which has now reached it's ten years in service date. Combine the refit of the weapons with a life-extension refit, and the cost is very reasonable and it prepares the ship for another 15 years of service.


Z-203, Germany Destroyer laid down 1924

Displacement:
1,486 t light; 1,554 t standard; 1,680 t normal; 1,780 t full load

Dimensions: Length overall / water x beam x draught
355.78 ft / 350.07 ft x 35.10 ft x 11.81 ft (normal load)
108.44 m / 106.70 m x 10.70 m x 3.60 m

Armament:
4 - 5.04" / 128 mm guns (2x2 guns), 63.99lbs / 29.02kg shells, 1934 Model
Quick firing guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1929 Model
Machine guns in deck mounts
on centreline, all amidships, 2 raised mounts - superfiring
Weight of broadside 258 lbs / 117 kg
Shells per gun, main battery: 240
8 - 23.6" / 600 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm -
2nd: 0.98" / 25 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 34,364 shp / 25,636 Kw = 33.56 kts
Range 4,500nm at 12.00 kts
Bunker at max displacement = 225 tons

Complement:
130 - 170

Cost:
£0.613 million / $2.452 million

Distribution of weights at normal displacement:
Armament: 32 tons, 1.9 %
Armour: 17 tons, 1.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 17 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 851 tons, 50.7 %
Hull, fittings & equipment: 546 tons, 32.5 %
Fuel, ammunition & stores: 193 tons, 11.5 %
Miscellaneous weights: 40 tons, 2.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
473 lbs / 215 Kg = 7.4 x 5.0 " / 128 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.18
Metacentric height 1.4 ft / 0.4 m
Roll period: 12.4 seconds
Steadiness - As gun platform (Average = 50 %): 66 %
- Recoil effect (Restricted arc if above 1.00): 0.44
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.405
Length to Beam Ratio: 9.97 : 1
'Natural speed' for length: 21.63 kts
Power going to wave formation at top speed: 67 %
Trim (Max stability = 0, Max steadiness = 100): 66
Bow angle (Positive = bow angles forward): 15.00 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 (20 %): 14.76 ft / 4.50 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (15 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 15.29 ft / 4.66 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 181.7 %
- Above water (accommodation/working, high = better): 73.7 %
Waterplane Area: 7,874 Square feet or 732 Square metres
Displacement factor (Displacement / loading): 65 %
Structure weight / hull surface area: 36 lbs/sq ft or 176 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.06
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

The misc. weight is entirely devoted to the autoloading 128mm mountings.

Another 10years before the hull is 20years old and then needs a 50% rebuild (but it'll be scrap anyway by that point)

I'd maybe go with a larger vessel to test the guns on. For testing the RN's new 5.25" HMS Iron Duke was used with B turret replaced by a 5.25" one.

Using something the size of Iron Duke would be prohibitive under our rules, the costs would be higher than a purpose-built ship. I could refit one of my CLs, but I don't have that many of those that I can really afford to use one as a test-bed.