WesWorld

Quoted

Originally posted by Red Admiral
I'm pretty sure that we're so different from OTL now that basing it exactly off it just won't work. I think _reasonable cause_ should be in place as well for more outlandish ideas.

I am not so sure about the first contention, and even if some field has crept ahead, one can always freeze it until the rest catches up. I think the reasonable cause mechanism is already there in the idea of letting backing stories cut more slack. The further from historic, the more I think the rational matters.

Here we've got the Danish 57mm scheduled to go into service in 1936... were there any large, functional, autocannons in service in 1941? Or, since we seem to have Italy, Iberia, Denmark, and the UK all introducing them, maybe they are not 'bleeding edge' and 1939 should be the proper time frame.

If there are, great, congrats you have a nice gun. If not, well a number of weapons over the years have not worked out in the projected time line, or simply never lived up to promise.

Only real-life one I'm familiar with is the 50mm FLaK 41, which was used but not put into full-scale production (apparently it was unstable on it's mounting at least while being towed, and not very accurate when firing).

Thanks for the comments guys. Kasier's break down was very helpful and I must agree B1 was the best choice.

Here is a revised version, by no means the final design. It has more draught, a torpedo bulkhead (one 1in and one 0.5in bulkhead) and an 8in inclined belt. (I'm still doing calcs to see if this is overkill or not)

Princess Royal Class, Great Britain Heavy Cruiser laid down 1936

Displacement:
18,676 t light; 19,666 t standard; 21,806 t normal; 23,518 t full load

Dimensions: Length overall / water x beam x draught
720.92 ft / 710.00 ft x 76.00 ft x 26.00 ft (normal load)
219.74 m / 216.41 m x 23.16 m x 7.92 m

Armament:
12 - 9.20" / 234 mm guns (4x3 guns), 510.00lbs / 231.33kg shells, 1936 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 4.50" / 114 mm guns (4x2 guns), 45.56lbs / 20.67kg shells, 1935 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships, all raised mounts - superfiring
8 - 2.24" / 57.0 mm guns (4x2 guns), 5.65lbs / 2.56kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
36 - 0.66" / 16.8 mm guns (6x6 guns), 0.14lbs / 0.06kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, 4 raised mounts - superfiring
Weight of broadside 6,535 lbs / 2,964 kg
Shells per gun, main battery: 150
8 - 24.5" / 622.3 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8.00" / 203 mm 500.00 ft / 152.40 m 10.00 ft / 3.05 m
Ends: Unarmoured
Main Belt covers 108 % of normal length

- Torpedo Bulkhead:
1.50" / 38 mm 500.00 ft / 152.40 m 24.00 ft / 7.32 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 7.00" / 178 mm 4.00" / 102 mm 7.00" / 178 mm
2nd: 1.00" / 25 mm 0.50" / 13 mm 2.00" / 51 mm
3rd: 0.50" / 13 mm - -
4th: 0.50" / 13 mm - -

- Armour deck: 3.50" / 89 mm, Conning tower: 3.00" / 76 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 116,000 shp / 86,536 Kw = 32.13 kts
Range 10,000nm at 16.00 kts
Bunker at max displacement = 3,852 tons

Complement:
896 - 1,166

Cost:
£8.666 million / $34.662 million

Distribution of weights at normal displacement:
Armament: 636 tons, 2.9 %
Armour: 6,059 tons, 27.8 %
- Belts: 1,657 tons, 7.6 %
- Torpedo bulkhead: 666 tons, 3.1 %
- Armament: 1,162 tons, 5.3 %
- Armour Deck: 2,524 tons, 11.6 %
- Conning Tower: 50 tons, 0.2 %
Machinery: 3,255 tons, 14.9 %
Hull, fittings & equipment: 8,526 tons, 39.1 %
Fuel, ammunition & stores: 3,130 tons, 14.4 %
Miscellaneous weights: 200 tons, 0.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
32,118 lbs / 14,568 Kg = 82.5 x 9.2 " / 234 mm shells or 4.6 torpedoes
Stability (Unstable if below 1.00): 1.08
Metacentric height 3.8 ft / 1.2 m
Roll period: 16.3 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.82
Seaboat quality (Average = 1.00): 1.08

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.544
Length to Beam Ratio: 9.34 : 1
'Natural speed' for length: 30.42 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 56
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 30.00 ft / 9.14 m
- Forecastle (20 %): 25.00 ft / 7.62 m
- Mid (50 %): 20.00 ft / 6.10 m
- Quarterdeck (15 %): 20.00 ft / 6.10 m
- Stern: 20.00 ft / 6.10 m
- Average freeboard: 22.15 ft / 6.75 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 99.5 %
- Above water (accommodation/working, high = better): 150.9 %
Waterplane Area: 38,981 Square feet or 3,621 Square metres
Displacement factor (Displacement / loading): 122 %
Structure weight / hull surface area: 146 lbs/sq ft or 711 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.26
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent


On the 57mm issue I have a few points.

First the gun is semi-automatic, revised specs are now; 6pdr shell will have around 1.1lbs of HE filling. Rate of fire will be around 95rpm and effective ceiling 15,500ft. Now it may be noticed some of my 1935 designs mount both 6pdr and 2pdr guns, a sign that the heavier gun lacks the RoF of the 2pdr and that it may fail in service. I was planning improved versions from 1939 onwards anyway and such a gun is a prototype system. These CAs may have quad or octuple 2pdr instead when they commission anyway, only weight concerns (and space) have stopped me putting 2pdrs on as well. The RoF in practice will be much lower than 95rpm since the guns are belt loaded. No doubt that will cause problems too. I must admit future developments I planned do include the Mollins autoloader system.

If you allow her displacement to raise to ca. 20kts is it still a wise choice to have 234mm guns?

You can have 8 or 9 28cm guns on that displacement for example and I doubt the 234mm gun offers any ROF advantage. So why the small guns?

I suspect the reason for the 9.2" guns is that that's the culturally correct bore size: the UK didn't use 28cm guns, and these 9.2" with heavy shells fire heavier rounds than the 10" guns used on a few classes of RN ships at the turn of the century (510 vs 500 pounds).

On the 57mm: ah, belt fed. For certain purposes, that's good, for others, it's bad. In the short term, firing at a single target, it's probably just fine, you won't burn through the belt (probably). But when there are several different targets coming in in quick succession, not so good, because the belts (if they contain any large number of rounds) are HEAVY, and if they don't, you have to link them together in the belt-box. The German BK.5 and MK-214 are examples of belt-fed 50mm guns, both used on aircraft (and which may see service on Luftwaffe aircraft in the future for tank-killing duties).