WW2 battleships proved to be very survivable against gunfire at close range - think of Bismarck, South Dakota and Scharnhorst to name but three ships that survived a torrent of gunfire before two of them were torpedoed. But the critical damage was always done at long range by plunging fire which all too often managed to penetrate beneath the waterline or destroy some vital part of the superstructure. WW2 ships had much deeper belts than their WW1 counterparts but the main belt could never cover far enough beneath the waterline to protect from plunging fire. The KGV's had perhaps the deepest main belts of all the WW2 designs but even they were inadequate since Prince of Wales was holed beneath the waterline by Prinz Eugene's 8" guns. It was Prince of Wales that scored the vital hit on Bismarck by puncturing the fuel tanks beneath Bismarck's belt with plunging fire at long range. Warspbite holed Guilo Cesare in the bow in the same way.
A better solution would have been to consider protecting the hull from the waterline down rather than from the waterline up. More consideration should have been given to deck armour and to box type protection around the engineering spaces and magazines. I will develop this theory by taking one of my own designs and changing the armour scheme. It would mean a much reduced belt but increased TBH and a return to armoured bulges.
Something like this?
HMS Trafalgar,
GB Battleship laid down 1937
Displacement:
36,229 t light; 38,012 t standard; 39,646 t normal; 40,953 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(816.30 ft / 800.00 ft) x 100.00 ft (Bulges 104.00 ft) x (31.00 / 31.80 ft)
(248.81 m / 243.84 m) x 30.48 m (Bulges 31.70 m) x (9.45 / 9.69 m)
Armament:
8 - 15.00" / 381 mm 42.0 cal guns - 1,920.00lbs / 870.90kg shells, 100 per gun
Breech loading guns in turret on barbette mounts, 1937 Model
4 x Twin mounts on centreline ends, evenly spread
2 raised mounts - superfiring
16 - 4.50" / 114 mm 45.0 cal guns - 45.95lbs / 20.84kg shells, 250 per gun
Dual purpose guns in deck and hoist mounts, 1937 Model
8 x Twin mounts on sides, evenly spread
32 - 1.57" / 40.0 mm 45.0 cal guns - 1.97lbs / 0.89kg shells, 1,000 per gun
Anti-air guns in deck mounts, 1937 Model
16 x Twin mounts on sides, evenly spread
Weight of broadside 16,158 lbs / 7,329 kg
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 380.00 ft / 115.82 m 10.00 ft / 3.05 m
Ends: 1.00" / 25 mm 420.00 ft / 128.02 m 12.12 ft / 3.69 m
Upper: 1.00" / 25 mm 520.00 ft / 158.50 m 15.00 ft / 4.57 m
Main Belt covers 73 % of normal length
- Torpedo Bulkhead:
3.00" / 76 mm 520.00 ft / 158.50 m 28.51 ft / 8.69 m
- Hull Bulges:
6.00" / 152 mm 520.00 ft / 158.50 m 11.00 ft / 3.35 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 15.0" / 381 mm 8.00" / 203 mm 15.0" / 381 mm
2nd: 2.00" / 51 mm 2.00" / 51 mm 2.00" / 51 mm
3rd: 2.00" / 51 mm - -
- Armoured deck - multiple decks: 6.00" / 152 mm For and Aft decks
Forecastle: 2.00" / 51 mm Quarter deck: 4.00" / 102 mm
- Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 124,793 shp / 93,095 Kw = 30.00 kts
Range 7,000nm at 13.00 kts
Bunker at max displacement = 2,940 tons
Complement:
1,404 - 1,826
Cost:
£16.177 million / $64.708 million
Distribution of weights at normal displacement:
Armament: 2,212 tons, 5.6 %
Armour: 14,900 tons, 37.6 %
- Belts: 2,576 tons, 6.5 %
- Torpedo bulkhead: 1,646 tons, 4.2 %
- Bulges: 1,270 tons, 3.2 %
- Armament: 3,467 tons, 8.7 %
- Armour Deck: 5,841 tons, 14.7 %
- Conning Tower: 100 tons, 0.3 %
Machinery: 3,459 tons, 8.7 %
Hull, fittings & equipment: 15,409 tons, 38.9 %
Fuel, ammunition & stores: 3,417 tons, 8.6 %
Miscellaneous weights: 250 tons, 0.6 %
- Hull above water: 250 tons
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
68,773 lbs / 31,195 Kg = 40.8 x 15.0 " / 381 mm shells or 12.8 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 6.1 ft / 1.9 m
Roll period: 17.6 seconds
Steadiness - As gun platform (Average = 50 %): 61 %
- Recoil effect (Restricted arc if above 1.00): 0.67
Seaboat quality (Average = 1.00): 1.15
Hull form characteristics:
Hull has low quarterdeck ,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.538 / 0.542
Length to Beam Ratio: 7.69 : 1
'Natural speed' for length: 32.83 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 53
Bow angle (Positive = bow angles forward): 27.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 32.00 ft / 9.75 m, 22.00 ft / 6.71 m
- Forward deck: 30.00 %, 22.00 ft / 6.71 m, 22.00 ft / 6.71 m
- Aft deck: 35.00 %, 22.00 ft / 6.71 m, 22.00 ft / 6.71 m
- Quarter deck: 15.00 %, 18.00 ft / 5.49 m, 18.00 ft / 5.49 m
- Average freeboard: 22.20 ft / 6.77 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 72.6 %
- Above water (accommodation/working, high = better): 171.5 %
Waterplane Area: 57,461 Square feet or 5,338 Square metres
Displacement factor (Displacement / loading): 118 %
Structure weight / hull surface area: 201 lbs/sq ft or 983 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.21
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
