This class utilizes the two spare turrets removed from the battlecruiser Evanor in her convertion to experimental aircraft carrier in 1917. The twin 6" turret is of a new design while the 3" guns are the current standard AA weapon.
M1/M2, Atlantis Moniter laid down 1921
Displacement:
7,585 t light; 7,918 t standard; 8,207 t normal; 8,405 t full load
Loading submergence 736 tons/feet
Dimensions:
340.00 ft x 88.00 ft x 12.00 ft (normal load)
103.63 m x 26.82 m x 3.66 m
Armament:
2 - 12.00" / 305 mm guns (1 Main turrets x 2 guns)
2 - 6.00" / 152 mm guns
6 - 3.00" / 76 mm AA guns
8 - 1.00" / 25 mm guns
Weight of broadside 2,029 lbs / 920 kg
Armour:
Belt 2.00" / 51 mm, upper belt 2.00" / 51 mm, end belts 2.00" / 51 mm
Belts cover 100 % of normal area
Main turrets 9.00" / 229 mm, 2nd gun shields 3.00" / 76 mm
AA gun shields 1.00" / 25 mm
Armour deck 4.00" / 102 mm, Conning tower 6.00" / 152 mm
Torpedo bulkhead 6.00" / 152 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 5,675 shp / 4,233 Kw = 14.53 kts
Range 8,000nm at 8.00 kts
Complement:
431 - 560
Cost:
£1.288 million / $5.151 million
Distribution of weights at normal displacement:
Armament: 254 tons, 3.1 %
Armour: 3,423 tons, 41.7 %
Belts: 502 tons, 6.1 %, Armament: 373 tons, 4.5 %, Armour Deck: 1,907 tons, 23.2 %
Conning Tower: 53 tons, 0.6 %, Torpedo bulkhead: 589 tons, 7.2 %
Machinery: 195 tons, 2.4 %
Hull, fittings & equipment: 3,638 tons, 44.3 %
Fuel, ammunition & stores: 622 tons, 7.6 %
Miscellaneous weights: 75 tons, 0.9 %
Metacentric height 8.4
Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable and able to fight her guns in the heaviest weather
Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.52
Shellfire needed to sink: 28,058 lbs / 12,727 Kg = 32.5 x 12.0 " / 305 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 8.7
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 80 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.12
Relative quality as seaboat: 1.56
Hull form characteristics:
Block coefficient: 0.800
Sharpness coefficient: 0.57
Hull speed coefficient 'M': 5.15
'Natural speed' for length: 18.44 kts
Power going to wave formation at top speed: 43 %
Trim: 51
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)
Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 43.9 %
Relative accommodation and working space: 182.2 %
(Average = 100%)
Displacement factor: 139 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 1.01
(Structure weight / hull surface area: 121 lbs / square foot or 589 Kg / square metre)
Relative longitudinal hull strength: 2.32
(for 16.00 ft / 4.88 m average freeboard, freeboard adjustment 1.44 ft)
Relative composite hull strength: 1.09