Lexington-Class Battlecruiser

[cv10]

    So for a lark, I decided to put the specifications for the Lexington-Class Battlecruiser into the SAI Ship Designer. As I was putting the specifications in, I noticed that the Lexington-Class Battlecruisers were only going to have a 7 Inch Armored Belt 9Ranging from 5 inches to 7 inches. This made me wonder how successful they would have been if built as battlecruisers. While the battlecruiser concept (a fast ship with battleship guns to hunt down enemy cruisers) does have a deal of merit (The Battle of the Falklands confirmed how effective they were), I think that there would have been too much temptation to try and use them in the battle-line (which tended to not work out for them). Given that they were supposed to be capable of 33 knots and have 16 inch guns, perhaps the plan was to simply have them stay out of range and hammer the enemy from afar. However I keep coming back to the armor: how would they have stood up against other modern battlecruisers (Renown-Class and the like)? That 7 inch belt wouldn't be very durable, but with 33 knots and 16 inch guns, they could have stood off out of the enemy's effective range.

Here's the design, I tried to follow the specifications as best as I could: Note- the tertiary guns are meant to represent the planned AA guns

[oldpop2000]

I thought this drawing might be interesting. It is the actual approved design proposal for the Lexington class battlecruisers with all pertinent information. Just as a note. The Lexington's had a very extreme length to beam, which after testing in the David Taylor tanks was used for the Iowa's except it was reduced due to the different bow. This gave them their speed. My dad served on the Sara and during the run from San Diego to Pearl Harbor after the attack, she hit 38 knots at 150,000 hp. It was the fastest run until the USS Nimitz broke the record. unfortunately, they could not turn fast or in a tight circle, which is why Sara was torpedoed twice. She just could not turn quick enough. The tin cans would consistently complain to Sara that she was going too fast for the sea conditions and they were struggling to keep up.

www.shipscribe.com/styles/S-584/images/s-file/s584102.jpg

[cv10]

Jul 29, 2017 14:04:36 GMT -6 oldpop2000 said:

I thought this drawing might be interesting. It is the actual approved design proposal for the Lexington class battlecruisers with all pertinent information. Just as a note. The Lexington's had a very extreme length to beam, which after testing in the David Taylor tanks was used for the Iowa's except it was reduced due to the different bow. This gave them their speed. My dad served on the Sara and during the run from San Diego to Pearl Harbor after the attack, she hit 38 knots at 150,000 hp. It was the fastest run until the USS Nimitz broke the record. unfortunately, they could not turn fast or in a tight circle, which is why Sara was torpedoed twice. She just could not turn quick enough. The tin cans would consistently complain to Sara that she was going too fast for the sea conditions and they were struggling to keep up.

www.shipscribe.com/styles/S-584/images/s-file/s584102.jpg

Thank god that they planned to increase the turret armor to 11 inches once they modified the design to 33 knots and 16 inch guns, as if I'm reading those specifications correctly, those turrets would have been horribly vulnerable to hits. Since Jutland was just two weeks or so before this design was preposed (according to the bit at the top), I wonder if anyone from the BCR worried about the turrets being vulnerable to the same kind of damage that caused the British battlecruisers to explode (though I know that that problem was a result of a less stable cordite mix and poor safety and handling procedures).

[oldpop2000]

Jul 30, 2017 10:46:00 GMT -6 cv10 said:

Jul 29, 2017 14:04:36 GMT -6 oldpop2000 said:

I thought this drawing might be interesting. It is the actual approved design proposal for the Lexington class battlecruisers with all pertinent information. Just as a note. The Lexington's had a very extreme length to beam, which after testing in the David Taylor tanks was used for the Iowa's except it was reduced due to the different bow. This gave them their speed. My dad served on the Sara and during the run from San Diego to Pearl Harbor after the attack, she hit 38 knots at 150,000 hp. It was the fastest run until the USS Nimitz broke the record. unfortunately, they could not turn fast or in a tight circle, which is why Sara was torpedoed twice. She just could not turn quick enough. The tin cans would consistently complain to Sara that she was going too fast for the sea conditions and they were struggling to keep up.

www.shipscribe.com/styles/S-584/images/s-file/s584102.jpg

Thank god that they planned to increase the turret armor to 11 inches once they modified the design to 33 knots and 16 inch guns, as if I'm reading those specifications correctly, those turrets would have been horribly vulnerable to hits. Since Jutland was just two weeks or so before this design was preposed (according to the bit at the top), I wonder if anyone from the BCR worried about the turrets being vulnerable to the same kind of damage that caused the British battlecruisers to explode (though I know that that problem was a result of a less stable cordite mix and poor safety and handling procedures).

Here is another proposal #3 of 4 on the Lexington's. The final drawing wasn't completed until just before construction. www.shipscribe.com/styles/S-584/images/s-file/s584148.jpg

[aeson]

Given that they were supposed to be capable of 33 knots and have 16 inch guns, perhaps the plan was to simply have them stay out of range and hammer the enemy from afar. However I keep coming back to the armor: how would they have stood up against other modern battlecruisers (Renown-Class and the like)? That 7 inch belt wouldn't be very durable, but with 33 knots and 16 inch guns, they could have stood off out of the enemy's effective range.

Personally, I tend to feel that "staying beyond the opponent's effective range" is not really that practical with 16" vs 15" or 14" guns as long as you're limited to visual range, and might still be questionable even with something allowing you to engage from beyond it; WWI-era 14" and heavier guns (and probably also some of the lighter heavy guns) could reach the horizon or beyond when elevated to 20 degrees or so. Moreover, while the Lexington-class battlecruiser's designed belt armor might have been resistant to heavy guns at extreme visual range, I'm somewhat more doubtful about the adequacy of its deck armor for that purpose - consider that the deck armor of the planned South Dakota-class battleships of the same period was designed to be up to 6" thick, and would have been intended to resist heavy shells at reasonably long ranges.

[cv10]

Jul 30, 2017 19:43:51 GMT -6 aeson said:

Given that they were supposed to be capable of 33 knots and have 16 inch guns, perhaps the plan was to simply have them stay out of range and hammer the enemy from afar. However I keep coming back to the armor: how would they have stood up against other modern battlecruisers (Renown-Class and the like)? That 7 inch belt wouldn't be very durable, but with 33 knots and 16 inch guns, they could have stood off out of the enemy's effective range.

Personally, I tend to feel that "staying beyond the opponent's effective range" is not really that practical with 16" vs 15" or 14" guns as long as you're limited to visual range, and might still be questionable even with something allowing you to engage from beyond it; WWI-era 14" and heavier guns (and probably also some of the lighter heavy guns) could reach the horizon or beyond when elevated to 20 degrees or so. Moreover, while the Lexington-class battlecruiser's designed belt armor might have been resistant to heavy guns at extreme visual range, I'm somewhat more doubtful about the adequacy of its deck armor for that purpose - consider that the deck armor of the planned South Dakota-class battleships of the same period was designed to be up to 6" thick, and would have been intended to resist heavy shells at reasonably long ranges.

The other consideration is that both the Amagi-Class and G3-Class Battlecruisers that Japan and Great Britain were designing were both projected to have 16 inch guns as well, so there would have been no range advantage anyway, except for against some of the older pre-World War I battlecruisers. Both of them were also better armored, while the Amagi-Class was only slightly better armored with 9 inches belt armor and 3.7 inches of deck armor, the G3-Class was designed to have a 12-14 inch belt and 3-8 inches of deck armor.

[oldpop2000]

Here is something to enjoy: a fictional set of Japanese Naval Vessels with other nations included.

www.combinedfleet.com/furashita/furamain.htm

[oldpop2000]

Here is my attempt to recreate the specifications of the Lexington's as battlecruisers. If you compare them to the ones on the second drawing, they are within a reasonable error.

USS Lexington, USA Battlecruiser laid down 1919

Displacement:
31,274 t light; 33,483 t standard; 35,002 t normal; 36,216 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(874.68 ft / 850.00 ft) x 91.00 ft x (31.30 / 32.09 ft)
(266.60 m / 259.08 m) x 27.74 m x (9.54 / 9.78 m)

Armament:
8 - 16.00" / 406 mm 45.0 cal guns - 2,065.47lbs / 936.88kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1919 Model
4 x Twin mounts on centreline ends, evenly spread
14 - 6.00" / 152 mm 45.0 cal guns - 108.93lbs / 49.41kg shells, 150 per gun
Breech loading guns in casemate mounts, 1919 Model
14 x Single mounts on sides, evenly spread
4 - 3.00" / 76.2 mm 45.0 cal guns - 13.62lbs / 6.18kg shells, 150 per gun
Breech loading guns in deck mounts, 1919 Model
4 x Single mounts on sides, evenly spread
Weight of broadside 18,103 lbs / 8,211 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 382.50 ft / 116.59 m 16.00 ft / 4.88 m
Ends: Unarmoured
Main Belt covers 69 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 4.00" / 102 mm 5.00" / 127 mm

- Box over machinery & magazines:
2.00" / 51 mm
Forecastle: 2.00" / 51 mm Quarter deck: 2.00" / 51 mm

- Conning towers: Forward 5.00" / 127 mm, Aft 5.00" / 127 mm

Machinery:
Oil fired boilers, steam turbines,
Electric cruising motors plus geared drives, 4 shafts, 200,304 shp / 149,427 Kw = 35.00 kts
Range 10,000nm at 10.00 kts
Bunker at max displacement = 2,733 tons

Complement:
1,279 - 1,663

Cost:
£8.084 million / $32.337 million

Distribution of weights at normal displacement:
Armament: 2,916 tons, 8.3 %
- Guns: 2,916 tons, 8.3 %
Armour: 5,220 tons, 14.9 %
- Belts: 1,357 tons, 3.9 %
- Armament: 1,534 tons, 4.4 %
- Armour Deck: 2,098 tons, 6.0 %
- Conning Towers: 231 tons, 0.7 %
Machinery: 7,113 tons, 20.3 %
Hull, fittings & equipment: 16,026 tons, 45.8 %
Fuel, ammunition & stores: 3,727 tons, 10.6 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
37,286 lbs / 16,913 Kg = 18.2 x 16.0 " / 406 mm shells or 2.5 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 5.3 ft / 1.6 m
Roll period: 16.6 seconds
Steadiness - As gun platform (Average = 50 %): 59 %
- Recoil effect (Restricted arc if above 1.00): 1.38
Seaboat quality (Average = 1.00): 1.51

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.506 / 0.511
Length to Beam Ratio: 9.34 : 1
'Natural speed' for length: 33.43 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 39
Bow angle (Positive = bow angles forward): 33.00 degrees
Stern overhang: -20.00 ft / -6.10 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 38.00 ft / 11.58 m, 32.00 ft / 9.75 m
- Forward deck: 30.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Aft deck: 25.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Quarter deck: 15.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Average freeboard: 32.72 ft / 9.97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 109.0 %
- Above water (accommodation/working, high = better): 256.8 %
Waterplane Area: 53,895 Square feet or 5,007 Square metres
Displacement factor (Displacement / loading): 101 %
Structure weight / hull surface area: 192 lbs/sq ft or 939 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.92
- Longitudinal: 2.11
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[oldpop2000]

I went one further, by substituting 18inch 48 cal. guns that were underdevelopment from 1927-1945 for the 16inch guns. The displacement went up but the speed had to drop by 2 knots to 33 knots. Now the ship is a little cramped, which according to my Dad was actually true of the Saratoga as a carrier.... she was cramped.

USS Gettysburg, USA Battlecruiser laid down 1919

Displacement:
33,920 t light; 36,856 t standard; 38,460 t normal; 39,743 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(874.68 ft / 850.00 ft) x 91.00 ft x (31.30 / 32.09 ft)
(266.60 m / 259.08 m) x 27.74 m x (9.54 / 9.78 m)

Armament:
8 - 18.00" / 457 mm 48.0 cal guns - 3,054.05lbs / 1,385.30kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1919 Model
4 x Twin mounts on centreline ends, evenly spread
14 - 6.00" / 152 mm 45.0 cal guns - 108.93lbs / 49.41kg shells, 150 per gun
Breech loading guns in casemate mounts, 1919 Model
14 x Single mounts on sides, evenly spread
4 - 3.00" / 76.2 mm 45.0 cal guns - 13.62lbs / 6.18kg shells, 150 per gun
Breech loading guns in deck mounts, 1919 Model
4 x Single mounts on sides, evenly spread
Weight of broadside 26,012 lbs / 11,799 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 382.50 ft / 116.59 m 16.00 ft / 4.88 m
Ends: Unarmoured
Main Belt covers 69 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 4.00" / 102 mm 5.00" / 127 mm

- Box over machinery & magazines:
2.00" / 51 mm
Forecastle: 2.00" / 51 mm Quarter deck: 2.00" / 51 mm

- Conning towers: Forward 5.00" / 127 mm, Aft 5.00" / 127 mm

Machinery:
Oil fired boilers, steam turbines,
Electric cruising motors plus geared drives, 4 shafts, 173,220 shp / 129,222 Kw = 33.00 kts
Range 10,000nm at 10.00 kts
Bunker at max displacement = 2,887 tons

Complement:
1,373 - 1,785

Cost:
£9.930 million / $39.720 million

Distribution of weights at normal displacement:
Armament: 4,267 tons, 11.1 %
- Guns: 4,267 tons, 11.1 %
Armour: 5,257 tons, 13.7 %
- Belts: 1,362 tons, 3.5 %
- Armament: 1,807 tons, 4.7 %
- Armour Deck: 1,843 tons, 4.8 %
- Conning Towers: 245 tons, 0.6 %
Machinery: 6,151 tons, 16.0 %
Hull, fittings & equipment: 18,245 tons, 47.4 %
Fuel, ammunition & stores: 4,541 tons, 11.8 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
37,058 lbs / 16,809 Kg = 12.7 x 18.0 " / 457 mm shells or 2.4 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 4.9 ft / 1.5 m
Roll period: 17.3 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 2.04
Seaboat quality (Average = 1.00): 1.53

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.556 / 0.560
Length to Beam Ratio: 9.34 : 1
'Natural speed' for length: 33.24 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 39
Bow angle (Positive = bow angles forward): 33.00 degrees
Stern overhang: -20.00 ft / -6.10 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 38.00 ft / 11.58 m, 32.00 ft / 9.75 m
- Forward deck: 30.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Aft deck: 25.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Quarter deck: 15.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Average freeboard: 32.72 ft / 9.97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 111.9 %
- Above water (accommodation/working, high = better): 250.9 %
Waterplane Area: 56,525 Square feet or 5,251 Square metres
Displacement factor (Displacement / loading): 93 %
Structure weight / hull surface area: 214 lbs/sq ft or 1,043 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.92
- Longitudinal: 2.09
- Overall: 1.00
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[oldpop2000]

In this model, I've removed the tertiary guns, and reduced the secondary's to 8 x 6in. guns. I now have 34.5 knots of speed, which is close to what it is in the original 16in design. My goal is to show all, how we can manipulate the designs to gain the speed and firepower. Next, I will increase the armor belt in height and length.

USS Antietam, USA Battlecruiser laid down 1919 (Gettysburg Class)

Displacement:
33,979 t light; 36,856 t standard; 38,460 t normal; 39,743 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(874.68 ft / 850.00 ft) x 91.00 ft x (31.30 / 32.09 ft)
(266.60 m / 259.08 m) x 27.74 m x (9.54 / 9.78 m)

Armament:
8 - 18.00" / 457 mm 48.0 cal guns - 3,054.05lbs / 1,385.30kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1919 Model
4 x Twin mounts on centreline ends, evenly spread
8 - 6.00" / 152 mm 45.0 cal guns - 108.92lbs / 49.41kg shells, 150 per gun
Breech loading guns in casemate mounts, 1919 Model
8 x Single mounts on sides, evenly spread
Weight of broadside 25,304 lbs / 11,478 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 382.50 ft / 116.59 m 16.00 ft / 4.88 m
Ends: Unarmoured
Main Belt covers 69 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 4.00" / 102 mm 5.00" / 127 mm

- Box over machinery & magazines:
2.00" / 51 mm
Forecastle: 2.00" / 51 mm Quarter deck: 2.00" / 51 mm

- Conning towers: Forward 5.00" / 127 mm, Aft 5.00" / 127 mm

Machinery:
Oil fired boilers, steam turbines,
Electric cruising motors plus geared drives, 4 shafts, 205,421 shp / 153,244 Kw = 34.50 kts
Range 10,000nm at 10.00 kts
Bunker at max displacement = 2,887 tons

Complement:
1,373 - 1,785

Cost:
£10.210 million / $40.842 million

Distribution of weights at normal displacement:
Armament: 4,160 tons, 10.8 %
- Guns: 4,160 tons, 10.8 %
Armour: 4,144 tons, 10.8 %
- Belts: 1,362 tons, 3.5 %
- Armament: 1,807 tons, 4.7 %
- Armour Deck: 730 tons, 1.9 %
- Conning Towers: 245 tons, 0.6 %
Machinery: 7,295 tons, 19.0 %
Hull, fittings & equipment: 18,380 tons, 47.8 %
Fuel, ammunition & stores: 4,482 tons, 11.7 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
32,481 lbs / 14,733 Kg = 11.1 x 18.0 " / 457 mm shells or 2.2 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 5.2 ft / 1.6 m
Roll period: 16.8 seconds
Steadiness - As gun platform (Average = 50 %): 48 %
- Recoil effect (Restricted arc if above 1.00): 1.79
Seaboat quality (Average = 1.00): 1.32

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.556 / 0.560
Length to Beam Ratio: 9.34 : 1
'Natural speed' for length: 33.24 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 33.00 degrees
Stern overhang: -20.00 ft / -6.10 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 38.00 ft / 11.58 m, 32.00 ft / 9.75 m
- Forward deck: 30.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Aft deck: 25.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Quarter deck: 15.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Average freeboard: 32.72 ft / 9.97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120.5 %
- Above water (accommodation/working, high = better): 250.9 %
Waterplane Area: 56,525 Square feet or 5,251 Square metres
Displacement factor (Displacement / loading): 91 %
Structure weight / hull surface area: 214 lbs/sq ft or 1,047 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.93
- Longitudinal: 2.06
- Overall: 1.00
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

[oldpop2000]

On this alternative design, I've increased the length and width of the main armor belt. The thickness is the same but we lost 1.5 knots of speed. You don't get something for nothing. I've also add 2 in. to the ends. Something of interest is that the turning radius of a ship is about 3-5 times its length. I will confirm in my marine engineering books but if so, the Lexington' s had a turning radius of about 3400 feet or 1036 meters. I will work to change that on another design.

USS Chickamauga(Gettysburg class), USA Battlecruiser laid down 1919

Displacement:
33,979 t light; 36,856 t standard; 38,460 t normal; 39,743 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(874.68 ft / 850.00 ft) x 91.00 ft x (31.30 / 32.09 ft)
(266.60 m / 259.08 m) x 27.74 m x (9.54 / 9.78 m)

Armament:
8 - 18.00" / 457 mm 48.0 cal guns - 3,054.04lbs / 1,385.29kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1919 Model
4 x Twin mounts on centreline ends, evenly spread
8 - 6.00" / 152 mm 45.0 cal guns - 108.93lbs / 49.41kg shells, 150 per gun
Breech loading guns in casemate mounts, 1919 Model
8 x Single mounts on sides, evenly spread
Weight of broadside 25,304 lbs / 11,478 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 650.00 ft / 198.12 m 28.50 ft / 8.69 m
Ends: 2.00" / 51 mm 200.00 ft / 60.96 m 11.44 ft / 3.49 m
Main Belt covers 118 % of normal length
Main belt does not fully cover magazines and engineering spaces
Main Belt inclined 4.00 degrees (positive = in)

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 4.00" / 102 mm 5.00" / 127 mm

- Box over machinery & magazines:
2.00" / 51 mm
Forecastle: 2.00" / 51 mm Quarter deck: 2.00" / 51 mm

- Conning towers: Forward 5.00" / 127 mm, Aft 5.00" / 127 mm

Machinery:
Oil fired boilers, steam turbines,
Electric cruising motors plus geared drives, 4 shafts, 205,421 shp / 153,244 Kw = 34.50 kts
Range 10,000nm at 10.00 kts
Bunker at max displacement = 2,887 tons

Complement:
1,373 - 1,785

Cost:
£10.210 million / $40.842 million

Distribution of weights at normal displacement:
Armament: 4,160 tons, 10.8 %
- Guns: 4,160 tons, 10.8 %
Armour: 6,700 tons, 17.4 %
- Belts: 3,921 tons, 10.2 %
- Armament: 1,807 tons, 4.7 %
- Armour Deck: 726 tons, 1.9 %
- Conning Towers: 245 tons, 0.6 %
Machinery: 7,295 tons, 19.0 %
Hull, fittings & equipment: 15,824 tons, 41.1 %
Fuel, ammunition & stores: 4,482 tons, 11.7 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
28,504 lbs / 12,929 Kg = 9.8 x 18.0 " / 457 mm shells or 2.2 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 5.3 ft / 1.6 m
Roll period: 16.6 seconds
Steadiness - As gun platform (Average = 50 %): 49 %
- Recoil effect (Restricted arc if above 1.00): 1.77
Seaboat quality (Average = 1.00): 1.35

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.556 / 0.560
Length to Beam Ratio: 9.34 : 1
'Natural speed' for length: 33.24 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 33.00 degrees
Stern overhang: -20.00 ft / -6.10 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 38.00 ft / 11.58 m, 32.00 ft / 9.75 m
- Forward deck: 30.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Aft deck: 25.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Quarter deck: 15.00 %, 32.00 ft / 9.75 m, 32.00 ft / 9.75 m
- Average freeboard: 32.72 ft / 9.97 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120.5 %
- Above water (accommodation/working, high = better): 250.9 %
Waterplane Area: 56,525 Square feet or 5,251 Square metres
Displacement factor (Displacement / loading): 86 %
Structure weight / hull surface area: 186 lbs/sq ft or 910 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.81
- Longitudinal: 1.77
- Overall: 0.87
Caution: Hull subject to strain in open-sea
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

[oldpop2000]

I've been researching the problem of turning circle for Lexington class of warship, both the battlecruisers but actual the carriers. The problem was the slenderness ratio or lengthtobeam and the single rudder. The latter I believe is the key to the problem. Note that Titanic had a single rudder and this feature has been linked to the slowness of her reaction to the wheel which allowed her to graze the iceberg. I have a early 20th century series of textbooks on Marine Engineering and one has a chapter on turning, I will review it.

[cv10]

Aug 1, 2017 15:28:07 GMT -6 oldpop2000 said:

I've been researching the problem of turning circle for Lexington class of warship, both the battlecruisers but actual the carriers. The problem was the slenderness ratio or lengthtobeam and the single rudder. The latter I believe is the key to the problem. Note that Titanic had a single rudder and this feature has been linked to the slowness of her reaction to the wheel which allowed her to graze the iceberg. I have a early 20th century series of textbooks on Marine Engineering and one has a chapter on turning, I will review it.

Thank you for the springsharp designs! It's interesting to see the specifications of the ship put into the program. I have it, but I'm not very good at using it. Just a quick question from a nautical novice: does the speed a ship is going affect its turning circle? For example, would a Aircraft Carrier have a smaller turning circle if it was moving at a slower speed, or does the turning circle remain constant?

[oldpop2000]

Aug 1, 2017 18:03:38 GMT -6 cv10 said:

Aug 1, 2017 15:28:07 GMT -6 oldpop2000 said:

I've been researching the problem of turning circle for Lexington class of warship, both the battlecruisers but actual the carriers. The problem was the slenderness ratio or lengthtobeam and the single rudder. The latter I believe is the key to the problem. Note that Titanic had a single rudder and this feature has been linked to the slowness of her reaction to the wheel which allowed her to graze the iceberg. I have a early 20th century series of textbooks on Marine Engineering and one has a chapter on turning, I will review it.

Thank you for the springsharp designs! It's interesting to see the specifications of the ship put into the program. I have it, but I'm not very good at using it. Just a quick question from a nautical novice: does the speed a ship is going affect its turning circle? For example, would a Aircraft Carrier have a smaller turning circle if it was moving at a slower speed, or does the turning circle remain constant?

The force necessary to turn the ship is caused by the deflection of the rudder. The larger the rudder and numbers of rudders, the more force is produced. The value is also based on the square of speed of the water meeting the rudder and the angle to which the rudder is placed. The shape of the stern can cause problems with the flow of water and hence, ability of the rudder to get enough water at sufficient speed to cause the deflection.


There are other factors such as the shape of the underwater body of the ship, weight concentrated amidships will turn faster than one with weights on either end, like a battleship.

So, the simple answer is yes, speed does have a great effect on how fast you can turn.


Dreadnought was 490 feet long and had a tactical diameter or turning radius of 463 yard or 2.84 times the ships length. A twin screw ship or multiple screw ship can reverse engines on one side and turn faster. Its a complex subject.

As to Springsharp, one of the thread on this forum has some links to Springsharp tips and a blog that has been around for a long time and uses the Springsharp software. I can help if you ask me. It's a good learning tool.

[cv10]

Thank you for the answer, and the advice!