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Post by oldpop2000 on Sept 7, 2016 12:05:02 GMT -6
Something to consider in carrier history. The Yorktowns were designed and built with 1930's technology including weapons. Now once the war started and we gained direct combat experience, we could see that the light AA weapons were of no value, so we installed the 20mm Oerlikon's and 40mm Bofors. By the time of Okinawa, we now had more carriers of much better design, AA cruisers like the USS San Diego, more destroyers like the Gearing class and many upgraded post 1930 London Naval Treaty cruisers. All these new ships and weapons increased the air defense capability of the fleet plus the addition of faster, better armed and longer ranged fighters with long range search radar and fire control systems. We even added airborne search on the TBF, which was very helpful.
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Post by oldpop2000 on Sept 7, 2016 13:36:46 GMT -6
I got creative today. I used Springsharp to create a hull for a Yorktown class carrier circa 1937 - keep in mind that engine power calculations in Springsharp are not entirely accurate but there ok. It probably wouldn't require such a high engine power in reality.
Yorktown, USA Carrier laid down 1937
Displacement: 44,041 t light; 45,040 t standard; 49,929 t normal; 53,840 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep) (873.93 ft / 850.00 ft) x 110.00 ft x (30.00 / 31.96 ft) (266.37 m / 259.08 m) x 33.53 m x (9.14 / 9.74 m)
Armour: - Belts: Width (max) Length (avg) Height (avg) Main: 4.80" / 122 mm 297.50 ft / 90.68 m 12.59 ft / 3.84 m Ends: 3.00" / 76 mm 552.48 ft / 168.40 m 12.59 ft / 3.84 m Upper: 3.00" / 76 mm 297.50 ft / 90.68 m 8.00 ft / 2.44 m Main Belt covers 54 % of normal length
- Armoured deck - single deck: For and Aft decks: 1.50" / 38 mm Forecastle: 1.50" / 38 mm Quarter deck: 1.50" / 38 mm
Machinery: Oil fired boilers, steam turbines, Geared drive, 4 shafts, 217,249 shp / 162,068 Kw = 32.00 kts Range 10,000nm at 18.00 kts Bunker at max displacement = 8,800 tons
Complement: 1,669 - 2,171
Cost: £13.006 million / $52.024 million
Distribution of weights at normal displacement: Armament: 0 tons, 0.0 % Armour: 3,958 tons, 7.9 % - Belts: 2,008 tons, 4.0 % - Armour Deck: 1,950 tons, 3.9 % Machinery: 6,021 tons, 12.1 % Hull, fittings & equipment: 34,063 tons, 68.2 % Fuel, ammunition & stores: 5,888 tons, 11.8 % Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability: Survivability (Non-critical penetrating hits needed to sink ship): 191,562 lbs / 86,891 Kg = 1,773.7 x 6 " / 152 mm shells or 10.5 torpedoes Stability (Unstable if below 1.00): 1.02 Metacentric height 6.1 ft / 1.8 m Roll period: 18.8 seconds Steadiness - As gun platform (Average = 50 %): 100 % - Recoil effect (Restricted arc if above 1.00): 0.00 Seaboat quality (Average = 1.00): 2.00
Hull form characteristics: Hull has a flush deck, a normal bow and a cruiser stern Block coefficient (normal/deep): 0.623 / 0.631 Length to Beam Ratio: 7.73 : 1 'Natural speed' for length: 29.15 kts Power going to wave formation at top speed: 54 % Trim (Max stability = 0, Max steadiness = 100): 50 Bow angle (Positive = bow angles forward): 20.00 degrees Stern overhang: 5.00 ft / 1.52 m Freeboard (% = length of deck as a percentage of waterline length): Fore end, Aft end - Forecastle: 50.00 %, 52.00 ft / 15.85 m, 52.00 ft / 15.85 m - Forward deck: 20.00 %, 52.00 ft / 15.85 m, 52.00 ft / 15.85 m - Aft deck: 15.00 %, 52.00 ft / 15.85 m, 52.00 ft / 15.85 m - Quarter deck: 15.00 %, 52.00 ft / 15.85 m, 52.00 ft / 15.85 m - Average freeboard: 52.00 ft / 15.85 m
Ship space, strength and comments: Space - Hull below water (magazines/engines, low = better): 40.6 % - Above water (accommodation/working, high = better): 414.6 % Waterplane Area: 69,865 Square feet or 6,491 Square metres Displacement factor (Displacement / loading): 312 % Structure weight / hull surface area: 257 lbs/sq ft or 1,255 Kg/sq metre Hull strength (Relative): - Cross-sectional: 1.56 - Longitudinal: 8.26 - Overall: 1.84 Excellent machinery, storage, compartmentation space Excellent accommodation and workspace room Ship has slow, easy roll, a good, steady gun platform Excellent seaboat, comfortable, rides out heavy weather easily
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Post by oldpop2000 on Sept 7, 2016 13:53:28 GMT -6
My second version with lower freeboard, engine power is less but essentially the same.
Yorktown, USA Carrier laid down 1937
Displacement: 34,869 t light; 35,665 t standard; 39,831 t normal; 43,164 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep) (869.56 ft / 850.00 ft) x 110.00 ft x (30.00 / 31.88 ft) (265.04 m / 259.08 m) x 33.53 m x (9.14 / 9.72 m)
Armour: - Belts: Width (max) Length (avg) Height (avg) Main: 4.80" / 122 mm 297.50 ft / 90.68 m 12.59 ft / 3.84 m Ends: 3.00" / 76 mm 552.48 ft / 168.40 m 12.59 ft / 3.84 m Upper: 3.00" / 76 mm 297.50 ft / 90.68 m 8.00 ft / 2.44 m Main Belt covers 54 % of normal length
- Armoured deck - single deck: For and Aft decks: 1.50" / 38 mm Forecastle: 1.50" / 38 mm Quarter deck: 1.50" / 38 mm
Machinery: Oil fired boilers, steam turbines, Geared drive, 4 shafts, 178,517 shp / 133,174 Kw = 32.00 kts Range 10,000nm at 18.00 kts Bunker at max displacement = 7,499 tons
Complement: 1,409 - 1,832
Cost: £10.435 million / $41.740 million
Distribution of weights at normal displacement: Armament: 0 tons, 0.0 % Armour: 3,735 tons, 9.4 % - Belts: 2,002 tons, 5.0 % - Armour Deck: 1,733 tons, 4.4 % Machinery: 4,948 tons, 12.4 % Hull, fittings & equipment: 26,186 tons, 65.7 % Fuel, ammunition & stores: 4,963 tons, 12.5 % Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability: Survivability (Non-critical penetrating hits needed to sink ship): 143,729 lbs / 65,194 Kg = 1,330.8 x 6 " / 152 mm shells or 9.7 torpedoes Stability (Unstable if below 1.00): 1.17 Metacentric height 7.8 ft / 2.4 m Roll period: 16.6 seconds Steadiness - As gun platform (Average = 50 %): 100 % - Recoil effect (Restricted arc if above 1.00): 0.00 Seaboat quality (Average = 1.00): 2.00
Hull form characteristics: Hull has a flush deck, a normal bow and a cruiser stern Block coefficient (normal/deep): 0.497 / 0.507 Length to Beam Ratio: 7.73 : 1 'Natural speed' for length: 29.15 kts Power going to wave formation at top speed: 50 % Trim (Max stability = 0, Max steadiness = 100): 50 Bow angle (Positive = bow angles forward): 20.00 degrees Stern overhang: 5.00 ft / 1.52 m Freeboard (% = length of deck as a percentage of waterline length): Fore end, Aft end - Forecastle: 50.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Forward deck: 20.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Aft deck: 15.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Quarter deck: 15.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Average freeboard: 40.00 ft / 12.19 m
Ship space, strength and comments: Space - Hull below water (magazines/engines, low = better): 41.8 % - Above water (accommodation/working, high = better): 335.9 % Waterplane Area: 62,127 Square feet or 5,772 Square metres Displacement factor (Displacement / loading): 292 % Structure weight / hull surface area: 259 lbs/sq ft or 1,266 Kg/sq metre Hull strength (Relative): - Cross-sectional: 1.70 - Longitudinal: 3.96 - Overall: 1.85 Excellent machinery, storage, compartmentation space Excellent accommodation and workspace room Ship has slow, easy roll, a good, steady gun platform Excellent seaboat, comfortable, rides out heavy weather easily
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Post by axe99 on Sept 7, 2016 14:07:38 GMT -6
Nice posts, and agree you've got a strong argument for keeping larger calibre AA off carriers (at the very least, later war US carriers - I'd probably still keep it on earlier war British carriers, as they didn't have the same escort strength (by some margin), and going from memory a lot of the British (or US) ships didn't have radar in '39/'40.
On those Springsharp ships, they look good, but perhaps a tad large for 37? Even the Essex class were only about 27K standard. Again, just talking more for the sake of contribution and to encourage other, brighter contributors to set me straight, but I'd think that carriers would need to be proved a bit in wartime before nations could start making 30K+ monsters outside of BB/BC conversions.
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Post by oldpop2000 on Sept 7, 2016 15:00:41 GMT -6
Ok, I made mods to the design in the area of length and beam.
Yorktown, USA Carrier laid down 1937
Displacement: 16,438 t light; 16,829 t standard; 19,553 t normal; 21,732 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep) (780.56 ft / 761.00 ft) x 83.00 ft x (21.80 / 23.62 ft) (237.91 m / 231.95 m) x 25.30 m x (6.64 / 7.20 m)
Armour: - Belts: Width (max) Length (avg) Height (avg) Main: 4.80" / 122 mm 266.35 ft / 81.18 m 10.93 ft / 3.33 m Ends: 3.00" / 76 mm 494.63 ft / 150.76 m 10.93 ft / 3.33 m Upper: 3.00" / 76 mm 266.35 ft / 81.18 m 8.00 ft / 2.44 m Main Belt covers 54 % of normal length Main belt does not fully cover magazines and engineering spaces
- Armoured deck - single deck: For and Aft decks: 1.50" / 38 mm Forecastle: 1.50" / 38 mm Quarter deck: 1.50" / 38 mm
Machinery: Oil fired boilers, steam turbines, Geared drive, 4 shafts, 117,821 shp / 87,894 Kw = 32.00 kts Range 10,000nm at 18.00 kts Bunker at max displacement = 4,902 tons
Complement: 826 - 1,074
Cost: £5.632 million / $22.528 million
Distribution of weights at normal displacement: Armament: 0 tons, 0.0 % Armour: 2,728 tons, 14.0 % - Belts: 1,557 tons, 8.0 % - Armour Deck: 1,171 tons, 6.0 % Machinery: 3,266 tons, 16.7 % Hull, fittings & equipment: 10,445 tons, 53.4 % Fuel, ammunition & stores: 3,115 tons, 15.9 % Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability: Survivability (Non-critical penetrating hits needed to sink ship): 63,008 lbs / 28,580 Kg = 583.4 x 6 " / 152 mm shells or 5.0 torpedoes Stability (Unstable if below 1.00): 1.07 Metacentric height 4.3 ft / 1.3 m Roll period: 16.8 seconds Steadiness - As gun platform (Average = 50 %): 100 % - Recoil effect (Restricted arc if above 1.00): 0.00 Seaboat quality (Average = 1.00): 2.00
Hull form characteristics: Hull has a flush deck, a normal bow and a cruiser stern Block coefficient (normal/deep): 0.497 / 0.510 Length to Beam Ratio: 9.17 : 1 'Natural speed' for length: 27.59 kts Power going to wave formation at top speed: 50 % Trim (Max stability = 0, Max steadiness = 100): 50 Bow angle (Positive = bow angles forward): 20.00 degrees Stern overhang: 5.00 ft / 1.52 m Freeboard (% = length of deck as a percentage of waterline length): Fore end, Aft end - Forecastle: 50.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Forward deck: 20.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Aft deck: 15.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Quarter deck: 15.00 %, 40.00 ft / 12.19 m, 40.00 ft / 12.19 m - Average freeboard: 40.00 ft / 12.19 m
Ship space, strength and comments: Space - Hull below water (magazines/engines, low = better): 55.4 % - Above water (accommodation/working, high = better): 387.1 % Waterplane Area: 41,969 Square feet or 3,899 Square metres Displacement factor (Displacement / loading): 211 % Structure weight / hull surface area: 123 lbs/sq ft or 603 Kg/sq metre Hull strength (Relative): - Cross-sectional: 0.98 - Longitudinal: 4.55 - Overall: 1.14 Excellent machinery, storage, compartmentation space Excellent accommodation and workspace room Ship has slow, easy roll, a good, steady gun platform Excellent seaboat, comfortable, rides out heavy weather easily
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Post by axe99 on Sept 7, 2016 20:21:02 GMT -6
Looks good What kind of hangar size do you think you could fit into her?
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Post by oldpop2000 on Sept 7, 2016 20:31:05 GMT -6
Looks good What kind of hangar size do you think you could fit into her? I would guess just about the same size as the actual Yorktown class, 546 ft., x 63 ft. x 17 ft. If we use the actual Yorktown ratios of the length and beam to the actual hangar size, it would be about 526 feet in length and 50 feet in width. With folding wings on the birds, I think 80-90 aircraft like the Yorktown. Just a SWAG.
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Post by oldpop2000 on Sept 7, 2016 20:57:06 GMT -6
Here is something for everyone to examine. It is the Aircraft Carrier Study from which the Midway Class was based. Note the hull is too wide for the Panama Canal. I can't believe that that wasn't adjusted in the later drawings. shipscribe.com/styles/S-511/images/s-file/s511-42c.htm
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Post by axe99 on Sept 8, 2016 0:36:11 GMT -6
Nice find, a very interesting look .
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Post by oldpop2000 on Sept 8, 2016 7:40:46 GMT -6
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Post by axe99 on Sept 9, 2016 2:14:39 GMT -6
Cheers for those links, the last is particularly interesting. I remember reading that Slade/Worth article a year or two ago, and thinking it wasn't "quite right", but I was even more clueless then, so couldn't put my finger on why. I never found it convincing though, even when it had a fairly easy run (ie, I hadn't read much about much, so I didn't have much in the way of preconceptions) to convince me.
Those Spring Styles links are also very interesting - some very ambitious designs in there, like that hybrid CA/CV!
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Post by oldpop2000 on Sept 9, 2016 12:24:39 GMT -6
Cheers for those links, the last is particularly interesting. I remember reading that Slade/Worth article a year or two ago, and thinking it wasn't "quite right", but I was even more clueless then, so couldn't put my finger on why. I never found it convincing though, even when it had a fairly easy run (ie, I hadn't read much about much, so I didn't have much in the way of preconceptions) to convince me. Those Spring Styles links are also very interesting - some very ambitious designs in there, like that hybrid CA/CV! It is interesting to examine those drawings to get an idea of mind set of the Bureau of Aeronautics and the Bureau of Construction and Repair.
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Post by oldpop2000 on Sept 9, 2016 12:51:42 GMT -6
Here is a brief summary of how aircraft were launched by the US Navy.
This is a basic procedure based on normal operations where scouts have detected an enemy force and you are going to launch a strike.
Depending on the situation, all aircraft would be in a deck park, fueled and ready for launch. They could also be in the hangar. In this case, they would be fueled and engines warmed up then each aircraft, with wings still folded would be moved to the nearest elevator and brought up on the deck. Torpedo bombers at the back, dive bombers next, then fighters first. Fighters are the first to take off because of a shorter deck length to fly off. Next would come the dive bombers, next the torpedo bombers. All would rendezvous and form up, then fly to the target.
On their return, each aircraft would get into the landing pattern, land with power to zero, the fold wings, then taxi forward to be parked. The barrier would then rise, and another aircraft landed. Once all the birds had landed, all would be pushed back to the deck park except damaged or aircraft reporting problems. Those would be brought down into the hangar for repairs.
After all aircraft were pushed back to the deck park, they would be refueled and get ready for another launch, if necessary. In order to land and refuel CAP, room would have to be available to land. This procedure would be subject to combat and environmental conditions.
This procedure might change and this is the advantage of a deck park and open hangars... flexibility. British and Japanese carriers did not have this flexibility. The Japanese had to bring all aircraft down into the hangars during Midway, because of our torpedo and dive bomber attacks so that they could launch and recover combat air patrol aircraft. This made those hangars disasters waiting to happen, as it did. We could dump aircraft over the side, launch all remaining aircraft, clear the hangars and prepare for such an attack. As we did, many times. One of the fallacies of the history of Midway was that the Japanese decks were full of aircraft ready to launch. They were not, because the Japanese had to clear the decks when the torpedo bombers were detected incoming. If we time the Japanese launch and recover, those decks were not full when the dive bombers arrived, they were empty. BTW, the reason the Japanese had to launch and recover CAP so many times, is the low amount of ammunition for the 20mm cannons on the A6M2 Model 21 Zero fighters. It was 60 rounds, which means you could run out very quickly and those were the only rounds that could have a chance against our armored aircraft. We carried at least 400 rounds of .50 Cal ammunition for six guns, 600 rounds for four guns, depending on preference.
We did change this procedure as heavier aircraft became available and began to use the catapults to alleviate the problems.
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Post by axe99 on Sept 9, 2016 16:45:58 GMT -6
Another interesting read, cheers .
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Post by oldpop2000 on Sept 9, 2016 20:34:55 GMT -6
Another interesting read, cheers . Glad that you enjoyed them.
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