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Kaiser Kirk

Lightbringer and former European Imperialist

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1

Monday, January 4th 2010, 5:17am

Dutch CVs

With the completion of the Walcheren , the Dutch have Fighter and Scout cover for each of the three fleet commands, as well as a training carrier (the venerable CVx Hund) as a spare.

This means they can indulge in a strike carrier with a longer build time. Tonnage wise, they can almost build yet two more Walcheren class, completing sooner and with a larger aggregate airgroup, and with more 'resiliance' for the same "cost".

However, the short decks (main and flying off) of the Eendrachts and Walcheren forces low wingloadings, which was complicating aircraft design and performance. This is why the last torpedo bomber was a biplane, so I could keep loaded wingloading down and wingspans reasonable.

So...I'm entertaining two designs. The first is unarmored, the second armored.

Desired airgroups are 64-85, speed 30-32, tonnage 20-30, length no more than 270, preferably 220 or less.

Quoted


CV 1
Fokker, Netherlands CV laid down 1938

Displacement:
26,699 t light; 27,542 t standard; 32,413 t normal; 36,310 t full load

Dimensions: Length overall / water x beam x draught
742.38 ft / 721.78 ft x 82.02 ft (Bulges 91.86 ft) x 28.71 ft (normal load)
226.28 m / 220.00 m x 25.00 m (Bulges 28.00 m) x 8.75 m

Armament:
8 - 4.92" / 125 mm guns (4x2 guns), 59.59lbs / 27.03kg shells, 1938 Model
Breech loading guns in deck mounts with hoists
on side, all amidships, all raised mounts - superfiring
8 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1938 Model
Breech loading guns in deck mounts with hoists
on side ends, evenly spread, all raised mounts - superfiring
32 - 1.57" / 40.0 mm guns (8x4 guns), 1.95lbs / 0.88kg shells, 1938 Model
Breech loading guns in deck mounts
on side, evenly spread, all raised mounts
20 - 0.91" / 23.0 mm guns in single mounts, 0.37lbs / 0.17kg shells, 1938 Model
Breech loading guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 1,023 lbs / 464 kg
Shells per gun, main battery: 300

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.94" / 100 mm 485.56 ft / 148.00 m 13.12 ft / 4.00 m
Ends: 1.57" / 40 mm 236.19 ft / 71.99 m 10.86 ft / 3.31 m
Main Belt covers 103 % of normal length

- Torpedo Bulkhead and Bulges:
1.57" / 40 mm 485.56 ft / 148.00 m 24.74 ft / 7.54 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm 0.98" / 25 mm 0.98" / 25 mm
2nd: 1.57" / 40 mm 0.98" / 25 mm -
3rd: 0.39" / 10 mm 0.83" / 21 mm -
4th: 0.39" / 10 mm - -

- Armour deck: 3.35" / 85 mm, Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 168,897 shp / 125,997 Kw = 33.00 kts
Range 21,650nm at 15.00 kts
Bunker at max displacement = 8,768 tons

Complement:
1,207 - 1,570

Cost:
£9.522 million / $38.088 million

Distribution of weights at normal displacement:
Armament: 128 tons, 0.4 %
Armour: 4,808 tons, 14.8 %
- Belts: 1,204 tons, 3.7 %
- Torpedo bulkhead: 700 tons, 2.2 %
- Armament: 87 tons, 0.3 %
- Armour Deck: 2,783 tons, 8.6 %
- Conning Tower: 34 tons, 0.1 %
Machinery: 4,625 tons, 14.3 %
Hull, fittings & equipment: 9,638 tons, 29.7 %
Fuel, ammunition & stores: 5,714 tons, 17.6 %
Miscellaneous weights: 7,500 tons, 23.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
50,136 lbs / 22,741 Kg = 841.3 x 4.9 " / 125 mm shells or 6.5 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 4.4 ft / 1.3 m
Roll period: 18.5 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.11
Seaboat quality (Average = 1.00): 1.52

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.596
Length to Beam Ratio: 7.86 : 1
'Natural speed' for length: 30.93 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 24.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.53 ft / 9.61 m
- Forecastle (20 %): 31.53 ft / 9.61 m
- Mid (50 %): 31.53 ft / 9.61 m
- Quarterdeck (15 %): 31.53 ft / 9.61 m
- Stern: 31.53 ft / 9.61 m
- Average freeboard: 31.53 ft / 9.61 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 100.0 %
- Above water (accommodation/working, high = better): 223.7 %
Waterplane Area: 44,955 Square feet or 4,176 Square metres
Displacement factor (Displacement / loading): 144 %
Structure weight / hull surface area: 125 lbs/sq ft or 612 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.92
- Longitudinal: 2.00
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

LxB = 220mx 25m=5,500 / 70 =78.5


Misc : SQRT (6084) = 78 aircraft
The 1416 tons extra misc are
100 tons ATC/ fire control
100 tons 'electronics'
100 tons fire fighting and ventilation for hangers
100 tons flag officers quarters

400 tons "spares"
616 tons for growth

Ship bunkerage is 16,650nm, the additional 5,100nm of fuel (1,271t) is additional avgas.

Weaponry is arranged with 4 twin 125mm mounts fore/aft of the island, and the remaining 8 single mounts in galleries below the flight deck fore and aft, much like CV 6's 5" guns.


Quoted


CV-2
van Meel, Netherlands CVA laid down 1938

Displacement:
28,000 t light; 28,872 t standard; 33,846 t normal; 37,825 t full load

Dimensions: Length overall / water x beam x draught
840.08 ft / 820.21 ft x 82.02 ft (Bulges 91.86 ft) x 26.25 ft (normal load)
256.06 m / 250.00 m x 25.00 m (Bulges 28.00 m) x 8.00 m

Armament:
8 - 4.92" / 125 mm guns (4x2 guns), 59.59lbs / 27.03kg shells, 1938 Model
Breech loading guns in deck mounts with hoists
on side, all amidships, all raised mounts - superfiring
8 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1938 Model
Breech loading guns in deck mounts with hoists
on side ends, evenly spread, all raised mounts - superfiring
32 - 1.57" / 40.0 mm guns (8x4 guns), 1.95lbs / 0.88kg shells, 1938 Model
Breech loading guns in deck mounts
on side, evenly spread, all raised mounts
20 - 0.91" / 23.0 mm guns in single mounts, 0.37lbs / 0.17kg shells, 1938 Model
Breech loading guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 1,023 lbs / 464 kg
Shells per gun, main battery: 300

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 643.04 ft / 196.00 m 13.12 ft / 4.00 m
Ends: 1.57" / 40 mm 173.85 ft / 52.99 m 13.12 ft / 4.00 m
3.31 ft / 1.01 m Unarmoured ends
Upper: 1.97" / 50 mm 643.04 ft / 196.00 m 23.33 ft / 7.11 m
Main Belt covers 121 % of normal length

- Torpedo Bulkhead and Bulges:
1.57" / 40 mm 643.04 ft / 196.00 m 24.74 ft / 7.54 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.57" / 40 mm 0.98" / 25 mm 0.98" / 25 mm
2nd: 1.57" / 40 mm 0.98" / 25 mm -
3rd: 0.39" / 10 mm 0.83" / 21 mm -
4th: 0.39" / 10 mm - -

- Armour deck: 4.13" / 105 mm, Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 148,019 shp / 110,422 Kw = 32.00 kts
Range 20,850nm at 15.00 kts
Bunker at max displacement = 8,953 tons

Complement:
1,246 - 1,621

Cost:
£9.328 million / $37.310 million

Distribution of weights at normal displacement:
Armament: 128 tons, 0.4 %
Armour: 7,313 tons, 21.6 %
- Belts: 2,346 tons, 6.9 %
- Torpedo bulkhead: 927 tons, 2.7 %
- Armament: 86 tons, 0.3 %
- Armour Deck: 3,918 tons, 11.6 %
- Conning Tower: 35 tons, 0.1 %
Machinery: 4,053 tons, 12.0 %
Hull, fittings & equipment: 10,506 tons, 31.0 %
Fuel, ammunition & stores: 5,846 tons, 17.3 %
Miscellaneous weights: 6,000 tons, 17.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
66,669 lbs / 30,240 Kg = 1,118.7 x 4.9 " / 125 mm shells or 9.7 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 4.8 ft / 1.5 m
Roll period: 17.6 seconds
Steadiness - As gun platform (Average = 50 %): 85 %
- Recoil effect (Restricted arc if above 1.00): 0.11
Seaboat quality (Average = 1.00): 1.71

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.599
Length to Beam Ratio: 8.93 : 1
'Natural speed' for length: 32.63 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 24.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 29.89 ft / 9.11 m
- Forecastle (20 %): 29.89 ft / 9.11 m
- Mid (50 %): 29.89 ft / 9.11 m
- Quarterdeck (15 %): 29.89 ft / 9.11 m
- Stern: 29.89 ft / 9.11 m
- Average freeboard: 29.89 ft / 9.11 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 82.5 %
- Above water (accommodation/working, high = better): 234.1 %
Waterplane Area: 51,232 Square feet or 4,760 Square metres
Displacement factor (Displacement / loading): 151 %
Structure weight / hull surface area: 126 lbs/sq ft or 616 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.33
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

LxB = 270mx 25m=6,750 / 70 =96.4
Hanger = 196m x 25m = 4900 / 70 = 70

Misc : SQRT (4900) = 70 aircraft
The 1100 tons extra misc are
100 tons ATC/ fire control
100 tons 'electronics'
200 tons fire fighting and ventilation for hangers
100 tons flag officers quarters

400 tons "spares"
200tons for growth

Ship bunkerage is 16,650nm, the additional 4,200nm of fuel (968t) is additional avgas.

Hangers are in a 50mm "Box" , 196m long, with a 65mm roof, intended to exclude GP bombs and common shell. Armor deck is 40mm, to stop shell splinters and chunks that penetrate the "deck".

Weaponry is arranged with 4 twin 125mm mounts fore/aft of the island, and the remaining 8 single mounts in galleries below the flight deck fore and aft, much like CV 6's 5" guns.

This post has been edited 1 times, last edit by "Kaiser Kirk" (Jan 4th 2010, 5:19am)


2

Monday, January 4th 2010, 5:42am

Interesting. Some parallels to many of my own designs, in fact, but the last one is larger than anything I've seriously considered.

I express a preference for the larger flight deck of the CV2; as Red Admiral is extremely fond of pointing out, it has good growth potential, though we don't of course know that at present.

I was not aware we were adding range to simulate avgas bunkers. That ought to be accounted for elsewhere, IMHO.

Kaiser Kirk

Lightbringer and former European Imperialist

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3

Monday, January 4th 2010, 6:22am

Quoted

Originally posted by Brockpaine
I express a preference for the larger flight deck of the CV2; as Red Admiral is extremely fond of pointing out, it has good growth potential, though we don't of course know that at present.

I was not aware we were adding range to simulate avgas bunkers. That ought to be accounted for elsewhere, IMHO.


The larger one has the problem of far fewer repair facilities. At this time Dutch wingloadings have been in the low 20s, so both are a luxury, and I didn't feel like maximizing the 270m potential. To look-forwardish. The size was requisite for fielding a sufficiently larger airgroup to bother. Would have preferred 85 planes, but that is a great deal more weight.

Edit : Went and checked for comparison.
The British armored carriers, the Illustrious and Implacables, were 229-233m OA. Not far off the unarmored carrier. They however had smaller airgroups due to hanger size. However, I believe they were operating Corsairs at war's end, so their length is workable for WWII aircraft.
The Essex was 265m, and had larger hangers with a larger airgroup. My armored carrier has a large armored hanger to accomodate the airgroup, which made it heavy, so I made it long.


I don't know if we are accounting for extra avgas in a different way. I presume some is worked into the aircraft calculations.

I know the USN kept Avgas in the double bottoms (and bulges?) of the Yorktowns class, while the Brits had special storage tanks carefully separate from the hull. I was thinking more of the former, so sticking it in with the fuel oil seemed better than misc weight, which is still treated as above WL.

This post has been edited 1 times, last edit by "Kaiser Kirk" (Jan 4th 2010, 6:34am)


4

Monday, January 4th 2010, 6:34am

Not a bad theory, I suppose. I certainly can't think of any reason to object...

Quoted

Originally posted by Kaiser Kirk
The Essex was 265m, and had larger hangers with a larger airgroup. My armored carrier has a large armored hanger to accomodate the airgroup, which made it heavy, so I made it long.

That's overall length. The Essex was 820 feet at the waterline, matching your dimensions flawlessly. :P

The long-hull Essex (Ticonderogas) were a total of 888 feet. Don't know offhand their w.l. length.

Kaiser Kirk

Lightbringer and former European Imperialist

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5

Monday, January 4th 2010, 6:41am

A valid point for discussion though. RA has muttered something about there should be more avgas allowance on carriers. Seemed a good way to deal with it.

Personally, I'm thinking the formula for carrier loadouts likely needs changing. Some large fixed tonnage to be a "carrier" and then the SQRT equation. As it is, smaller carriers can be more efficient, when OTL, larger carriers saw the efficiencies. Elevators, repair shops, arresting cables, catapults, ventilation...all are pretty much fixed regardless of airgroup size. Yet 10 planes is 100 tons, and 50 planes is 2500 tons...25x more for 5x more aircraft. Somethings fishy.

I also tossed in an edit with some length comparisons to my first reply while you were posting. Oh, you caught that :)

This post has been edited 1 times, last edit by "Kaiser Kirk" (Jan 4th 2010, 6:42am)


6

Monday, January 4th 2010, 6:56am

just something I'd like to point out: all your guns are breech loading guns.

7

Monday, January 4th 2010, 7:07am

Quoted

Originally posted by Kaiser Kirk
A valid point for discussion though. RA has muttered something about there should be more avgas allowance on carriers. Seemed a good way to deal with it.

Personally, I'm thinking the formula for carrier loadouts likely needs changing. Some large fixed tonnage to be a "carrier" and then the SQRT equation. As it is, smaller carriers can be more efficient, when OTL, larger carriers saw the efficiencies. Elevators, repair shops, arresting cables, catapults, ventilation...all are pretty much fixed regardless of airgroup size. Yet 10 planes is 100 tons, and 50 planes is 2500 tons...25x more for 5x more aircraft. Somethings fishy.


Agreed in a limited sense; but most of the modified equations proposed so far have been worse solutions than the problem they intend to fix, either because they cripple existing vessels or have unnecessary complexity. I think a lot of this really should be fixed more by a healthy dose of common sense, rather than by a new equation: for instance, my Chilean escort carrier Chiloe technically could have had the miscellaneous weight for 62 planes and room for 46; but comparing it against the OTL American CVEs, I cut that airgroup in half. Chile's Mapuche has a similar issue: miscellaneous weight for 56 planes, room for 47, but I made her standard airgroup 36 planes for the same reasons. (Libertad will receive the airgroup her weight allotment permits, because I can point to OTL carriers which successfully operated even larger airgroups.)

The other "microcarriers" - the Persian and Chinese (ex-Siamese) CVLs come to mind - are in my humble opinion just manpower drains posing as scouting assets. It's a matter of "minimum gauge" - useful designs can only be shrunk so much.

Kaiser Kirk

Lightbringer and former European Imperialist

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8

Monday, January 4th 2010, 7:29am

Breechloading : whoops. Also left the dates and shell weights default instead of "Dutch".

Yeah it's probably waaaaay to late in this sim to introduce a new way of doing carriers. Just something I think of each time I introduce one.

As for group sizes, the Eendrachts and Walcheren all have smaller groups than allowed. I bump to the "limit" here, but the ship sizes are reasonable for it, and here I went for very high freeboards, to make the hanger part of the ship structure, and in a way "pay" for the weight that way.

Of course there is always the deck park route, but in this era being able to strike everything is nice.

9

Monday, January 4th 2010, 6:30pm

Longer is always better when it comes to aircraft carriers. I probably wouldn't go for the heavily bulged hull form. It'll create a hour-glass cross section of the hull (with the flight deck overhanging above) which'll most likely have some nasty stability charactersitics. Best go without bulges and a beamier hull.

For these sizes of ship, you really want to have around 100tons/aircraft so I'd add in a bit more misc weight.

Quoted

I was not aware we were adding range to simulate avgas bunkers. That ought to be accounted for elsewhere, IMHO.


Extra avgas doesn't really weigh that much. Really it's in the design process that this is a factor - where you can fit it in the hull.

10

Monday, January 4th 2010, 9:26pm

My assumption on the Carrier rules had an unsaid collorary; You can fit a lot of aircraft on a smaller carrier as the sqrt calculations allow, but no matter what, a larger carrier simply has more of the needed amenities and facilities (Hangar deck space-per-plane, ready rooms, repair shops, etc) to operate it's complement more efficiently.

Kaiser Kirk

Lightbringer and former European Imperialist

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11

Tuesday, January 5th 2010, 6:16am

Bulges are only 3m, or 1.5m per side. hardly "heavily bulged"

I'd be happy to allocate 100tons/AC, if we wish to change the rules for all folks to that and there is some reason for that particular number. I'm also happy to engage in discourse as to the appropriate form of carrier rules regardless of if we change the rules. I'm partial to the idea of itemizing carrier parts to serve as a fixed cost.

As for carrier area, bigger= more repair I don't quite agree. For example my Eendrachts have smaller groups than "max" by hanger. So their room around each aircraft is larger than these big beasties.

also consider, there is no variation of the hanger space number by
block coefficient. A 220m x 22m hull is the same regardless if it's BC is 0.450 or 0.625. That 0.625 carrier, even if only 200m x 20m should have more usable space.

Two, additional "size" could simply be the keel is an extra 2m down. While the rules presume the superstructure is "free" a hanger on top of the hull. Which seems silly. If you have a standard hull thats taller, one should therefore have more room for hangerspace, and thus for repair shops, R& R etc. 2