Modelling an ASW Light Cruiser (Full Version)

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MateDow -> Modelling an ASW Light Cruiser (9/24/2012 2:41:22 PM)

For my own personal mod, I was wondering what the best way to model a US ASW cruiser would be.

Here is my design:

7,500 tons (standard)
8x5"/38 DP
32x1.1" AA
2 Catapults with 8 aircraft
2 DC Racks on the stern
4 DC Throwers

Now here are my questions...

Will a CL use ASW weaponry for detection and attacks?
Would the game engine handle the vessel better as a CL or CS?

Please let me know if there is any other information that you need.




castor troy -> RE: Modelling an ASW Light Cruiser (9/24/2012 3:10:19 PM)


quote:

ORIGINAL: MateDow

For my own personal mod, I was wondering what the best way to model a US ASW cruiser would be.

Here is my design:

7,500 tons (standard)
8x5"/38 DP
32x1.1" AA
2 Catapults with 8 aircraft
2 DC Racks on the stern
4 DC Throwers

Now here are my questions...

Will a CL use ASW weaponry for detection and attacks?
Would the game engine handle the vessel better as a CL or CS?

Please let me know if there is any other information that you need.



it does. I had IJ heavy cruisers drop DC on my subs




Gridley380 -> RE: Modelling an ASW Light Cruiser (9/24/2012 6:13:37 PM)

And the Aussies have a CL with an ASW rating in Babes, and I'm pretty sure in stock (not sure if I've ever seen her attack IJN sub, though).

Have to question EIGHT FP plus all that armament loaded onto only 7,500 tons - that's an Atlanta, or therabouts, with most of her AA firepower, extra ASW armament, and a FP det twice the size of any US cruiser of the period. I suggest making her a 10,000 tonner or halving the A/C complement.




Shark7 -> RE: Modelling an ASW Light Cruiser (9/24/2012 7:03:27 PM)

There are also some AKs in there that are DC armed and will attacked if they spot a sub in range.

Have to agree with Gridley380, all that stuff on a 7,500 ton hull is badly overloaded, it would likely be top heavy and unstable.

Here is what I came up with based on a Cleveland class hull, done in Springsharp:

11,800 tons standard
32 kts, 4 Oil fired boilers, 4 geared steam engines, 4 shafts. 15,400nm at 15 knts. Bunkerage: 3,488 tons max
Armor: 5in belt (max) 5in tower, 2in deck, 6in gun face and barbette, 1.5in gun sides
Guns:

3x3 6in/45 centerline distributed (2x3 fore, 1x3 aft) 150rds per gun
5x2 5in/38 (4x2 sides distributed, 1x2 fore centerline superfiring main guns) 150 rds per gun
6x4 40mm/60 (sides distributed) 2000 rds per gun
10x1 20mm/70 (sides distributed) 2000 rds per gun

Other weapons:

2x1 Mk 1 DC rack (8x Mk 7 DC with 1 reload)
6x1 Mk 6 K gun (2x Mk 6 DC with 1 reload)

Aircraft:

4 x OS2U Kingfisher, 2 Catapults, Hangar in quarter deck

Radars appropriate for 1942.

This would be a stable boat, though wet up front an suffers from reduced performance in heavy weather.

Basically this is a Cleveland class CL that trades in 1 of its aft 6in turrets and its aft 5 in turret to gain the ASW equipment.




Dili -> RE: Modelling an ASW Light Cruiser (9/24/2012 8:37:04 PM)

I don't see how 8 x 5" in 4 mounts can be overweight in a 7500t , Dido Class had 10x5,25" in 5 mounts and was 6000t standard.




MateDow -> RE: Modelling an ASW Light Cruiser (9/24/2012 9:07:17 PM)

quote:

ORIGINAL: Shark7

There are also some AKs in there that are DC armed and will attacked if they spot a sub in range.

Have to agree with Gridley380, all that stuff on a 7,500 ton hull is badly overloaded, it would likely be top heavy and unstable.

Here is what I came up with based on a Cleveland class hull, done in Springsharp:

...This would be a stable boat, though wet up front an suffers from reduced performance in heavy weather.

Basically this is a Cleveland class CL that trades in 1 of its aft 6in turrets and its aft 5 in turret to gain the ASW equipment.


I used Springsharp when I came up with the design and here is what I came up with...

quote:


Boise, United States ASW Light Cruiser laid down 1937

Displacement:
7,093 t light; 7,406 t standard; 9,012 t normal; 10,296 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(540.97 ft / 530.00 ft) x 55.00 ft x (20.00 / 22.14 ft)
(164.89 m / 161.54 m) x 16.76 m x (6.10 / 6.75 m)

Armament:
8 - 5.00" / 127 mm 38.0 cal guns - 55.18lbs / 25.03kg shells, 500 per gun
Dual purpose guns in turret on barbette mounts, 1932 Model
2 x Quad mounts on centreline, forward deck forward
1 raised mount - superfiring
24 - 1.10" / 27.9 mm 75.0 cal guns - 0.75lbs / 0.34kg shells, 1,000 per gun
Anti-air guns in deck mounts, 1929 Model
4 x Quad mounts on centreline ends, evenly spread
4 raised mounts
2 x Quad mounts on centreline, aft evenly spread
2 double raised mounts
Weight of broadside 459 lbs / 208 kg
Main Torpedoes
8 - 21.0" / 533 mm, 22.60 ft / 6.89 m torpedoes - 1.525 t each, 12.197 t total
In 2 sets of deck mounted side rotating tubes
2nd Torpedoes
16 - 21.0" / 533 mm, 22.60 ft / 6.89 m torpedoes - 1.525 t each, 24.394 t total
In 2 sets of deck mounted reloads
Main DC/AS Mortars
2 - 745.00 lbs / 337.93 kg Depth Charges + 100 reloads - 33.924 t total
in Stern depth charge racks

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.50" / 64 mm 350.00 ft / 106.68 m 12.00 ft / 3.66 m
Ends: Unarmoured
Main Belt covers 102 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.75" / 19 mm 0.75" / 19 mm 2.00" / 51 mm
2nd: - 0.50" / 13 mm -

- Armoured deck - single deck:
For and Aft decks: 1.00" / 25 mm

- Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 82,997 shp / 61,916 Kw = 33.00 kts
Range 13,200nm at 15.00 kts
Bunker at max displacement = 2,890 tons

Complement:
462 - 601

Cost:
3.333 million / $13.331 million

Distribution of weights at normal displacement:
Armament: 205 tons, 2.3 %
- Guns: 107 tons, 1.2 %
- Weapons: 97 tons, 1.1 %
Armour: 885 tons, 9.8 %
- Belts: 434 tons, 4.8 %
- Armament: 95 tons, 1.1 %
- Armour Deck: 319 tons, 3.5 %
- Conning Tower: 37 tons, 0.4 %
Machinery: 2,300 tons, 25.5 %
Hull, fittings & equipment: 3,143 tons, 34.9 %
Fuel, ammunition & stores: 1,919 tons, 21.3 %
Miscellaneous weights: 560 tons, 6.2 %
- Hull below water: 120 tons
- Hull above water: 30 tons
- On freeboard deck: 280 tons
- Above deck: 130 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
12,835 lbs / 5,822 Kg = 205.4 x 5.0 " / 127 mm shells or 1.4 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 2.5 ft / 0.8 m
Roll period: 14.6 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.21
Seaboat quality (Average = 1.00): 1.23

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.541 / 0.558
Length to Beam Ratio: 9.64 : 1
'Natural speed' for length: 26.23 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 4.00 ft / 1.22 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 26.00 ft / 7.92 m, 23.00 ft / 7.01 m
- Forward deck: 30.00 %, 23.00 ft / 7.01 m, 21.00 ft / 6.40 m
- Aft deck: 35.00 %, 21.00 ft / 6.40 m, 22.00 ft / 6.71 m
- Quarter deck: 15.00 %, 22.00 ft / 6.71 m, 22.00 ft / 6.71 m
- Average freeboard: 22.27 ft / 6.79 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 90.6 %
- Above water (accommodation/working, high = better): 172.2 %
Waterplane Area: 20,997 Square feet or 1,951 Square metres
Displacement factor (Displacement / loading): 140 %
Structure weight / hull surface area: 86 lbs/sq ft or 420 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.91
- Longitudinal: 2.32
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily


I figured 280 tons for the aircraft complement in my design.

I also made some different choices regarding armor protection. I went with significantly less armor coverage (less than an Omaha-class CL).

I also dreamed of a quad 5" mount similar to those used by the French on the Dunkerque. Not exactly historical, but I liked the idea and it does concentrate some of the weight on the design.

The design does work though, or at least in the design realm that is Springsharp. [;)]

For a 1942 refit, the weight gained reduces the freeboard and a tenth of a knot of speed for the throwers and radar.




dwg -> RE: Modelling an ASW Light Cruiser (9/27/2012 1:35:22 AM)

Without getting into any of the designs, I'm surprised no one has mentioned USS Norfolk, CLK-1 (DL-1 by the time she commissioned) http://en.wikipedia.org/wiki/USS_Norfolk_(DL-1)




MateDow -> RE: Modelling an ASW Light Cruiser (9/27/2012 4:31:49 PM)


quote:

ORIGINAL: dwg

Without getting into any of the designs, I'm surprised no one has mentioned USS Norfolk, CLK-1 (DL-1 by the time she commissioned) http://en.wikipedia.org/wiki/USS_Norfolk_(DL-1)


Actually, that was one of the concepts that I was using, except instead of being a big destroyer, it was a small cruiser.

My other thought was battleline scouting in addition to the ASW role. My thought was; if you detach the carriers from the battleline, which was happening in the late-30s, what platform could take up the role of long range scout without being deployed where it was vulnerable to counter-strikes. The ASW role really would have been a byproduct of the first years of the Battle of the Atlantic.




traskott -> RE: Modelling an ASW Light Cruiser (9/28/2012 12:45:16 PM)

I have tested an USA CL with 12 5'' DP, 13.000 tons, and a good number of AAs and ASW devices. Works well as a Leader of the escort of great convoys but ONLY as its. At a ASW task force has all the chances of being sunk.




Gridley380 -> RE: Modelling an ASW Light Cruiser (10/1/2012 6:59:06 PM)


quote:

ORIGINAL: MateDow

I figured 280 tons for the aircraft complement in my design.



Found your problem. :-)

Aircraft, cranes, catapults, fuel storage & pumps, magazine & handling equipment, flight & deck crew quarters & support, hanger structure, tooling for maintenance & repairs... that's just off the top of my head. Note that on just about every surface combatant that carried aircraft ever built the hanger is one of the recognition features and often forced design decisions of either the hull, the superstructure, or both.




mike scholl 1 -> RE: Modelling an ASW Light Cruiser (10/1/2012 9:28:40 PM)

The real question is WHY? Why build a larger ship for a job that a smaller one can do better? With today's weapons systems, it makes some sense..., but the only reason I can see to do so in the WW II era is increased range. The obvious answer in WW II was the "Hunter-Killer" TF of a CVE and a half dozen DE's. Unfortunately the game doesn't really allow such TF's.




traskott -> RE: Modelling an ASW Light Cruiser (10/2/2012 12:37:20 PM)

I tested one of this "super-escort". It was a heavy gunned cleveland, with one more turret, more lenght, less speed, more endurance, less armour (to overcome the weight of a new turret ), depth charges, mousetraps and so... It can hit but no hold more than 40' hits...




msieving1 -> RE: Modelling an ASW Light Cruiser (10/3/2012 1:44:21 AM)

As others have said, the aircraft complement seems overdone.

As an ASW platform, three Fletcher class destroyers would be more effective.




msieving1 -> RE: Modelling an ASW Light Cruiser (10/3/2012 1:48:10 AM)


quote:

ORIGINAL: mike scholl 1

The obvious answer in WW II was the "Hunter-Killer" TF of a CVE and a half dozen DE's. Unfortunately the game doesn't really allow such TF's.


Would a CVE TF with a CVE and 2 DEs combined with a ASW TF with 4 DEs work?




mike scholl 1 -> RE: Modelling an ASW Light Cruiser (10/3/2012 2:59:46 AM)


quote:

ORIGINAL: msieving1


quote:

ORIGINAL: mike scholl 1

The obvious answer in WW II was the "Hunter-Killer" TF of a CVE and a half dozen DE's. Unfortunately the game doesn't really allow such TF's.


Would a CVE TF with a CVE and 2 DEs combined with a ASW TF with 4 DEs work?


Sort of works as a "band-aid"..., but why doesn't the game allow the historically correct TF grouping? It has the historically rediculous "ASW ratings" of the Japanese "Escorts", but not the historically deadly composition of the Allied "Hunter-Killer TF".




MateDow -> RE: Modelling an ASW Light Cruiser (10/12/2012 1:04:40 PM)


quote:

ORIGINAL: Gridley380

Found your problem. :-)

Aircraft, cranes, catapults, fuel storage & pumps, magazine & handling equipment, flight & deck crew quarters & support, hanger structure, tooling for maintenance & repairs... that's just off the top of my head. Note that on just about every surface combatant that carried aircraft ever built the hanger is one of the recognition features and often forced design decisions of either the hull, the superstructure, or both.


What would be a more realistic value?

I haven't been able to find values for the air outfit on the US cruisers. I do know that it was significant enough that they were willing to cut the air complement of the pre-war heavy cruisers in half as compensation for AA guns and radar equipment. It also couldn't have been that heavy since they were able to build a Fletcher-class destroyer that could carry a single aircraft and the only compensation was a single 5"/38 mount.




MateDow -> RE: Modelling an ASW Light Cruiser (10/12/2012 1:08:32 PM)


quote:

ORIGINAL: mike scholl 1

The real question is WHY? Why build a larger ship for a job that a smaller one can do better? With today's weapons systems, it makes some sense..., but the only reason I can see to do so in the WW II era is increased range. The obvious answer in WW II was the "Hunter-Killer" TF of a CVE and a half dozen DE's. Unfortunately the game doesn't really allow such TF's.


My thought behind the design is the aircraft. This would have been effective for driving the submarine beneath the surface and allowing the force to move through the area. Because this was my focus, I wanted a vessel that could support air operations for a fair number of aircraft sacrificing guns for that duty. It would also be an effective scouting vessel for a surface force allowing carriers to operate independently of the battle fleet.

I also suppose that it could work with the carriers as a scout to free up combat aircraft in a similar fashion to the Japanese, but that wasn't a part of American doctrine (not that this vessel really fits that as well).




traskott -> RE: Modelling an ASW Light Cruiser (10/15/2012 11:21:28 AM)

It would be interesting for British ASW service? As a convoy leader at the Atlantic (i.e.): More room for the boss of the convoy, huge endurance, larger stock of ammo, planes, posibility of fend off raider cruisers or ( with some luck!!) a heavy cruiser, etc...




Gridley380 -> RE: Modelling an ASW Light Cruiser (10/15/2012 6:00:52 PM)


quote:

ORIGINAL: MateDow

What would be a more realistic value?

I haven't been able to find values for the air outfit on the US cruisers. I do know that it was significant enough that they were willing to cut the air complement of the pre-war heavy cruisers in half as compensation for AA guns and radar equipment. It also couldn't have been that heavy since they were able to build a Fletcher-class destroyer that could carry a single aircraft and the only compensation was a single 5"/38 mount.


Big difference between carrying one bird and a cat and being able to effectively maintain and operate that bird - note the Fletchers were quickly reconverted. IIRC they also lacked hangers but I'd have to look that up.

Sadly, I don't have data on component weights (catapult, crane, etc.) in my notes, nor does a quick web search turn them up. The birds themselves and fuel, etc. needs are easy, but are arguably only part of the full-load displacement (depending on which definition you use).

I suggest some good old fashioned reverse engineering. Take a US cruiser class you have good stats on and put them into your program (without aircraft or any allowance thereof). See what it produces as a displacement. Compare that to the actual displacement. For best results do this for multiple classes - luckily a 4 FP det was standard for most of the wartime US cruisers.




JeffK -> RE: Modelling an ASW Light Cruiser (10/15/2012 10:07:29 PM)

Too many guns, are you trying for an ASW ship or an ASW/AA/SC allrounder.

Too many aircraft, where are they going to be stored?

Lots of AAA for the time period, dont forget they didnt know what the air threat would be




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