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Blackbuck
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 17th, 2018, 8:46 pm
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The Zaras made in excess of 90k on two shafts I believe, so yes.

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Rhade
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 18th, 2018, 9:06 am
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Mini Dunkerque, I like it.

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Novice
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 18th, 2018, 8:54 pm
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erik_t wrote: *
Extremely attractive. Is 90kshp on two shafts realistic in that era?
Italian cruisers Pola, Zara et al had 95kshp on two shafts, so I believe it's possible.

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Shigure
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 19th, 2018, 8:30 pm
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Alright everyone, I've borrowed a judging sheet template from ABN so you all can have a look.

https://docs.google.com/spreadsheets/d/ ... sp=sharing

At this stage I'm looking for judges! If anyone (who hasn't entered the challenge) would like to judge, let me know right here and I'll give you a link to edit the sheet.

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JSB
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 19th, 2018, 9:08 pm
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Shigure wrote: *
I've borrowed a judging sheet template from ABN so you all can have a look.

https://docs.google.com/spreadsheets/d/ ... sp=sharing
I have a question when it talks about fighting ability etc is that relative to its size or cost or in total?
I'm working (slowly) on a ship (well ships indecisively) and was wondering if this is a completion that only 9,999t 8" late 30s ships can win?

Not that I don't fully realise that some of the already posted ships will be better anyway 8-)


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Shigure
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 20th, 2018, 4:41 am
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Fighting ability simply refers to its a ability to fight with other warships, the highest meaning it can hold it's own against 8" gun heavy cruisers with good speed and armor, whilst the lowest meaning it will struggle to fight torpedo boats.

If your warship is only built to fight destroyers or small cruisers it will be in the 5/10 or 6/10 range. Whilst a cruiser with good protection and a heavy broadside of 8" guns will number around 8-10/10

Armor and firepower are what needs to be considered here.

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Garlicdesign
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 20th, 2018, 12:42 pm
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Hi everyone!

After having had a look at the judging sheet, I wonder how 'reliability' can be judged for paper designs. Otherwise, looks OK.

Just to show the performance date is not entirely made up, I added Springsharp calculations for the Yoshino-class.

Greetings
GD


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Shigure
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 20th, 2018, 1:18 pm
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Garlicdesign wrote: *
Hi everyone!

After having had a look at the judging sheet, I wonder how 'reliability' can be judged for paper designs. Otherwise, looks OK.

Just to show the performance date is not entirely made up, I added Springsharp calculations for the Yoshino-class.

Greetings
GD
Having another look at it I guess reliability can be merged with performance, so I'll do that.

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Shigure
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 20th, 2018, 1:37 pm
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Alexandria class heavy cruiser

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Originally supposed to be part of the previous Juno class, the shortcomings of that class became apparent and were addressed with a major redesign in the form of the Alexandria class. Notable differences between the classes was a thicker 152mm belt, thick 50mm deck armor, shorter length, wider beam and smaller superstucture to remove serious balance issues, revisement of the aircraft handling centers (Alexandria features an actual hanger amidships), as well as an updated secondary armament in the form of twins that sit aft, rather than single mounts that took up too much space around ship. However the secondary battery had very limited firing arcs, which were once again revised in succeding classes.

As built, the Alexandrias mount the standard 203mm/55 gun in three triple mounts, three twin 127mm/50s mounted aft, a few 20mm singles and two triple 40mm anti-aircraft guns. While they were designed with the Japanese Myoko class in mind, which was larger, faster and had one more gun, the Antarans were satisfied with the ship's design. Robust Antaran fire-control, accurate artillery and hard-hitting shells is often said to be the reason for their belief in their cruisers' superiority, and this was no different with Alexandria.

Displacement - 9700 tonnes
Main battery - 3x3 203mm/55
Secondary battery - 3x2 127mm/50
Speed - 33 knots
Range - 8000nm at 18 knots
Armor belt - 152mm
Deck - 50mm

ARS Alexandria

Alexandria, along with Jessamy and Summerwood, were laid down by Martin and Co. Shipyards in 1932, launched in 1933 and commisioned in 1934. She completed her working up and was transferred to the Pacific Fleet's naval base of Port Isla, Tuscadia. As with most warships built before 1942, Alexandria was painted in Standard 18 (camouflage with contrasting black and white colors) well into the war. She was transferred to Corusca Naval base in 1940 for refits, thus she was not present during the surprise attack on Port Isla, in which her sistership ARS Jezebel was torpedoed. Her refit at Corusca was moderate as it mostly an update to her older AA mounts and a repainting of her camouflage scheme.

Being one of the few warships fully ready for combat, Alexandria sailed with cruiser Juno to the Philipines to counter the Japanese advance into South-East Asia. She was docked at Darwin in June, then she became the flagship of the ABDA Force after being rebased in Surubaya. In December 1940,Alexandria was assigned to escort some of the convoys going to and from the Philipines evacuating Antaran Army forces. In the afternoon of 3 December, Alexandria received a request for support from destroyer ARS Speirs which had been engaged by an IJN task force off Manila. At the time Alexandria, along with several destroyers, was escorting another convoy bound for Manila - which was now blockaded and being repeatedly bombed by IJA aircraft. Alexandria put out its own call for support from any sorrounding units to assist in engaging the Japanese task force, thus beginning the Battle off Manila.

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Alexandria, along with destroyers Urana and Harper, engaged the IJN taskforce at at 16:40 - which was made up of Takao and Atago and several destroyers. Atago withdrew due to evading torpedoes from Urana, the latter of which ended up getting torpedoed by destroyer Sagiri. Takao and Alexandria exchanged in an indecisive gun duel, Takao retreated due to receiving heavy damage from 8" and 5" fire (from Harper), whilst Alexandria's command deck was destroyed. The confusion due to the lack of leadership (the command crew was killed) ended in the cruiser wandering away from the battlefield for nearly an hour. The blockade had essentually been defeated and the battle was concluded. Alexandria returned to Surubaya for repairs. Alexandria lead the charge during the Second Battle of Makassar Straight (most commonly known as Battle of the Java Sea) in which ABDA forces attempted to stop an IJN invasion force bound for Surubaya. The battle would've been an utter defeat, CA Juno was sunk by Haguro, along with De Ruyter, but Alexandria sunk Naka in her 4th salvo and went on to be the battle's only Allied survivor and escaping somewhat unharmed.

Alexandria was rebased to Sydney in January 1942 after Darwin was bombed by land based aircraft. Between January and March Alexandria sortied several times along with destroyers in response to submarine attacks along the Australian coast. Alexandria joined a carrier taskforce in April and provided AA support during the Battle of the Solomon Sea on 7 April, shooting down only three aircraft. Alexandria covered the evacuation of Port Moresby on 18 April and returned to Brisbane a day later. Along with the rest of the Antaran Naval forces stationed in Australia, Alexandria retreated to Port Isla once it became clear they wouldn't be able to halt an eventual invasion of Australia.

Alexandria was present during the Battle of Vescadia, escorting a poorly prepared carrier force attempting to intercept the Japanese invasion force attacking the Vescadia Atoll (mostly commonly known as Midway). Alexandria provided AA support for most of the length of the battle, attempting to protect her carriers from IJN bombers, ultimatly failing as ARS Westwood and ARS Caprillo were both lost. Alexandria's captain originally intended to engage the cruiser Tone which had recently came into vision, and a few salvoes were traded, however the force's commander demanded a full retreat when it was the full scope of the IJN invasion force was realized. Alexandria deflected a bomb off her aft turret from a D3A 'Val'during her retreat from the AO.


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In November 1942, while based at Port Isla, Alexandria was fitted with SA and SG radar sets, Mk3 and Mk4 radar for her directors and additional AA. Her camouflage scheme was also updated to standard 38 (splinter pattern with dark and light grey). Alexandria was present during the First Battle of Guadalcanal in April 1943 and during the night if the 9th she assisted in the sinking of destroyer Yuudachi, and later that night she collided with Aoba. Aoba was eventually sunk by Alexandria, who in turn took a torpedo that blew off her stern. Alexandria was targetted by 5" shell fire from both IJN and Antaran ships (accidently). The next morning the commanders of the Antaran force debated whether or not to scuttle the cruiser, but decided that she was going be towed back to Port Isla by destroyer ARS Ember. 200km away from Port Isla, Alexandria and Ember were spotted by an aircraft launched from I-6. With a salvo of three torpedoes, both Ember and Alexandria were sunk.

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Ships in class

Alexandria - Torpedoed, 1943
Jessamy - Sunk during surface action, 1943
Summerwood - Sold to Chile, 1948
Lucas - Sold to Chile, 1948
Jezebel - Sunk during attack on Port Isla, 1940
Athena - Sunk during surface action, 1944

__________SpringSharp Report_____________

Alexandria, Antaran heavy cruiser laid down 1932 (Engine 1933)

Displacement:
9 303 t light; 9 713 t standard; 10 192 t normal; 10 575 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(617.50 ft / 606.96 ft) x 65.62 ft x (19.69 / 20.20 ft)
(188.21 m / 185.00 m) x 20.00 m x (6.00 / 6.16 m)

Armament:
9 - 7.99" / 203 mm 50.0 cal guns - 270.21lbs / 122.57kg shells, 120 per gun
Breech loading guns in turret on barbette mounts, 1932 Model
2 x Triple mounts on centreline, forward deck forward
1 raised mount - superfiring
1 x Triple mount on centreline, aft deck aft
6 - 5.00" / 127 mm 50.0 cal guns - 66.16lbs / 30.01kg shells, 200 per gun
Dual purpose guns in deck mounts, 1932 Model
3 x Twin mounts on sides, aft deck forward
Weight of broadside 2 829 lbs / 1 283 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.98" / 152 mm 333.83 ft / 101.75 m 9.71 ft / 2.96 m
Ends: Unarmoured
Main Belt covers 85% of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 7.09" / 180 mm 1.97" / 50 mm 5.00" / 127 mm
2nd: 1.97" / 50 mm 0.98" / 25 mm -

- Armoured deck - multiple decks:
For and Aft decks: 1.97" / 50 mm

- Conning towers: Forward 3.94" / 100 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 81 963 shp / 61 144 Kw = 32.50 kts
Range 4 000nm at 14.00 kts
Bunker at max displacement = 862 tons

Complement:
506 - 659

Cost:
£4.247 million / $16.989 million

Distribution of weights at normal displacement:
Armament: 674 tons, 6.6%
- Guns: 674 tons, 6.6%
Armour: 1 988 tons, 19.5%
- Belts: 825 tons, 8.1%
- Armament: 424 tons, 4.2%
- Armour Deck: 699 tons, 6.9%
- Conning Tower: 40 tons, 0.4%
Machinery: 2 388 tons, 23.4%
Hull, fittings & equipment: 4 252 tons, 41.7%
Fuel, ammunition & stores: 889 tons, 8.7%
Miscellaneous weights: 0 tons, 0.0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
11 574 lbs / 5 250 Kg = 45.3 x 8.0 " / 203 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 2.7 ft / 0.8 m
Roll period: 16.9 seconds
Steadiness - As gun platform (Average = 50 %): 73 %
- Recoil effect (Restricted arc if above 1.00): 0.67
Seaboat quality (Average = 1.00): 1.03

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and small transom stern
Block coefficient (normal/deep): 0.455 / 0.460
Length to Beam Ratio: 9.25 : 1
'Natural speed' for length: 26.61 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 71
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00%, 27.10 ft / 8.26 m, 22.18 ft / 6.76 m
- Forward deck: 30.00%, 22.18 ft / 6.76 m, 22.18 ft / 6.76 m
- Aft deck: 25.00%, 13.12 ft / 4.00 m, 13.12 ft / 4.00 m
- Quarter deck: 20.00%, 13.12 ft / 4.00 m, 13.12 ft / 4.00 m
- Average freeboard: 18.60 ft / 5.67 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 100.9%
- Above water (accommodation/working, high = better): 177.5%
Waterplane Area: 26 104 Square feet or 2 425 Square metres
Displacement factor (Displacement / loading): 109%
Structure weight / hull surface area: 118 lbs/sq ft or 577 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.35
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

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reytuerto
Post subject: Re: Treaty Cruiser Design ChallengePosted: April 23rd, 2018, 2:47 pm
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Edited, task acomplished!


Last edited by reytuerto on April 24th, 2018, 1:59 pm, edited 2 times in total.

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