WesWorld

This cruiser is designed to act as a destroyer flotilla flagship, and shes equiped with guns large enough to dish out sufficient punishment to enemy DD's.
Does the design have merrit?

Undaunted, Atlantis light cruiser laid down 1916

Displacement:
4,870 t light; 5,032 t standard; 5,768 t normal; 6,333 t full load
Loading submergence 502 tons/feet

Dimensions:
452.00 ft x 58.00 ft x 14.00 ft (normal load)
137.77 m x 17.68 m x 4.27 m

Armament:
6 - 5.50" / 140 mm guns
4 - 3.00" / 76 mm AA guns
6 - 1.00" / 25 mm guns
Weight of broadside 556 lbs / 252 kg
6 - 18.0" / 457.2 mm above water torpedoes, 2 - 18.0" / 457.2 mm submerged torpedo tubes

Armour:
Belt 3.00" / 76 mm, upper belt 1.00" / 25 mm, end belts 1.00" / 25 mm
Belts cover 132 % of normal area
Main gun shields 2.00" / 51 mm
Armour deck 1.50" / 38 mm, Conning tower 2.00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 56,330 shp / 42,022 Kw = 30.02 kts
Range 10,000nm at 12.00 kts

Complement:
330 - 430

Cost:
£0.855 million / $3.421 million

Distribution of weights at normal displacement:
Armament: 70 tons, 1.2 %
Armour: 1,176 tons, 20.4 %
Belts: 649 tons, 11.3 %, Armament: 26 tons, 0.4 %, Armour Deck: 487 tons, 8.5 %
Conning Tower: 14 tons, 0.2 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 2,099 tons, 36.4 %
Hull, fittings & equipment: 1,476 tons, 25.6 %
Fuel, ammunition & stores: 898 tons, 15.6 %
Miscellaneous weights: 50 tons, 0.9 %

Metacentric height 3.7

Remarks:
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.34
Shellfire needed to sink: 3,416 lbs / 1,549 Kg = 41.1 x 5.5 " / 140 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.8
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.09
Relative quality as seaboat: 1.00

Hull form characteristics:
Block coefficient: 0.550
Sharpness coefficient: 0.38
Hull speed coefficient 'M': 7.71
'Natural speed' for length: 21.26 kts
Power going to wave formation at top speed: 63 %
Trim: 70
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 131.9 %
Relative accommodation and working space: 179.3 %
(Average = 100%)
Displacement factor: 96 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.61
(Structure weight / hull surface area: 54 lbs / square foot or 265 Kg / square metre)
Relative longitudinal hull strength: 1.14
(for 20.00 ft / 6.10 m average freeboard, freeboard adjustment 6.44 ft)
Relative composite hull strength: 0.65

Wes,

why is this design laid down 1916?

Further more its hull strength should be around 1,0. I´ve designed several light cruisers in the 5000ts-category myseld and I had no problem to get a hull strength of 1,0. See my Yaoundé-class (laid down 1919 for example) I presented in the News Section some time ago (The Navalist, issue 3-10-20). Its hull strength section reads like this

Relative cross-sectional hull strength: 1.05
(Structure weight per square
metre of hull surface: 463 kg)

Relative longitudinal hull strength: 1.81
(for 5.00 m average freeboard;
freeboard adjustment +0.88 m)

Relative composite hull strength: 1.11

In general I think having several light cruisers in the 5000ts category is quite usefull. Their low size and costs allow to build more than just two or three while they´re large enough to back a sufficient punch (if single mounts are used, that is, barbets/turrets are too heavy to have 4x2 on 5000ts in the early 20s).

There's a useful post about appropriate hull strengths for small vessels of various displacement:

http://pub165.ezboard.com/fwarships1disc…2.topic&index=2

By this, a cruiser displacing ~5000 tons should try for a hull strength of 0.75 or more, and this latest one is a bit short of that. You could probably reduce the deck a few millimeters to get there.

Also, it might have some trouble operating with destroyers with a top speed of only 30 kts.

Visit my Russian/French fantasy fleet page:
http://admkuznetsov.tripod.com

I´ve never seen a link to one of my posts from another board. ;o)


But I have to add one note: For me - personally - I don´t let hull strength drop below 1,00 even at 5000ts. I wrote 6000ts on the warships1 design board because Rick once said something similar (long time ago) but whenever possible or realistic I try to avoid hull-strength warnings on all my designs and I noticed it is possible to get balanced designs on 5000ts without one.

(Further note: "Balanced" doesn´t mean a 6" belt, 8+ 6" guns and 32kn on 5000ts - "balanced" stands for adequate designs that look realistic compared to what was designed historically in a given time frame. See example below:

Enter ship name, Enter country Enter ship type laid down 1920

Displacement:
5.371 t light; 5.583 t standard; 6.205 t normal; 6.679 t full load
Loading submergence 475 tons/feet

Dimensions:
492,13 ft x 53,81 ft x 16,40 ft (normal load)
150,00 m x 16,40 m x 5,00 m

Armament:
8 - 5,91" / 150 mm guns (4 Main turrets x 2 guns, 2 superfiring turrets)
6 - 4,13" / 105 mm guns
8 - 1,57" / 40 mm AA guns
12 - 0,79" / 20 mm guns
Weight of broadside 1.054 lbs / 478 kg
6 - 21,0" / 533 mm above water torpedoes

Armour:
Belt 1,97" / 50 mm, ends unarmoured
Belts cover 118% of normal area
Main turrets 1,97" / 50 mm, 2nd gun shields 0,98" / 25 mm
AA gun shields 0,98" / 25 mm
Armour deck 0,98" / 25 mm, Conning tower 1,38" / 35 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 55.007 shp / 41.035 Kw = 30,26 kts
Range 9.500nm at 12,00 kts

Complement:
349 - 454

Cost:
£1,342 million / $5,370 million

Distribution of weights at normal displacement:
Armament: 132 tons, 2,1%
Armour: 756 tons, 12,2%
Belts: 270 tons, 4,4%, Armament: 172 tons, 2,8%, Armour Deck: 303 tons, 4,9%
Conning Tower: 10 tons, 0,2%, Torpedo bulkhead: 0 tons, 0,0%
Machinery: 1.923 tons, 31,0%
Hull, fittings & equipment: 2.510 tons, 40,4%
Fuel, ammunition & stores: 835 tons, 13,5%
Miscellaneous weights: 50 tons, 0,8%

Metacentric height 3,0

Remarks:
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1,25
Shellfire needed to sink: 5.951 lbs / 2.699 Kg = 57,8 x 5,9 " / 150 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 1,0
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 52 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0,34
Relative quality as seaboat: 1,03

Hull form characteristics:
Block coefficient: 0,500
Sharpness coefficient: 0,34
Hull speed coefficient 'M': 8,19
'Natural speed' for length: 22,18 kts
Power going to wave formation at top speed: 59 %
Trim: 50
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 117,9%
Relative accommodation and working space: 138,3%
(Average = 100%)
Displacement factor: 109%
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0,96
(Structure weight / hull surface area: 92 lbs / square foot or 447 Kg / square metre)
Relative longitudinal hull strength: 1,47
(for 18,04 ft / 5,50 m average freeboard, freeboard adjustment 4,28 ft)
Relative composite hull strength: 1,00

Sure, it is somewhat slow but SS sims a ships speed not under trial conditions where its top speed might be higher.)

I read that post, and forgot to thank you for posting it.

Thank you.

It's very useful to know all that. Should you keep to Standard or Normal Displacement with those numbers ?

BTW how high would the trial speed roughly be ? Something like 105% of the speed given in SS or between 100 and 105 % ?

Walter

Glad you liked it.

Tonnage? I´m always referring to standard displacement if nothing else is noted.

Speed/Power output during trials can only be quessed. When designing a ship _I_ normally choose a speed that my design has to achieve as minimum. Let´s say 30kn. Then I look at shp or kw which indicated I would need (for example) 51345kw. Well, actually designers never designed powerplants to have 51345kw. They would opt for either 50000kw or 55000kw. Personally I use 5000kw steps and choose the one that assures me 30kn. For our example this means 55000kw and maybe 30,123kn.

When the whole design is finished I test how fast the ship would be if I raise its engines power output. But how far should I go?
Browsing through my books I noticed most navies achieved up to 5-15% extra power during trials, some even more. The Italians for example often went far beyond where security was assured and managed to get 20% or 25% more power. Together with light ship conditions this made up for very high speeds during trials. With the exception of some very special cases (where I need something like this for storytelling for example) this is unrealistic and I´m not going to push the limits that far. So _I_ generally use 12% or 15% and I noticed that it doesn´t really matter what kind of design it is. Around 30-31kn another 15% more output normally means exactely another knot of speed. So for the example above "my trials" would indicate 63250kw and ~31,25kn at top speed what sounds very realistic to me when comparing those stats to historical data.

As an example here are the stats of my Yaoundé-class light cruisers laid down 1919:

Maximum speed for 35008 shaft kw = 29.65 knots
(Trials with 14,3% overload for 40000 shaft kw = 30.64 knots)
Approximate cruising radius, 11200 nm / 10 knots

In this case I simple went up another 5000kw step but with 14,3% this fits the rule discribed above quite good.

Hope this helps,

HoOmAn

I acctually saw Hoomans post after I designed this ship. I have a few holes in my cruiser and destroyer developement that I had to fill and this was one of them. How can I further Improve on this designother than the lack of armor coverage). Its turning out to be tough getting her composite hull strength up to 1.00 and shes now getting larger!

Undaunted, Atlantis light cruiser laid down 1915

Displacement:
6,423 t light; 6,619 t standard; 7,514 t normal; 8,200 t full load
Loading submergence 574 tons/feet

Dimensions:
520.00 ft x 58.00 ft x 16.00 ft (normal load)
158.50 m x 17.68 m x 4.88 m

Armament:
6 - 5.50" / 140 mm guns
4 - 3.00" / 76 mm AA guns
6 - 1.00" / 25 mm guns
Weight of broadside 556 lbs / 252 kg
6 - 18.0" / 457.2 mm above water torpedoes, 2 - 18.0" / 457.2 mm submerged torpedo tubes

Armour:
Belt 1.97" / 50 mm, ends unarmoured
Belts cover 120 % of normal area
Main belt does not fully protect magazines and engineering spaces
Main gun shields 1.97" / 50 mm
Armour deck 1.00" / 25 mm, Conning tower 1.97" / 50 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 84,378 shp / 62,946 Kw = 32.57 kts
Range 10,000nm at 12.00 kts

Complement:
403 - 524

Cost:
£1.063 million / $4.251 million

Distribution of weights at normal displacement:
Armament: 70 tons, 0.9 %
Armour: 716 tons, 9.5 %
Belts: 303 tons, 4.0 %, Armament: 25 tons, 0.3 %, Armour Deck: 372 tons, 4.9 %
Conning Tower: 16 tons, 0.2 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 3,196 tons, 42.5 %
Hull, fittings & equipment: 2,391 tons, 31.8 %
Fuel, ammunition & stores: 1,091 tons, 14.5 %
Miscellaneous weights: 50 tons, 0.7 %

Metacentric height 3.7

Remarks:
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.33
Shellfire needed to sink: 4,240 lbs / 1,923 Kg = 51.0 x 5.5 " / 140 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.8
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.08
Relative quality as seaboat: 1.00

Hull form characteristics:
Block coefficient: 0.545
Sharpness coefficient: 0.36
Hull speed coefficient 'M': 8.12
'Natural speed' for length: 22.80 kts
Power going to wave formation at top speed: 62 %
Trim: 70
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 149.1 %
Relative accommodation and working space: 170.7 %
(Average = 100%)
Displacement factor: 97 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.83
(Structure weight / hull surface area: 75 lbs / square foot or 366 Kg / square metre)
Relative longitudinal hull strength: 1.25
(for 20.00 ft / 6.10 m average freeboard, freeboard adjustment 5.70 ft)
Relative composite hull strength: 0.86

Well, I think 32,5kn is an aweful lot of speed for 1915. Was there even a single design out there historically that was that fast?

I would reduce her speed by 0,5-1kn. Given that you already have a hs of 0,86 this should do. This will have another effect: incresing your seakeeping (remember, ss calculates seakeeping at max speed). So you might also be able to reduce freeboard somewhat to save even more weight and gain some hull strength.

Playing around with those variable (speed and freeboard) should also allow to lengthen your belt somewhat.

Just my thoughts....

What if I remove the belt completely, if shes to fight alongside destroyers wouldn't it make sence for her to be armored similarily? These cruisers will be fairly old and will be replaced by newer second line ships in the future.

Undaunted, Atlantis light cruiser laid down 1915

Displacement:
5,567 t light; 5,737 t standard; 6,547 t normal; 7,169 t full load
Loading submergence 498 tons/feet

Dimensions:
465.00 ft x 56.00 ft x 16.00 ft (normal load)
141.73 m x 17.07 m x 4.88 m

Armament:
5 - 5.50" / 140 mm guns
4 - 3.00" / 76 mm AA guns
6 - 1.00" / 25 mm guns
Weight of broadside 473 lbs / 215 kg
6 - 18.0" / 457.2 mm above water torpedoes, 2 - 18.0" / 457.2 mm submerged torpedo tubes

Armour:
Main gun shields 1.59" / 40 mm
Armour deck 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 68,639 shp / 51,205 Kw = 31.11 kts
Range 10,000nm at 12.00 kts

Complement:
363 - 473

Cost:
£0.885 million / $3.540 million

Distribution of weights at normal displacement:
Armament: 59 tons, 0.9 %
Armour: 340 tons, 5.2 %
Belts: 0 tons, 0.0 %, Armament: 17 tons, 0.3 %, Armour Deck: 323 tons, 4.9 %
Conning Tower: 0 tons, 0.0 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 2,600 tons, 39.7 %
Hull, fittings & equipment: 2,518 tons, 38.5 %
Fuel, ammunition & stores: 980 tons, 15.0 %
Miscellaneous weights: 50 tons, 0.8 %

Metacentric height 3.2

Remarks:
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.26
Shellfire needed to sink: 4,707 lbs / 2,135 Kg = 56.6 x 5.5 " / 140 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.8
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.08
Relative quality as seaboat: 1.01

Hull form characteristics:
Block coefficient: 0.550
Sharpness coefficient: 0.37
Hull speed coefficient 'M': 7.60
'Natural speed' for length: 21.56 kts
Power going to wave formation at top speed: 64 %
Trim: 69
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 140.3 %
Relative accommodation and working space: 161.7 %
(Average = 100%)
Displacement factor: 108 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 1.01
(Structure weight / hull surface area: 90 lbs / square foot or 437 Kg / square metre)
Relative longitudinal hull strength: 1.90
(for 20.00 ft / 6.10 m average freeboard, freeboard adjustment 6.09 ft)
Relative composite hull strength: 1.08

Quoted

What if I remove the belt completely, if shes to fight alongside destroyers wouldn't it make sence for her to be armored similarily?

Given the range of destroyer combat, I'd keep the belt and lose the deck armor. Otherwise, it looks pretty good for a flotilla leader

Visit my Russian/French fantasy fleet page:
http://admkuznetsov.tripod.com

Cruisers around 1915 seemed to have deck and CT armor but lacked side armor. That seems a bit odd but heres a design that swaps the deck armor for side armor.

Undaunted, Atlantis light cruiser laid down 1915

Displacement:
5,567 t light; 5,737 t standard; 6,547 t normal; 7,169 t full load
Loading submergence 498 tons/feet

Dimensions:
465.00 ft x 56.00 ft x 16.00 ft (normal load)
141.73 m x 17.07 m x 4.88 m

Armament:
5 - 5.50" / 140 mm guns
4 - 3.00" / 76 mm AA guns
6 - 1.00" / 25 mm guns
Weight of broadside 473 lbs / 215 kg
6 - 18.0" / 457.2 mm above water torpedoes, 2 - 18.0" / 457.2 mm submerged torpedo tubes

Armour:
Belt 1.97" / 50 mm, ends unarmoured
Belts cover 170 % of normal area
Main gun shields 1.59" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 68,639 shp / 51,205 Kw = 31.11 kts
Range 10,000nm at 12.00 kts

Complement:
363 - 473

Cost:
£0.885 million / $3.540 million

Distribution of weights at normal displacement:
Armament: 59 tons, 0.9 %
Armour: 397 tons, 6.1 %
Belts: 380 tons, 5.8 %, Armament: 17 tons, 0.3 %, Armour Deck: 0 tons, 0.0 %
Conning Tower: 0 tons, 0.0 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 2,600 tons, 39.7 %
Hull, fittings & equipment: 2,461 tons, 37.6 %
Fuel, ammunition & stores: 980 tons, 15.0 %
Miscellaneous weights: 50 tons, 0.8 %

Metacentric height 3.2

Remarks:
Hull space for machinery, storage & compartmentation is cramped
Room for accommodation & workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.27
Shellfire needed to sink: 4,718 lbs / 2,140 Kg = 56.7 x 5.5 " / 140 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.8
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.08
Relative quality as seaboat: 1.02

Hull form characteristics:
Block coefficient: 0.550
Sharpness coefficient: 0.37
Hull speed coefficient 'M': 7.60
'Natural speed' for length: 21.56 kts
Power going to wave formation at top speed: 64 %
Trim: 69
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 140.3 %
Relative accommodation and working space: 161.7 %
(Average = 100%)
Displacement factor: 107 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.99
(Structure weight / hull surface area: 87 lbs / square foot or 427 Kg / square metre)
Relative longitudinal hull strength: 1.85
(for 20.00 ft / 6.10 m average freeboard, freeboard adjustment 6.09 ft)
Relative composite hull strength: 1.05

"These cruisers will be fairly old and will be replaced by newer second line ships in the future."

Ehm... Wes? Laid down 1915 -> fairly old? If the first units of this class were laid down in 1915, with later units following in 1916+, they will not enter service before 1916+. So in 1921 they´re just (!) ~5 years old which is _nothing_ for a ship. In fact, they should be among the latest designs you have.... Old enough to have the bugs worked out but easily young enough to serve for another 10 years (maybe including a modernisation).

_I_ would be quite carefull when designing my ships laid down ~1915+. They´re among the most important units you have right now.

Btw, shouldn´t you´ve settled all this down month ago? I mean, we´ve all posted our fleets in Dec. 1920 to make sure everybody knows where we´re starting form, right?... Just wondering...

Cheers,

HoOmAn

The ships laid down in 1915 are my older ships, most of the newer ones are built in 1917/18, but your right they are not old. As for the dates I'm trying to get them sorted out as at a second glance they seem all to be new.
My cruiser fleet is for the most part already laid out save this class, so if the interpretation is that I'm trying to sneak in another class that is not the case. I'm simply trying to make sure my designs are sound.
Unlike most here I'm fairly new at springsharp and in laying out my fleet I've noticed a few gaps in ship development. Take a look at my BB post and you'll see how I've taken great care on developing an evolutionary line for my Capital ships.