WesWorld

During the Great War the RSAN suffered from a real shortage of multi purpose warships suitable for both independant missions and fleet duties. The few cruisers then at hand were hardly enough to cover the important trade routes around the Cape, across the South Atlantic and the Indian Ocean.

Hence it was decided in 1920, when the war ended and funds could be put in future planning instead of short-time programs, to build up a considerable cruiser force for the RSAN. It was planned to lay down an average of 2 cruisers per year for a period of eight years and modify those units worth it for future service. This program became known as the "Cruiser Paper" and ends 31-12-1928.

Today experts discuss if another such program is necessary for the RSAN. Funds are limited and the cruiser force now at hand is relatively modern in size and layout but some elderly units are aging rapidely. The ships of Town Class 08, though rebuild in the early 20s, are now 20 years old and cannot be rated as firstrank units anymore. Their follow-ons of the Class 10 have already been scrapped and even though the units of Town Class 13 just underwent modifications to lengthen their lives they are also no match for modern cruisers and lack the space to carry large facilities to field floatplanes or house enlarged crews which became necessary due to increased armament. It is expected they will be put out of service within the next 6 years.

So what does the board think? Is a new cruiser program, now including also flotilla leaders of 2,000ts - 4,000ts, necessary? What, if any, specialist ships are needed and why?

Current planning includes the modernization of the Town-class 16 to modern standards regarding fire controll and AAA equipment while their main armament will be replaced by 4x2 15cm shields. Further more two new cruisers of 8,000ts are to be laid down in 1929 and 1930 respectively should the funds be available. These units will introduce a new 15cm triple mounts and are meant to act as leaders for cruiser formations or smaller units and thus will incooperate flag facilities.

Please note that large (or heavy) cruisers are not part of the planning yet as a new "Cruiser Paper" would focus on cruisers of 8,000ts and smaller.

Further note that I´m not asking for tons of springsharp stuff here. It´s more about strategic deployment and role definition.

An interesting question. In order to determine what type of forces are need we need to determine what the prospect threat/risks are.
What is the potential for regional war? And with who?
What is the potential for general war? And involving what nations?
Are potentially hostile nations developing conventional forces or are they developing forces focusing on anti-shipping related operations?
What about carriers & submarines?

Well, waters around South America are rated hostile by RSAN experts and there is some potential for a crisis at Africa´s east coast. Finally sea lanes have to be secured to NEI through potentially hostile/difficult political regions, too.

And don't forget that your route to the NEI takes you awfully close to the Explosiveness of the Filipinos.
:-)

Not the kind of answer I hoped for but yes - you´re right. Those pesky detonators are what I meant. ;o)

(So far no detailled answers - and I wonder why? Too complex a question? I know it means to dig a little bit into the data and also to think about RSAN design philosophy but otherwise - where´s the chellange? I could answer it myself easily then....)

For those of you who need SS-data to get an idea of what _I_ currently aim for - here´s the data for CL29 as planned today. It´s more or less a slightly smaller FIJI without floatplane facilities, just 10 years earlier thanks to springsharp. I expect her to be as cramped and top heavy as the original HMS FIJI was.

I´ll also add the SS-data for the rebuild CL16-class.

But again - this is not a design contest or something similar. The designs below are only meant to back up my earlier post. Thanks.

Kreuzer Kategorie B, South African Light Cruiser laid down 1929

Displacement:
7.741 t light; 8.108 t standard; 9.280 t normal; 10.217 t full load

Dimensions: Length overall / water x beam x draught
557,45 ft / 547,90 ft x 58,40 ft x 19,52 ft (normal load)
169,91 m / 167,00 m x 17,80 m x 5,95 m

Armament:
12 - 5,91" / 150 mm guns (4x3 guns), 102,98lbs / 46,71kg shells, 1929 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 4,13" / 105 mm guns (4x2 guns), 35,32lbs / 16,02kg shells, 1929 Model
Breech loading guns in deck mounts
on side, all amidships
12 - 1,57" / 40,0 mm guns (4x3 guns), 1,95lbs / 0,88kg shells, 1929 Model
Breech loading guns in deck mounts
on side, evenly spread
16 - 0,79" / 20,0 mm guns (4x4 guns), 0,24lbs / 0,11kg shells, 1929 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 1.546 lbs / 701 kg
Shells per gun, main battery: 200
12 - 21,0" / 533 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,15" / 80 mm 374,80 ft / 114,24 m 10,01 ft / 3,05 m
Ends: Unarmoured
Main Belt covers 105% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3,35" / 85 mm 1,57" / 40 mm 3,15" / 80 mm
2nd: 0,98" / 25 mm 0,59" / 15 mm -
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -

- Armour deck: 1,97" / 50 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 82.000 shp / 61.172 Kw = 31,72 kts
Range 9.500nm at 15,00 kts
Bunker at max displacement = 2.109 tons

Complement:
472 - 614

Cost:
£3,143 million / $12,573 million

Distribution of weights at normal displacement:
Armament: 193 tons, 2,1%
Armour: 1.572 tons, 16,9%
- Belts: 491 tons, 5,3%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 290 tons, 3,1%
- Armour Deck: 791 tons, 8,5%
- Conning Tower: 0 tons, 0,0%
Machinery: 2.518 tons, 27,1%
Hull, fittings & equipment: 3.437 tons, 37,0%
Fuel, ammunition & stores: 1.539 tons, 16,6%
Miscellaneous weights: 20 tons, 0,2%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
9.743 lbs / 4.419 Kg = 94,6 x 5,9 " / 150 mm shells or 1,4 torpedoes
Stability (Unstable if below 1.00): 1,10
Metacentric height 2,7 ft / 0,8 m
Roll period: 15,0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,48
Seaboat quality (Average = 1.00): 1,00

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,520
Length to Beam Ratio: 9,38 : 1
'Natural speed' for length: 23,41 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 70
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 26,25 ft / 8,00 m
- Forecastle (25%): 22,97 ft / 7,00 m
- Mid (50%): 22,97 ft / 7,00 m (15,09 ft / 4,60 m aft of break)
- Quarterdeck (15%): 15,09 ft / 4,60 m
- Stern: 15,09 ft / 4,60 m
- Average freeboard: 19,36 ft / 5,90 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 105,2%
- Above water (accommodation/working, high = better): 119,5%
Waterplane Area: 21.714 Square feet or 2.017 Square metres
Displacement factor (Displacement / loading): 114%
Structure weight / hull surface area: 99 lbs/sq ft or 484 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,96
- Longitudinal: 1,41
- Overall: 1,00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform



Town CL16, South African Light Cruiser laid down 1916 (Engine 192

Displacement:
4.593 t light; 4.806 t standard; 5.351 t normal; 5.786 t full load

Dimensions: Length overall / water x beam x draught
474,00 ft / 465,88 ft x 47,24 ft x 18,70 ft (normal load)
144,48 m / 142,00 m x 14,40 m x 5,70 m

Armament:
8 - 5,91" / 150 mm guns (4x2 guns), 102,98lbs / 46,71kg shells, 1916 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 3,46" / 88,0 mm guns (4x2 guns), 20,79lbs / 9,43kg shells, 1916 Model
Breech loading guns in deck mounts
on side, all amidships
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,88kg shells, 1924 Model
Breech loading guns in deck mounts
on side, evenly spread
8 - 0,79" / 20,0 mm guns (4x2 guns), 0,24lbs / 0,11kg shells, 1924 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 1.008 lbs / 457 kg
Shells per gun, main battery: 180
6 - 21,0" / 533 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2,36" / 60 mm 440,12 ft / 134,15 m 9,19 ft / 2,80 m
Ends: Unarmoured
Upper: 1,38" / 35 mm 295,28 ft / 90,00 m 8,04 ft / 2,45 m
Main Belt covers 145% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,38" / 35 mm 0,59" / 15 mm -
2nd: 0,79" / 20 mm - -
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -

- Armour deck: 1,38" / 35 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 67.024 shp / 50.000 Kw = 32,55 kts
Range 6.000nm at 15,00 kts
Bunker at max displacement = 980 tons

Complement:
312 - 406

Cost:
£0,914 million / $3,657 million

Distribution of weights at normal displacement:
Armament: 126 tons, 2,4%
Armour: 910 tons, 17,0%
- Belts: 510 tons, 9,5%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 41 tons, 0,8%
- Armour Deck: 359 tons, 6,7%
- Conning Tower: 0 tons, 0,0%
Machinery: 2.087 tons, 39,0%
Hull, fittings & equipment: 1.439 tons, 26,9%
Fuel, ammunition & stores: 758 tons, 14,2%
Miscellaneous weights: 30 tons, 0,6%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2.255 lbs / 1.023 Kg = 21,9 x 5,9 " / 150 mm shells or 0,6 torpedoes
Stability (Unstable if below 1.00): 1,24
Metacentric height 2,4 ft / 0,7 m
Roll period: 12,8 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,25
Seaboat quality (Average = 1.00): 0,92

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,455
Length to Beam Ratio: 9,86 : 1
'Natural speed' for length: 21,58 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 76
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22,31 ft / 6,80 m
- Forecastle (30%): 20,34 ft / 6,20 m
- Mid (40%): 20,34 ft / 6,20 m (12,47 ft / 3,80 m aft of break)
- Quarterdeck (15%): 12,47 ft / 3,80 m
- Stern: 12,47 ft / 3,80 m
- Average freeboard: 15,85 ft / 4,83 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 145,3%
- Above water (accommodation/working, high = better): 97,2%
Waterplane Area: 14.097 Square feet or 1.310 Square metres
Displacement factor (Displacement / loading): 87%
Structure weight / hull surface area: 60 lbs/sq ft or 293 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,74
- Longitudinal: 1,25
- Overall: 0,78
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

If you don't build any cruisers, what would you build?

I'm asking this because you'll soon have 36 light cruisers in service(CL13 onwards, as well as the CL08 rebuilds). Of those, 8 are 8,000 tons, the rest under 6,000. I'd postpone building cruisers for a (small) while, and build smaller destroyer leaders(of which there seems to be a lot of unused tonnage). The idea would be to free the light cruisers from leader duties as much as possible, keeping the older cruisers on less critical sectors(if any), and putting the newer cruisers on more dangerous ones. After some 4-5 years, it's back to building cruisers.

BTW, liked the CL16 rebuild. The 12-gun cruiser, on the other hand, makes me a bit nervous(partially because I like my ships overbuilt - I'd rather have a 9-gun cruiser in that case).

What would I build? Good question.

The idea of DLs appearred to me as well but then again I just started with a class of 2,000 tonners (DL2 of which 8 units will be build in short order (two years period). Over all I have 35kts for these type of ship available. That´s about 17 units - or two classes of 8 units each and 3kts to be spend on two standard 1,500 tonners.

I think that these category A destroyers will be able to act as flotilla leaders where no CL is at hand.

On the other hand the category A cruisers are where I´m most flexible. Most tonnage available - and no block obsolecense. Add to this that a 2,000 tonner is still not a very large ship and hardly differs that much from a good 1,600ts unit the RSAN might need something more powerful but equally "expandable" - a class of DLs in the 2,500ts to 4,000ts range, armed with up to 15cm guns and a speed in excess of 32kn in most sea states. It would also be easier to fit staff facilities on such a unit than on a 2,000 tonner (think HMS TRIBAL when it comes to a large DD also meant to act as flotilla leader - and how cramped and overloaded she was).

The questions are - how many and in what time frame?

Further more one has to consider that the RSAN cannot be allowed to loose ground regarding some potential enemies. Given the large area to cover eight 8,000ts-CLs - which are meant to be able to do independant operations/patrols - are hardly enough. How to deploy them for example? Are those units really powerful enough to project the will of the RSAN compared to foreign designs (number of guns comes to mind)?

What about the old cruisers? How long can they really be used? What´s realistic? Especially the small CL08-class seems to be of questionable value today....

I'd avoid small cruisers - even for leaders. You have big areas to control - little ships can't do that. I'd question the value of rebuilding old cruisers (yes Greece did but I don't think it was worth the expense) unless you needed to hold onto old hulls because of a rise in tensions.

Cheers,

If I read things correctly, you'll shortly have 14 capital ships and 2 aircraft carriers in service. Your cruiser fleet will consist of 8 heavy and 32 light cruisers (I'm omitting Argentina here). Is the capital ship/carrier to cruiser ratio of 2:5 acceptable?

Are you satisfied that the cruisers planned or in service are adequate to function as escorts for your larger vessels (in particular, the aircraft carriers, with their frequent runs at high speed)?

Is the RSAN going to continue operating its cruisers and destroyers and independent squadrons? If so, a leader-type unit may be warranted; if not, better to leave space for flag functions in a full-sized CL.

What about larger light cruisers that dip into the heavy cruiser tonnage range. Sure they will have lighter guns, but more of them compared with what I'd assume are your potental enemies. Making a light cruiser that is worth one and a half to two light cruisers instead of the heavy cruiser might also give your enemies a false sense of security as you'll have less heavy cruisers than the treaty allows you to have (but instead you'll have likely have faster and more powerful light cruisers than they would normally build, thus allowing your forces to get to trouble spots faster than your present models of light cruisers).

Quoted

Originally posted by alt_naval
I'd avoid small cruisers - even for leaders. You have big areas to control - little ships can't do that.

What is a small cruiser to you? Anything below 8,000ts?

Historically the British tried to design the smallest useful cruiser in the 1930s and came up with the ARETHUSAs - small and cramped but they gave good service in WW2. I wonder if this was due to design or luck...

Quoted

Originally posted by Ithekro
What about larger light cruisers that dip into the heavy cruiser tonnage range. Sure they will have lighter guns, but more of them compared with what I'd assume are your potental enemies. Making a light cruiser that is worth one and a half to two light cruisers instead of the heavy cruiser might also give your enemies a false sense of security as you'll have less heavy cruisers than the treaty allows you to have (but instead you'll have likely have faster and more powerful light cruisers than they would normally build, thus allowing your forces to get to trouble spots faster than your present models of light cruisers).

Large light cruisers are appealing - but I won´t build them yet. Category A cruisers are strictly limited and even though I have three old ACs left to replace which will free some tonnage I can´t waste my allotment on units not as powerful as possible when it comes to firepower. So the RSAN won´t build CLs larger than 8,000ts.

Quoted

Originally posted by The Rock Doctor
If I read things correctly, you'll shortly have 14 capital ships and 2 aircraft carriers in service. Your cruiser fleet will consist of 8 heavy and 32 light cruisers (I'm omitting Argentina here). Is the capital ship/carrier to cruiser ratio of 2:5 acceptable?

Such a ratio would be acceptable but you´re counting CAs into the cruiser category here to achieve such ratio. That´s not what I had in mind.

The RSAN will deploy her heavy cruisers to areas no capital unit is present. They´re also meant to act as the core of independant cruiser forces (read what I wrote about the introduction of the CAPE GOOD HOPE class in 1923). So I don´t rate them as escorts for my capital ships and carriers.

This leaves me with a ratio of about 1:2 - including old and small hulls of questionable value or units with guns in shields instead of turrets which shouldn´t be used for battle fleet duties.

Quoted

Are you satisfied that the cruisers planned or in service are adequate to function as escorts for your larger vessels (in particular, the aircraft carriers, with their frequent runs at high speed)?

That´s exactly the question I currently can´t answer and where I hoped to get some input from the board. Both in number and individual strength.

Quoted

Is the RSAN going to continue operating its cruisers and destroyers and independent squadrons? If so, a leader-type unit may be warranted; if not, better to leave space for flag functions in a full-sized CL.

The RSAN actually plans to use her cruisers in cooperation with destroyer squadrons independantly even though the bulk of the available DDs will be tied to fleet (thus escort) duties.

What so you think such a leader should look like? Do you agree with alt_naval regarding the size of cruisers?

Presently Nordmark only has 5 classes of CL in full service, with most of the rest of our Cl's built from 1904 onwards are still in reserve. Despite this, the proportion of our active cruisr force is from 1915, and haven't yet been refitted. I am considering flottila leaders, but am unsure of their usefulness in a more multitask role.

Build as big as possible, i.e. 8.000ton ships rather than 6.000tons or smaller. Room for growth and stability should be paramount, even at the expense of other qualities.

With a hull that large, multipurpose has to creep in, so hangar for 2 aircraft, a bit of excess weight for extra stores, not too many torpedoes, 6 or 8, a few AA guns.

Something like La Galissonnière?

Speed should be 30-31knts to keep up with carriers and other capital ships.

I think that the RSAN will eventually get into Colony Class ships, the needs of the two navies being broadly similar.

ave you thought about using 8000t Oyodos? With flag facilities they would make fine CL leaders.

Quoted

Originally posted by HoOmAn
What would I build? Good question.

The idea of DLs appearred to me as well but then again I just started with a class of 2,000 tonners (DL2 of which 8 units will be build in short order (two years period). Over all I have 35kts for these type of ship available. That´s about 17 units - or two classes of 8 units each and 3kts to be spend on two standard 1,500 tonners.

I think that these category A destroyers will be able to act as flotilla leaders where no CL is at hand.

On the other hand the category A cruisers are where I´m most flexible. Most tonnage available - and no block obsolecense. Add to this that a 2,000 tonner is still not a very large ship and hardly differs that much from a good 1,600ts unit the RSAN might need something more powerful but equally "expandable" - a class of DLs in the 2,500ts to 4,000ts range, armed with up to 15cm guns and a speed in excess of 32kn in most sea states. It would also be easier to fit staff facilities on such a unit than on a 2,000 tonner (think HMS TRIBAL when it comes to a large DD also meant to act as flotilla leader - and how cramped and overloaded she was).

The questions are - how many and in what time frame?

Further more one has to consider that the RSAN cannot be allowed to loose ground regarding some potential enemies. Given the large area to cover eight 8,000ts-CLs - which are meant to be able to do independant operations/patrols - are hardly enough. How to deploy them for example? Are those units really powerful enough to project the will of the RSAN compared to foreign designs (number of guns comes to mind)?

What about the old cruisers? How long can they really be used? What´s realistic? Especially the small CL08-class seems to be of questionable value today....

I'd replace the CL08 right now with the DL28 class. 16 DL units looks good, probably won't be enough for all leader duties, but it'd help. Even if they are poorer seaboats and more cramped than 4,000 ton cruisers, I'd prefer them to small CLs, because the way I see it, you need as much big cruisers as possible.

After that, I'd build at least 4 8,000 cruisers, something like La Galissonière, like Red Admiral said. What I'm not sure is what I'd build after those cruisers(CL30?), another DL class or more cruisers.

Quoted

What is a small cruiser to you? Anything below 8,000ts?

Historically the British tried to design the smallest useful cruiser in the 1930s and came up with the ARETHUSAs - small and cramped but they gave good service in WW2. I wonder if this was due to design or luck...

The Arethusas and Didos were the same size. I think a 'small' cruiser is one that can only just do its job.

A Destroyer leader is not a cruiser. A Yubari is not big enough to do cruiser roles. In this age it needs an aircraft so we are up to 7,000-8,000 tons.

I agree with RA that if you are going to build useful cruisers they need to be about 8000 tons.

Cheers,

Nordmarks next CL's will be just under 7000 tons standard displacement, these may carry floatplanes though this isn't certain as yet.