Trade Defence Ship?

[The Rock Doctor]

I've been pondering the matter of trade defence to and from Congo.  The existence of such large cruisers as the Orange Furies or the CSA Wheelers complicates convoy defence - even a OTL treaty CA would be overwhelmed by such an attacker.  I'd need to commit a capital unit to fend these types of ships off.

At the same time, I've got a niche for naval artillery support and, perhaps, defence of amphibious assault groups.  If I allocate a battleship to this role, I lose it from the battleline.  My battleline's not so big that I can afford to spare a unit from it.

If I had decent semi-dreadnoughts, I'd use them for these roles, but I did not like aspects of the Invencibles (and, at any rate, I've sold them both).  So, instead, I'd build something powerful enough to match modern armored cruisers, threaten or deter raiding capital units, and have a shore bombardment function - while being relatively inexpensive.  This is my initial thinking on the matter:  slow, but well armed and reasonably armored.


(Work in progress)

Gunship18, Enter country Enter ship type laid down 1916

Displacement:
   9,962 t light; 10,508 t standard; 11,387 t normal; 12,091 t full load

Dimensions: Length overall / water x beam x draught
   437.24 ft / 433.07 ft x 82.02 ft x 18.70 ft (normal load)
   133.27 m / 132.00 m x 25.00 m  x 5.70 m

Armament:
      6 - 12.01" / 305 mm guns (2x3 guns), 865.70lbs / 392.67kg shells, 1916 Model
     Breech loading guns in turrets (on barbettes)
     on centreline, all forward, 1 raised mount - superfiring
      5 - 5.51" / 140 mm guns in single mounts, 83.72lbs / 37.97kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all aft, 4 raised mounts - superfiring
      2 - 2.56" / 65.0 mm guns in single mounts, 8.38lbs / 3.80kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
      2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 5,633 lbs / 2,555 kg
   Shells per gun, main battery: 100

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   5.91" / 150 mm   281.50 ft / 85.80 m   14.76 ft / 4.50 m
   Ends:   1.97" / 50 mm   151.54 ft / 46.19 m   14.76 ft / 4.50 m
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   9.84" / 250 mm   2.95" / 75 mm      9.84" / 250 mm
   2nd:   1.97" / 50 mm   0.98" / 25 mm      2.95" / 75 mm
   3rd:   0.39" / 10 mm         -               -
   4th:   0.39" / 10 mm         -               -

   - Armour deck: 1.97" / 50 mm, Conning tower: 3.94" / 100 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 12,492 shp / 9,319 Kw = 18.12 kts
   Range 12,000nm at 10.00 kts (Bunkerage = 1,584 tons)

Complement:
   550 - 716

Cost:
   £1.645 million / $6.580 million

Distribution of weights at normal displacement:
   Armament: 704 tons, 6.2 %
   Armour: 3,217 tons, 28.3 %
      - Belts: 1,261 tons, 11.1 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 967 tons, 8.5 %
      - Armour Deck: 946 tons, 8.3 %
      - Conning Tower: 43 tons, 0.4 %
   Machinery: 465 tons, 4.1 %
   Hull, fittings & equipment: 5,209 tons, 45.7 %
   Fuel, ammunition & stores: 1,425 tons, 12.5 %
   Miscellaneous weights: 367 tons, 3.2 %
-250 t:  FC Mk2
-25 t:  LR Wireless
-25 t:  Flag facilities
67 t:  Weight reserve/other stuff

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     20,057 lbs / 9,098 Kg = 23.2 x 12.0 " / 305 mm shells or 3.2 torpedoes
   Stability (Unstable if below 1.00): 1.17
   Metacentric height 5.0 ft / 1.5 m
   Roll period: 15.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.55
   Seaboat quality  (Average = 1.00): 1.53

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.600
   Length to Beam Ratio: 5.28 : 1
   'Natural speed' for length: 20.81 kts
   Power going to wave formation at top speed: 45 %
   Trim (Max stability = 0, Max steadiness = 100): 46
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: -3.28 ft / -1.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      23.62 ft / 7.20 m
      - Forecastle (20 %):   19.69 ft / 6.00 m
      - Mid (60 %):      19.69 ft / 6.00 m (11.81 ft / 3.60 m aft of break)
      - Quarterdeck (15 %):   11.81 ft / 3.60 m
      - Stern:      11.81 ft / 3.60 m
      - Average freeboard:   16.85 ft / 5.14 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 63.7 %
      - Above water (accommodation/working, high = better): 149.9 %
   Waterplane Area: 25,979 Square feet or 2,414 Square metres
   Displacement factor (Displacement / loading): 112 %
   Structure weight / hull surface area: 154 lbs/sq ft or 753 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.91
      - Longitudinal: 2.16
      - 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

[Guinness]

Here's my question: what can this ship do that an Arquero can't? Would it make more sense to build a few more of those instead? I know they're a bit more expensive, but it seems to me that the additional utility would be useful.

Of course, if you think you need at least 6x305mm to defeat a Wheeler...

[The Rock Doctor]

I don't mind the overkill of the heavier battery.  If I had triple 275mm - which I currently don't - I could fit them and gain about three knots and 50mm of belt armor.

The Arqueros can do everything these could, but at almost twice the cost.  In situations where speed is not so important, these may be a more realistic answer.

I am thinking of additional Arqueros, but only after I finish the next engine tech, which is a year or two away.

[Jefgte]

...6x305mm to defeat a Wheeler...

right, good & economical choice Rocky.

IMO, a little to slow, 22kts should be better but, a nice "Pocket Dunkerque".


Jef  ;)

[miketr]

A medium sized convential cruiser would be a better use of resources.

[Desertfox]

A medium unconventional cruiser would be a better use of resources... ;D

I like the look of her, but anything under 21 knots is waaaay too slow.

[The Rock Doctor]

The aforementioned version with the non-existent triple 275mm:


Enter ship name, Enter country Enter ship type laid down 1916

Displacement:
   9,803 t light; 10,315 t standard; 11,188 t normal; 11,886 t full load

Dimensions: Length overall / water x beam x draught
   437.24 ft / 433.07 ft x 82.02 ft x 18.37 ft (normal load)
   133.27 m / 132.00 m x 25.00 m  x 5.60 m

Armament:
      6 - 10.83" / 275 mm guns (2x3 guns), 634.55lbs / 287.83kg shells, 1916 Model
     Breech loading guns in turrets (on barbettes)
     on centreline, all forward, 1 raised mount - superfiring
      5 - 5.51" / 140 mm guns in single mounts, 83.72lbs / 37.97kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline, all aft, 4 raised mounts - superfiring
      2 - 2.56" / 65.0 mm guns in single mounts, 8.38lbs / 3.80kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
      2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 4,246 lbs / 1,926 kg
   Shells per gun, main battery: 120

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   7.87" / 200 mm   281.50 ft / 85.80 m   14.76 ft / 4.50 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   9.84" / 250 mm   2.95" / 75 mm      9.84" / 250 mm
   2nd:   1.97" / 50 mm   0.98" / 25 mm      2.95" / 75 mm
   3rd:   0.39" / 10 mm         -               -
   4th:   0.39" / 10 mm         -               -

   - Armour deck: 1.97" / 50 mm, Conning tower: 3.94" / 100 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 22,000 shp / 16,412 Kw = 21.02 kts
   Range 12,000nm at 10.00 kts (Bunkerage = 1,570 tons)

Complement:
   543 - 707

Cost:
   £1.479 million / $5.915 million

Distribution of weights at normal displacement:
   Armament: 531 tons, 4.7 %
   Armour: 3,310 tons, 29.6 %
      - Belts: 1,464 tons, 13.1 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 858 tons, 7.7 %
      - Armour Deck: 946 tons, 8.5 %
      - Conning Tower: 42 tons, 0.4 %
   Machinery: 820 tons, 7.3 %
   Hull, fittings & equipment: 4,736 tons, 42.3 %
   Fuel, ammunition & stores: 1,385 tons, 12.4 %
   Miscellaneous weights: 406 tons, 3.6 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     19,406 lbs / 8,803 Kg = 30.6 x 10.8 " / 275 mm shells or 3.2 torpedoes
   Stability (Unstable if below 1.00): 1.13
   Metacentric height 4.7 ft / 1.4 m
   Roll period: 16.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.43
   Seaboat quality  (Average = 1.00): 1.21

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.600
   Length to Beam Ratio: 5.28 : 1
   'Natural speed' for length: 20.81 kts
   Power going to wave formation at top speed: 52 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: -3.28 ft / -1.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      23.62 ft / 7.20 m
      - Forecastle (20 %):   19.69 ft / 6.00 m
      - Mid (60 %):      19.69 ft / 6.00 m (11.81 ft / 3.60 m aft of break)
      - Quarterdeck (15 %):   11.81 ft / 3.60 m
      - Stern:      11.81 ft / 3.60 m
      - Average freeboard:   16.85 ft / 5.14 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 64.4 %
      - Above water (accommodation/working, high = better): 151.8 %
   Waterplane Area: 25,979 Square feet or 2,414 Square metres
   Displacement factor (Displacement / loading): 117 %
   Structure weight / hull surface area: 141 lbs/sq ft or 687 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 2.07
      - 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
   Good seaboat, rides out heavy weather easily

[Jefgte]

...triple 275mm...

Panzerschiff... :D

(Cruisers protection don't like very much Panzerschiff's shells...)


Jef  ;)

[maddox]

I like her.  A better, but unfortunatly slower Gloire II.

I should nick the design.

[The Rock Doctor]

With 500 extra tonnes displacement, I can boost the original's speed to 21 kts.

Mike:  Define "medium sized conventional cruiser"?

[miketr]

GC has 234mm, 240mm and 275mm gun designs with the 275's the most up to date.

How much displacement would you need to have a design like the Arquero Class, 3 twin 275's and 200mm armor, but with a speed of say 28 or 29 knots?

I am thinking of something in the 8K to 14K range.  Iberia has a very up to date 250mm gun for example, just finished as of 1918 H1 a L55 design.

The problem I have with your current design is its SO slow that about all it can do is shore bombardment and attempt to scare off cruisers.  While it can't fight with the line of battle and if faced with a real BB or even some of the PDN's out there its going to have its hands full let alone any of the big cruisers around.  It just lax flexibility I guess.

Michael

[Guinness]

I also wonder if a ship such as Wheeler couldn't use superior speed to maneuver in such a way to minimize it's exposure to those 305's long enough to cripple or kill this ship with it's own 9.2in guns.

[Borys]

Ahoj!
If I understood the mission of the gunships correctly, then the Wheelers would be attacking them somewhere in the middle of the Atlantic, near the Equator.
Would the CSA sklipper risk slugging it out so far away from home?
The Bahamas, I believe, would be the nearest base ...
Frankly, I think a 3x2x11" design would be best.
Borys

[Guinness]

We'd have to ask the folks now running the Confederate Navy, but I'd think that a suitably aggressive CO on board Wheeler would be able to use his (vastly) superior speed to control the range and other particulars of the engagement. Wheeler is fantastically heavily armored, but it could certainly safely absorb one or two hits from one of these.

Now imagine there are two Wheelers there. I'd always envisioned them working in pairs anyway. Haiti or the Bahamas is a ways from the theoretical engagement zone. Montevideo and Italian Chuvosa might be a bit closer, as would be French West Africa.

[miketr]

Somthing like this perhaps.

Michael

Escort, GC Cruiser laid down 1916

Displacement:
   12,000 t light; 12,583 t standard; 13,795 t normal; 14,764 t full load

Dimensions: Length overall / water x beam x draught
   551.18 ft / 551.18 ft x 68.90 ft x 22.97 ft (normal load)
   168.00 m / 168.00 m x 21.00 m  x 7.00 m

Armament:
      6 - 10.83" / 275 mm guns (3x2 guns), 634.55lbs / 287.83kg shells, 1916 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, majority forward, 1 raised mount - superfiring
      8 - 5.51" / 140 mm guns in single mounts, 83.72lbs / 37.98kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on side, all amidships
   Weight of broadside 4,477 lbs / 2,031 kg
   Shells per gun, main battery: 120

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   7.87" / 200 mm   358.27 ft / 109.20 m   9.97 ft / 3.04 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   9.84" / 250 mm   3.94" / 100 mm      9.84" / 250 mm
   2nd:   2.95" / 75 mm         -               -

   - Armour deck: 1.97" / 50 mm, Conning tower: 3.94" / 100 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 65,346 shp / 48,748 Kw = 28.00 kts
   Range 10,000nm at 12.00 kts
   Bunker at max displacement = 2,181 tons

Complement:
   636 - 827

Cost:
   £2.014 million / $8.057 million

Distribution of weights at normal displacement:
   Armament: 560 tons, 4.1 %
   Armour: 3,301 tons, 23.9 %
      - Belts: 1,199 tons, 8.7 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 1,085 tons, 7.9 %
      - Armour Deck: 968 tons, 7.0 %
      - Conning Tower: 49 tons, 0.4 %
   Machinery: 2,435 tons, 17.6 %
   Hull, fittings & equipment: 5,405 tons, 39.2 %
   Fuel, ammunition & stores: 1,794 tons, 13.0 %
   Miscellaneous weights: 300 tons, 2.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     16,117 lbs / 7,311 Kg = 25.4 x 10.8 " / 275 mm shells or 2.0 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 3.4 ft / 1.0 m
   Roll period: 15.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.68
   Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.554
   Length to Beam Ratio: 8.00 : 1
   'Natural speed' for length: 23.48 kts
   Power going to wave formation at top speed: 56 %
   Trim (Max stability = 0, Max steadiness = 100): 48
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      24.61 ft / 7.50 m
      - Forecastle (20 %):   22.97 ft / 7.00 m
      - Mid (50 %):      18.04 ft / 5.50 m
      - Quarterdeck (15 %):   16.40 ft / 5.00 m
      - Stern:      16.40 ft / 5.00 m
      - Average freeboard:   19.37 ft / 5.90 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 90.8 %
      - Above water (accommodation/working, high = better): 149.2 %
   Waterplane Area: 26,592 Square feet or 2,470 Square metres
   Displacement factor (Displacement / loading): 107 %
   Structure weight / hull surface area: 134 lbs/sq ft or 653 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.56
      - Overall: 1.01
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent