SpringSharp and how to create Battlecruiser/Raider

Long time lurker here, Hello everyone.

For little novel I think about writing I was looking to create ship that was multipurpose but still good in combat. For that I used SpringSharp program, took Alaska for the ride and made some changes to it creating my weird ship that I call Heavy cruiser but maybe it should be classified as Battlecruiser or Raider.
Overall thought behind it was to get fast ship that will sacrifice its
main battery (305mm) firepower for more heavy (155mm) multipurpose guns and more seaplanes/helicopters for fighting submarines, transports and scouting.

The problem is I'm more of warships enthusiasts and lack some knowledge so I'm in need of help, and would be grateful if people, and by that I also mean certain somebody, to answer few questions and to tell me how do you think this ship would do in its role.
1. Could you look and data and tell me if I did any critical mistakes and how would you make it better without going over limit of 30 000 standard(t).
2. Main battery is concentrated forward so how many of seaplanes/helicopters up to models from 1950 could it have for day to day operation in Atlantic/pacific .

And here goes RCN Commonwealth

RCN Commonwealth, Commonwealth Battlecruiser laid down 1945

Displacement:
27 289 t light; 28 549 t standard; 31 148 t normal; 33 226 t full load

Dimensions: Length overall / water x beam x draught
816,31 ft / 803,81 ft x 82,02 ft x 29,53 ft (normal load)
248,81 m / 245,00 m x 25,00 m x 9,00 m

Armament:
4 - 12,01" / 305 mm guns (2x2 guns), 865,70lbs / 392,67kg shells, 1945 Model
Breech loading guns in Coles/Ericsson turrets
on centreline, all forward, 1 raised mount
12 - 6,10" / 155 mm guns in single mounts, 113,62lbs / 51,54kg shells, 1945 Model
Dual purpose guns in turrets (on barbettes)
on side, all amidships, all raised mounts - superfiring
100 - 2,95" / 75,0 mm guns (50x2 guns), 12,87lbs / 5,84kg shells, 1945 Model
Dual purpose guns in deck mounts
on side, evenly spread
50 - 1,18" / 30,0 mm guns (25x2 guns), 0,82lbs / 0,37kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
6 - 6,10" / 155 mm guns in single mounts, 113,62lbs / 51,54kg shells, 1945 Model
Dual purpose guns in turrets (on barbettes)
on side, all aft
Weight of broadside 6 836 lbs / 3 101 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 11,8" / 300 mm 442,91 ft / 135,00 m 13,12 ft / 4,00 m
Ends: Unarmoured
Main Belt covers 85% of normal length

- Torpedo Bulkhead:
2,56" / 65 mm 442,91 ft / 135,00 m 27,89 ft / 8,50 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 13,4" / 340 mm 8,07" / 205 mm -
2nd: 3,54" / 90 mm 2,36" / 60 mm 0,59" / 15 mm
3rd: 1,18" / 30 mm 0,59" / 15 mm -
4th: 0,59" / 15 mm - -
5th: 3,54" / 90 mm 2,36" / 60 mm 0,59" / 15 mm

- Armour deck: 5,31" / 135 mm, Conning tower: 10,63" / 270 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 154 749 shp / 115 443 Kw = 33,00 kts
Range 12 000nm at 15,00 kts
Bunker at max displacement = 4 677 tons

Complement:
1 171 - 1 523

Cost:
£15,338 million / $61,354 million

Distribution of weights at normal displacement:
Armament: 855 tons, 2,7%
Armour: 11 616 tons, 37,3%
- Belts: 2 947 tons, 9,5%
- Torpedo bulkhead: 1 170 tons, 3,8%
- Armament: 2 518 tons, 8,1%
- Armour Deck: 4 755 tons, 15,3%
- Conning Tower: 227 tons, 0,7%
Machinery: 3 908 tons, 12,5%
Hull, fittings & equipment: 10 711 tons, 34,4%
Fuel, ammunition & stores: 3 858 tons, 12,4%
Miscellaneous weights: 200 tons, 0,6%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
47 458 lbs / 21 527 Kg = 54,8 x 12,0 " / 305 mm shells or 7,3 torpedoes
Stability (Unstable if below 1.00): 1,08
Metacentric height 4,3 ft / 1,3 m
Roll period: 16,6 seconds
Steadiness
- As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,50
Seaboat quality (Average = 1.00): 1,02

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0,560
Length to Beam Ratio: 9,80 : 1
'Natural speed' for length: 32,19 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 22,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 30,94 ft / 9,43 m
- Forecastle (30%): 19,69 ft / 6,00 m
- Mid (40%): 19,69 ft / 6,00 m
- Quarterdeck (20%): 19,69 ft / 6,00 m
- Stern: 19,69 ft / 6,00 m
- Average freeboard: 21,04 ft / 6,41 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 84,2%
- Above water (accommodation/working, high = better): 154,9%
Waterplane Area: 48 364 Square feet or 4 493 Square metres
Displacement factor (Displacement / loading): 118%
Structure weight / hull surface area: 150 lbs/sq ft or 735 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1,00
- Longitudinal: 1,00
- Overall: 1,00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

Rafan wrote:Long time lurker here, Hello everyone.

For little novel I think about writing I was looking to create ship that was multipurpose but still good in combat. For that I used SpringSharp program, took Alaska for the ride and made some changes to it creating my weird ship that I call Heavy cruiser but maybe it should be classified as Battlecruiser or Raider.
Overall thought behind it was to get fast ship that will sacrifice its
main battery (305mm) firepower for more heavy (155mm) multipurpose guns and more seaplanes/helicopters for fighting submarines, transports and scouting.

And here goes RCN Commonwealth

RCN Commonwealth, Commonwealth Battlecruiser laid down 1945

Displacement:
27 289 t light; 28 549 t standard; 31 148 t normal; 33 226 t full load

Dimensions: Length overall / water x beam x draught
816,31 ft / 803,81 ft x 82,02 ft x 29,53 ft (normal load)
248,81 m / 245,00 m x 25,00 m x 9,00 m

Armament:
4 - 12,01" / 305 mm guns (2x2 guns), 865,70lbs / 392,67kg shells, 1945 Model
Breech loading guns in Coles/Ericsson turrets
on centreline, all forward, 1 raised mount
12 - 6,10" / 155 mm guns in single mounts, 113,62lbs / 51,54kg shells, 1945 Model
Dual purpose guns in turrets (on barbettes)
on side, all amidships, all raised mounts - superfiring
100 - 2,95" / 75,0 mm guns (50x2 guns), 12,87lbs / 5,84kg shells, 1945 Model
Dual purpose guns in deck mounts
on side, evenly spread

Massively over and undergunned at the same time....

The 12 inch guns are only useful if you envision this raider being able to knock aside enemy heavy cruisers along the lines of the US Baltimore or Des Moines classes. A heavy gun that can reach out and touch someone from outside the effective range of semi-automatic 8 inch gun return fire makes sense here. However 4 guns makes spotting salvos extremely questionable. I would go for a minimal of 6 12 inch guns as either 2 triples, or I would prefer 8/9 heavy guns (2 quads forward or a 2x1 triple arrangement)

At the same time, the 6 inch guns are great for killing merchies and destroyers and not bad for killing cruisers. However if you are killing cruisers with your secondary armament, they can get hits in against you. They won't kill you, but they can hurt you enough. And that is all cruisers need to do in a commerce protection role against a big raider -- get some wounds in against the raider that is far from base and can only do temporary field expedient repairs. 18 six inch guns with semi-auto loaders is an ungodly amount of firepower but it is either overkill against destroyers or inviting too much damage from trade protection cruisers. I would switch those guns out for the same number of twin 5/45 Mk42 as a heavy AA weapon and destroyer basher, or if you are using British equipment, twin 4.5 inch guns.

As far as the light AA, 50 twin 3 inch mounts is way too many for the deck space that you are projecting. A twin three inch mount takes about as much deck space as a quad 40mm Bofor mount. The USS Iowa class, which had an ungodly amount of deck space mounted had no more than 20 quad mounts. The Iowa war time crew was 2,000+ to handle the light AA. Same problem with the 30mm guns -- where are they located and who is crewing them?

How about this --- 2x4 12 inch guns forward, 8x2 4.5inch DP guns on broadside (4 each side), 18x2 75mm AA guns, 15x2 30mm light AA guns....

As far as aviation facilities, making the ship a helicopter cruiser makes it a bastard without parentage. A good helicopter cruiser has very different characteristics than a big gun surface warship (big minimally used flat surface in back with lots of flamable av-gas up top for instance). Same with seaplanes. I figure you can get a decent raider with 3 or 4 aircraft. I would drop the ASW mission as a big raider is not a sub hunter. A sub that detects the raider is either getting a kill, or more likely, radioing in for friendly units to get the kill.

I think this ship is trying to do too much and thus can't do much well.

More importantly, I am a little confused as why a navy would want a big capital ship as a raider in Our Time Line (OTL) when airpower is becoming dominant.

fester wrote:More importantly, I am a little confused as why a navy would want a big capital ship as a raider in Our Time Line (OTL) when airpower is becoming dominant.

Probably for the same reason that airpower alone cannot defeat "insurgents". there you need "boots on the ground"

At sea, you still need a "big ship presence" whether your strike force is airbound or not.

chrisd wrote:

fester wrote:More importantly, I am a little confused as why a navy would want a big capital ship as a raider in Our Time Line (OTL) when airpower is becoming dominant.

Probably for the same reason that airpower alone cannot defeat "insurgents". there you need "boots on the ground"

At sea, you still need a "big ship presence" whether your strike force is airbound or not.

Then we need hoplite formations as well?

The ship is laid down in 1945, so probably first operational sometime between 1947 to 1950 depending on priority.

What did navies learn about heavy raiders during WWII?

They're screwed as long as the commerce protecting forces can take some initial losses to get position fixes.
They are screwed once air power can be brought into play.
They are screwed because their silent maximum detection range at any one point is a 16 mile radius while a carrier aircraft in good weather can silently view a radius of 45 miles + at any resolution and 20+ plus with binoculurs. More importantly, aircraft can move the search bubble far more rapidly than a surface raider.

Now if the defending maritime patrol aircraft don't mind lighting up their radars, the search problem gets a whole lot easier for the defenders, and a whole lot harder for the attackers as lighting up the radar is a great way of calling in air strikes on oneself as HF/DF detects emissions from further away than useful information comes back to the emitter.

So in 1948, how does this raider operate? It can't safely operate against battleship escorted convoys, even if the escort is a WWI orphan. It can't operate against convoys with escort carrier or land based aviation support. It can't operate against integrated enemy main fleet units (battleships and strike carriers are a bad combination). It can operate against lightly escorted convoys (DD and below) but at significant operational risk due to the highly likely Oh Shit radio call plus the occassional torpedo inbound.

It can do well in shitty North Atlantic/North Pacific weather, but its detection range is cut in half or worse, so finding prey is difficult.

If this is an attritional fleet unit, then why are the resources used to build it best used on this unit instead of either armed merchant cruisers, submarines, or if you need gun ships, large light cruisers? If this is a main fleet unit, how does it survive long enough to be useful as convoy attacks are a tough way to make a living unless it is attacking a convoy carrying an enemy corps (but at that point, that convoy has opposition main fleet covering forces attached).

If the objective is to use this ship as part of a hunting group composed of several large capital ships and a carrier or two to break through a barrier patrol and fight off main fleet opposition, then the carriers by 1948 have most of the task forces' long range firepower, so the heavy gun armament is an orphan --- too big for cruiser bashing, too light for battleship bashing --- if cruiser bashing is the objective, then a 9.2 or 10 or 11 inch gun makes sense, if battleship protection, then a 14 inch or heavier gun is needed.

How does this ship get used? I am having a hard time seeing how a ship like this in OTL makes a lot of sense for a 1945 lay-down date.

We need soldiers with bayonets.
They serve much the same function.

HTM

fester wrote:
Then we need hoplite formations as well?

{snip - htm}

Hi. I am new to this particular forum & I am not sure what particular universe you are referring to but I would like to make this point.

After World War 2 when airpower, particularly naval airpower ha taken over from the Big Gun capital ship, the Soviet Union did lay down a class of 3 Battlecruisers that were comparable to the ones being suggested & which likely would have been used as raiders. Furthermore, they may have been more effective than people think because the air forces had contracted significantly in size & the maritime strike role was certainly neglected.

Rincewind wrote:Hi. I am new to this particular forum & I am not sure what particular universe you are referring to but I would like to make this point.

After World War 2 when airpower, particularly naval airpower ha taken over from the Big Gun capital ship, the Soviet Union did lay down a class of 3 Battlecruisers that were comparable to the ones being suggested & which likely would have been used as raiders. Furthermore, they may have been more effective than people think because the air forces had contracted significantly in size & the maritime strike role was certainly neglected.

The "Stalingrad"-class, yes. But they never were intended to be used as raiders. They have insufficient range to operate in oceans, and their anti-aircraft defense were seriously limited.

The idea behind them was to have "cruiser-killers", which would be able to deal with any NATO cruiser (including "Des Moines"-class), and support the light cruisers & destroyers in atcions against NATO attempts to enter Baltic/Black sea.

I realized this is a very belated comment

fester wrote:As far as the light AA, 50 twin 3 inch mounts is way too many for the deck space that you are projecting. A twin three inch mount takes about as much deck space as a quad 40mm Bofor mount. The USS Iowa class, which had an ungodly amount of deck space mounted had no more than 20 quad mounts. The Iowa war time crew was 2,000+ to handle the light AA. Same problem with the 30mm guns -- where are they located and who is crewing them?

Another point, Friedman's book on British Cruisers made the point that several of the mid-war to early post-war cruiser designs, featuring twin 3 inch guns for AA, fell apart because of the magazine size it took to feed those beasts. Because of their vastly higher rates of fire each mount needed a much larger (IIRC over 2x as large) magazine than their dual purpose BB secondary 4.5" twin mounts. (Because the British required their ships to be able to sustain X many minutes of AA firing)

They could fit the mounts, but couldn't make room for safe storage of all the ammo you'd need to make the mounts useful - not with everything else a cruiser needed to carry on the displacements they were willing to contemplate.


So even a big 30,000 ton helicopter/gun hybrid cruiser isn't going to have room for enough ammo for the number of mounts he wants - not if you want them to be able to fire for more than 5 seconds apiece. I don't think Springsharp really handles magazine feasibility as it's primarily a hull form designer.

Must also point out, that the Coles/Ericcson turrets are the early, "tincan" turrets without barbettes. By the 1940s they could be found only on museum ships.

In the Bearing sea, air use is limited, You might want to consider a smaller boat tender with lots off AA. A set of torpedo launchers and anti sub capability. PT boats and or Submarine tender would work better. It can stay outside of range of most big boats and send raiders out to attack. Sub's work great where ice is a concern. Just a thought...