American Scout Cruisers with 10" Guns (Before Treaty of Washington)

I still notice you have difficulties in the purpose of a shipdesign, espcially the British Hawkins class, which was, as the speicifcation mentioned, a Multi-purpose design, with a serious focus on tradeprotection and patrolrange. Yhis demanded a certain size to accomodate enough enginepower and fuel to carry, as well as sufficient armament to fulfill its function as a Multi-Purpose vessel. Also note that at this time there were no contemporary Multi-Purpose cruisers in foreign navies, nor were they deisgned. The fact the Hawkins was to carry 7.5 inch was not the main issue here, as this gun was not very enthousiastically supported in the Royal Navy. The designers simply put it in the hawkins class, sinne it was based on a rumor the Kaiserliche Marine was about to create larger than previously build cruisers with a uniform 5.9 inch battery, as well as there were problems with armed merchant cruisers, likewise armed with 5.9 inch guns. This latest fact was the principle reason to mount a gun with longer range and more stoppingpower, meaning the anti-commercraiding nature of the Hawkins class was the main role intended for this type of warship.

Of course, it is not relevant to the British, who didn't like it at all. I do realize this; it was mentioned several times. However, whether the British liked it or not had no bearing on the US design process, who viewed the British use of the 7.5" and had to one-up the design. My point is, if the Pensacola or other heavy cruiser was designed earlier, then they would use the best cruiser caliber gun (as defined by the largest guns in use at the time by US Cruisers: the 8"/45 on the Pennsylvania and the 10"/40 on the Tennessee) that would have been available. The answer would have been the 10" if designed earlier, as the 8"/55 was not under development.

The US designers viewed the Hawkins as having the capability to kill every single cruiser in the US arsenal at the time; the only ones who'd have a chance of fighting back were the old armored cruisers, of which the Hawkins could easily outrun. The US did view them as a threat to the cruiser force, which is what prompted the response, one based on more than rumor. (although, the delayed reaction of the response did speak to the British wartime security)

A ship may be built for one purpose, but it can be utilized for other purposes. And it was those concerns that it would be able to hunt down US cruisers with relative impunity that prompted the design of a ship specifically to counter it.

The typical demands for a scout cruiser: High speed and weapons to defend itself. That was all. Omaha at first was created to these requirements, as were the innitial succeeding Pensacola's, though these were later enlarged to give the ship more gunpower, which was not compensated by other necessary backing to make it a fighting ship at the same time. Basically the Pensacola design was an overgunned large unprotected cruiser, that had to do jobs, it could not do. For a pure scout it was too large and too vulnerable. For a fighting ship, it lacked protection and again was far too large a target. For a tradeprotection role, if this was a suggestion anyway, it lacked the Multi-Purpose capabilities of such a vessel, as well as being a very badly designed seaboat. Bascially the Penacola became what we often call a "Glasscannon", a very thinskinned big gun vessel, that can hit hard, but cannot take damage in return.[snip]

The original designs were left undergunned, which prompted the increase in armament. Technically, that could mean an increase in a number of guns or increase of caliber. That choice was guided by the WNT, though, as the design had been delayed time and time again.

I'm not trying to create some idealized ship here. It would have its flaws, certainly, and is exceedingly large size wouldn't necessarily make it the best scout.

The USN doctrine to create the so called "Fighting Scouts" was based on the idea, that a force of vessels with 8 inch, or so guns could outrange an enemy scout, or group of scouts under normal conditions, with no capital ship support for these scouts at least. This outranging would allow the USN 8 inch "scouts" to scout an enemy fleet in theory, while holding off enemy smaller scouts at bay with their longer ranging guns. That was the thinking behind it, not the active hunting of enemy scouts and other ships, as that would compromise the missionobjective for a scoutship. By putting more heavy guns on these so called "fighting scouts" it became tempting to do just that though, therefor killing their Original purpose, that being to scout for the fleet. As such the ship became a "cruiserkiller" a role normally suited for a battlecruiser and armored cruiser of the past.

So it's not even that putting larger guns on it that are is a flaw, but putting guns might make it tempting to use in that role, even though the two different weapons had relatively similar performance? Having longer range guns while also having similar armor, along with being responsible for multiple aerial scouts who can't land in gunfight conditions, would encourage continued use of standoff range.

A Pensacola could not operate on its won, lacking the necessary flexibility of equipment and seaworthyness, It could not brawl at shorter range with anything, not even a destroyer, or armed merchant cruiser.

That's what I'm trying to avert with this ship, though. It's a much more seaworthy platform because of its intended mission as a aerial scout carrier, is fast enough to both scout and maintain its range so that its aircraft can scout, has the best weapons to defend itself from enemy heavy cruisers based on the time it was built (a later design would give it 8" guns, an earlier has it keep the 10"), and could brawl with your hypothetical destroyer or armed merchant cruiser.

It is a better sea platform, better suited for aerial scouts. It performs the scouting role better. It is more seaworthy, and can perform the escorting role better. It can handle small ship attacks and act against commerce raiders.

I went ahead and spent yesterday trying to design the ship using the best resources that I could, based on the OTL design for the Pensacola pre treaty, among others. One does get tired over arguing hypotheticals, so I went ahead to spend the time to get a concrete ship proposal made. One optimized for best seakeeping abilities and a steady deck to make launching aircraft much easier.

Part of the impetus for this is an earlier Omaha that is smaller than the one built OTL, and has the poorly designed charactersitics and seakeeping ability and is used as a large destroyer (and doesn't have the ability to launch scouts). That's part of the reason why the Omahas wouldn't be delayed for additional destroyers. This is the impetus for an alternate Pensa: a large cruiser that is capable of carrying scouts and being a good platform for launching them. Frankly, I'm inclined to have this all add up to Admiral Sims getting his way with the design board, having the Colorado class cancelled, and the US instead dedicate to the fast battleship doctrine. Jutland did show how poor battlecruisers perform in a pitched battle, and instead go with the DD/Scout Cruiser/Heavy Cruiser/Fast Battleship lineup, which was considered OTL.

Instead of the Lexingtons being laid down, it'd be an altered South Dakota class with 4x3 16" and capable of 30+ knots.

This cruiser follows Sims's design philosophy: increase displacement to maintain desired armament, armor, and speed.

Augusta, United States Armored Scout Cruiser laid down 1920

Displacement:
14,306 t light; 15,047 t standard; 15,898 t normal; 16,579 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(686.00 ft / 681.50 ft) x 72.00 ft x (21.00 / 21.70 ft)
(209.09 m / 207.72 m) x 21.95 m x (6.40 / 6.61 m)

Armament:
8 - 10.00" / 254 mm 52.0 cal guns - 533.92lbs / 242.18kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1921 Model
4 x Twin mounts on centreline, evenly spread
12 - 5.00" / 127 mm 51.0 cal guns - 66.47lbs / 30.15kg shells, 150 per gun
Breech loading guns in deck mount, 1911 Model
1 x Single mount on sides amidships
Weight of broadside 5,069 lbs / 2,299 kg
Main Torpedoes
6 - 21.0" / 533 mm, 21.00 ft / 6.40 m torpedoes - 1.362 t each, 8.172 t total
In 2 sets of deck mounted side rotating tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 400.00 ft / 121.92 m 12.50 ft / 3.81 m
Ends: 0.75" / 19 mm 281.50 ft / 85.80 m 12.50 ft / 3.81 m
Main Belt covers 90 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Torpedo Bulkhead - Strengthened structural bulkheads:
2.50" / 64 mm 400.00 ft / 121.92 m 12.50 ft / 3.81 m
Beam between torpedo bulkheads 68.00 ft / 20.73 m

- Hull void:
3.00" / 76 mm 400.00 ft / 121.92 m 10.00 ft / 3.05 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.50" / 64 mm 2.00" / 51 mm 2.00" / 51 mm

- Armoured deck - single deck:
For and Aft decks: 2.50" / 64 mm

- Conning towers: Forward 1.25" / 32 mm, Aft 1.25" / 32 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 110,000 shp / 82,060 Kw = 32.05 kts
Range 10,000nm at 10.00 kts
Bunker at max displacement = 1,532 tons

Complement:
707 - 920

Cost:
£3.649 million / $14.595 million

Distribution of weights at normal displacement:
Armament: 1,250 tons, 7.9 %
- Guns: 1,233 tons, 7.8 %
- Weapons: 16 tons, 0.1 %
Armour: 3,669 tons, 23.1 %
- Belts: 1,149 tons, 7.2 %
- Torpedo bulkhead: 463 tons, 2.9 %
- Void: 444 tons, 2.8 %
- Armament: 270 tons, 1.7 %
- Armour Deck: 1,308 tons, 8.2 %
- Conning Towers: 34 tons, 0.2 %
Machinery: 3,846 tons, 24.2 %
Hull, fittings & equipment: 5,182 tons, 32.6 %
Fuel, ammunition & stores: 1,592 tons, 10.0 %
Miscellaneous weights: 360 tons, 2.3 %
- On freeboard deck: 360 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
15,432 lbs / 7,000 Kg = 30.9 x 10.0 " / 254 mm shells or 2.1 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 3.7 ft / 1.1 m
Roll period: 15.8 seconds
Steadiness - As gun platform (Average = 50 %): 75 %
- Recoil effect (Restricted arc if above 1.00): 0.67
Seaboat quality (Average = 1.00): 1.06

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.540 / 0.545
Length to Beam Ratio: 9.47 : 1
'Natural speed' for length: 26.11 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 71
Bow angle (Positive = bow angles forward): 8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 12.00 %, 32.00 ft / 9.75 m, 28.00 ft / 8.53 m
- Forward deck: 21.00 %, 28.00 ft / 8.53 m, 24.00 ft / 7.32 m
- Aft deck: 48.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 19.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 19.73 ft / 6.01 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 114.2 %
- Above water (accommodation/working, high = better): 171.8 %
Waterplane Area: 33,925 Square feet or 3,152 Square metres
Displacement factor (Displacement / loading): 96 %
Structure weight / hull surface area: 126 lbs/sq ft or 615 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 1.05
- Overall: 1.00
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

360 tons of additional weight is surplus for both aviation facilities and for any additional AA guns that are to be mounted.

So, 14.3k light displacement, and that's with the long hull form. I did try to make as much of the armor as OTL as I could, although some things I'm not sure about. And, to point out where the majority of the extra displacement comes from... Reducing the length to Pensacola size brings the light displacement down to 12.1k. Reducing the beam to Pensacola size brings the light displacement to 10.9k, and that's without reworking the ship's parameters to suit one of that size (less armor coverage, smaller engines, etc).

Also, it's cramped, but not too cramped: the builder does list 110% as being adequate, so this is pushing the limit a bit.

Basically, if you took out the section dedicated to aviation, you get a ship of only 12.1k tons displacement (without adjusting parameters for the smaller ship, mind you. It likely is less due to reduced armor/engines). Which is right back where we started in terms of a large pre-Treaty Pensacola, which is not a battlecruiser. So, yes, the ship may have the capacity to engage in cruiser killing (which, incidentally, the Hawkins does as well over the smaller 6" cruisers, regardless of design intent).

Bascially the Penacola became what we often call a "Glasscannon", a very thinskinned big gun vessel, that can hit hard, but cannot take damage in return. (That is the same definition as for a battlecruiser though).

And here's the problem. You're defining the Hawkins by the purpose for which it has been designed, while defining the Pensacola by the role in which it ended up. The latter definitely was designed to serve in the role of a large scout cruiser/light cruiser, but with the emphasis of range and armament rather than British design goals.

If, by increasing the ability of the ship's seakeeping, allowing it to both act as a better scout both on sea and in the air, while also being able to engage against destroyers and merchant vessels and other vessels acting as commerce raiders, you turn a 14,306 ton displacement ship into a battlecruiser. But, well, if you define ships by roles as they served (instead of the roles they were designed for), even US treaty cruisers were battlecruisers.
 
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Seeing the spoiler, the design was becomming a small battlecruiser still, seriously overgunned and too much foccused on outgunning a hypothetical large gunned cruiser, whcih did not exist yet, other than the Hawkins class and the Furutaka project under development. Such a ship is seriosly like an old armored cruiser with simmilar sclae of protection, driving up the weight sriously. (Belt of 5 inch, which in the OTL Pensacola class was not more than 50mm, of slightly less than 2 inch as originally build, besides being only protecting the enginespaces, not the magazines.) Besides that the ship will need more boilers as well to get it moving at teh designed speed, with old model low presure boilers of the period. You will end up with a cruiser very simmilar to the HMS Minotaur class of 1906, though with more heavy guns.

BTW, getting a South Dakota (1921 design) moving at 30 knots is impossible, as that would require so many alterations on hull, engines and powerplant, the ship was likely to grow significantly beyond the size of a Yamato, due to inefficient older model engines and boilers mainly. If the thing was to make 30 knots, the Lexongton type was to be redevelopped into it, not the South Dakota type. (Hullshape was finer and more addapted to higher speed in Lexington, while the wide and short South Dakota hull would create so much drag, it would start pushing a tsunami ahead of it, rather than slide through the water.)

BTW, I do not understand why the USN would lay so much forcus on a poor masn battlecruiser design, rather than a more powerful larger true battelcruiser, as that was why the Lexingtons were developped in the first place, for the same job, as well as to fight against enemy battlecruisers, in Jutland style fights (where they would be ending up like Beaty's ships, being blown out of the water likely.)
 
Belt of 5 inch, which in the OTL Pensacola class was not more than 50mm, of slightly less than 2 inch as originally build, besides being only protecting the enginespaces, not the magazines.

Pensacola had a 2.5" to 4" belt as originally designed, though I cannot find the distribution on the ship as built. And what I showed you would only be enough to cover the engines at best; magazine was not protected with the 5" armor.

And the original March 24 1921 Scout Cruiser had 4" sloping armor and a 2.5" deck or a 4.5" flat belt and 2.5" deck. That's what I based it on; it's literally increasing by 1/2" from the 1921 design. Reducing the armor was another fault of the treaty limitations, not based on the original design criteria. (It came after the fact, not prior)

Besides that the ship will need more boilers as well to get it moving at teh designed speed, with old model low presure boilers of the period.

Accounted for: the new ship would be at least 100 ft longer than the original Pensacola and 7 feet wider. The engines would take up an exceedingly large portion at the hull, of course.

Granted, this ship would definitely occupy the strategic scouting role more than tactical scouting, but it would literally be a slightly larger-displacing Tone-class cruiser, just 20 years earlier as an experiment.

BTW, getting a South Dakota (1921 design) moving at 30 knots is impossible, as that would require so many alterations on hull, engines and powerplant, the ship was likely to grow significantly beyond the size of a Yamato, due to inefficient older model engines and boilers mainly.

Quite a bit smaller than the Yamato, actually. Correct on the point of redesigning the Lexington rather than the South Dakota. I meant to emphasize the two towards each other.

s584130.jpg


BTW, I do not understand why the USN would lay so much forcus on a poor masn battlecruiser design, rather than a more powerful larger true battelcruiser, as that was why the Lexingtons were developped in the first place, for the same job, as well as to fight against enemy battlecruisers, in Jutland style fights (where they would be ending up like Beaty's ships, being blown out of the water likely.)

Because the redesign would occur after Jutland and the revelation that battlecruisers did indeed get blown out of the water, combined with the appearance of the Hood? A battlecruiser, based on the standards of the time, was rather pointless: better to expend the men and material on a true fast battleship with the arms and armor and speed by sacrificing displacement. Of course, this would require the General Board to listen to the advice of Admiral Sims, James L. Bates (who they likely would, as he helped design the smaller Omaha), and British designer Stanley Goodall, who brought the designs of the Hood to rework them.

Best instead to build a fast battleship, and spend the rest of resources on scouts both capable of tactical scouting (in battle, line of sight) and strategic (away from battle fleet, lots of aircraft to extend reach).
 
One sidenote, from an engineering point of view, the USN were not capable at the time to produce turbines, that were reliable and delivered the wanted hp to propel a large ship at the wanted speed. Most likely the New Mexico type Turbo-Electric hybrid form of power would be speculated, thoguh this still was not capable of delivering the power to propel a large ship at more than 23-25 knots at best. Only true turbines could do that, which was problematic, given the contemporary state of engineering in the USA at that time in history. (They could try to import these turbines, though these were likely labaled as strategic military equipment, resulting in a bann on export of such military harddware.)

Alternatively, the aged Tripple Expansion steamengine could be installed as wel, though these heavy and bulky things would reult in rocketting up weight as well, if the speed was to be as required for a scoutship with high speed. You will end up with a ship that had a displacement of around a third more, when compared to a simmilar design with turbines.
 
In 1922 and 1928, studies were done on upgrading the Tennessee class, with the recommendation of conversion to use a new turbine drive; in the latter case, it was the turbine being built for the Ranger that was suggested to increase the speed of the old ships from 22 to 26-28 knots.

Most likely the New Mexico type Turbo-Electric hybrid form of power would be speculated, thoguh this still was not capable of delivering the power to propel a large ship at more than 23-25 knots at best.

The Lexington class was designed with a Turbo-Electric drive for use, and was built with it in aircraft carrier form. This was easily enough to propel 36k ton, 8.38 beam ratio ship at 33.25 knots, max. 8.25-10.25 knots above your proposed maximum speed.

The Chester scout cruisers, authorized in 1904, were turbine-powered ships. 16k SHP. The Omaha-class used geared turbines, as the preferred turbo-electric design would have taken up too much space, creating 90k SHP. (pg 78).

Oh, and I didn't have access yesterday, but Friedman confirms my thoughts on the Pensacola. A combined 2.5"/4" belt, with the 4" covering the machinery.

-

Also, another thing that could shape the board's design would be Fletcher's experience during the War College games of Red vs Blue fleet. In rough seas and a rather terrible storm, small destroyers and cruisers were scattered immensely, and it took several days to relocate them. The small scout cruisers at the time were just as helpless in rough seas.

This is also where I get my reference for the 10" gun being preferred over the 8" gun earlier, btw. The 10" gun was viewed as the minimum that could be used against torpedo craft and protected cruisers, which were still a factor pre-Jutland. The 6" was viewed, to the US, as insufficient for a cruiser. It was only after further development of the 8" that it changed.
 
Sideline Drawing
Alright, here's what I got after a bit of work done in drawing. A cruiser that matches most of the criteria I outlined prior, while having the hanger area I listed, with a 5" belt of 400 ft, with plenty of space for boilers (only 10.6 boilers of the period are needed, consulting Pensacola et al, and I was able to fit 12 total boilers).

That means the ship could potentially dash at up to 35.17 knots(!) However, this would mean composite strength would fall down to 0.7, and seakeeping would diminish. Still, a 3 knot advantage over listed speeds, and the warship could probably manage 36 knots total with the engines running full out.

The only problem is that there is no back observation tower (that would need to be used for lifeboat crane, probably) and that there is limited space for lifeboats. It would be potentially best to place them behind the forward tower (perpendicular to the beam and stacked) and on the main deck aft of the rear hanger and forward of the turrets.

She's a handsome boat, but the size of the hangers really do stretch available space forward and backwards. It might be best in forward iterations to move as many aviation facilities to the rear as possible to keep the magazine/citadel compact and to save weight on armor and displacement (note that this is what the Japanese did with Tone). An interesting design challenge, all around.

cruiser drawing sideview 2.jpg
 
Looks really nice, but I do agree you could fit a lot more if you are willing to go all forward with the 10" guns, even more so if the USN was willing to go for 3x3 to really fit it in?
 
Looks really nice, but I do agree you could fit a lot more if you are willing to go all forward with the 10" guns, even more so if the USN was willing to go for 3x3 to really fit it in?

Oh, indeed, that's probably likely. This is more to be the first generation of ships in this type. In a later generation, you'd probably see the shift to triples to try and save the weight from one gun, condense the aircraft section, etc. Triples would take making new barbettes, no mounts, etc. Staying with the 4x2 means that they can save money and resources by using what is available and just upgrading that.

Basically, the same trend as going from the Pensacola to the Northampton.

And, by having 6 new cruisers so early, there probably won't be new ones built for half a decade, if not more. Possibly a small class to try and improve upon these, but other than that, not too much too soon.

But yeah, if you imagine a Brooklyn arrangement of guns, save all forward and with 10" triples... be something.
 
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