Atlanta class design question

[fester]

I'm working on a timeline right now with a slightly more prepared USN in the pre-war period including a few more engineering studies and mock-ups (no, I am not wanking away torpedo issues, I think I have test firings scheduled at Newport in April 1942 from the 1941 appropriation).

One of the little ideas that won't have much impact on the story line is a modification of the Atlanta class so that the first four ships are still 16 barrel ships but with a bit of a different layout:

The OTL Atlantas were three turrets on the centerline forward with the rear most two respectively superfiring each other, a pair of turrets, one on each broadside behind the forward battery, a pair of quad torpedo tubes and then the rear three turrets on centerline, superfiring for the inner most two.



What if the ship was re-arranged and given an extra 500 tons at light displacement and a weapons layout like the following. Two forward turrets on the center line, the innermost one superfiring. Two turrets on each broadside with a pair of triple torpedo tubes inbetween. Then two more turrets aft of the superstructure with the centermost one superfiring. Six turrets are on the main deck. The goal is to increase stability on the ships by bringing a lot of weight lower on the ship. Another departure would be the addition of two more directors so four targets could be engaged at once. There is slightly less broadside fire (14 versus 12 tubes) but a much more stable design.

Does this arrangement make sense?

 

[BlueTrousers]

You gain in stability and end-on fire, lose in broadside weight and speed - two extra wing turrets arranged that way will require you to fill out the hullform some. Magazine and structural arrangements will get a bit more awkward, but not too bad as they're only 5-inch guns.

Ship design is a series of tradeoffs, that tradeoff could certainly be made and was probably looked at.

 

[Derek Pullem]

Never worked out why they didn't build an "Atlanta" class configured like a Brooklyn CA i.e 15 * 5" in 5 triples?

Surely that would have been light enough under the treaty to do the job and much easier to fight until the Clevelands came along (which were almost twice the displacement)

 

[BlueTrousers]

Can you imagine trying to keep the centre gun of a triple 5"/38 fed in an anti-air action?

That's why it wasn't done.

 

[fester]

Thanks

You gain in stability and end-on fire, lose in broadside weight and speed - two extra wing turrets arranged that way will require you to fill out the hullform some. Magazine and structural arrangements will get a bit more awkward, but not too bad as they're only 5-inch guns.

Ship design is a series of tradeoffs, that tradeoff could certainly be made and was probably looked at.

I don't have spring sharp, so I appreciate the validation that this arrangement is not off the walls and within the realm of plausible.

 

[PuffyClouds]

I would remove the wing turrets completely, have one superfiring dual 5" pair in front and back (total of 4 main turrets). Definitely jump up the fire controllers and AAA. It would be nice if the USN could have got their torpedoes working better.

 

[BlueTrousers]

I don't have spring sharp, so I appreciate the validation that this arrangement is not off the walls and within the realm of plausible.

SpringSharp wouldn't actually help much here - it's primarily a weight estimating tool and will let you pile all sorts of stuff into a ship that won't fit.

The ATLANTAs are odd ships, they're pretty much the only USN foray into a space that the RN knew well - the flotilla cruiser.

 

[Anarch King of Dipsodes]

Never worked out why they didn't build an "Atlanta" class configured like a Brooklyn CA i.e 15 * 5" in 5 triples?

Because the USN had a standard twin 5"/38 turret, variants of which were used on all battleships, carriers, and cruisers in this period. Designing and producing a triple 5"/38 turrret would have added substantially to the costs and time of the Atlanta class.

 

[fester]

Big destroyer versus small light cruiser

I would remove the wing turrets completely, have one superfiring dual 5" pair in front and back (total of 4 main turrets). Definitely jump up the fire controllers and AAA. It would be nice if the USN could have got their torpedoes working better.

I really don't see that as plausible that the USN would convince Congress to fund a 6,000 ton cruiser that was visibly no better armed armed than an 1,850 ton destroyer Porter class it had just funded a couple of cycles ago.

Sure the dual 5" guns would all be DP's, the magazines deeper, the AA better but the number of barrels would be the same, the number of torpedo tubes would be the same and the crew would be twice as large.

What I envision is BuShips receiving a decent size authorization to build mock-ups with 2x4's and plywood test out configurations with different firing arcs and human interaction factors a bit more.

The USN in this timeline would still want a light light cruiser to replace the Omaha's as destroyer leaders but the design would be slightly tweaked. My entire goal of the tweaking is not for plot purposes but to give the readers a hint that this universe is slightly, ever so slightly, different than our universe and history by giving a logical design alternative to a common need that varies slightly....

 

[Cryhavoc101]

I would build them as you suggested but replace the Broadside weapons with 4 x Quad 40mm Bofor 40/60 AA mounts - 2 per side

Reduces weight and ammo handling issues and gives the type a better mix of AAA.

 

[Redbeard]

What about keeping six centreline turrets, but having the centremost not superfiring? It would increase stability at the cost of reducing the number of guns firing straight ahead at low angle, but wouldn't reduce AAA capacity much.

 

[PMN1]

What about keeping six centreline turrets, but having the centremost not superfiring? It would increase stability at the cost of reducing the number of guns firing straight ahead at low angle, but wouldn't reduce AAA capacity much.

So something like OTL Juneau(II), Spokane and Fresno?

 

[fester]

Too specialized

I would build them as you suggested but replace the Broadside weapons with 4 x Quad 40mm Bofor 40/60 AA mounts - 2 per side

Reduces weight and ammo handling issues and gives the type a better mix of AAA.

Three major problems with this idea for the first flight of Atlanta. First the 40mm Bofors still won't be the standard medium AA gun for the USN when the design is stabilized. Secondly the ship would be way too specialized as an AA ship instead of a good generalist flotilla/"light" light cruiser. The need for incredible amounts of AA is not recognized yet. Finally, you try to get Congress to authorize a light cruiser that is more lightly armed than a couple of destroyer classes that are no more than 5 years old. The ship displaces 3x as much as a Porter and has 2x the crew.... Congress won't be fooled by this inflated destroyer design that is an end run on something or other....

 

[PuffyClouds]

I really don't see that as plausible that the USN would convince Congress to fund a 6,000 ton cruiser that was visibly no better armed armed than an 1,850 ton destroyer Porter class it had just funded a couple of cycles ago.

Sure the dual 5" guns would all be DP's, the magazines deeper, the AA better but the number of barrels would be the same, the number of torpedo tubes would be the same and the crew would be twice as large.

The thought is that with decreasing the weight and clutter you gain volume that can be used to increase the range and possibly the speed. The new-Atlanta should be more useful in an engagement too with the increase in firecontrol.

 

[BlueTrousers]

The thought is that with decreasing the weight and clutter you gain volume that can be used to increase the range and possibly the speed. The new-Atlanta should be more useful in an engagement too with the increase in firecontrol.

It makes sense from an engineering viewpoint - the extra 4,000 tons means you can use those eight 5-inch guns far better.

Politically, it's still eight 5-inch guns on a hull three times the size.

 

[Talwar]

Can you imagine trying to keep the centre gun of a triple 5"/38 fed in an anti-air action?

That's why it wasn't done.

Because the USN had a standard twin 5"/38 turret, variants of which were used on all battleships, carriers, and cruisers in this period. Designing and producing a triple 5"/38 turrret would have added substantially to the costs and time of the Atlanta class.

...and a triple mount would be that much heavier and more difficult to move around to track hostile aircraft, compared to a twin mount.

 

[fester]

Congress

The thought is that with decreasing the weight and clutter you gain volume that can be used to increase the range and possibly the speed. The new-Atlanta should be more useful in an engagement too with the increase in firecontrol.

It makes sense from an engineering viewpoint - the extra 4,000 tons means you can use those eight 5-inch guns far better.

Politically, it's still eight 5-inch guns on a hull three times the size.

Exactly --- an 8 gun, 6,000 ton ship should be far more effective than an 8 gun 1,850 ton ship. It will also be significantly more expensive (an extra 25,000 horsepower) with a much larger crew. A 12 gun ship on 6,000 tons is far easier to sell to Congress than an 8 gun ship...

I am not looking for a radical ship like the post-war Norfolk but a tweak on an OTL design that is clearly logical and perhaps slightly better than OTL. It still is carrying too much weight (the Oaklands probably lose a pair of wing turrets after all) but it is a logical alternative to a 1938/1939 designed Atlanta