The Weird and Wonderful World of North Carolina Designs (also general ship design stuff)

[ShamefurDispray]

Regarding the US adopting triple turrets much later than some other nations:

 

The US' first ships that could have really benefitted from triples are the Delaware class, and it appears that for them (and the Floridas when the 14" wasn't ready in time) that weight at the aft end of the ship was very limited, to the point they accepted only one turret able to fire straight backwards to avoid even the extra weight that making the number 4 turret superfiring would have added. Unfortunately I don't know what was up with the Wyomings. The New Yorks ended up like that just because they were designed before the triple was really finished, the Delawares are the real mystery and I don't know why.

The US went with triples because they'd seen just how clumsy the five and six turret layouts that resulted otherwise were. They were still concerned about excessive weight aft it seems, the first draft of what became the Nevada was based on the New York with the number 4 turret eliminated and number 3 raised before all turrets were turned into triples rather than eliminating number 3. It's also worth a quick note that all this is with 14" guns rather than the 12s on previous triples, which makes the weight on the ends a much bigger problem. Only after Delaware's magazine cooling was reported a failure did they push the turrets all the way out on the ends. The triple was actually adopted after the New York class as a weight and length saving measure. The USN was actually very tightly limited in ship cost by its political setup, with a lot of repeat ship classes out of a desire to not raise costs. That translated into a direct limit on armor and machinery weight.

The US had previously considered triples (and they'd had de facto quads with the Virginias) all the way back in 1905 (I don't want to know what "semisuperposed" means incidentally) for the South Carolina. The biggest problem for them seems to have been getting the turret working the way they ran things, since each gun was elevated by a single pointer per and they weren't sure where the middle gun's pointer would go. The solution was a single pointer per turret with the guns elevating as a unit, but that left concerns about a single blow knocking out the entire turret and the alignment of the guns in the unit. They also used a very strong front plate to make up for three holes, and tried to get a turret prototyped (it took until two classes with it had been contracted though). Incidentally this is where the US got a lot of their information on gun interference. They hedged their bets by considering twin 15 inch turrets.

Later on BuOrd wanted to avoid working on twin and triple turrets at once when going to 16 inch turrets, preferring a New York style layout (BuEng wanted to keep the machinery the same and go with four turrets). General Board went with five doubles based on fleet experience with doubles and inexperience with triples, as well as theorycrafting that another double would be pretty cheap weight-wise and turboelectric machinery would allow a layout that wouldn't heat the middle turret's magazine. Josephus Daniels said fuck this noise we're building a repeat of last class, pick the caliber you want and that became the Colorado.

I'll point out that the Dante Aligheri and Gangut classes both had two midsection turrets, while the US seemed to have sought to minimize the amount of turrets there. The Tegetthoff class was the familiar ABXY layout, but I don't know if they had any issues with the layout. Frankly I don't take inclusion on that class to be an automatic sign that something doesn't have significant problems, and I'm sure you'd agree there.

 

I've read that German battleships, Bismarck and Scharnhorst classes were planned to have double 15" guns because their ammunition hoists were inefficient in terms of space (especially width), therefore triples would further increase the width of these oversized ships and there will be either a speed loss or a further upsizing of the already oversized ships.

For some reason, the Japanese never had any triple turrets in battleships until the Yamato, but there were plans for triple 14" and 16.1" mounts. My hypothesis is that due to their doctrine, they preferred to have higher speeds for their operations theatre and having triple turrets would have meant that they would need to install more heavy, powerful and expensive turbines or further increase the size of their ships.

When it came to the Yamato however, they were more focused on building the most powerful battleship for the eventual decisive battle more than anything else. 

[StrelaCarbon]

So what's the consensus on Turbo-Electric propulsion for warships? Good or Bad? 

[Collimatrix]

21 hours ago, StrelaCarbon said:

So what's the consensus on Turbo-Electric propulsion for warships? Good or Bad? 

 

What I had read was that it was good when first introduced, but it was quickly eclipsed by advances in mechanical powertrains.

[xthetenth]

I have been remiss, and not been through this thread in a while.

 

Turbo-Electric was largely a curiosity. Kind of cool, lets you do some nifty stuff, but reduction gears kept getting lighter in a way that tons of electrical gear didn't. Considering its main home was the USN, and up until the start of WWII they didn't make a design where weight wasn't limited (pre-treaty ships were limited as a proxy for budget), this really limited its adoption.

 

During the treaty period, where everyone's ships were weight limited, yeah nobody was very interested in a bunch of weight in return for some smallish benefits.

 

They would have been perfect for the Bismarcks, but the Germans were idiots had interesting requirements tangential to actual combat capacity (in this case they required the ability to go from full ahead to full astern within one minute for reasons.

 

They actually do show up once more in warships, in an unlikely place: the Buckley class destroyer escort. Much like the glorious Sherman, the Destroyer escorts used a variety of engine technologies in order to avoid various bottlenecks. So the Buckleys have turbo-electric, and the Cannon class were diesel-electric. This is because reduction gearing was a bottleneck. 

 

Second, regarding triple turrets, the US turrets were space efficient, their triple 14"s were pretty close in diameter to the British twin 15" (New Mexico vs. QEs). This was at the cost of a greater use of manpower rather than machinery, which is potentially troublesome. I'd have to see if it was Friedman and look up the actual numbers and points brought up in British commentary. (I should also probably check in at some point whether there were any refits between then and Surigao and whether they actually missed many salvoes, but I remember that being almost entirely a function of the radar carried. I'll see if I have that much effort in me.)

[xthetenth]

Addenda based on looking at sources:

 

First off, somehow the ability to reverse polarity on a turboelectric drive to instantly obtain full reverse power didn't satisfy the Germans. I'd want confirmation but I would not be surprised to hear that the contract had been written in such a way as to accidentally preclude it. Also, in 1914, a GE electric system was $162,441 less than a direct drive. Another thing that I think is possible with them is significantly better resistance to two damage modes, flooding of the vitals, and a PoW style disembowelment (not actually preventing it but allowing for shorter shafts that deposit less energy less deeply into the hull). Also turboelectric lets you steam astern continuously for much longer in case of bow damage.

 

Machinery was a big problem, literally, in that the Tennessee had one of her generators break down and removing it for repairs was very difficult.

 

Regarding turrets, the advantages of the US design over UK practice were the elimination of shell rooms (with more than half the shells stored inside the roller path support and ready use shells in the turret and on the horizontal transverse platform at the end of the guns, simplification through a fixed loading angle, and not using a platform or supports behind the barbette armor. This meant a US triple 14 or twin 16 required an inner diamater of the barbette of 31 feet versus the 30.5 feet of a British twin 15".

 

On the other hand, Director of Naval Ordnance was much happier with the British designs, which used entirely hydraulic power, compared to US designs, which used more manpower than mechanical power in the transport of shells. The US turrets also used electric and air power, while the British preferred hydraulic, which they felt offered better reliability, simplicity, ease of repair, and quick detection of defects.

 

One possible consideration for the US is that machinery adds displacement while larger turret crew wouldn't necessarily be as expensive.

[Lord_James]

*Breaking out necromancy book* 

 

Does anyone know where to find these design studies for North Carolina? Since the available spring styles books have a big gap between 1925 and 1939, that’s not an option, so I am inclined to think it’s in Friedman’s “US battleships”?