I had a few thoughts in the Muscatuck thread that I posted that really belong here, both as a legitimate self criticism of what I did wrong in this AU and as a background for why it turns out this way.
From USS Arkansas on the US shipbuilders used recuperators exclusively.
But even before that happened:
1. The Mark 4 introduced the barbette/gunhouse style of construction to US ships and used a spring return system.
5. These turrets used the "grass-hopper" counter recoil system whereby a spring box, located under the gun pit, was connected via two heavy, pivoted arms to the gun yoke. See 10"/40 (25.4 cm) datapage for a sketch.
Now what I find interesting is that as early as 1898, the British were installing recognizable modern hydraulic recuperators aboard the HMS Formidable and the HMS Implacable, then building. They had no end of trouble with the tech clear into WW I. The cylinders leaked, the fluids were fire hazards and so forth.
My guess is that the Americans were extremely conservative and stayed with mechanical rocker systems until at least the 1906 timeframe I suggested. The South Carolina may have been their first battleship class to use French style cradle mounts.
[In 1898, the bag charges were] laid inside the brass button at the time of mounting on the feed tray or rammed separately depending on the model of the gun. You see this safety practice clear into WW II. This allows for visual inspection of the bag and last minute rejection if the gun crew notices tears, mold, crystallization or any other visible to the eye defects in the charge.
[Combining] the fore and base charges into one case?
For mechanical handling reasons the Germans did not think so. I've seen old films of US gun crews loading old Endicott 12 in coast defense mortars (Edison filmed a practice) and [one notices], that the practices used were extremely unsafe. The speed at which the army crews were able to fire (1 shot per 15 seconds) on dry land was simply incredible, and this was all done by hand and wheeled trolley. I have seen an old film of a British gun crew load an old dreadnought style gun in a gun house and they were far slower and much more careful. Both used bag charges and the de Bang system modified by either Rogers or Wellin interrupted screw breech blocks. I (Research since I first wrote this has shown me that the Germans were as concerned about propellant burn as the French, and their parallel experiments showed that past a certain size, the propellant bag sputtered and did not burn thoroughly... Tobias) cannot say why the Germans used fore and aft charges. I [thought I did] know why those who used the de Bang system used multiple bag charges in a powder train. Controlled overpressure burn in the breech chamber and the bags were at the limit of what one average man could move by size and weight without the risk of tear or damage to the bag or the spill of highly flammable propellant in an extremely dangerous fire prone and cramped work space.
... for obvious reasons I'm not a fan of manganese in any way shape or form around a breech block. Prefer creosote sponge or LEAD, as they sensibly used in those days.
Going back to be resized and reloaded first?
A brass case exposed to overpressure in the breech tends to balloon around the mid-body or at weak point in the case wall. This happens because the breech heats up to around softening point of brass every time the propellant burns.
Can the case be made of a brass base obturator and thin manganese wall that would burn out leaving just the brass base to reduce the amount of space taken up by empty cases and reduces the mass of the internal ejection (heavy case vs light disk)?
Yes, but why would [one] want to do that when weight is not an issue and lead is much safer, cheaper and more plentiful for either the case or the brass base button? The lead will remain and after factory reset is reusable.
Could the brass cases be lifted mouth up or do they need to be sideways on the lifts? If mouth up, could a ring system similar to the shells be used for storage?
This is what I assume the Americans do in my AU. The continuous step chain hoist is easier to design for a shell or bag charge on its side (US battleships in general), but for a unit round, stand it on its base. Unless the propellant is a preformed stick or molded candle (modern practice) might want to make sure the granules/pellets do not slosh and bunch up in clumps in handling. Uneven burn means two dangers: flame flash from unburnt propellant and bag silk or spot burn which torches the breech chamber walls and creates weak spots. That happens anyway, but juggling the bag charges as the stocks are rotated around to make sure the granules are evenly distributed reduces the occurrences and the dangers. With a unit round, there has to be an open the cartridge and rotate the bags inside inspection or somebody has to learn how to make a burn candle which is akin to a solid rocket mortar. In 1910, that is not going to happen. So that unit round will have to be separated, the bag charges inside rotated and those charges visually inspected.
Hopefully at least every three months.
Unit rounds can be insulated. and are easier to move by machines
. The bag charges are somewhat safer inside brass from a spark hazard, but standing heat, moisture, and accidental tears in movement remain other hazards nonetheless. Nothing changes the dangers from nitrocellulose powders used in the period. Nothing. [One's] chief dangers remain moisture and crystallization. [One should] think about air conditioning your battleships' magazines.
Shell storage, point up lifts work or would the shells need to be sideways lifted? A shell lift system somewhat similar to the US use of inner and outer rings on two levels?
The US used horizontal bag charge lifts and point up shell hoists to feed trays in some of their ships. With unit rounds the point up shell hoist with flipper tray would be [a preferred] choice.
The Mutsu comment is that about shells or propellant safety, wasn't there a magazine cook off from an electrical fire?
Since the people who caused the accident died in the explosion; one can only guess. From what [one] can discern from similar debacles in British, French and American warships, the causes are most likely:
a. someone smoked in the powder room. With the IJN, do not laugh... it is possible.
b. something hydraulic
c. Something chemical in nature was left standing to spontaneously combust. (Couple of American aircraft carriers became dockyard cases because someone did not police the rag bins.)
d. or the lighting system shorted out. Again with the IJN this is possible.
e. or a service panel shorted out and the trips did not work. See d.
The coal bunkers if behind a separate bulk head and air-spaced from barbette, would this be enough to help prevent a coal firing ignition of propellant?
[One] tends to think not enough. Safe practices are essential and far more important, no matter what the designed layout. Coal dust in air can act like a fuel air explosive bomb. One spark or one flame point and goodbye. The Maine blew up because her bunkers were not clean, were not kept clean and the coal was mishandled. p[My opinion. Tobias] [One] could have charged Sicard with dereliction; for not making ... sure that his stokers and deck apes did their jobs to wet wipe and dry wipe the bunkers before the last coaling and to properly handle the coal transfer from deck to bunkers. thereafter. That coal can be stacked wrong and that when stacked wrong as it shuffles around as the ship pitches and rolls it can rub and sandpaper itself to generate black fog is a known hazard.
That is coal can overheat in a steel box as the box becomes an oven is inevitable. That simple cross ventilation is not enough to keep the coal dust from accumulating as black fog is a known hazard. All in 1898. Sicard screwed up and lost his ship.
At least Hiram Rickover thought so.