Reloading Guns in a turret

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USS ALASKA

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Sirs, wanted to get into a more technical discussion so broke this out from the 'Period Civil War Photos & Examinations' sub-forum - https://civilwartalk.com/threads/the-20-inch-rodman-gun.139202/ . Thanks for your consideration.

I wonder how useful it would be in battle, given how the 15 inch guns already had very long reload times.
At least they could be reloaded from INSIDE the turret...

duilio_1880_003-jpg.jpg


Reloading the muzzle-loading guns of Caio Duilio

https://upload.wikimedia.org/wikipedia/commons/e/ec/Duilio_1880_003.jpg

:smile:
USS ALASKA

That's actually an improvement. The guns are lining up with a below-decks powered rammer, so the actual reloading takes place behind armour - you're not winching up a giant powder bag to put into the front of the gun exposed to fire aimed at the turret.

It's also more than a bit quicker.
Sir, so if I understand you correctly, putting a pit / slot / hole in the outer deck, (which means more strengthening to provide the same level of structural integrity as a solid deck ), open to plunging fire and shrapnel, (unless it has a moveable covering which adds another level of complexity ) with exposed powder bags in it and the guns more exposed to fire while angled down and limiting your reloading position to align with that deck area is more desirable than just slewing the turret away from fire to reload then bringing it back to bear on the target? To protect this sequence, you would have to turn the entire ship away from fire, not just the turret.

Seem like a very convoluted Rube Goldbergesque way of doing things...

Cheers,
USS ALASKA
 

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67th Tigers

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If you look at the large muzzle loaded rifles of the 1870's-80's that's how they were loaded.

Forgotten weapons has recently explored the largest every muzzle loader, which was in a shore battery, and explained the loading system:

 

Mark F. Jenkins

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The mechanism was different for different vessels... it being a time of experimentation, it's tough to generalize. I know that in Britain's "Black Battlefleet," certain turreted vessels had to train their guns to a certain angle inboard for the reload, but then on later ones the power rammer rotated with the gun so it could be done at many more angles along the arc (not sure it was a full 360, but it was a substantial improvement).

That Caio Duilio arrangement looks really weird to me. Generally speaking, the longer barrels came in with smokeless powder (which burned more slowly than the old black powder, so you needed a longer barrel to accelerate the projectile), and by then all the big guns (those not left over from the 1860s) were breechloading.
 
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Saphroneth

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Sir, so if I understand you correctly, putting a pit / slot / hole in the outer deck, (which means more strengthening to provide the same level of structural integrity as a solid deck ), open to plunging fire and shrapnel, (unless it has a moveable covering which adds another level of complexity ) with exposed powder bags in it and the guns more exposed to fire while angled down and limiting your reloading position to align with that deck area is more desirable than just slewing the turret away from fire to reload then brining it back to bear on the target? To protect this sequence, you would have to turn the entire ship away from fire, not just the turret.
Plunging fire is simply not a significant concern in ship combat in this time period. It's not until the very end of the 19th century that accuracy (and range) become sufficient to allow it beyond pure luck or the specific situation of a shore mortar.

The actual reloading equipment, including the powder bags, is all behind armour for the entire process when using a powered rammer. Meanwhile, the problems with having to align the turret a specific way are actually common to the powered-rammer process and the process used by an Ericsson turret with a large gun (as the turret has to align with the winch hole in the deck for the large Ericsson gun).

It should also be noted that the powered-ram process was developed after the simple ramming process and represented at least a threefold increase in speed. (The 17.72" guns took about 5-6 minutes to reload this way; smaller guns were considerably faster.) It's a considerable increase in speed and a not insignificant increase in protection for no real downside.

An additional benefit is that the gun can be made considerably longer as it doesn't need to fit entirely within the turret.


That Caio Duilio arrangement looks really weird to me. Generally speaking, the longer barrels came in with smokeless powder (which burned more slowly than the old black powder, so you needed a longer barrel to accelerate the projectile), and by then all the big guns (those not left over from the 1860s) were breechloading.
Are you not thinking of prismatic powder? That was an 1870s and 1880s thing, and I know the Rodman/Dahlgren marks were usually too short to take advantage of the slower burning powder.
 

Saphroneth

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The gun turrets on the Duilio were about 10m in diameter, with the gun trunion (thus balance point) 260 inches aft of the muzzle. To allow totally internal-to-turret reloading the turrets would need to be at least 280 inches in radius, an increase to about a 14 m turret diameter - functionally a 40% increase in turret mass. To allow working space inside the turret it's quite possible you'd need a 15m or 16m turret.
This is a significant increase in top weight (and overall weight - the turrets were 17" thick and 11 feet high, meaning that each foot of radius means an armour weight of 17x11x(pi)x40 lb, about ten tons - going up from 10 m to 15 m radius means the mass of each turret goes up by 150 tons) and constrains the space on the ship, and the result is that the reloading is significantly slowed.
 
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USS ALASKA

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Plunging fire is simply not a significant concern...
You might want to explain that to the gents going up against the batteries at places like Drewry's Bluff, Vicksburg, Malta, Gibraltar, or anywhere else the adversary has weapons mounted above sea level. :wink:

Cheers,
USS ALASKA
 

Saphroneth

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You might want to explain that to the gents going up against the batteries at places like Drewry's Bluff, Vicksburg, Malta, Gibraltar, or anywhere else the adversary has weapons mounted above sea level. :wink:
That's a fair point - though I'll note that the Caio wasn't designed with plunging fire in mind anyway! She doesn't seem to have an armoured deck atop the citadel.
Though I could be wrong there - she has an armoured deck deck somewhere...

The angle of a shell fired from a gun 100 feet above sea level is going to be about arctan(20/430) though if fired level, which means that the angle of the plunge to a first approximation comes from the angle of the firing. I'm not sure you can get more than about 10 degrees of plunge - that would indicate a vertical speed of about 70 metres per second, for about a 14 second flight time and a horizontal range approximating 6,000 yards (which would by contemporary standards be an excellent shot).

This actually means that the shell guns of the 1850s produce much more acutely plunging fire, because their muzzle velocity is so much lower.
 
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Saphroneth

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If I remember correctly, at least in British usage, the rammer (or a separate sponger also hydraulically driven) had a tube inside it to spray water inside the gun; that was how they avoided embers from igniting the charge early.
 

rebelatsea

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If I remember correctly, at least in British usage, the rammer (or a separate sponger also hydraulically driven) had a tube inside it to spray water inside the gun; that was how they avoided embers from igniting the charge early.
Indeed , that's right, with the arrival of the big breech loaders the water spray gave way to air blast. to clear the long bores of debris from the fired charges. Well out of our time period, but in the evidence given at the enquiry into the loss of the Hood, more than one eye witness on Prince of Wales noted that B turret seemed to be having problems with the air blast system. Not germane to the loss of the ship but technically interesting.
 

Saphroneth

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That is interesting, yes. There's a lot of machinery that went into the process of firing a big gun like that, which is why it took so long and why the early RN BL guns weren't a huge improvement in loading speed over the late RMLs. (The switchover took place after an accidental double loading and consequent gun burst.)

I quite like this snippet from Brown:

In particular, one may note the evidence of Lieutenant McNeile, gunnery officer of Monarch. Asked if it was possible to stand at the muzzle of one gun, run back for loading, while the other was fired, he replied that he’d done it and it wasn’t very pleasant!

Brown, David K. Warrior to Dreadnought: Warship Design and Development 1860-1905 (Kindle Location 2106). Naval Institute Press. Kindle Edition.
 
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Saphroneth

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I would think having the muzzle pointed into the hull for reloading would be frowned upon. I certainly would not want to be on a ship with the muzzles of our own guns regularly pointed into the interior of the ship. A misfire or accidental ignition would mean certain destruction by friendly fire.
Certainly in the Devastation class ironclads which used a similar system the angle was designed so that in the event of a premature firing the shell would exit the hull above the waterline; one assumes the advantages in reloading speed were considered worth it. Notably the Thunderer did have a reloading accident after some years of testing and service, but it wasn't a premature firing - it was a double loading, which was blamed on the hydraulics as they didn't give the warning signs that human gunners would have noticed.
 
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rebelatsea

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That is interesting, yes. There's a lot of machinery that went into the process of firing a big gun like that, which is why it took so long and why the early RN BL guns weren't a huge improvement in loading speed over the late RMLs. (The switchover took place after an accidental double loading and consequent gun burst.)

I quite like this snippet from Brown:

In particular, one may note the evidence of Lieutenant McNeile, gunnery officer of Monarch. Asked if it was possible to stand at the muzzle of one gun, run back for loading, while the other was fired, he replied that he’d done it and it wasn’t very pleasant!

Brown, David K. Warrior to Dreadnought: Warship Design and Development 1860-1905 (Kindle Location 2106). Naval Institute Press. Kindle Edition.
I'm not surprised !
What was gained in ease and speed of loading mechanically was lost in getting the guns back on the target !
 

rebelatsea

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Certainly in the Devastation class ironclads which used a similar system the angle was designed so that in the event of a premature firing the shell would exit the hull above the waterline; one assumes the advantages in reloading speed were considered worth it. Notably the Thunderer did have a reloading accident after some years of testing and service, but it wasn't a premature firing - it was a double loading, which was blamed on the hydraulics as they didn't give the warning signs that human gunners would have noticed.
It was noted at the enquiry that the noise and concussion was so great that no one noticed the gun hadn't fired - or recoiled.
 

Saphroneth

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What was gained in ease and speed of loading mechanically was lost in getting the guns back on the target !
Well, the alternatives are:

1) Traverse gun to the position where it is flush with the tubes.
2) Traverse gun to face away from enemy ship in order to reload.
3) Reload gun while still pointing at enemy ship, exposed to enemy fire.

Or, the later one:

4) Traverse gun to fixed position for breech-loading.

All aspect breech loading came along quite late, and if you want to reload safely you're thus going to need to traverse the gun to do it. Option 2 actually involves more traversing than option 1.
 
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267.JPG


Something similar must've been done to "improve" the servicing of land-based monsters like these 15" Rodman smoothbores positioned in the defenses of Washington at Fort Foote, Maryland. The marker below depicts how they were loaded and fired art the time they were installed here during the war.

270.JPG


However, the marker below describes an "improved" King's Depression Carriage adopted postwar that seems to have drawn the gun down into the shallow ravine or depression where it could be reloaded without exposing the crew to counter-battery fire. (Note the Rodman in the previous photo in the background in its firing position.) This idea was no doubt the genesis for the system in vogue at the time of the Spanish-American War of the so-called "disappearing" guns.

261.JPG
 

Saphroneth

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Mention of disappearing guns led me to the Temeraire (1873) which used a hydraulic loading system in combination with a disappearing mount:


There was an armoured pit in the upper deck, fore and aft, containing an 11in, 25-ton gun on a hydraulically worked, disappearing mounting. The gun was loaded hydraulically in the lower position and would then be raised to the firing position by further hydraulic rams, taking up a pre-set training angle as it rose, though elevation had to be applied manually. The normal crew was six but it could be worked by three if necessary (excluding ammunition suppliers) which compares well with a crew of nineteen for a similar gun on a broadside mount. One round could be fired every 105 seconds.

Brown, David K. Warrior to Dreadnought: Warship Design and Development 1860-1905 (Kindle Locations 2632-2636). Naval Institute Press. Kindle Edition.

When you compare that with the much greater reloading time for a manually loaded 11" turret gun (Monitor certainly had a fire rate greatly slower than 105 seconds) it's quite worth it.


Brown also addresses the disappearing mount in shore usage, and he notes that in a test firing the disappearing mount made little difference - they set up an automatically appearing and disappearing mount on Portland Bill, and the Hercules failed to even hit the emplacement with plentiful broadsides, much independent 6-pounder fire and even hundreds of rounds of machine gun fire - though I can't find offhand the range of the test.
 
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