Ironclad Union ironclads - plausible improvements

[Saphroneth]

I got to thinking about the possible ways in which, without the application of hindsight (much) or over-advanced technology, the Union's ironclads could have been better than what was actually produced.


The "low hanging fruit" IMO is:

Monitor types - backed turret armour (wooden backing inside the turret) in place of some of the layers, though what I'm not sure about here is whether 12"-24" of wood would reduce the inner diameter too much.

Monitor types - a delineation in each turret of one AP gun (64 pounder high velocity smoothbore, or Parrott 8" gun, for example) and one HE gun (11" Dahlgren, for example), where a gun effective at both is not available.

Monitor types (Passaic) - building for the 15" gun as a weapon that was actually available, so the gun ports are the right size.

New Ironsides - a rudder which can be raised or lowered, including lowered below the bulk of the hull (historically the water flow missed her rudder, but the lowering-rudder arrangement was used on some Aetna class or Erebus class ironclad floating batteries and was reported in the news at the time, so it's not a wholly new problem).

Galena - not sure, her wooden hull means that "all or nothing" is risky. Perhaps reconfiguring her to "belt and battery" with a thicker battery? That might be too advanced to qualify, though.

Casco class - do the weight calculations properly!

 

[Belfoured]

I got to thinking about the possible ways in which, without the application of hindsight (much) or over-advanced technology, the Union's ironclads could have been better than what was actually produced.


The "low hanging fruit" IMO is:

Monitor types - backed turret armour (wooden backing inside the turret) in place of some of the layers, though what I'm not sure about here is whether 12"-24" of wood would reduce the inner diameter too much.

Monitor types - a delineation in each turret of one AP gun (64 pounder high velocity smoothbore, or Parrott 8" gun, for example) and one HE gun (11" Dahlgren, for example), where a gun effective at both is not available.

Monitor types (Passaic) - building for the 15" gun as a weapon that was actually available, so the gun ports are the right size.

New Ironsides - a rudder which can be raised or lowered, including lowered below the bulk of the hull (historically the water flow missed her rudder, but the lowering-rudder arrangement was used on some Aetna class or Erebus class ironclad floating batteries and was reported in the news at the time, so it's not a wholly new problem).

Galena - not sure, her wooden hull means that "all or nothing" is risky. Perhaps reconfiguring her to "belt and battery" with a thicker battery? That might be too advanced to qualify, though.

Casco class - do the weight calculations properly!

"Monitor types (Passaic) - building for the 15" gun as a weapon that was actually available, so the gun ports are the right size."

I think this got resolved with the next class, that combined the use of a redesigned smoke box with a redesign of the 15-inch Dahlgren in the taper of the chase.

 

[Saphroneth]

"Monitor types (Passaic) - building for the 15" gun as a weapon that was actually available, so the gun ports are the right size."

I think this got resolved with the next class, that combined the use of a redesigned smoke box with a redesign of the 15-inch Dahlgren in the taper of the chase.

Indeed, but the problem could have been solved with the Passaics if they'd built to the weapons they had on hand - it's one of the downsides that can result from simultaneously developing interlocking parts of a design. Plus, building for the 15" and installing the 13" instead (if it works) doesn't actually result in an unworkable ship - just one which has a slightly larger porthole than needed.


Actually, speaking of that, I wonder if there's a way to fit ready ammunition for the 15" in the Passaic turret. It'd greatly improve the firing rate for the first few rounds.

 

[Belfoured]

Indeed, but the problem could have been solved with the Passaics if they'd built to the weapons they had on hand - it's one of the downsides that can result from simultaneously developing interlocking parts of a design. Plus, building for the 15" and installing the 13" instead (if it works) doesn't actually result in an unworkable ship - just one which has a slightly larger porthole than needed.


Actually, speaking of that, I wonder if there's a way to fit ready ammunition for the 15" in the Passaic turret. It'd greatly improve the firing rate for the first few rounds.

I think that's correct about the Passaics. The problem appears to have been the timing of design/construction and the interworkings of Fox, Ericsson, and Dahlgren. Given the Navy's insistence on pushing the 15-inch, the interim solution was to narrow the diameter of the 15-inch at the muzzle - but this still required the smoke box. In other words, they tried to make the 15-inch fit the designed turret rather than changing the latter to accommodate the gun.

This is from a Cincinnati newspaper in 1862 about the test firing of the 15-inch by the Passaic:

"A skillful gunner might throw a shell into a porthole large enough for these guns; therefore the porthole was fixed for firing through without protruding the gun, being little large than the ball. The first fire was as much as the crew cared to risk in that experiment. The smoke and flame filled the turret. Then a flange was fitted to the muzzle of the gun and the curve of the turret to increase the space. The last trial was this contrivance. Thirty five pounds of powder and a hollow shot were fired. The concussion lifted the perforated shield plates on top of the turret, one of which fell on Captain Worden's foot. The volume of flame from the muzzle set the tackle for hoisting the shot on fire, burned the eyebrows and hair of one of the gun's crew, and the force of the gas tore off the flange. It was found also that although the extra flange might fit the inside curve of the turret, the gun must recoil before the charge left it. It was rather queer that ordnance officers should have to experiment to find that out. The result proved that the porthole must be enlarged so as to let the muzzle of the gun protrude, or some sliding arrangement like the joints of a telescope must be contrived to keep up the connection with the porthole while the gun recoils."

 

[Saphroneth]

And even then, you have the issue with aiming which is what I'm really focused on - though I suppose you could use a sighting seat above the gun position instead. It's my understanding that they couldn't really aim the 15", which obviously has significant implications for its use as a gun platform at anything above ~50 yards or so.

 

[Belfoured]

And even then, you have the issue with aiming which is what I'm really focused on - though I suppose you could use a sighting seat above the gun position instead. It's my understanding that they couldn't really aim the 15", which obviously has significant implications for its use as a gun platform at anything above ~50 yards or so.

That's correct regarding the "short" 15-inch - which was the type installed on the Passaic. The smoke box actually interfered with aiming. On the Passaic pointing for both guns apparently was done using the 11-inch Dahlgren.

 

[Saphroneth]

That's correct regarding the "short" 15-inch - which was the type installed on the Passaic. The smoke box actually interfered with aiming. On the Passaic pointing for both guns apparently was done using the 11-inch Dahlgren.

I sort of wonder whether the Passaics could have benefitted from construction starting later and another few weeks or so to finish the design - they certainly overran historically, but I'm not sure how much you could avoid further delay if you had the materiel building up at the shipyards before the design finalized.


Alternatively, a form of director firing did exist in the Royal Navy (firing to converge). Maybe they could have used that - aim down the 11 inch, angle the 15 inch by an offset from the 11 inch according to estimated range (which you need anyway for firing a time shell) and use that.


Though I now wonder if there was any scope for a broadside ship with 15 inch guns...

 

[Saphroneth]

On the Galena, the tricky thing is that on her actual displacement it's hard to get a fightable ironclad ship unless you accept that you can't make her shotproof. HMS Reseach was considered too small to be worthwhile and was twice the size.

If you accept shot resistant, though, as built she's not terrible. I think you probably need to reduce the armour on the ends though and accept having only a few guns on each broaside.

 

[Belfoured]

I sort of wonder whether the Passaics could have benefitted from construction starting later and another few weeks or so to finish the design - they certainly overran historically, but I'm not sure how much you could avoid further delay if you had the materiel building up at the shipyards before the design finalized.


Alternatively, a form of director firing did exist in the Royal Navy (firing to converge). Maybe they could have used that - aim down the 11 inch, angle the 15 inch by an offset from the 11 inch according to estimated range (which you need anyway for firing a time shell) and use that.


Though I now wonder if there was any scope for a broadside ship with 15 inch guns...

My guess is "probably" on the construction timeline. It's clear that Fox intervened late in the construction process because he was fixated on the 15-inch as a necessity for going after Charleston. In addition to trying to squeeze that gun into a turret designed for the 11-inch, this ran into a production constraint because there weren't enough 15-inch guns being turned out. So you end up with the mixed battery and one of the two guns not really being efficient.

 

[Belfoured]

My guess is "probably" on the construction timeline. It's clear that Fox intervened late in the construction process because he was fixated on the 15-inch as a necessity for going after Charleston. In addition to trying to squeeze that gun into a turret designed for the 11-inch, this ran into a production constraint because there weren't enough 15-inch guns being turned out. So you end up with the mixed battery and one of the two guns not really being efficient.

A bit of an update after I looked at a few resources. It appears that Ericsson had the 15-inch Dahlgren design in his hands by April 1862 but pressed forward with the Passaic turret design anyway. We should keep in mind also that Dahlgren himself was skeptical about the 15-inch and ultimately gave it a service life of only 300 firings instead of c. 1,000 he gave the 9- and 11-inch guns. When - late in the game - it was proposed to enlarge the gun ports on the Passaics to accommodate the 15-inch, Ericsson rejected that because he believed the drilling would weaken the turret walls.

 

[rebelatsea]

Fire Ericson from one of the 15" guns, and refit the monitors with Eads turrets !

 

[Saphroneth]

Fire Ericson from one of the 15" guns, and refit the monitors with Eads turrets !

That would probably help, yes.

Though I'm not sure whether the Coles or Eads design is superior overall - Coles requires manpower to rotate but by that very fact you can get a much finer movement. Similarly I'm not sure if the Coles roller-path or the Eads whole-structure rotation is superior for durability/reliability, just that the spindle design is worse.

 

[rebelatsea]

That was a tad tongue in cheek ! but anything is better than the "spindle". I deliberately said Eads as the Coles patent was taken by the Admiralty until Lairds were granted permission to use it. Mind you the USN could have just gone ahead and used Coles drawings from The Engineer and argued the toss afterwards.

 

[Saphroneth]

That's fair, and I was wondering about which was outright better rather than which would be available. Putting all of these into action you'd end up with e.g. the original Monitor equipped with an 11" gun and a 64 pounder, still on a spindle, and the Passaics equipped with a 15" gun they can actually use along with either an 11" or 64 pounder gun on an Eads turret.

The original Monitor with a 64 pounder is an interesting prospect because her HV smoothbore might actually pierce Virginia's glacis, and that could have knock-on effects on the whole war!

 

[rebelatsea]

I would vote for a Passaic with an Eads turret carrying two 64pdrs (for rate of fire). I believe The 64pdr at RN battle range in 1861 or nearly so would penetrate Virginia's casemate : 5.5" plate equivalent, if the impact was direct.

 

[Saphroneth]

I would vote for a Passaic with an Eads turret carrying two 64pdrs (for rate of fire). I believe The 64pdr at RN battle range in 1861 or nearly so would penetrate Virginia's casemate : 5.5" plate equivalent, if the impact was direct.

I'm worried about the supply of 64 pounders, since it was to my recollection an old pattern. You could definitely give Monitor one, but a class of Passaics each with two might strain the supply.

 

[Saphroneth]

Ah, I see you mentioned only 16 were produced, previously:

Brass Napoleon Award - Were Confederate Ironclads Worth The Effort/Cost? | Naval War - At Sea & Along Inland Waterways

The Blockaders stood inshore during the hours of darkness which prevented the runners from steaming parallel to the shore, imagine if they didn't do that for fear of a light ironclad coming out to sink them in the dark, it would only have to happen a few times to make them stand off the...

civilwartalk.com

and some of them I believe ended up in Confederate hands. So two per Passaic is actually the whole supply gone and a deficit!

 

[Belfoured]

Fire Ericson from one of the 15" guns, and refit the monitors with Eads turrets !

Trust me, from what I've seen the first thought may have crossed Dahlgren's mind. I think he would have used one of its 300 service-life firings for Ericsson and another for Rodman.

 

[Belfoured]

I'm worried about the supply of 64 pounders, since it was to my recollection an old pattern. You could definitely give Monitor one, but a class of Passaics each with two might strain the supply.

Given the production/supply problems with the 15-inch (which is why they ended up with mixed batteries), they probably should have just gone with the dual 11-inch battery, as Dahlgren wanted.

 

[Saphroneth]

Given the production/supply problems with the 15-inch (which is why they ended up with mixed batteries), they probably should have just gone with the dual 11-inch battery, as Dahlgren wanted.

The tricky thing about that is that the 11" has very limited AP capabilities. It's just not a powerful enough gun to pierce ironclads, which is part of the job; the 64 pounder is rather better because it has such a high muzzle velocity.