Everybody gets an ironclad (Ironclads II)

Later information in the timeline somewhat answers our questions about ironclads; however, it is not an improvement.


This is from Chapter 12 of the unrevised version (the revised version has not gotten this far), and is in December 1862.

The Americans, however, had been focused on ironclads, both built from the keel up and extemporized from existing warships, as the ideal blockade breakers; and with shipyards capable of building or converting such from the Chesapeake to Portsmouth, New Hampshire, the numbers were not any less on the American side. By the end of 1862, some 26 ships had been built or converted; these included the first three built under the direction of the Ironclad Board formed in September, 1861. These included the sloop of war Philadelphia (18) built in her namesake city by Cramp & Merrick; the broadside gunboat Galena (6) and the turret gunboat Monitor (2), both part of Farragut’s Home Squadron, based in New York. These had been followed by Boston (19), the former steam frigate Franklin, converted on the stocks at the Portsmouth Navy Yard; conversions of 10 smaller steam sloops, laid down in 1861 as part of the wartime program, but converted to broadside or casemate designs in 1862 (four in New England at Portsmouth or Boston, and three each in New York and Philadelphia); the two big sisters New York (40) and New Jersey (40), laid down as ironclad frigates in 1861 by Webb in New York for Italy but taken over and rushed to completion; and 10 larger semi-sisters of Monitor, the Passaic class, including five built in New York, three in Philadelphia, and two in Boston. In addition, the Navy’s large prewar screw steamers, the frigates Niagara, Colorado, Minnesota, Roanoke, and Wabash, and thesloops Brooklyn, Hartford, Pensacola, Richmond, and San Jacinto, had been converted to so-called “chain clads,” with mast and yards cut down and improvised protection added. These ships were not capable of facing an ironclad, but they certainly were strong enough to deter attempts by the Royal Navy’s wooden steamers - which had to keep their masts and sails for the endurance needed for blockade duty - to come too close to the ports and harbors where the chainclads were stationed.

The text makes clear that the following ironclads have been built (and are in service) as of December 1862:



1 Monitor
1 Galena
1 New Ironsides (here Philadelphia)
1 Boston (ahistorical super-quick conversion)
10 ironclad sloops (conversions)
2 ironclads seized from the Italian government
And 10 Passaic class ironclads.


This totals 26.


This is a very important number, because the total number of US coastal/ocean ironclads that entered service during the Civil War is:


1 Monitor
1 Galena
1 New Ironsides
10 Passaics
1 Roanoke
1 Keokuk
1 Onondaga
5 Canonicus
1 Monadnock
1 Tunxis (corrected Casco)
1 Dictator

Total 24.

Thus, by the end of 1862 in this timeline, the Union has built more ironclads to serve on the US East Coast than it managed in the entire OTL Civil War.


This is completely outrageous - the US in the real world was desperate for more ironclads, and suddenly upping their production rate by a factor of four makes no sense - and delving into the minutiae makes it even worse.




In the OTL, most Union ironclads were Monitors, and were built with an armour scheme known at the time as "laminate" - individual 1 inch (actually 15/16 inch, "40 lb") plates layered on top of one another. The reason for this was that the rolling mills in the Union could only handle plate of this thickness, and the metal quality was not very good either (quite silicaceous, it was not far from cast iron in quality). As of the start of the Civil War, the only rolling mill in America able to produce 2 inch plate was in Richmond.
This imposes some major constraints on the resistance of American ironclads built with this armour method - for example, the original configuration of Monitor's turret armour (8 plates) resisted at 11 foot tons per inch, and the later Union ironclads using 5x 2 inch plates resisted at 28 foot tons per inch, while the thick armour imposed the full weight penalty according to the mass of the combined layers.

The alternative available to the Union was hammered wrought iron armour, where multiple thin plates are hammered and fused together under a drop hammer. This produces much more solid plates (French 4.7 inch hammered plates resisted at 16 foot tons per inch, about as well as 11 inches of 1" laminate) but is a slow process - ironclads with armour produced by this method came out roughly once a year, New Ironsides in 1862 then Roanoke in 1863 then the two Webb Frigates in late 1864.


(All the resistances above are for unbacked plate. For reference, the plates used in Warrior resisted at 28 foot tons per inch unbacked. Once backed, French 4.7 inch plates resisted at 41 foot tons per inch and American 4.5 inch plates resisted at 39 foot tons per inch. Warrior had the best scheme of any early ironclad and resisted at 61 foot tons per inch, but this was costly in both time and materials.)



The Union ironclads of the Monitor type produced in this timeline with laminate armour (the Monitor and ten Passaic ironclads) are, arguably, possible. If they are armed with the same weapons as they had in reality most of them would not be commissioning until the new year (the 15 inch gun was being developed at maximum speed OTL) but we are not told which guns they have - though it assuredly matters, as the 11 inch is incapable of penetrating Warrior.

Galena's armour is different, and not very tough at all - this appears sustained as she is essentially destroyed very quickly.

The rest of the ironclads (Philadelphia, Boston, the Webb frigates and the ten ironclad sloops) are either built with laminate or hammered. If built with hammered then the author is asking for 14 ironclads to be armoured with hammered iron in the time during which the Union could produce the iron for 1 1/2; if built with laminate they will be at once very overweight and very vulnerable to damage.

This may be why the author does not actually specify any details - not only the armour scheme, but the weaponry of the ships he describes remain elusive. We are told the number of guns, in some cases, but not what those guns are.


Specific ships also have problems. The Webb Frigates were very slow to complete in reality, and were taken by Italy unfinished in autumn 1864 (where they sailed to France for remedial work, including refitting the engines, putting the plating on and supplying guns); here they have been finished very quickly indeed, in just a year apiece.
The Passaics would not actually be modified versions of Monitor TTL because the Monitor has not been in a battle (and hence there has been no chance to garner experience, especially as the first Passaic was being constructed the week after Monitor was launched.)
As has been noted elsewhere, the Boston is both ahistorical and frankly cheating.
Chaincladding is a very specific thing and does not grant much if any actual protection; certainly sawing the masts off a frigate should not save enough weight to make it suddenly able to outmatch a ship of the line (or a rifle-armed frigate)