The Monitor had 8 inches of armor, the Galena had 3 - that's a lot more than "somewhat better armoured".
The armour material, structure and backing also matters, focusing on raw thickness in this period is a recipe for mistakes. Galena's armour was thin, but it was properly backed and so she was much less likely to generate dangerous amounts of spall; it was also presumably not as plain
bad as the silicaceous iron used for
Monitor.
Galena's armour is worse for resisting penetration, but better for avoiding spall.
Where is your source for the claim that Monitor only fired two shots every twelve minutes?
She fired 41 shots (20 per gun) over the course of a three-and-a-half hour engagement. That's 19 reloads over the course of 210 minutes.
Based on that reasoning, Monitor would have been pounded to bits by CSS Virginia. You are ignoring size of the target and armor penetration.
Actually the Monitor did take a lot of
hits from Virginia, but Virginia didn't have much ammunition left that wasn't shell. She was still pretty battered by the shell, but I strongly suspect that if
Virginia had a full load of solid shot (rather than expending most of it the day before) the
Monitor would have been at risk of a major defeat. (OTL she took about twenty hits, IIRC, and
Virginia's broadside was only about four guns.)
Incidentally, one of the reasons why Virginia had expended a lot of her shot was that it was fired as hot shot - her reconstruction had placed her boiler somewhere she could easily use it to create hot shot. This, not shell, is the most dangerous weapon against a wooden ship.
The point is that the shallow draft Monitor can go a good deal of places that the Gloire cannot, which is an advantage.
To some extent, but it doesn't really help in defeating her - not when the strategy is to get in as close as possible.
"Despite the care taken over her design and build the ship did have some weaknesses...the major weakness criticised at the time, her rudder was very exposed by the design of the stern and furthermore the rudder and tiller head were outside the armoured citadel." -
HMS Warrior: Ironclad Frigate 1860, Wyn Davies and Geoff Dennison
...and underwater.
Again, they're not very large targets. Are there any examples of a wooden warship disabled specifically by having her rudder shot away? (Heck, any iron ones?)
They're relatively vulnerable compared to the rest of the ship, but it's not a major one simply because the 'target' is hidden and is in the middle of the ship.
You have missed my point. Gloire's center of balance is high - even in calm waters, when turning or firing she has a less stable gun platform.
Oh, right, the metacentric height.
Out of interest, what's the metacentric height of the
Monitor? You know, for comparison, since I happen to know
Gloire had about 6 feet and other Monitor types (
Miantonomoh) was 15 feet, so we can't just say "Gloire is unstable" without comparing her to other ships.
"We, on the contrary, possessed large herds of cattle, which we had brought along or gathered in the country, and our wagons still contained a reasonable amount of breadstuffs and other necessaries, and the fine rice crops of the Savannah and Ogeechee Rivers furnished to our men and animals a large amount of rice and rice straw. We also held the country to the south and west of the Ogeechee as foraging ground." -
William T Sherman
Continuing the quote:
Still, communication with the fleet was of vital importance; and I directed General Kilpatrick to cross the Ogeechee by a pontoon bridge, to reconnoiter Fort McAllister, and to proceed to Saint Catherine’s Sound, in the direction of Sunbery or Kilkenny Bluff, and open communication with the fleet. General Howard had previously, by my direction, sent one of his best scouts down the Ogeechee in a canoe for a like purpose. But more than this was necessary. We wanted the vessels and their contents; and the Ogeechee River, a navigable stream, close to the rear of our camps, was the proper avenue of supply.
This shouldn't be surprising, as his account says his wagons when full carried roughly twenty days of person food and three days of animal food. By consuming everything in a line sixty miles across and 230 long they avoided using up all of those supplies over the course of about a month, but operating thirty miles out of Savannah in a semicircle is going to cover only about 1350 square miles (while the above line of movement covered ten times that area).
In actual history Grant got a flying column going in a few hours, sustained it for a week, and still had enough spare rations to feed the surrendered enemy - its called the Appomattox Campaign. If the Army of Northern Virginia comes out from behind their entrenchments, the Army of the Potomac should be able to crush them.
Well, Grant had been collecting supplies for several days for an operation in that direction, which undoubtedly helped, and
It's also during the spring, which is an easier time for all this (especially for grazing) than the mid-winter.
But let's go with that - the Appomattox campaign went roughly ten miles a day (70-80 miles over the course of a week) and was in part over as-yet-untouched ground.
To get across the North Anna it's about forty-five straight line miles, but the route goes directly through both Petersburg and Richmond so that won't do - instead you have to move around the flanks, making the operation longer, and essentially exposing the flank of the army to the Confederate forces in Richmond and Petersburg.
This kind of thing is why the Union didn't just send their army around Richmond to cut off the rail lines straight away, which is that an army moving with their flank to an enemy position is vulnerable - they're not mutually supporting. The Army of the Potomac at this point is large enough that a single column on a road would stretch about thirty-five miles (
before allowing for intervals between brigades, divisions and corps), and the more you divide it up the more roads you need and the more the flank column is a vulnerable target. Lee could easily mount demonstration attacks (i.e. threaten the Union column of march), force them to close up, make them lose time and generally screw up their supply situation. (This didn't matter in the Appomattox campaign because the enemy was generally
ahead of the Union army - but it'd be far more difficult with the enemy on the flank.)
Even in the best case for the Union where they get out of trouble, however, with the supplies cut off you have the Confederate capital saved (and the morale of the Army of the Potomac, presumably, shot.)
