Ironclad USS Monitor: Rifled Guns or Smoothbores?

Did the civil war ironclad USS Monitor have rifled guns or smoothbore guns?

I suppose there are two parts to this question:

  1. She was designed by John Ericsson. Ericsson had invented guns, so-called hoop-type guns, and I vaguely recall that he had planned for Monitor to mount his own guns. But there was controversy, probably from the incident with a rival described here, and at least at some point Monitor used 11-inch Dahlgren guns instead. Did she ever mount Ericsson guns during her short life? If so, which guns was she armed with during the actual battle of Hampton Roads?

  2. Were the 11-inch Dahlgrens smoothbore or not? The page cited above indicates that Dahlgren’s “shell guns” were all Columbiads, which are apparently uniformly smoothbores. It mentions some rifled guns Dahlgren worked on, but none are described as being “11-inch.”

I ask because, in two places recently, I’ve seen references to the USS Monitor’s rifled guns, and I’d always thought they were 11-inch Dahlgren smoothbores.

One of the sources I can cite online:

Admittedly, it’s the Internet, and fraught with error – note the misspelling of Dahlgren’s name.

The other source, however, I would normally regard as unimpeachable: Shelby Foote’s massive and well-received Civil War: A Narrative. I have the highest respect for Mr. Foote’s work. That’s why I was startled to see a reference to the Monitor’s “massive rifles” – I will have to add a page citation when I get home, unfortunately.

That shook my confidence in my previous understanding.

One possible source for the confusion is that the 11-inch Dahlgrens, used extensively by the Union Navy, were, although smoothbores, good armor-breaking guns for fighting ironclads, at least at close range. This property may have led later readers to confuse them with the generally-higher-muzzle-velocity rifled gun type (by assuming “anything that good at armor-breaking must have been rifled.”)

What’s the Straight Dope?

I sent an email to the Mariners’ Museum in Newport News, VA; they have the Monitor and are doing the conservation work, so if they answer at all, it will be definitive.

All the references I found in Google News archives (which admittedly, goes back only to 1998 on the subject) refer to smoothbore cannons.

Calling the smoothbores “rifles” may have been sloppy. They were shell guns (right?), and some folks may think that you need rifling to fire shells.

I don’t recall it being given in anything I’ve read on the Monitor, but the pictures I’ve seen don’t suggest rifling:…&p=monitor+ironclad&oid=4b242a6820b332d05328df79db3e2682&fr2=&no=15&tt=3270&sigr=115vc0jbi&sigi=113dp3nal&sigb=12thr7fc2&.crumb=UKCydYmXxxq…&p=monitor+ironclad&oid=6cf0391abfacf71c73447a6e73e19e4a&fr2=&no=9&tt=3270&sigr=11fufik2s&sigi=11e3bsuv0&sigb=12thr7fc2&.crumb=UKCydYmXxxq
Certainly the Wikipedia article on “smoothbore” thinks the Monitor’s guns were smoothbores, and uses one of these photos to illustrate the point:

Assuming the Monitor mounted the 11-inch Dahlgrens, they were indeed shell guns. Somewhat confusingly, that means that they were capable of firing a variety of projectiles, not just explosive shell. Also, Dahlgren’s design was intended to give more muzzle velocity (something he felt had been lacking in the first shell guns):

Holy cow! I never would have thought of doing that. Thanks! It would be neat if they do reply.

Pm me in a few days if you don’t get a response and I’ll just swing by there. It’s not too far out of my way so I don’t mind taking a look and seeing what I can find out at the actual museum.

The *USS Monitor *mounted two 11-inch Dahlgren smoothbore muzzle-loading shell guns. These were Nos 27 and 28 manufactured at the West Point foundry in 1859 and originally installed as slide-mounted pivot guns on the gunboat Dacotah. They could fire either a 166lb sperical solid shot or a 135lb spherical shell.

For the subsequent monitor-type Civil War ships, the Passiac-class monitors replaced one of the 11-inch guns with a 15-inch, and the following Canonicus-class, the late-war Miantonomoh-class, and the never-completed Kalamazoo-class all had two 15-inch Dalghren smoothbores. Various other classes of light and river monitors all had twin 11-inch Dalghrens.

The only monitor with rifled guns was the one-off USS Onondaga, which had two turrets, each armed with a 15-inch Dalghren smoothbore and an 8-inch/150pdr Parrot rifled gun. (The triple-turreted USS Roanoke, sometimes incorrectly classed as a monitor, had 2 11-inch and 2 15-inch Dalghrens, and 2 8-inch Parrot rifles.)

So far as I can find, none of these ships were re-armed during the war.

(Ref: Warship Profile # 36 - United States Navy Monitors of the Civil War and New Vanguard #45 - Union Monitors 1861-65)

Definitely smoothbores:

See also:

Just checked at home. According to James Tertius deKay’s concise but excellent book Monitor, the guns were indeed Dahlgren smoothbores. They were not swapped out during the ironclad’s less-than-one-year in service in 1862; those being conserved at the Mariners’ Museum today are the very same with which she fought the CSS Virginia.

Another point of interest: The Monitor and the Virginia did relatively little serious damage to each other, and the Federal ironclad’s second in command, Lt. Charles Dana Greene, was convinced that the Navy Department’s orders to use just 15 pounds of gunpowder per shot meant that a knockout blow was almost impossible. The restriction was later doubled to 30 pounds, permitting the Passaic-class monitor USS Weehawken to defeat the CSS Atlanta, which was very similar to the Virginia, with just five shots in a duel the next year.

Looks as though she was fightingtwo monitors and ran aground. :slight_smile:

Thanks! I’d always read they were smoothbore Dahlgrens, but a source as credible as Foote threw me into doubting my certainty.

The Civil War, A Narrative: Fort Sumter to Perryville, Shelby Foote, 1958

IIRC, the Atlanta was built on the hull of a deep-draft oceangoing vessel, the *Fingal *, which had run the blockade. It’s worth noting that only one of the two monitors did the shooting, and that one (Weehawken) sported a 15-inch Dahlgren in the turret beside the 11-incher.

Jack Aubrey or Horatio Hornblower could run aground fighting two better armed vessels and win, maybe even Rhett Butler, but your average Joe figures it’s time to haul down the colors. :slight_smile: