# Ironclad USS Monitor: Rifled Guns or Smoothbores? **URL:** \ **Category:** Factual Questions\ **Created:** [February 14, 2011, 7:02pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341 "2011-02-14T19:02:38Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 14, 2011, 7:02pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/1 "2011-02-14T19:02:38Z")
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](http://en.wikipedia.org/wiki/John_Ericsson#Propeller_design), and at least at some point Monitor used [11-inch Dahlgren guns](http://en.wikipedia.org/wiki/Dahlgren_guns#XI-inch) 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](http://en.wikipedia.org/wiki/Columbiad), 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: [http://www.rpi.edu/~fiscap/history\_files/monitor.htm](http://www.rpi.edu/~fiscap/history_files/monitor.htm) > [@](#): > > For armament, the USS Monitor used two eleven-inch Dahlgran guns (Doughty 218). These Dahlgran guns were massive rifled cannons that were capable of firing a variety of shot. 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? ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [February 14, 2011, 9:00pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/2 "2011-02-14T21:00:09Z")
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. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [February 14, 2011, 9:13pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/3 "2011-02-14T21:13:02Z")
All the references I found in Google News archives (which admittedly, goes back only to 1998 on the subject) refer to smoothbore cannons. ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [February 14, 2011, 9:30pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/4 "2011-02-14T21:30:27Z")
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. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [February 14, 2011, 9:48pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/5 "2011-02-14T21:48:30Z")
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: [http://images.search.yahoo.com/images/view?back=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3F\_adv\_prop%3Dimage%26va%3Dmonitor%2Bironclad%26fr%3Dyfp-t-980&w=580&h=459&imgurl=www.hnsa.org%2Fships%2Fimg%2Fmonitor3.jpg&rurl=http%3A%2F%2Fwww.hnsa.org%2Fships%2Fmonitor.htm&size=56KB&name=Civil+war+photog...&p=monitor+ironclad&oid=4b242a6820b332d05328df79db3e2682&fr2=&no=15&tt=3270&sigr=115vc0jbi&sigi=113dp3nal&sigb=12thr7fc2&.crumb=UKCydYmXxxq](http://images.search.yahoo.com/images/view?back=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3F_adv_prop%3Dimage%26va%3Dmonitor%2Bironclad%26fr%3Dyfp-t-980&w=580&h=459&imgurl=www.hnsa.org%2Fships%2Fimg%2Fmonitor3.jpg&rurl=http%3A%2F%2Fwww.hnsa.org%2Fships%2Fmonitor.htm&size=56KB&name=Civil+war+photog...&p=monitor+ironclad&oid=4b242a6820b332d05328df79db3e2682&fr2=&no=15&tt=3270&sigr=115vc0jbi&sigi=113dp3nal&sigb=12thr7fc2&.crumb=UKCydYmXxxq) [http://images.search.yahoo.com/images/view?back=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3F\_adv\_prop%3Dimage%26va%3Dmonitor%2Bironclad%26fr%3Dyfp-t-980&w=640&h=502&imgurl=www.civilwaracademy.com%2Fimages%2Fuss-monitor.jpg&rurl=http%3A%2F%2Fwww.civilwaracademy.com%2Fuss-monitor.html&size=83KB&name=USS+Monitor%2C+Civ...&p=monitor+ironclad&oid=6cf0391abfacf71c73447a6e73e19e4a&fr2=&no=9&tt=3270&sigr=11fufik2s&sigi=11e3bsuv0&sigb=12thr7fc2&.crumb=UKCydYmXxxq](http://images.search.yahoo.com/images/view?back=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3F_adv_prop%3Dimage%26va%3Dmonitor%2Bironclad%26fr%3Dyfp-t-980&w=640&h=502&imgurl=www.civilwaracademy.com%2Fimages%2Fuss-monitor.jpg&rurl=http%3A%2F%2Fwww.civilwaracademy.com%2Fuss-monitor.html&size=83KB&name=USS+Monitor%2C+Civ...&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: > **[Smoothbore](https://en.wikipedia.org/wiki/Smoothbore)** > > A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars. > Early firearms had smoothly bored barrels that fired projectiles without significant spin. To minimize inaccuracy-inducing tumbling during flight, their projectiles required an aerodynamically uniform shape, such as a sphere. However, surface imperfections on the projectile and/or the barrel will cause even a sphere to rotate randomly during ... ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 15, 2011, 4:22pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/6 "2011-02-15T16:22:15Z")
> [@mlees](#): > > 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. 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): [QUOTE=excerpt from Wikipedia link given above] Throughout the 18th and early 19th Century, the primary ship to ship weapon were muzzle loading smoothbore broadside guns firing solid shot modestly short distances. This all changed when the French Navy adopted a design of Col. Henri-Joseph Paixhans for a shell gun (canon-obusier) of 22 cm (8.7-inch) capable of throwing a 59 lb. shell in a reasonably flat trajectory (Gardiner 1992, p. 154). The U.S. Navy followed suit adopting the 8-inch, 63 cwt. Paixhans-style shell gun in 1841. Dahlgren was determined to design a new generation of shell gun that would be capable of firing explosive shells at higher velocity and greater range. They would also have the capacity to effectively fire solid shot. The ability to fire solid shot would become increasingly important as armored warships appeared on the scene: ``` "Paixhans had so far satisfied naval men of the power of shell guns as to obtain their admission on shipboard; but by unduly developing the explosive element, he had sacrificed accuracy and range.... The difference between the system of Paixhans and my own was simply that Paixhans guns were strictly shell guns, and were not designed for shot, nor for great penetration or accuracy at long ranges. They were, therefore, auxiliary to, or associates of, the shot-guns. This made a mixed armament, was objectionable as such, and never was adopted to any extent in France... My idea was, to have a gun that should generally throw shells far and accurately, with the capacity to fire solid shot when needed. Also to compose the whole battery entirely of such guns." —Admiral John A. Dahlgren.[2] ``` All of the Dahlgren shell guns were cast iron columbiads, had a distinctive soda bottle shape and all but two had an elevating screw running through the cascabel. Although some Dahlgren shell guns were tested to failure, no Dahlgren shell gun burst during service, a notable distinction for the time. Dahlgren shell guns were capable of firing shot, shell, shrapnel, canister, and (with the exception of the XV-inch shell gun) grape-shot. [/QUOTE] > [@Nametag](#): > > 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. Holy cow! I never would have thought of doing that. Thanks! It would be neat if they do reply. ---
**Author:** ![Atrael](https://avatars.discourse-cdn.com/v4/letter/a/6a8cbe/32.png) [@Atrael](https://boards.straightdope.com/u/Atrael)\ **Post date:** [February 16, 2011, 7:41pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/7 "2011-02-16T19:41:42Z")
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. ---
**Author:** ![Bookkeeper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bookkeeper/32/281_2.png) [@Bookkeeper](https://boards.straightdope.com/u/Bookkeeper)\ **Post date:** [February 17, 2011, 4:45am UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/8 "2011-02-17T04:45:02Z")
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_) ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [February 17, 2011, 9:08pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/9 "2011-02-17T21:08:29Z")
Definitely smoothbores: [http://www.publicaffairs.noaa.gov/releases2004/sep04/noaa04-r467.html](http://www.publicaffairs.noaa.gov/releases2004/sep04/noaa04-r467.html) See also: [http://www.marinersmuseum.org/uss-monitor-center/conservation-uss-monitors-dahlgren-guns-webcam](http://www.marinersmuseum.org/uss-monitor-center/conservation-uss-monitors-dahlgren-guns-webcam) ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [February 17, 2011, 11:31pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/10 "2011-02-17T23:31:58Z")
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. > **[USS Atlanta (1861)](https://en.wikipedia.org/wiki/USS_Atlanta_%281861%29)** > > Atlanta was a casemate ironclad that served in the Confederate and Union Navies during the American Civil War. She was converted from a British-built blockade runner named Fingal by the Confederacy after she made one run to Savannah, Georgia. After several failed attempts to attack Union blockaders, the ship was captured by two Union monitors in 1863 when she ran aground. Atlanta was floated off, repaired, and rearmed, serving in the Union Navy for the rest of the war. She spent most of her tim... ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 17, 2011, 11:47pm UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/11 "2011-02-17T23:47:46Z")
> [@Elendil\_s\_Heir](#): > > 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. > > [USS Atlanta (1861) - Wikipedia](http://en.wikipedia.org/wiki/USS_Atlanta_%281861%29) Looks as though she was fighting[two monitors](http://www.history.navy.mil/photos/sh-us-cs/csa-sh/csash-ag/atlanta.htm) and ran aground. 🙂 ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 18, 2011, 12:32am UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/12 "2011-02-18T00:32:26Z")
Thanks! I’d always read they were smoothbore Dahlgrens, but a source as credible as Foote threw me into doubting my certainty. [QUOTE=Foote, pp 259] As Welles had said, she had only two guns, but they were hard-hitting 11-inch rifles, housed in a revolving turret (another Ericsson invention) which gave them the utility of many times their number… [/QUOTE] _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. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 18, 2011, 2:01am UTC](https://boards.straightdope.com/t/ironclad-uss-monitor-rifled-guns-or-smoothbores/571341/13 "2011-02-18T02:01:32Z")
> [@Sailboat](#): > > 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. 🙂