Moving the Big Guns on Alabama

Posted in Technology by Andy Hall on October 21, 2012

Over at Civil War Talk, there was an inquiry as to how the big, mounted artillery on ships like Alabama were moved about. When you look at a model or drawing of a CW-era ship, the deck often seems to be covered with metal arcs, obviously related to moving the gun, but in no clear pattern that’s easy to discern. (See this example on a model of U.S.S. Kearsarge.)Fortunately, Andrew Bowcock covers this procedure in some detail in his C.S.S. Alabama: Anatomy of a Confederate Raider. Although he described the procedure for a specific gun on that vessel, the process would be similar on other ships.

There are three basic components to the gun — the tube, the carriage on which the tube is mounted, and the slide in which the carriage was run forward and back (with recoil). It’s the arrangement of the slide here that’s important. The key to the whole process is that each end of the slide is fitted with a hole through which a brass pivot pin could be dropped, going through the carriage and into a matching, iron-reinforced hole in the deck. The key to shifting the gun from one position to another was to swing the slide on one pivot to line up the pivot hole at the other end with another point, put that pin in place, remove the first pin, and then swing the whole thing from the other end. It sounds complicated, but it is practical and (relatively) safe on a rolling deck, since the slide will (at worst) swing in an arc, rather than go barreling across the deck like a loose gun on trucks.

Here is a diagram of the eight pivot positions (marked in red) used for Alabama’s aft 8-inch smoothbore pivot — the one Captain Semmes was famously photographed with:

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And this shows the pivot points on the slide for that gun:

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And here is that process illustrated on the digital model:

Gun positioned on center-line of deck, normal stowed position.

Back end of slide is swung to an intermediate pivot point on the port side and pinned there.

Front end of the slide in unpinned and swung toward the port side.

The swing complete, the forward end of the slide in pinned at the ship’s side, and the back end in unpinned to allow the back end of the slide to swing freely.

The gun is now ready for action.

The model is simplified for clarity, and omits all the block-and-tackle, breeching ropes, and the dozen or more crew members required to provide the muscle power to do this. (Bowcock notes that the official complement to work this gun in action would be sixteen men.) Anyway, I hope this makes the process a little clearer.

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Tagged with: Andrew Bowcock, artillery, C.S.S. Alabama, naval, U.S.S. Kearsarge

7 comments

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pedrog said, on October 22, 2012 at 8:58 am

Similar pic from the HMS Warrior…

Presumably, there was there a steering station below decks…singed spokes?

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Reed said, on October 22, 2012 at 8:09 pm

This makes a lot of sense but, geeez, it sure looks complicated and time consuming. Even with a full complement of men—and all the block & tackle, etc.—how long would a shift like this take? Could a crew manage this (e.g. moving a cannon from, say, port to starboard) in the time it would take for a ship to come about?

Which raises another question (and forgive my ignorance here, perhaps you’ve covered this before), wouldn’t it be simpler to outfit the ship with cannon on both sides? What’s the advantage of this system? I assume the cost-savings of fewer cannon is a big factor, but perhaps there is something else in its favor? More cargo space? Less weight and shallower draft? Inquiring minds want to know…

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- James F. Epperson said, on October 23, 2012 at 2:18 pm
  
  The large caliber guns are BIG, so carrying one instead of two saves a lot of weight (= more speed)
  
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  - Andy Hall said, on October 23, 2012 at 2:24 pm
    
    Yes. I imagine that with a lot of drill they could shift the guns relatively rapidly, but still a lot of work. It may play into the fact that when Alabama met the similarly-armed Kearsarge off Cherbourg, they steamed in circles, always engaging on the same side:
    
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Jay Roig said, on January 21, 2016 at 11:12 am

Speaking of the USS Kearsarge, since the gun tracks it used are designed differently and appear to be more complicated than those used by Alabama, how were it’s large guns shifted?

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- Andy Hall said, on January 21, 2016 at 12:21 pm
  
  Jay:
  
  Thanks for your inquiry. I haven’t looked closely at Kearsarge, so I’m not sure how they differed.
  
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  - Jay Roig said, on January 21, 2016 at 1:07 pm
    
    I have yet to find an explanation anywhere on the internet.
    
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