Sunday, February 28, 2016

2/28/16 Report - More On Ship Artillery Including Swivel Guns and Others.

Written by the TreasureGuide for the exclusive use of

I am far from arriving at a conclusion about the item shown yesterday, but in the process of doing a little research have found a lot of interesting information that I want to post.

The item I showed yesterday seems from the photos to me to be close to the size of a swivel gun. Swivel guns were varied in size and shape, but you can see one example above.

The swivel gun was a small cannon named for it's mechanism of attachment. It was about the only 18th century gun that was not a "crew-served" weapon, although it's effectiveness was multiplied when manned by more than the gunner. Once mounted, almost always on a fixed base (as the block of wood shown) it may be pointed quickly to any quarter. But the swivel mechanism cannot stand heavy recoil, so the size, and hence effectiveness, of a swivel gun is severely limited.

Cannon calibers became relatively standardized during the 1600s based on the weight of the ball projectile used in the gun. The smallest standard cannon was the two-pounder, and the largest was the fifty-pounder.

That text and image is from, which is a very nice web site with good information about Revolutionary War artillery.

Another web site (link found below) says,  Clearly the 24lb and 16lb guns were prevalent at the time.( Note that due to a lack of internal gun foundries, most Spanish cannons were produced either in Italy or the Spanish Netherlands. But much of the shot was forged in Spain. 

The smallest caliber cannons were not mounted on wooden carriages but on the railings of the ship. These were principally guns of 5lbs or less, and their principal purpose was not to damage an enemy ship, but to repel boarders. As such they often did not carry an iron ball as shot, but sharp fragments of sharded metal which formed a deadly curtain of shrapnel when fired.
Here is the link to the web site providing that information.

The shot manufactured in Spain was of poor quality and frequently cracked.

I don't know much about artillery, but from what I've seen so far, I'm starting to wonder if the gun shown yesterday might be a swivel gun.  That seems to me to be closer to its size, even though the exact size is difficult to judge because of advanced state of corrosion.

Click here to see a large variety of swivel gun images.  I have seen a few examples that seem to me to match the approximate size of the one shown in yesterday's post.

It also appears to me from yesterday's photos that the breech could have been squared off some.  As you might have seen some swivel guns had a square or rectangular breech, particularly those that were breech loaded.  That opening in the breech might have also contributed to the way the item corroded.

Illustration from Peterson's Encyclopedia of Markings and Decorations on Artillery, Vol. 1. 
Click here to go directly to vol. 1 of Peterson's work. (It is a pdf file so might take a while to load.) It also also includes an excellent reference list.

In the photos of the find, I see no evidence of reinforcing rings, which seems to me to support the idea of it being a swivel gun.  It is possible that they are just worn away.

I also see no evidence of side trunnions, which also seems to me to be consistent with the idea of a swivel gun.

Like I said, I'm don't know much about artillery, and all I am doing at this point is wondering about possibilities.  I hope others will add their thoughts.  If you can tell me I'm completely wrong, please do so.

I really like these kinds of research projects because even if you don't come up with the correct answer right away, you always learn a lot in the process.  I enjoyed looking into the subject, and learned a lot myself.

For me leaning what you found can be as much fun as making the find.  It definitely adds a lot.


On the Treasure Coast it is simply a beautiful day.  The surf is smooth.  Great day to be on the beach or in the water.

Happy hunting,