Conservation Research Laboratory Reports

Site 8SJ3478, possibly the Industry: a British 18th-century shipwreck

The Artifacts: The Swivel Gun 8SJ3478-39

The swivel gun was discovered at the start of the 1999 field season after the site was salvaged and pillaged by persons unknown. Prop wash deflectors were used to clear the site and two of the six cast iron guns still on the bottom were stolen, sometime prior to July. The mailboxes that were used exposed an area approximately one meter deep all around the perimeter of the stowed cannons and the anchors previously recorded. At 47.58 cm below the SOAR datum established at the site, the swivel gun was discovered between and slightly below two of the larger guns. Plans were immediately made to recover and conserve the gun to protect it from further illegal salvage.

Gun concretionThe gun was recovered in July and transported to the Conservation Research Laboratory in College Station, Texas in September of 1999. Figure Two shows the encrusted gun tube, yoke, and wedge concreted as one unit. The gun was hooked up to a power supply and allowed to undergo electrolysis for approximately one month to help loosen the outer layer of marine growth before mechanical cleaning with an air scribe. Figure 3 shows a photograph of the gun after mechanical cleaning. While the final outer layer of corrosion products was left undisturbed in order to encourage electrolytic reduction, it seems at this time that the swivel gun is free of all markings. It appears that there is no weight or Broad Arrow etched on the gun.


The bore of swivel gun 8SJ3478-39 is still slightly encrusted, but appears to measure at least one and 1/4 inches (3.5cm). This would suggest that the gun fired .50 pound or .75 pound balls. A gun similar in size and appearance was recovered from Arnold's gondola the Philadelphia in Lake Champlain. The Philadelphia gun fired a .75 pound ball and its bore measured 1-7/8 inches (Bratten 1997:185). 

E.R.Swivel guns mounted on deck were also sometimes loaded with musket balls to be used as anti-personnel weapons at close range. Historic documents suggest that swivel guns were greatly favored by early colonial merchant ships (Tucker 1989:98). Tucker also states that the typical swivel gun varied between 34 and 36 inches in length, 1.5 to 1.75 inches in bore, and utilized shot that weighed either .50 or .75 pounds (1989:98).

Swivel gun 8SJ3478 measures 33.5 inches (86 cm) in overall length. A small portion of the monkey tail that would have held a wooden swivel grip assembly extends from the cascabel. The wedge still inserted between the gun tube and the yoke suggests that, if the gun was mounted, it would be locked into a position to repel boarders. The touch hole is visible, and there is no lighting platform or pan. 

After mechanical cleaning and recording swivel gun 8SJ3478-39 was reattached to a low voltage, high density current in three places: at the wedge, on the yoke pivot mount, and just aft of the bell. The gun will continue to undergo carefully monitored electrolytic reduction (see Figure avove.)


Citation Information:

Franklin, Marianne
2000, Site 8SJ3478, possibly the Industry: A British 18th-Century Shipwreck, Conservation Research Laboratory Research Report #10, World Wide Web,
URL, Nautical Archaeology Program, Texas A&M University


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