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Florida State University
Research in Underwater Archaeology


The 9-pdr iron cannon, cleaned of concretion, is lowered into a vat for conservation treatment.

Cannon From HMS Fowey

The breech end of this cannon was barely visible when first encountered on the wrecksite. As a fifth-rate man of war, HMS Fowey would have had (by the Admiralty Establishment of guns) a twenty-gun lower deck battery of 18-pounder cannons, a twenty-two gun upper deck battery made up of 9-pounder cannon, and two 6-pounder bow-chaser cannon mounted on the forecastle. (The terms 18-, 9-, and 6-pounders refer to the cannon's size; a 9-pounder cannon, for example, would fire a ball weighing 9 pounds). Of these 44 guns, only four were observed on the site, but we know that the captain had ordered the cannon disabled and thrown overboard during the wrecking.

There were also numerous cannonballs or shot on the wrecksite. Three sizes of shot were recorded from the Fowey--6, 9, and 18 pounds. The cannonballs were located primarily in two concentrations, which correspond to the known location of shot lockers on such ships as the HMS Victory. A circular, bronze cannonball gauge was also recovered from the site.

The cannon is raised and transported to Tallahassee for conservation The four guns observed on the wreck by FSU and Park Service archaeologists represented two of the calibers associated with the cannonball sizes. One 18-pounder was present, along with three 9-pounders. It was decided to raise one of the cannon. A second 9-pounder was removed after the initial field season by Park Service staff. Raising the cast-iron 9-pounder cannon presented quite a challenge. With its coral encrustation, it weighed over 3,000 pounds. Divers utilized two modified jet fuel tanks as rigid lift bags. Chained to either side of the cannon, the two tanks were filled with air and brought the gun to the surface. It was then towed by boat back to shore, with FSU Academic Diving Program Director Gregg Stanton astride the prize, along for the ride.

The cannon was winched onto a waiting truck and transported to Tallahassee for conservation at the State of Florida's Conservation Laboratory. Once there, it was weighed, documented, and then cleaned of coral encrustation. After the concretion was completely chipped off the cannon, its weight was 2,935 pounds.

The cannon, covered in concretion, is brought to the state laboratory where it will be conserved by James Levy (left).

The cannon was treated by electrolysis. Once iron is removed from the marine environment, the corrosion process accelerates unless it is properly conserved. Electrolytic reduction is the most common form of iron conservation (Hamilton 1976). The cannon was placed into a vat of an electronically conductive solution and connected to an electronic power supply. The electronic current slowly draws out all salts and chlorides from the artifact. A typical iron cannon treatment can take one to two or more years and cost thousands of dollars.

The first step is to remove the encrusting layer of concretion, which must be done before electrolysis can begin.






The cannon recovered had several interesting markings on its surface. Cast into the right and left trunnions (short cylinders projecting at right angles, upon which the gun was mounted to the carriage) were the letters "G" and "H" respectively. They may have been maker's marks (Peterson 1973: 154; Peterson 1969: 42). On the top of the cannon was inscribed the British Broad Arrow, an arrow mark that designated official British royal property. Adjacent to the broad arrow are the numbers "26-0-23," which signify the weight of the cannon in hundredweights (112 pounds) and fractions of hundredweights. The weight of the cannon, according to its inscription, is 2,935 pounds. This exact weight was confirmed in the laboratory.

Once cleaned, marking could be seen on the surface of the gun, including this Tudor Rose and a mysterious number 19

Also clearly visible on the cannon was a cast Tudor Rose, which was a royal crest during the reign of Queen Anne (1702-1714). There also appeared a number, "18", on one of the recovered cannon, and "19" on the other. The function of this last marking is unknown; it may represent a date of testing and acceptance by the Board of Ordnance or simply a piece number (Peterson 1973: 110).

A list of references and books for further reading follows. Another website of interest is Naval Artillery in La Salle's Day, part of the Belle Shipwreck page. Another page of interest might be Muzzle Loading Naval Guns.

To look at a sketch of a cannon with labeled parts click here Or take a look at a different sketch.

References and Further Reading

Bryce, Douglas

1984 Weaponry from the Machault: An 18th Century French Frigate. Parks Canada.

Hamilton, Donald L.

1976 Conservation of Metal Objects from Underwater Sites: A Study in Methods. The Texas Memorial Museum and the Texas Antiquities Committee, Austin.

Hogg, Ian V.

1974 A History of Artillery. Hamlyn, London.

Manucy, Albert

1949 Artillery Through the Ages. United States Government Printing Office, Washington D.C.

Peterson, Harold L.

1969 Round Shot and Rammers. Bonanza Books, New York.

Peterson, Mendel

1973 History Under the Sea. Self published, Alexandria, Virginia.

Skowronek, Russell K.

1984 Archaeological Testing and Evaluation of the Legare Anchorage Shipwreck Site, Biscayne National Park, Summer 1983. National Park Service, Southeast Archaeological Center, Tallahassee, Florida.

Skowronek, Russell K., Richard E. Johnson, Richard H. Vernon, and George R. Fischer

1987 The Legare Anchorage Shipwreck Site-Grave of HMS Fowey, Biscayne National Park, Florida. The International Journal of Nautical Archaeology 16(4): 313-324.

Thatcher, Joseph

1985 Cast for War: A History of Muzzle-Loading Artillery. New York State Bureau of Historic Sites, Waterford, New York.