USS Alligator

Piled stones from a shipwreck covered with marine life.
Stone ballast covers sections of wooden hull structure at the USS Alligator shipwreck site. Photo: Matt Lawrence/NOAA

The USS Alligator was built at the Charlestown Navy Yard in Boston, Massachusetts. Commissioned in March 1821, the warship measured 86 feet long, with a beam of 24 feet, 9 inches wide and a draft of just over 10 feet. For its size, the topsail schooner-rigged vessel was heavily built, having frames constructed of live oak, with white oak hull planking and structural knees. The vessel's wooden structure was held together with treenails carved from locust wood and copper-alloy fastenings. Below the waterline, copper sheathing protected Alligator from wood boring teredo worms. Unlike most other ships of the time that used stone ballast, the warship had approximately 16 tons of heavy iron blocks known as kentledge for ballast. Its armament included a single 18-pound pivoting cannon and 12 6-pound carronades.


The USS Alligator was one of five schooners built for the suppression of slavery and piracy during the presidency of James Madison. Shortly after being commissioned, the schooner sailed on its first assignment to the coast of West Africa under the command of Lt. Robert F. Stockton. Stockton's mission in Africa was to purchase land to be used to resettle former slaves of the United States.The land purchased by Stockton became the Republic of Liberia. During the remainder of its first cruise, Alligator captured several slavers, including the schooners Mathilde, L'Eliza, and Daphne.

Drawing of a sailing ship with sails set
Drawing of the USS Alligator with all sails set. Image: National Archives and Records Administration

On its second voyage to Africa in November 1821, Alligator battled with a suspected Portuguese pirate ship that lasted several hours before the Alligator's superior gunnery won the day. The Portuguese vessel became a prize of Alligator and was sailed to the U.S. to be condemned in by an admiralty court. Ultimately, the captured vessel was returned to its owners at the request of the Portuguese government. Before returning to the U.S. at the end of 1821, Alligator captured several more slave ships off the coast of West Africa.

When the United States acquired Florida in 1822, The U.S. Navy dispatched Alligator to the Caribbean to combat the rampant piracy in the area. After encountering a pirate schooner off Cuba, Alligator's crew engaged it in battle. The American sailors showed extreme heroism when they boarded the schooner and seized control from the pirates, but the fight resulted in eight crewmen being injured or killed. Alligator's captain, William H. Allen was mortally wounded during the fight and died shortly afterward. The crew and new captain Lt. John Dale left Cuba November 18, 1822 with seven merchant vessels recaptured from the pirates. Alligator was escorting the convoy of merchant ships north passing the Florida Keys, when it ran aground on an uncharted reef. The reef is now known as Alligator Reef.


A lighthouse rises from beautiful blue water
Alligator Reef Lighthouse, located 4.6 miles (4 nautical miles) east of Indian Key, was named after the U.S. warship that ran aground on the reef in 1822. Photo: Brenda Altmeier/NOAA

Although Alligator is one of only three Navy anti-piracy/anti-slavery patrol vessels whose approximate wreck location was documented, Alligator's shipwreck has not been conclusively identified. A shipwreck near Alligator Lighthouse has long been attributed to Alligator, but recent research suggests otherwise. NOAA and the U.S. Navy's Naval History and Heritage Command have undertaken several archaeological surveys to search for the final resting spot of the USS Alligator, but more research is necessary. No shipwreck site containing iron ingot ballast has not been found in the vicinity of Alligator Reef thus far.

(Hunter & Schmidt, 2005)

Site Map

Archaeological drawing of a shipwreck site.
Suspected Alligator Reef Shipwreck site map. Credit: David Moore