from THE NAVAL HISTORY OF THE AMERICAN REVOLUTION, VOLUME 2
https://books.google.com/books?id=R9pWRDSu7w4C&dq=inauthor%3Aallen%20william%20pickles%20morris&lr=&pg=PA394#v=onepage&q=pickles&f=false

Oliver Pollock, the commercial agent of Congress at New Orleans, had supervision of naval affairs on the Mississippi River and was authorized to commission both vessels and officers for the Continental service and for privateers. In commissioning and fitting out vessels and in otherwise executing the orders of Congress, Pollock was encouraged and assisted by the Spanish governor of Louisiana, Bernardo de Galvez, who was very friendly to American interests. In 1778, Pollock purchased the ship Rebecca, one of several prizes taken on the Mississippi by a party of Americans under Captain James Willing, who had come down the river from Ohio. A year later this vessel, renamed the Morris, had been armed with twenty-four guns, fully manned, under the command of Captain William Pickles, and ready for sea, when she was unfortunately destroyed by a hurricane, August 18, 1779, and eleven of her crew were lost. Governor Galvez then provided an armed schooner for the use of the Americans; this vessel seems also to have been called the Morris, or Morris's tender. Pickles cruised in this schooner and " Captur'd in Septr. a Vessell of very superior force in Lake Ponchetrain, after a very severe conflict."  The prize was a British sloop called the West Florida. She was fitted out by Pollock and under the command of Pickles cruised on Lake Pontchartrain during the fall and captured a British settlement. The surrender of the British posts on the Mississippi to Galvez soon followed. Later the West Florida assisted the governor in the capture of Mobile and then proceeded to Philadelphia, where she was sold out of the service.