Commissioned on October 10, 1776, he was active on the Gulf Coast. He was given command of , a British ship that had been captured on the Mississippi River, in 1779, but she was destroyed by a hurricane. He was then given another ship, also called , by Bernardo de Gálvez, the governor of Spanish Louisiana, to deal with British military shipping on Lake Pontchartrain. In September 1779 he captured a British ship. He then took over command of the prize, HMS "West Florida", with instructions from Oliver Pollock, Congress' agent in New Orleans, to assist Gálvez in a planned expedition to capture the West Florida port of Mobile. The ship was re-rigged and renamed . Following that successful expedition, he sailed on to Philadelphia, where the ship was sold.