The US Frigate Potomac collection is made up of a letter book and log book concerning the ship's service along the Atlantic coast, in the Gulf of Mexico, and in the Caribbean in the mid-1840s.
The Letter Book contains 107 pages of copied outgoing letters that John Gwinn wrote to various United States Navy personnel, such as Secretaries of the Navy John Y. Mason and George Bancroft, from October 11, 1844-December 29, 1847 (primarily in 1844 and 1845). The first letter is a copy of the Navy Department's official order for Gwinn to assume command of the Potomac , and the remaining letters pertain to the ship's service along the Atlantic coast, in the Gulf of Mexico, and in the Caribbean. Gwinn discussed the ship's movements, personnel, and maintenance. Many letters concern a leak sustained by the Potomac and its repair, and another group of letters addresses Gwinn's concern about possible cases of yellow fever on another ship. Gwinn wrote far less frequently after the Potomac 's arrival at the Gosport Shipyard in December 1846, and his later correspondence includes a lengthy letter from Philadelphia with his opinions regarding possible improvements to the Pensacola Navy Yard (February 2, 1846). A letter by Gwinn dated July 3, 1847, is laid into the volume's back pages, alongside a transcription written directly into the book.
The Potomac 's Journal (198 pages) is a log of the ship's movements and incidents onboard, with daily entries covering October 16, 1844-December 17, 1845. Entries written while the Potomac was at sea include charts with hourly records of the ship's course and wind direction, and every entry has prose remarks, often concerning weather conditions. The remarks also address issues such as activities at various ports, encounters with other ships, rations and cargo, and crew discipline and deaths. This log was compiled while the Potomac visited ports such as Norfolk, Pensacola, Port Royal, Port-au-Prince, Havana, and Veracruz. The final entry was written as the ship entered dry dock at the Gosport Shipyard. Two sheets of blotting paper are laid into the volume.