An interesting selection of books are available online at books.Google.com. A series of Naval books with lists of officers and officials are available to read and search online. The following title included a detailed listing of Trinity House pilots for 1857. Mercantile Navy List and Appendage to the Commercial Code for All Nations by JH Brown. The details include the names of the channel or place the pilot was licensed to work and the draught of the vessel they could pilot.
THE MERCANTILE NAVY LIST