Although a relatively small force during the Age of Sail, the US Navy was nevertheless closely watched by larger maritime powers impressed by the radical thinking and innovative design manifest in so many of its warships. This gives the subject an interest that stretches far beyond the shores of America itself. For over fifty years knowledge of these ships has relied heavily on the works of Howard Chapelle, a practical naval architect with a fine understanding of design, but an amateur historian who was less than professional in his use of sources.