Joshua Humphreys' design was deep, long on keel and narrow of beam (width) to allow the mounting of very heavy guns while affording high speed downwind and efficiency when close-hauled. The design was to extremely heavy scantlings, including the planking, and incorporated Humphreys' innovative diagonal rib to limit hogging. This gave the hull greater strength than those of more lightly built frigates. Humphreys developed his design after realizing that the fledgling United States could not match for size the navies of the European states. He therefore designed his frigates to be able to overpower other frigates, but with the speed to escape from a "ship of the line" (equivalent to a modern-day "battleship").