American naval architect who created the first extreme clipper ship, the Rainbow, which was designed to engage in the China trade. The Rainbow was launched in 1845 and began a new era in shipbuilding.

Griffiths began to write and lecture on shipbuilding in 1836 and soon became the leading spokesman for a scientific approach to shipbuilding. He was both an influential theorist and a practical designer of ships. His sharp and slender vessels were attacked at first by skeptics who called them unsafe, but they quickly proved to be the fastest ships of their time. His extreme clipper Sea Witch was launched in 1846. Griffiths made numerous innovations in shipbuilding, including an iron keelson, a timber-bending machine, a bilge keel, and an improved rivet. In 1858 he was appointed a naval constructor, and in that capacity he built the Pawnee, a naval gunboat propelled by twin screws. He edited American Ship from 1878 and was the author of The Ship-builder's Manual and Nautical Referee (1853) and The Progressive Ship Builder (1874–75).