From an article "Eight Bells: John Letcher" by Dan Spurr, September 25, 2018 in Professional Boatbuilder:

Letcher had a PhD in aerodynamics from the California Institute of Technology.

Letcher founded AeroHydro, a software engineering business focused on boat and industrial design, including MultiSurf 3D design software; SurfaceWorks, an add-on to SolidWorks; and AHVPP, a velocity prediction program. He served with several America’s Cup brain trusts: the American syndicates Stars & Stripes and Oracle Team USA, Italy’s Il Moro di Venezia, and Team New Zealand’s Black Magic. He was the author of several books, including one on celestial navigation, as well as The Geometry of Ships, Volume 1 of what was intended to be a nine-volume set called Principles of Naval Architecture; it was published in 2009 by the Society of Naval Architects and Marine Engineers. Much earlier he wrote one for lay folks with small boats, like me, Self-Steering for Sailing Craft, which included instructions for sheet-to-tiller steering.