Roger Jones Windsurfing: Basic and Fun Boarding Technique Harper & Row: San Francisco, 1985, 128 pp., 1967
"The idea of an articulated mast, which led to the patent, was conceived by Jim [Drake] while driving westbound, alone, on the San Bernadino Freeway. By early 1967 he was experimenting with two versions of a free-sail system, one with a fully-articulated universal on the mast foot, the other with the mast attached rigidly to the centerboard. The rigid connection made the centeboard swivel back as the mast was tilted forward. Both versions allowed the sail to swing in a full circle.