Mr. Marsh was undobtedly known as a brilliant designer before designing the tornado.
Also he didn't disappear afterwards. He designed the fiberglass version for Panther Craft. Then the Dart. He has just kept a low profile.
When the tornado('67?) came out , no one knew how to build a glass version at min. weight.. Foam sandwich constuction wasn't evolved enough at that time to do a good enough job.
the privately made wood boats were winning the worlds from time to time as the glass versions developed. Then the the Zutec structurally designed wood/epoxy boats dominated for a while. Now the prepreg/honeycomb/epoxy boats can't be beat, and are actually considered heavy for that type of construction.