I have a few photos of Tempests, no diagrams though. However, are you looking for info on the O'DAY TEMPEST "cruiser" (23'2" LOA) a Philip Rhodes design? or the INTERNATIONAL TEMPEST a class racing boat (22' LOA) a Ian Proctor design?
If you have the racing class boat, I would think there would be a class association web site somewhere.
I have some info about the O'DAY TEMPEST, most were built by a Canadian compay under contract/license for O'Day during the 1960's. I'll look to see what info I have in my various sources of old sailboat books.