How many seasons did Walt Downing's coach at the University of Michigan spend as head coach?
Walt Downing:  Downing played college football for Bo Schembechler at the University of Michigan from 1975 to 1977. Bo Schembechler:  In his 21 seasons as the head coach of the Michigan Wolverines, Schembechler's teams amassed a record of 194–48–5 and won or shared 13 Big Ten Conference titles.
21