R-Classes
R-Classes means Racing Inboards, where engine is inside of the boat hull. Normally they use car engines. Hull is hydroplane type or catamaran.
R-1 from about 1970
R-4 (R-2500) from 1970.
R1 from 1984, World Speed Record boat
Formula R-1000 from 2009
R-4 (R-2500) from 1975
R-7000 from 2010
R-2000 from 2001
KD
S-2 Sports Inboard 1500cc from 1972, World Speed Record boat
R-boats from USSR about 1965