Bingo.

The four stringer hull.

Very smart design there.

My 1986 20" CC measures 20'6", but it could be the 20'4" previously mentioned. My buddy's 1970 is 19'6". We both call our boats a 20 and mine is and has been registered as a 20. The most noticeable difference is at the transom where the 1970 has a sunken seat with a hatch on either side, my 1986 has no "seat" and the hatch covers an area that is completed boxed and level with the gunnels.