Boats subject to the provisions of this chapter are divided into four classes as follows: Class A. Less than sixteen feet in length. Class 1. Sixteen feet or over and less than twenty - six feet in length. Class 2. Twenty - six feet or over and less than forty feet in length. Class 3. Forty feet or over. Source: SL 1959, ch 125 , § 5; SDC Supp 1960, § 25.1405 (1); SL 1984, ch 279 , § 17; SDCL