For the purposes of ss. 30.61 and 30.62, motorboats are divided on the basis of their length into 4 classes as follows:
   (1)   Class A-those less than 16 feet.
   (2)   Class 1-those 16 feet or over but less than 26 feet.
   (3)   Class 2-those 26 feet or over but less than 40 feet.
   (4)   Class 3-those 40 feet or over.