\Son"der*class`\, n. [G. sonderklasse special
class.] (Yachting)
A special class of small yachts developed in Germany under
the patronage of Emperor William and Prince Henry of Prussia,
and so called because these yachts do not conform to the
restrictions for the regular classes established by the rules
of the International Yacht Racing Union. In yachts of the
sonderclass, as prescribed for the season of 1911, the
aggregate of the length on water line, extreme beam, and
extreme draft must be not more than 32 feet; the weight, not
less than 4,035 pounds (without crew); the sail area, not
more than 550 square yards; and the cost of construction (for
American boats) not more than $2400. The crew must be
amateurs and citizens of the country in which the yacht was
built.