PURPOSE: To achieve combination usage of yacht and sailing board by providing a centerboard box on the under face in the center of board body, rudder fixing hole at the rear and recesses for fixing sail section at the positions near and remote from centerboard.

CONSTITUTION: A box 14 for fixing a centerboard is provided on the under face in the center of board body while a rudder or rotary fin fixing section 22 is formed at the rear of hull. Recesses are provided at the positions 16, 18 near and remote respectively from the centerboard to enable fixing of sail section at different position. Furthermore a rope anchoring section 20 and a ballancer fixing section 24 are formed. With such arrangement, it can be used as a yacht as well as a sailingboard while when setting a wheel in the recess 26 it can be used as a sailingboard on the land.