The International 420 Class Dinghy is a monohull planing dinghy with centreboard, bermuda rig and centre sheeting. It is designed for a crew of two. The name describes the overall length of the boat in centimeters (the boat is exactly 4.2 meters long). The International 420 was designed by Andre Cornu in the 1960s as a general purpose two sail, transom sheeted, non-trapeze dinghy, with modest easily handled sail plan. The hull's seaworthyness and stability at speed proved to be better than most of its contemporaries, and this together with its modest sail area make it fun to sail in heavy weather and thus an excelent youth trainer, qualities that lead to its adoption for that role by the RYA in the mid 1970's.