Patent ID: 6855019

Claim:
A jet propulsion watercraft, comprising: a hull, said hull including a stern, said stern including a bottom surface having a step portion extending in a width direction of the watercraft to form a higher level surface, said higher level surface being at a level higher than said bottom surface and said lower level surface by a predetermined dimension in a direction toward said watercraft; at least one vent hole, said at least one vent hole passing vertically through said higher level surface at a position thereof close to said step portion; and a water jet propeller, said water jet propeller being disposed in said stern for expelling a water jet to propel said watercraft, a lower part of said water jet propeller is formed by a ride plate that is removable from said hull, said ride plate being provided with said step portion, said higher level surface, and said at least one vent hole, and said higher level surface and said lower level surface together form a bottom surface of said ride plate.