The ornamental design for a watercraft, as shown and described.
FIG. 1 is the environmental perspective view of the design of the frame of the watercraft.
FIG. 2 is a front elevational view of the frame of the watercraft.
FIG. 3 is a rear elevational view of the frame of the watercraft;
FIG. 4 is a top plan view of the frame of the watercraft.
FIG. 5 is a bottom view of the frame of the watercraft.
FIG. 6 is the left side elevational view of the frame of the watercraft; and,
FIG. 7 is the right side elevational view of the frame of the watercraft.
The floatation members, seat, shock absorbers, and the fasteners for the shock absorbers showing in dashed lines are included for the purpose of illustrating portions of the watercraft and form no part of the claimed design.