The ornamental design for a frontportion of a watercraft, as shown and described.
FIG. 1 is a front, top, left perspective view showing a front portion of a watercraft according to my design shown on a watercraft shown in dotted lines;
FIG. 2 is a right side elevation view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a front elevation view thereof; and,
FIG. 5 is a top plan view thereof.
Throughout the Figures, where shown: (i) the dotted lines showing additional structure of the front portion of a watercraft and the watercraft on which it is shown are for illustrative purposes only and form no part of the claimed design; and (ii) the unshaded surfaces do not form part of the claimed design.