The ornamental design for a boatrack, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a boat rack showing my new design, the broken line disclosure of a boat being understood to form no part of the claimed design;
FIG. 2 is an enlarged front elevational view thereof;
FIG. 3 is an enlarged rear elevational view thereof;
FIG. 4 is a right side elevational view of a second embodiment thereof, with the left side being a mirror image of that shown, and the horizontal members being shown broken-away to indicate unclaimed length, the only difference from the first embodiment residing in the element having an unclaimed length;
FIG. 5 is a bottom plan view of the second embodiment thereof; and,
FIG. 6 is a top plan view of the second embodiment thereof.