I claim the ornamental design for a mid-section of a surfboard, as shown and described.
FIG. 1 is a perspective view of a mid-section of a surfboard, showing my new design;
FIG. 2 is a left-side elevational view thereof, the right-side elevational view being a mirror image thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a cross-sectional view thereof, taken generally along lines 5-5 of FIG. 6.
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines showing a front and rear portion of the surfboard in FIG. 1 depict environmental matter and form no part of the claimed design. The remaining broken lines depict the mid-section of the surfboard having indeterminate length.